Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/w1/Kconfig b/drivers/w1/Kconfig
index 6743bde..3e7ad7b 100644
--- a/drivers/w1/Kconfig
+++ b/drivers/w1/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 menuconfig W1
 	tristate "Dallas's 1-wire support"
 	depends on HAS_IOMEM
@@ -18,14 +19,14 @@
 	default y
 	---help---
 	  This allows to communicate with userspace using connector. For more
-	  information see <file:Documentation/connector/connector.txt>.
+	  information see <file:Documentation/driver-api/connector.rst>.
 	  There are three types of messages between w1 core and userspace:
 	  1. Events. They are generated each time new master or slave device found
 		either due to automatic or requested search.
 	  2. Userspace commands. Includes read/write and search/alarm search commands.
 	  3. Replies to userspace commands.
 
-source drivers/w1/masters/Kconfig
-source drivers/w1/slaves/Kconfig
+source "drivers/w1/masters/Kconfig"
+source "drivers/w1/slaves/Kconfig"
 
 endif # W1
diff --git a/drivers/w1/Makefile b/drivers/w1/Makefile
index 6bb0b54..1ff0d42 100644
--- a/drivers/w1/Makefile
+++ b/drivers/w1/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # Makefile for the Dallas's 1-wire bus.
 #
diff --git a/drivers/w1/masters/Kconfig b/drivers/w1/masters/Kconfig
index 00827d2..24b9a8e 100644
--- a/drivers/w1/masters/Kconfig
+++ b/drivers/w1/masters/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # 1-wire bus master configuration
 #
@@ -64,5 +65,14 @@
 	  Say Y here if you want support for the 1-wire or HDQ Interface
 	  on an OMAP processor.
 
+config W1_MASTER_SGI
+	tristate "SGI ASIC driver"
+	help
+	  Say Y here if you want support for your 1-wire devices using
+	  SGI ASIC 1-Wire interface
+
+	  This support is also available as a module.  If so, the module
+	  will be called sgi_w1.
+
 endmenu
 
diff --git a/drivers/w1/masters/Makefile b/drivers/w1/masters/Makefile
index 18954ca..dae629b 100644
--- a/drivers/w1/masters/Makefile
+++ b/drivers/w1/masters/Makefile
@@ -11,3 +11,4 @@
 obj-$(CONFIG_W1_MASTER_DS1WM)		+= ds1wm.o
 obj-$(CONFIG_W1_MASTER_GPIO)		+= w1-gpio.o
 obj-$(CONFIG_HDQ_MASTER_OMAP)		+= omap_hdq.o
+obj-$(CONFIG_W1_MASTER_SGI)		+= sgi_w1.o
diff --git a/drivers/w1/masters/ds2482.c b/drivers/w1/masters/ds2482.c
index 8b5e598..b471779 100644
--- a/drivers/w1/masters/ds2482.c
+++ b/drivers/w1/masters/ds2482.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /**
  * ds2482.c - provides i2c to w1-master bridge(s)
  * Copyright (C) 2005  Ben Gardner <bgardner@wabtec.com>
@@ -7,10 +8,6 @@
  * There are two variations: -100 and -800, which have 1 or 8 1-wire ports.
  * The complete datasheet can be obtained from MAXIM's website at:
  *   http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4382
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; version 2 of the License.
  */
 
 #include <linux/module.h>
@@ -37,6 +34,11 @@
 MODULE_PARM_DESC(active_pullup, "Active pullup (apply to all buses): " \
 				"0-disable, 1-enable (default)");
 
+/* extra configurations - e.g. 1WS */
+static int extra_config;
+module_param(extra_config, int, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(extra_config, "Extra Configuration settings 1=APU,2=PPM,3=SPU,8=1WS");
+
 /**
  * The DS2482 registers - there are 3 registers that are addressed by a read
  * pointer. The read pointer is set by the last command executed.
@@ -70,8 +72,6 @@
 #define DS2482_REG_CFG_PPM		0x02	/* presence pulse masking */
 #define DS2482_REG_CFG_APU		0x01	/* active pull-up */
 
-/* extra configurations - e.g. 1WS */
-static int extra_config;
 
 /**
  * Write and verify codes for the CHANNEL_SELECT command (DS2482-800 only).
@@ -130,6 +130,8 @@
  */
 static inline u8 ds2482_calculate_config(u8 conf)
 {
+	conf |= extra_config;
+
 	if (ds2482_active_pullup)
 		conf |= DS2482_REG_CFG_APU;
 
@@ -405,7 +407,7 @@
 		/* If the chip did reset since detect, re-config it */
 		if (err & DS2482_REG_STS_RST)
 			ds2482_send_cmd_data(pdev, DS2482_CMD_WRITE_CONFIG,
-					ds2482_calculate_config(extra_config));
+					     ds2482_calculate_config(0x00));
 	}
 
 	mutex_unlock(&pdev->access_lock);
@@ -431,7 +433,8 @@
 		ds2482_wait_1wire_idle(pdev);
 		/* note: it seems like both SPU and APU have to be set! */
 		retval = ds2482_send_cmd_data(pdev, DS2482_CMD_WRITE_CONFIG,
-			ds2482_calculate_config(extra_config|DS2482_REG_CFG_SPU|DS2482_REG_CFG_APU));
+			ds2482_calculate_config(DS2482_REG_CFG_SPU |
+						DS2482_REG_CFG_APU));
 		ds2482_wait_1wire_idle(pdev);
 	}
 
@@ -484,7 +487,7 @@
 
 	/* Set all config items to 0 (off) */
 	ds2482_send_cmd_data(data, DS2482_CMD_WRITE_CONFIG,
-		ds2482_calculate_config(extra_config));
+		ds2482_calculate_config(0x00));
 
 	mutex_init(&data->access_lock);
 
@@ -559,7 +562,5 @@
 
 MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
 MODULE_DESCRIPTION("DS2482 driver");
-module_param(extra_config, int, S_IRUGO | S_IWUSR);
-MODULE_PARM_DESC(extra_config, "Extra Configuration settings 1=APU,2=PPM,3=SPU,8=1WS");
 
 MODULE_LICENSE("GPL");
diff --git a/drivers/w1/masters/ds2490.c b/drivers/w1/masters/ds2490.c
index 0f4ecfc..e17c8f7 100644
--- a/drivers/w1/masters/ds2490.c
+++ b/drivers/w1/masters/ds2490.c
@@ -1,22 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	ds2490.c  USB to one wire bridge
  *
  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
- *
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
 
