Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c
index 3094d81..a2162ff 100644
--- a/drivers/spi/spi-bcm2835aux.c
+++ b/drivers/spi/spi-bcm2835aux.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Driver for Broadcom BCM2835 auxiliary SPI Controllers
*
@@ -7,20 +8,11 @@
* Based on: spi-bcm2835.c
*
* Copyright (C) 2015 Martin Sperl
- *
- * 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>
#include <linux/completion.h>
+#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/interrupt.h>
@@ -36,6 +28,12 @@
#include <linux/spi/spi.h>
#include <linux/spinlock.h>
+/* define polling limits */
+static unsigned int polling_limit_us = 30;
+module_param(polling_limit_us, uint, 0664);
+MODULE_PARM_DESC(polling_limit_us,
+ "time in us to run a transfer in polling mode - if zero no polling is used\n");
+
/*
* spi register defines
*
@@ -88,10 +86,6 @@
#define BCM2835_AUX_SPI_STAT_BUSY 0x00000040
#define BCM2835_AUX_SPI_STAT_BITCOUNT 0x0000003F
-/* timeout values */
-#define BCM2835_AUX_SPI_POLLING_LIMIT_US 30
-#define BCM2835_AUX_SPI_POLLING_JIFFIES 2
-
struct bcm2835aux_spi {
void __iomem *regs;
struct clk *clk;
@@ -102,8 +96,53 @@
int tx_len;
int rx_len;
int pending;
+
+ u64 count_transfer_polling;
+ u64 count_transfer_irq;
+ u64 count_transfer_irq_after_poll;
+
+ struct dentry *debugfs_dir;
};
+#if defined(CONFIG_DEBUG_FS)
+static void bcm2835aux_debugfs_create(struct bcm2835aux_spi *bs,
+ const char *dname)
+{
+ char name[64];
+ struct dentry *dir;
+
+ /* get full name */
+ snprintf(name, sizeof(name), "spi-bcm2835aux-%s", dname);
+
+ /* the base directory */
+ dir = debugfs_create_dir(name, NULL);
+ bs->debugfs_dir = dir;
+
+ /* the counters */
+ debugfs_create_u64("count_transfer_polling", 0444, dir,
+ &bs->count_transfer_polling);
+ debugfs_create_u64("count_transfer_irq", 0444, dir,
+ &bs->count_transfer_irq);
+ debugfs_create_u64("count_transfer_irq_after_poll", 0444, dir,
+ &bs->count_transfer_irq_after_poll);
+}
+
+static void bcm2835aux_debugfs_remove(struct bcm2835aux_spi *bs)
+{
+ debugfs_remove_recursive(bs->debugfs_dir);
+ bs->debugfs_dir = NULL;
+}
+#else
+static void bcm2835aux_debugfs_create(struct bcm2835aux_spi *bs,
+ const char *dname)
+{
+}
+
+static void bcm2835aux_debugfs_remove(struct bcm2835aux_spi *bs)
+{
+}
+#endif /* CONFIG_DEBUG_FS */
+
static inline u32 bcm2835aux_rd(struct bcm2835aux_spi *bs, unsigned reg)
{
return readl(bs->regs + reg);
@@ -123,9 +162,6 @@
data = bcm2835aux_rd(bs, BCM2835_AUX_SPI_IO);
if (bs->rx_buf) {
switch (count) {
- case 4:
- *bs->rx_buf++ = (data >> 24) & 0xff;
- /* fallthrough */
case 3:
*bs->rx_buf++ = (data >> 16) & 0xff;
/* fallthrough */
@@ -178,24 +214,14 @@
BCM2835_AUX_SPI_CNTL0_CLEARFIFO);
}
-static irqreturn_t bcm2835aux_spi_interrupt(int irq, void *dev_id)
+static void bcm2835aux_spi_transfer_helper(struct bcm2835aux_spi *bs)
{
- struct spi_master *master = dev_id;
- struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
- irqreturn_t ret = IRQ_NONE;
-
- /* IRQ may be shared, so return if our interrupts are disabled */
- if (!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_CNTL1) &
- (BCM2835_AUX_SPI_CNTL1_TXEMPTY | BCM2835_AUX_SPI_CNTL1_IDLE)))
- return ret;
+ u32 stat = bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT);
/* check if we have data to read */
- while (bs->rx_len &&
- (!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT) &
- BCM2835_AUX_SPI_STAT_RX_EMPTY))) {
+ for (; bs->rx_len && (stat & BCM2835_AUX_SPI_STAT_RX_LVL);
+ stat = bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT))
bcm2835aux_rd_fifo(bs);
- ret = IRQ_HANDLED;
- }
/* check if we have data to write */
while (bs->tx_len &&
@@ -203,16 +229,21 @@
(!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