 #include <linux/module.h>
@@ -1016,15 +1002,15 @@
 	/* alternative 3, 1ms interrupt (greatly speeds search), 64 byte bulk */
 	alt = 3;
 	err = usb_set_interface(dev->udev,
-		intf->altsetting[alt].desc.bInterfaceNumber, alt);
+		intf->cur_altsetting->desc.bInterfaceNumber, alt);
 	if (err) {
 		dev_err(&dev->udev->dev, "Failed to set alternative setting %d "
 			"for %d interface: err=%d.\n", alt,
-			intf->altsetting[alt].desc.bInterfaceNumber, err);
+			intf->cur_altsetting->desc.bInterfaceNumber, err);
 		goto err_out_clear;
 	}
 
-	iface_desc = &intf->altsetting[alt];
+	iface_desc = intf->cur_altsetting;
 	if (iface_desc->desc.bNumEndpoints != NUM_EP-1) {
 		pr_info("Num endpoints=%d. It is not DS9490R.\n",
 			iface_desc->desc.bNumEndpoints);
diff --git a/drivers/w1/masters/matrox_w1.c b/drivers/w1/masters/matrox_w1.c
index d83d7c9..3110791 100644
--- a/drivers/w1/masters/matrox_w1.c
+++ b/drivers/w1/masters/matrox_w1.c
@@ -1,22 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	matrox_w1.c
  *
  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
- *
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
 
 #include <asm/types.h>
diff --git a/drivers/w1/masters/mxc_w1.c b/drivers/w1/masters/mxc_w1.c
index 50b46c4..1ca880e 100644
--- a/drivers/w1/masters/mxc_w1.c
+++ b/drivers/w1/masters/mxc_w1.c
@@ -1,15 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright 2005-2008 Freescale Semiconductor, Inc. All Rights Reserved.
  * Copyright 2008 Luotao Fu, kernel@pengutronix.de
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 
 #include <linux/clk.h>
@@ -100,7 +92,6 @@
 {
 	struct mxc_w1_device *mdev;
 	unsigned long clkrate;
-	struct resource *res;
 	unsigned int clkdiv;
 	int err;
 
@@ -128,8 +119,7 @@
 		dev_warn(&pdev->dev,
 			 "Incorrect time base frequency %lu Hz\n", clkrate);
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	mdev->regs = devm_ioremap_resource(&pdev->dev, res);
+	mdev->regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(mdev->regs)) {
 		err = PTR_ERR(mdev->regs);
 		goto out_disable_clk;
diff --git a/drivers/w1/masters/omap_hdq.c b/drivers/w1/masters/omap_hdq.c
index 3099052..4164045 100644
--- a/drivers/w1/masters/omap_hdq.c
+++ b/drivers/w1/masters/omap_hdq.c
@@ -660,7 +660,6 @@
 {
 	struct device *dev = &pdev->dev;
 	struct hdq_data *hdq_data;
-	struct resource *res;
 	int ret, irq;
 	u8 rev;
 	const char *mode;
@@ -674,8 +673,7 @@
 	hdq_data->dev = dev;
 	platform_set_drvdata(pdev, hdq_data);
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	hdq_data->hdq_base = devm_ioremap_resource(dev, res);
+	hdq_data->hdq_base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(hdq_data->hdq_base))
 		return PTR_ERR(hdq_data->hdq_base);
 
diff --git a/drivers/w1/masters/sgi_w1.c b/drivers/w1/masters/sgi_w1.c
new file mode 100644
index 0000000..1b2d96b
--- /dev/null
+++ b/drivers/w1/masters/sgi_w1.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * sgi_w1.c - w1 master driver for one wire support in SGI ASICs
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/platform_data/sgi-w1.h>
+
+#include <linux/w1.h>
+
+#define MCR_RD_DATA	BIT(0)
+#define MCR_DONE	BIT(1)
+
+#define MCR_PACK(pulse, sample) (((pulse) << 10) | ((sample) << 2))
+
+struct sgi_w1_device {
+	u32 __iomem *mcr;
+	struct w1_bus_master bus_master;
+	char dev_id[64];
+};
+
+static u8 sgi_w1_wait(u32 __iomem *mcr)
+{
+	u32 mcr_val;
+
+	do {
+		mcr_val = readl(mcr);
+	} while (!(mcr_val & MCR_DONE));
+
+	return (mcr_val & MCR_RD_DATA) ? 1 : 0;
+}
+
+/*
+ * this is the low level routine to
+ * reset the device on the One Wire interface
+ * on the hardware
+ */
+static u8 sgi_w1_reset_bus(void *data)
+{
+	struct sgi_w1_device *dev = data;
+	u8 ret;
+
+	writel(MCR_PACK(520, 65), dev->mcr);
+	ret = sgi_w1_wait(dev->mcr);
+	udelay(500); /* recovery time */
+	return ret;
+}
+
+/*
+ * this is the low level routine to read/write a bit on the One Wire
+ * interface on the hardware. It does write 0 if parameter bit is set
+ * to 0, otherwise a write 1/read.
+ */
+static u8 sgi_w1_touch_bit(void *data, u8 bit)
+{
+	struct sgi_w1_device *dev = data;
+	u8 ret;
+
+	if (bit)
+		writel(MCR_PACK(6, 13), dev->mcr);
+	else
+		writel(MCR_PACK(80, 30), dev->mcr);
+
+	ret = sgi_w1_wait(dev->mcr);
+	if (bit)
+		udelay(100); /* recovery */
+	return ret;
+}
+
+static int sgi_w1_probe(struct platform_device *pdev)
+{
+	struct sgi_w1_device *sdev;
+	struct sgi_w1_platform_data *pdata;
+	struct resource *res;
+
+	sdev = devm_kzalloc(&pdev->dev, sizeof(struct sgi_w1_device),
+			    GFP_KERNEL);
+	if (!sdev)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	sdev->mcr = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(sdev->mcr))
+		return PTR_ERR(sdev->mcr);
+
+	sdev->bus_master.data = sdev;
+	sdev->bus_master.reset_bus = sgi_w1_reset_bus;
+	sdev->bus_master.touch_bit = sgi_w1_touch_bit;
+
+	pdata = dev_get_platdata(&pdev->dev);
+	if (pdata) {
+		strlcpy(sdev->dev_id, pdata->dev_id, sizeof(sdev->dev_id));
+		sdev->bus_master.dev_id = sdev->dev_id;
+	}
+
+	platform_set_drvdata(pdev, sdev);
+
+	return w1_add_master_device(&sdev->bus_master);
+}
+
+/*
+ * disassociate the w1 device from the driver
+ */
+static int sgi_w1_remove(struct platform_device *pdev)
+{
+	struct sgi_w1_device *sdev = platform_get_drvdata(pdev);
+
+	w1_remove_master_device(&sdev->bus_master);
+
+	return 0;
+}
+
+static struct platform_driver sgi_w1_driver = {
+	.driver = {
+		.name = "sgi_w1",
+	},
+	.probe = sgi_w1_probe,
+	.remove = sgi_w1_remove,
+};
+module_platform_driver(sgi_w1_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Thomas Bogendoerfer");
+MODULE_DESCRIPTION("Driver for One-Wire IP in SGI ASICs");
diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c
index 55e11bf..d4632aa 100644
--- a/drivers/w1/masters/w1-gpio.c
+++ b/drivers/w1/masters/w1-gpio.c
@@ -1,11 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * w1-gpio - GPIO w1 bus master driver
  *
  * Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2
- * as published by the Free Software Foundation.
  */
 
 #include <linux/init.h>
diff --git a/drivers/w1/slaves/Kconfig b/drivers/w1/slaves/Kconfig
index e22fded..b784763 100644
--- a/drivers/w1/slaves/Kconfig
+++ b/drivers/w1/slaves/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # 1-wire slaves configuration
 #
@@ -100,6 +101,13 @@
 	  Say Y here if you want to use a 1-wire
 	  DS2438 Smart Battery Monitor device support
 
+config W1_SLAVE_DS250X
+	tristate "512b/1kb/16kb EPROM family support"
+	select CRC16
+	help
+	  Say Y here if you want to use a 1-wire
+	  512b/1kb/16kb EPROM family device (DS250x).
+
 config W1_SLAVE_DS2780
 	tristate "Dallas 2780 battery monitor chip"
 	help
diff --git a/drivers/w1/slaves/Makefile b/drivers/w1/slaves/Makefile
index eab29f1..8e9655e 100644
--- a/drivers/w1/slaves/Makefile
+++ b/drivers/w1/slaves/Makefile
@@ -14,6 +14,7 @@
 obj-$(CONFIG_W1_SLAVE_DS2805)	+= w1_ds2805.o
 obj-$(CONFIG_W1_SLAVE_DS2433)	+= w1_ds2433.o
 obj-$(CONFIG_W1_SLAVE_DS2438)	+= w1_ds2438.o
+obj-$(CONFIG_W1_SLAVE_DS250X)	+= w1_ds250x.o
 obj-$(CONFIG_W1_SLAVE_DS2780)	+= w1_ds2780.o
 obj-$(CONFIG_W1_SLAVE_DS2781)	+= w1_ds2781.o
 obj-$(CONFIG_W1_SLAVE_DS28E04)	+= w1_ds28e04.o
diff --git a/drivers/w1/slaves/w1_ds2405.c b/drivers/w1/slaves/w1_ds2405.c
index 42a1e81..86cd973 100644
--- a/drivers/w1/slaves/w1_ds2405.c
+++ b/drivers/w1/slaves/w1_ds2405.c
@@ -1,19 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	w1_ds2405.c
  *
  * Copyright (c) 2017 Maciej S. Szmigiero <mail@maciej.szmigiero.name>
  * Based on w1_therm.c copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
- *
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the therms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 
 #include <linux/device.h>
diff --git a/drivers/w1/slaves/w1_ds2406.c b/drivers/w1/slaves/w1_ds2406.c
index fac2663..762e5e4 100644
--- a/drivers/w1/slaves/w1_ds2406.c
+++ b/drivers/w1/slaves/w1_ds2406.c
@@ -1,11 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * w1_ds2406.c - w1 family 12 (DS2406) driver
  * based on w1_ds2413.c by Mariusz Bialonczyk <manio@skyboo.net>
  *
  * Copyright (c) 2014 Scott Alfter <scott@alfter.us>
- *
- * This source code is licensed under the GNU General Public License,
- * Version 2. See the file COPYING for more details.
  */
 
 #include <linux/kernel.h>
diff --git a/drivers/w1/slaves/w1_ds2408.c b/drivers/w1/slaves/w1_ds2408.c
index b535d5e..83f8d94 100644
--- a/drivers/w1/slaves/w1_ds2408.c
+++ b/drivers/w1/slaves/w1_ds2408.c
@@ -1,10 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *	w1_ds2408.c - w1 family 29 (DS2408) driver
  *
  * Copyright (c) 2010 Jean-Francois Dagenais <dagenaisj@sonatest.com>
- *
- * This source code is licensed under the GNU General Public License,
- * Version 2. See the file COPYING for more details.
  */
 
 #include <linux/kernel.h>
@@ -138,14 +136,37 @@
 		W1_F29_REG_CONTROL_AND_STATUS, buf);
 }
 
+#ifdef CONFIG_W1_SLAVE_DS2408_READBACK
+static bool optional_read_back_valid(struct w1_slave *sl, u8 expected)
+{
+	u8 w1_buf[3];
+
+	if (w1_reset_resume_command(sl->master))
+		return false;
+
+	w1_buf[0] = W1_F29_FUNC_READ_PIO_REGS;
+	w1_buf[1] = W1_F29_REG_OUTPUT_LATCH_STATE;
+	w1_buf[2] = 0;
+
+	w1_write_block(sl->master, w1_buf, 3);
+
+	return (w1_read_8(sl->master) == expected);
+}
+#else
+static bool optional_read_back_valid(struct w1_slave *sl, u8 expected)
+{
+	return true;
+}
+#endif
+
 static ssize_t output_write(struct file *filp, struct kobject *kobj,
 			    struct bin_attribute *bin_attr, char *buf,
 			    loff_t off, size_t count)
 {
 	struct w1_slave *sl = kobj_to_w1_slave(kobj);
 	u8 w1_buf[3];
-	u8 readBack;
 	unsigned int retries = W1_F29_RETRIES;
+	ssize_t bytes_written = -EIO;
 
 	if (count != 1 || off != 0)
 		return -EFAULT;
@@ -155,54 +176,33 @@
 	dev_dbg(&sl->dev, "mutex locked");
 
 	if (w1_reset_select_slave(sl))
-		goto error;
+		goto out;
 
-	while (retries--) {
+	do {
 		w1_buf[0] = W1_F29_FUNC_CHANN_ACCESS_WRITE;
 		w1_buf[1] = *buf;
 		w1_buf[2] = ~(*buf);
+
 		w1_write_block(sl->master, w1_buf, 3);
 
-		readBack = w1_read_8(sl->master);
-
-		if (readBack != W1_F29_SUCCESS_CONFIRM_BYTE) {
-			if (w1_reset_resume_command(sl->master))
-				goto error;
-			/* try again, the slave is ready for a command */
-			continue;
+		if (w1_read_8(sl->master) == W1_F29_SUCCESS_CONFIRM_BYTE &&
+		    optional_read_back_valid(sl, *buf)) {
+			bytes_written = 1;
+			goto out;
 		}
 
-#ifdef CONFIG_W1_SLAVE_DS2408_READBACK
-		/* here the master could read another byte which
-		   would be the PIO reg (the actual pin logic state)
-		   since in this driver we don't know which pins are
-		   in and outs, there's no value to read the state and
-		   compare. with (*buf) so end this command abruptly: */
 		if (w1_reset_resume_command(sl->master))
-			goto error;
+			goto out; /* unrecoverable error */
+		/* try again, the slave is ready for a command */
+	} while (--retries);
 
-		/* go read back the output latches */
-		/* (the direct effect of the write above) */
-		w1_buf[0] = W1_F29_FUNC_READ_PIO_REGS;
-		w1_buf[1] = W1_F29_REG_OUTPUT_LATCH_STATE;
-		w1_buf[2] = 0;
-		w1_write_block(sl->master, w1_buf, 3);
-		/* read the result of the READ_PIO_REGS command */
-		if (w1_read_8(sl->master) == *buf)
-#endif
-		{
-			/* success! */
-			mutex_unlock(&sl->master->bus_mutex);
-			dev_dbg(&sl->dev,
-				"mutex unlocked, retries:%d", retries);
-			return 1;
-		}
-	}
-error:
+out:
 	mutex_unlock(&sl->master->bus_mutex);
-	dev_dbg(&sl->dev, "mutex unlocked in error, retries:%d", retries);
 
-	return -EIO;
+	dev_dbg(&sl->dev, "%s, mutex unlocked retries:%d\n",
+		(bytes_written > 0) ? "succeeded" : "error", retries);
+
+	return bytes_written;
 }
 
 
diff --git a/drivers/w1/slaves/w1_ds2413.c b/drivers/w1/slaves/w1_ds2413.c
index 492e3d0..f1fb18a 100644
--- a/drivers/w1/slaves/w1_ds2413.c
+++ b/drivers/w1/slaves/w1_ds2413.c
@@ -1,11 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * w1_ds2413.c - w1 family 3a (DS2413) driver
  * based on w1_ds2408.c by Jean-Francois Dagenais <dagenaisj@sonatest.com>
  *
  * Copyright (c) 2013 Mariusz Bialonczyk <manio@skyboo.net>
- *
- * This source code is licensed under the GNU General Public License,
- * Version 2. See the file COPYING for more details.
  */
 
 #include <linux/kernel.h>
@@ -24,12 +22,17 @@
 #define W1_F3A_FUNC_PIO_ACCESS_READ        0xF5
 #define W1_F3A_FUNC_PIO_ACCESS_WRITE       0x5A
 #define W1_F3A_SUCCESS_CONFIRM_BYTE        0xAA
+#define W1_F3A_INVALID_PIO_STATE           0xFF
 
 static ssize_t state_read(struct file *filp, struct kobject *kobj,
 			  struct bin_attribute *bin_attr, char *buf, loff_t off,
 			  size_t count)
 {
 	struct w1_slave *sl = kobj_to_w1_slave(kobj);
+	unsigned int retries = W1_F3A_RETRIES;
+	ssize_t bytes_read = -EIO;
+	u8 state;
+
 	dev_dbg(&sl->dev,
 		"Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
 		bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
@@ -42,22 +45,37 @@
 	mutex_lock(&sl->master->bus_mutex);
 	dev_dbg(&sl->dev, "mutex locked");
 
-	if (w1_reset_select_slave(sl)) {
-		mutex_unlock(&sl->master->bus_mutex);
-		return -EIO;
+next:
+	if (w1_reset_select_slave(sl))
+		goto out;
+
+	while (retries--) {
+		w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
+
+		state = w1_read_8(sl->master);
+		if ((state & 0x0F) == ((~state >> 4) & 0x0F)) {
+			/* complement is correct */
+			*buf = state;
+			bytes_read = 1;
+			goto out;
+		} else if (state == W1_F3A_INVALID_PIO_STATE) {
+			/* slave didn't respond, try to select it again */
+			dev_warn(&sl->dev, "slave device did not respond to PIO_ACCESS_READ, " \
+					    "reselecting, retries left: %d\n", retries);
+			goto next;
+		}
+
+		if (w1_reset_resume_command(sl->master))
+			goto out; /* unrecoverable error */
+
+		dev_warn(&sl->dev, "PIO_ACCESS_READ error, retries left: %d\n", retries);
 	}
 
-	w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
-	*buf = w1_read_8(sl->master);
-
+out:
 	mutex_unlock(&sl->master->bus_mutex);
-	dev_dbg(&sl->dev, "mutex unlocked");
-
-	/* check for correct complement */
-	if ((*buf & 0x0F) != ((~*buf >> 4) & 0x0F))
-		return -EIO;
-	else
-		return 1;
+	dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",
+		(bytes_read > 0) ? "succeeded" : "error", retries);
+	return bytes_read;
 }
 
 static BIN_ATTR_RO(state, 1);
@@ -69,6 +87,7 @@
 	struct w1_slave *sl = kobj_to_w1_slave(kobj);
 	u8 w1_buf[3];
 	unsigned int retries = W1_F3A_RETRIES;
+	ssize_t bytes_written = -EIO;
 
 	if (count != 1 || off != 0)
 		return -EFAULT;
@@ -78,7 +97,7 @@
 	dev_dbg(&sl->dev, "mutex locked");
 
 	if (w1_reset_select_slave(sl))
-		goto error;
+		goto out;
 
 	/* according to the DS2413 datasheet the most significant 6 bits
 	   should be set to "1"s, so do it now */
@@ -91,18 +110,20 @@
 		w1_write_block(sl->master, w1_buf, 3);
 
 		if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) {
-			mutex_unlock(&sl->master->bus_mutex);
-			dev_dbg(&sl->dev, "mutex unlocked, retries:%d", retries);
-			return 1;
+			bytes_written = 1;
+			goto out;
 		}
 		if (w1_reset_resume_command(sl->master))
-			goto error;
+			goto out; /* unrecoverable error */
+
+		dev_warn(&sl->dev, "PIO_ACCESS_WRITE error, retries left: %d\n", retries);
 	}
 
-error:
+out:
 	mutex_unlock(&sl->master->bus_mutex);
-	dev_dbg(&sl->dev, "mutex unlocked in error, retries:%d", retries);
-	return -EIO;
+	dev_dbg(&sl->dev, "%s, mutex unlocked, retries: %d\n",
+		(bytes_written > 0) ? "succeeded" : "error", retries);
+	return bytes_written;
 }
 
 static BIN_ATTR(output, S_IRUGO | S_IWUSR | S_IWGRP, NULL, output_write, 1);
diff --git a/drivers/w1/slaves/w1_ds2423.c b/drivers/w1/slaves/w1_ds2423.c
index 050407c..f436728 100644
--- a/drivers/w1/slaves/w1_ds2423.c
+++ b/drivers/w1/slaves/w1_ds2423.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	w1_ds2423.c
  *
@@ -6,20 +7,6 @@
  * This driver will read and write the value of 4 counters to w1_slave file in
  * sys filesystem.
  * Inspired by the w1_therm and w1_ds2431 drivers.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the therms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
 
 #include <linux/kernel.h>
diff --git a/drivers/w1/slaves/w1_ds2431.c b/drivers/w1/slaves/w1_ds2431.c
index 5adecd3..e5bd7e2 100644
--- a/drivers/w1/slaves/w1_ds2431.c
+++ b/drivers/w1/slaves/w1_ds2431.c
@@ -1,12 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * w1_ds2431.c - w1 family 2d (DS2431) driver
  *
  * Copyright (c) 2008 Bernhard Weirich <bernhard.weirich@riedel.net>
  *
  * Heavily inspired by w1_DS2433 driver from Ben Gardner <bgardner@wabtec.com>
- *
- * This source code is licensed under the GNU General Public License,
- * Version 2. See the file COPYING for more details.
  */
 
 #include <linux/kernel.h>
diff --git a/drivers/w1/slaves/w1_ds2433.c b/drivers/w1/slaves/w1_ds2433.c
index 75ad70c..1f805c8 100644
--- a/drivers/w1/slaves/w1_ds2433.c
+++ b/drivers/w1/slaves/w1_ds2433.c
@@ -1,10 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *	w1_ds2433.c - w1 family 23 (DS2433) driver
  *
  * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
- *
- * This source code is licensed under the GNU General Public License,
- * Version 2. See the file COPYING for more details.
  */
 
 #include <linux/kernel.h>
diff --git a/drivers/w1/slaves/w1_ds2438.c b/drivers/w1/slaves/w1_ds2438.c
index bf641a1..d199e5a 100644
--- a/drivers/w1/slaves/w1_ds2438.c
+++ b/drivers/w1/slaves/w1_ds2438.c
@@ -1,10 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * 1-Wire implementation for the ds2438 chip
  *
  * Copyright (c) 2017 Mariusz Bialonczyk <manio@skyboo.net>
- *
- * This source code is licensed under the GNU General Public License,
- * Version 2. See the file COPYING for more details.
  */
 
 #include <linux/kernel.h>
@@ -186,8 +184,8 @@
 	return -1;
 }
 
-static uint16_t w1_ds2438_get_voltage(struct w1_slave *sl,
-				      int adc_input, uint16_t *voltage)
+static int w1_ds2438_get_voltage(struct w1_slave *sl,
+				 int adc_input, uint16_t *voltage)
 {
 	unsigned int retries = W1_DS2438_RETRIES;
 	u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/];
@@ -235,6 +233,25 @@
 	return ret;
 }
 
+static int w1_ds2438_get_current(struct w1_slave *sl, int16_t *voltage)
+{
+	u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/];
+	int ret;
+
+	mutex_lock(&sl->master->bus_mutex);
+
+	if (w1_ds2438_get_page(sl, 0, w1_buf) == 0) {
+		/* The voltage measured across current sense resistor RSENS. */
+		*voltage = (((int16_t) w1_buf[DS2438_CURRENT_MSB]) << 8) | ((int16_t) w1_buf[DS2438_CURRENT_LSB]);
+		ret = 0;
+	} else
+		ret = -1;
+
+	mutex_unlock(&sl->master->bus_mutex);
+
+	return ret;
+}
+
 static ssize_t iad_write(struct file *filp, struct kobject *kobj,
 			 struct bin_attribute *bin_attr, char *buf,
 			 loff_t off, size_t count)
@@ -257,6 +274,27 @@
 	return ret;
 }
 
+static ssize_t iad_read(struct file *filp, struct kobject *kobj,
+			struct bin_attribute *bin_attr, char *buf,
+			loff_t off, size_t count)
+{
+	struct w1_slave *sl = kobj_to_w1_slave(kobj);
+	int ret;
+	int16_t voltage;
+
+	if (off != 0)
+		return 0;
+	if (!buf)
+		return -EINVAL;
+
+	if (w1_ds2438_get_current(sl, &voltage) == 0) {
+		ret = snprintf(buf, count, "%i\n", voltage);
+	} else
+		ret = -EIO;
+
+	return ret;
+}
+
 static ssize_t page0_read(struct file *filp, struct kobject *kobj,
 			  struct bin_attribute *bin_attr, char *buf,
 			  loff_t off, size_t count)
@@ -272,9 +310,13 @@
 
 	mutex_lock(&sl->master->bus_mutex);
 
+	/* Read no more than page0 size */
+	if (count > DS2438_PAGE_SIZE)
+		count = DS2438_PAGE_SIZE;
+
 	if (w1_ds2438_get_page(sl, 0, w1_buf) == 0) {
-		memcpy(buf, &w1_buf, DS2438_PAGE_SIZE);
-		ret = DS2438_PAGE_SIZE;
+		memcpy(buf, &w1_buf, count);
+		ret = count;
 	} else
 		ret = -EIO;
 
@@ -289,7 +331,6 @@
 {
 	struct w1_slave *sl = kobj_to_w1_slave(kobj);
 	int ret;
-	ssize_t c = PAGE_SIZE;
 	int16_t temp;
 
 	if (off != 0)
@@ -298,8 +339,7 @@
 		return -EINVAL;
 
 	if (w1_ds2438_get_temperature(sl, &temp) == 0) {
-		c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", temp);
-		ret = PAGE_SIZE - c;
+		ret = snprintf(buf, count, "%i\n", temp);
 	} else
 		ret = -EIO;
 
@@ -312,7 +352,6 @@
 {
 	struct w1_slave *sl = kobj_to_w1_slave(kobj);
 	int ret;
-	ssize_t c = PAGE_SIZE;
 	uint16_t voltage;
 
 	if (off != 0)
@@ -321,8 +360,7 @@
 		return -EINVAL;
 
 	if (w1_ds2438_get_voltage(sl, DS2438_ADC_INPUT_VAD, &voltage) == 0) {
-		c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", voltage);
-		ret = PAGE_SIZE - c;
+		ret = snprintf(buf, count, "%u\n", voltage);
 	} else
 		ret = -EIO;
 
@@ -335,7 +373,6 @@
 {
 	struct w1_slave *sl = kobj_to_w1_slave(kobj);
 	int ret;
-	ssize_t c = PAGE_SIZE;
 	uint16_t voltage;
 
 	if (off != 0)
@@ -344,15 +381,14 @@
 		return -EINVAL;
 
 	if (w1_ds2438_get_voltage(sl, DS2438_ADC_INPUT_VDD, &voltage) == 0) {
-		c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", voltage);
-		ret = PAGE_SIZE - c;
+		ret = snprintf(buf, count, "%u\n", voltage);
 	} else
 		ret = -EIO;
 
 	return ret;
 }
 
-static BIN_ATTR(iad, S_IRUGO | S_IWUSR | S_IWGRP, NULL, iad_write, 1);
+static BIN_ATTR(iad, S_IRUGO | S_IWUSR | S_IWGRP, iad_read, iad_write, 0);
 static BIN_ATTR_RO(page0, DS2438_PAGE_SIZE);
 static BIN_ATTR_RO(temperature, 0/* real length varies */);
 static BIN_ATTR_RO(vad, 0/* real length varies */);
diff --git a/drivers/w1/slaves/w1_ds250x.c b/drivers/w1/slaves/w1_ds250x.c
new file mode 100644
index 0000000..e507117
--- /dev/null
+++ b/drivers/w1/slaves/w1_ds250x.c
@@ -0,0 +1,290 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * w1_ds250x.c - w1 family 09/0b/89/91 (DS250x) driver
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/crc16.h>
+
+#include <linux/w1.h>
+#include <linux/nvmem-provider.h>
+
+#define W1_DS2501_UNW_FAMILY    0x91
+#define W1_DS2501_SIZE          64
+
+#define W1_DS2502_FAMILY        0x09
+#define W1_DS2502_UNW_FAMILY    0x89
+#define W1_DS2502_SIZE          128
+
+#define W1_DS2505_FAMILY	0x0b
+#define W1_DS2505_SIZE		2048
+
+#define W1_PAGE_SIZE		32
+
+#define W1_EXT_READ_MEMORY	0xA5
+#define W1_READ_DATA_CRC        0xC3
+
+#define OFF2PG(off)	((off) / W1_PAGE_SIZE)
+
+#define CRC16_INIT		0
+#define CRC16_VALID		0xb001
+
+struct w1_eprom_data {
+	size_t size;
+	int (*read)(struct w1_slave *sl, int pageno);
+	u8 eprom[W1_DS2505_SIZE];
+	DECLARE_BITMAP(page_present, W1_DS2505_SIZE / W1_PAGE_SIZE);
+	char nvmem_name[64];
+};
+
+static int w1_ds2502_read_page(struct w1_slave *sl, int pageno)
+{
+	struct w1_eprom_data *data = sl->family_data;
+	int pgoff = pageno * W1_PAGE_SIZE;
+	int ret = -EIO;
+	u8 buf[3];
+	u8 crc8;
+
+	if (test_bit(pageno, data->page_present))
+		return 0; /* page already present */
+
+	mutex_lock(&sl->master->bus_mutex);
+
+	if (w1_reset_select_slave(sl))
+		goto err;
+
+	buf[0] = W1_READ_DATA_CRC;
+	buf[1] = pgoff & 0xff;
+	buf[2] = pgoff >> 8;
+	w1_write_block(sl->master, buf, 3);
+
+	crc8 = w1_read_8(sl->master);
+	if (w1_calc_crc8(buf, 3) != crc8)
+		goto err;
+
+	w1_read_block(sl->master, &data->eprom[pgoff], W1_PAGE_SIZE);
+
+	crc8 = w1_read_8(sl->master);
+	if (w1_calc_crc8(&data->eprom[pgoff], W1_PAGE_SIZE) != crc8)
+		goto err;
+
+	set_bit(pageno, data->page_present); /* mark page present */
+	ret = 0;
+err:
+	mutex_unlock(&sl->master->bus_mutex);
+	return ret;
+}
+
+static int w1_ds2505_read_page(struct w1_slave *sl, int pageno)
+{
+	struct w1_eprom_data *data = sl->family_data;
+	int redir_retries = 16;
+	int pgoff, epoff;
+	int ret = -EIO;
+	u8 buf[6];
+	u8 redir;
+	u16 crc;
+
+	if (test_bit(pageno, data->page_present))
+		return 0; /* page already present */
+
+	epoff = pgoff = pageno * W1_PAGE_SIZE;
+	mutex_lock(&sl->master->bus_mutex);
+
+retry:
+	if (w1_reset_select_slave(sl))
+		goto err;
+
+	buf[0] = W1_EXT_READ_MEMORY;
+	buf[1] = pgoff & 0xff;
+	buf[2] = pgoff >> 8;
+	w1_write_block(sl->master, buf, 3);
+	w1_read_block(sl->master, buf + 3, 3); /* redir, crc16 */
+	redir = buf[3];
+	crc = crc16(CRC16_INIT, buf, 6);
+
+	if (crc != CRC16_VALID)
+		goto err;
+
+
+	if (redir != 0xff) {
+		redir_retries--;
+		if (redir_retries < 0)
+			goto err;
+
+		pgoff = (redir ^ 0xff) * W1_PAGE_SIZE;
+		goto retry;
+	}
+
+	w1_read_block(sl->master, &data->eprom[epoff], W1_PAGE_SIZE);
+	w1_read_block(sl->master, buf, 2); /* crc16 */
+	crc = crc16(CRC16_INIT, &data->eprom[epoff], W1_PAGE_SIZE);
+	crc = crc16(crc, buf, 2);
+
+	if (crc != CRC16_VALID)
+		goto err;
+
+	set_bit(pageno, data->page_present);
+	ret = 0;
+err:
+	mutex_unlock(&sl->master->bus_mutex);
+	return ret;
+}
+
+static int w1_nvmem_read(void *priv, unsigned int off, void *buf, size_t count)
+{
+	struct w1_slave *sl = priv;
+	struct w1_eprom_data *data = sl->family_data;
+	size_t eprom_size = data->size;
+	int ret;
+	int i;
+
+	if (off > eprom_size)
+		return -EINVAL;
+
+	if ((off + count) > eprom_size)
+		count = eprom_size - off;
+
+	i = OFF2PG(off);
+	do {
+		ret = data->read(sl, i++);
+		if (ret < 0)
+			return ret;
+	} while (i < OFF2PG(off + count));
+
+	memcpy(buf, &data->eprom[off], count);
+	return 0;
+}
+
+static int w1_eprom_add_slave(struct w1_slave *sl)
+{
+	struct w1_eprom_data *data;
+	struct nvmem_device *nvmem;
+	struct nvmem_config nvmem_cfg = {
+		.dev = &sl->dev,
+		.reg_read = w1_nvmem_read,
+		.type = NVMEM_TYPE_OTP,
+		.read_only = true,
+		.word_size = 1,
+		.priv = sl,
+		.id = -1
+	};
+
+	data = devm_kzalloc(&sl->dev, sizeof(struct w1_eprom_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	sl->family_data = data;
+	switch (sl->family->fid) {
+	case W1_DS2501_UNW_FAMILY:
+		data->size = W1_DS2501_SIZE;
+		data->read = w1_ds2502_read_page;
+		break;
+	case W1_DS2502_FAMILY:
+	case W1_DS2502_UNW_FAMILY:
+		data->size = W1_DS2502_SIZE;
+		data->read = w1_ds2502_read_page;
+		break;
+	case W1_DS2505_FAMILY:
+		data->size = W1_DS2505_SIZE;
+		data->read = w1_ds2505_read_page;
+		break;
+	}
+
+	if (sl->master->bus_master->dev_id)
+		snprintf(data->nvmem_name, sizeof(data->nvmem_name),
+			 "%s-%02x-%012llx",
+			 sl->master->bus_master->dev_id, sl->reg_num.family,
+			 (unsigned long long)sl->reg_num.id);
+	else
+		snprintf(data->nvmem_name, sizeof(data->nvmem_name),
+			 "%02x-%012llx",
+			 sl->reg_num.family,
+			 (unsigned long long)sl->reg_num.id);
+
+	nvmem_cfg.name = data->nvmem_name;
+	nvmem_cfg.size = data->size;
+
+	nvmem = devm_nvmem_register(&sl->dev, &nvmem_cfg);
+	return PTR_ERR_OR_ZERO(nvmem);
+}
+
+static struct w1_family_ops w1_eprom_fops = {
+	.add_slave	= w1_eprom_add_slave,
+};
+
+static struct w1_family w1_family_09 = {
+	.fid = W1_DS2502_FAMILY,
+	.fops = &w1_eprom_fops,
+};
+
+static struct w1_family w1_family_0b = {
+	.fid = W1_DS2505_FAMILY,
+	.fops = &w1_eprom_fops,
+};
+
+static struct w1_family w1_family_89 = {
+	.fid = W1_DS2502_UNW_FAMILY,
+	.fops = &w1_eprom_fops,
+};
+
+static struct w1_family w1_family_91 = {
+	.fid = W1_DS2501_UNW_FAMILY,
+	.fops = &w1_eprom_fops,
+};
+
+static int __init w1_ds250x_init(void)
+{
+	int err;
+
+	err = w1_register_family(&w1_family_09);
+	if (err)
+		return err;
+
+	err = w1_register_family(&w1_family_0b);
+	if (err)
+		goto err_0b;
+
+	err = w1_register_family(&w1_family_89);
+	if (err)
+		goto err_89;
+
+	err = w1_register_family(&w1_family_91);
+	if (err)
+		goto err_91;
+
+	return 0;
+
+err_91:
+	w1_unregister_family(&w1_family_89);
+err_89:
+	w1_unregister_family(&w1_family_0b);
+err_0b:
+	w1_unregister_family(&w1_family_09);
+	return err;
+}
+
+static void __exit w1_ds250x_exit(void)
+{
+	w1_unregister_family(&w1_family_09);
+	w1_unregister_family(&w1_family_0b);
+	w1_unregister_family(&w1_family_89);
+	w1_unregister_family(&w1_family_91);
+}
+
+module_init(w1_ds250x_init);
+module_exit(w1_ds250x_exit);
+
+MODULE_AUTHOR("Thomas Bogendoerfer <tbogendoerfe@suse.de>");
+MODULE_DESCRIPTION("w1 family driver for DS250x Add Only Memory");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("w1-family-" __stringify(W1_DS2502_FAMILY));
+MODULE_ALIAS("w1-family-" __stringify(W1_DS2505_FAMILY));
+MODULE_ALIAS("w1-family-" __stringify(W1_DS2501_UNW_FAMILY));
+MODULE_ALIAS("w1-family-" __stringify(W1_DS2502_UNW_FAMILY));
diff --git a/drivers/w1/slaves/w1_ds2780.c b/drivers/w1/slaves/w1_ds2780.c
index a605281..c689b1b 100644
--- a/drivers/w1/slaves/w1_ds2780.c
+++ b/drivers/w1/slaves/w1_ds2780.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * 1-Wire implementation for the ds2780 chip
  *
@@ -6,11 +7,6 @@
  * Author: Clifton Barnes <cabarnes@indesign-llc.com>
  *
  * Based on w1-ds2760 driver
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  */
 
 #include <linux/kernel.h>
diff --git a/drivers/w1/slaves/w1_ds2780.h b/drivers/w1/slaves/w1_ds2780.h
index a1fba79..99e38ed 100644
--- a/drivers/w1/slaves/w1_ds2780.h
+++ b/drivers/w1/slaves/w1_ds2780.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * 1-Wire implementation for the ds2780 chip
  *
@@ -6,11 +7,6 @@
  * Author: Clifton Barnes <cabarnes@indesign-llc.com>
  *
  * Based on w1-ds2760 driver
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  */
 
 #ifndef _W1_DS2780_H
diff --git a/drivers/w1/slaves/w1_ds2781.c b/drivers/w1/slaves/w1_ds2781.c
index 645be6e..84d6cee 100644
--- a/drivers/w1/slaves/w1_ds2781.c
+++ b/drivers/w1/slaves/w1_ds2781.c
@@ -1,14 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * 1-Wire implementation for the ds2781 chip
  *
  * Author: Renata Sayakhova <renata@oktetlabs.ru>
  *
  * Based on w1-ds2780 driver
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  */
 
 #include <linux/kernel.h>
diff --git a/drivers/w1/slaves/w1_ds2781.h b/drivers/w1/slaves/w1_ds2781.h
index 557dfb0..fa902df 100644
--- a/drivers/w1/slaves/w1_ds2781.h
+++ b/drivers/w1/slaves/w1_ds2781.h
@@ -1,14 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * 1-Wire implementation for the ds2780 chip
  *
  * Author: Renata Sayakhova <renata@oktetlabs.ru>
  *
  * Based on w1-ds2760 driver
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  */
 
 #ifndef _W1_DS2781_H
diff --git a/drivers/w1/slaves/w1_ds2805.c b/drivers/w1/slaves/w1_ds2805.c
index 29348d2..ccb753a 100644
--- a/drivers/w1/slaves/w1_ds2805.c
+++ b/drivers/w1/slaves/w1_ds2805.c
@@ -1,10 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * w1_ds2805 - w1 family 0d (DS28E05) driver
  *
  * Copyright (c) 2016 Andrew Worsley amworsley@gmail.com
- *
- * This source code is licensed under the GNU General Public License,
- * Version 2. See the file COPYING for more details.
  */
 
 #include <linux/kernel.h>
@@ -288,7 +286,7 @@
 	.remove_slave   = w1_f0d_remove_slave,
 };
 
-static struct w1_family w1_family_2d = {
+static struct w1_family w1_family_0d = {
 	.fid = W1_EEPROM_DS2805,
 	.fops = &w1_f0d_fops,
 };
@@ -296,13 +294,13 @@
 static int __init w1_f0d_init(void)
 {
 	pr_info("%s()\n", __func__);
-	return w1_register_family(&w1_family_2d);
+	return w1_register_family(&w1_family_0d);
 }
 
 static void __exit w1_f0d_fini(void)
 {
 	pr_info("%s()\n", __func__);
-	w1_unregister_family(&w1_family_2d);
+	w1_unregister_family(&w1_family_0d);
 }
 
 module_init(w1_f0d_init);
diff --git a/drivers/w1/slaves/w1_ds28e04.c b/drivers/w1/slaves/w1_ds28e04.c
index ec234b8..8a640f1 100644
--- a/drivers/w1/slaves/w1_ds28e04.c
+++ b/drivers/w1/slaves/w1_ds28e04.c
@@ -1,10 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *	w1_ds28e04.c - w1 family 1C (DS28E04) driver
  *
  * Copyright (c) 2012 Markus Franke <franke.m@sebakmt.com>
- *
- * This source code is licensed under the GNU General Public License,
- * Version 2. See the file COPYING for more details.
  */
 
 #include <linux/kernel.h>
diff --git a/drivers/w1/slaves/w1_ds28e17.c b/drivers/w1/slaves/w1_ds28e17.c
index e78b63e..046ddda 100644
--- a/drivers/w1/slaves/w1_ds28e17.c
+++ b/drivers/w1/slaves/w1_ds28e17.c
@@ -1,10 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *	w1_ds28e17.c - w1 family 19 (DS28E17) driver
  *
  * Copyright (c) 2016 Jan Kandziora <jjj@gmx.de>
- *
- * This source code is licensed under the GNU General Public License,
- * Version 2. See the file COPYING for more details.
  */
 
 #include <linux/crc16.h>
diff --git a/drivers/w1/slaves/w1_smem.c b/drivers/w1/slaves/w1_smem.c
index e556b0c..09afcf2 100644
--- a/drivers/w1/slaves/w1_smem.c
+++ b/drivers/w1/slaves/w1_smem.c
@@ -1,22 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	w1_smem.c
  *
  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
- *
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the smems of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
 
 #include <asm/types.h>
diff --git a/drivers/w1/slaves/w1_therm.c b/drivers/w1/slaves/w1_therm.c
index 3c350df..e028e00 100644
--- a/drivers/w1/slaves/w1_therm.c
+++ b/drivers/w1/slaves/w1_therm.c
@@ -1,22 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	w1_therm.c
  *
  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
- *
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the therms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
 
 #include <asm/types.h>
diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index 890c038..e58c759 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -1,15 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 
 #include <linux/delay.h>
diff --git a/drivers/w1/w1_family.c b/drivers/w1/w1_family.c
index f14ab0b..97da4f1 100644
--- a/drivers/w1/w1_family.c
+++ b/drivers/w1/w1_family.c
@@ -1,15 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 
 #include <linux/spinlock.h>
diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c
index 1c77617..b3e1792 100644
--- a/drivers/w1/w1_int.c
+++ b/drivers/w1/w1_int.c
@@ -1,15 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 
 #include <linux/kernel.h>
diff --git a/drivers/w1/w1_internal.h b/drivers/w1/w1_internal.h
index 1623e2f..cb5a74e 100644
--- a/drivers/w1/w1_internal.h
+++ b/drivers/w1/w1_internal.h
@@ -1,15 +1,6 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
 /*
  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 
 #ifndef __W1_H
diff --git a/drivers/w1/w1_io.c b/drivers/w1/w1_io.c
index 0364d33..db3c952 100644
--- a/drivers/w1/w1_io.c
+++ b/drivers/w1/w1_io.c
@@ -1,15 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 
 #include <asm/io.h>
@@ -432,8 +423,7 @@
 	if (w1_reset_bus(dev))
 		return -1;
 
-	/* This will make only the last matched slave perform a skip ROM. */
-	w1_write_8(dev, W1_RESUME_CMD);
+	w1_write_8(dev, dev->slave_count > 1 ? W1_RESUME_CMD : W1_SKIP_ROM);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(w1_reset_resume_command);
diff --git a/drivers/w1/w1_netlink.c b/drivers/w1/w1_netlink.c
index f2f099c..fa490aa 100644
--- a/drivers/w1/w1_netlink.c
+++ b/drivers/w1/w1_netlink.c
@@ -1,15 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (c) 2003 Evgeniy Polyakov <zbr@ioremap.net>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 
 #include <linux/slab.h>
diff --git a/drivers/w1/w1_netlink.h b/drivers/w1/w1_netlink.h
index f876772..3041092 100644
--- a/drivers/w1/w1_netlink.h
+++ b/drivers/w1/w1_netlink.h
@@ -1,15 +1,6 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
 /*
  * Copyright (c) 2003 Evgeniy Polyakov <zbr@ioremap.net>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 
 #ifndef __W1_NETLINK_H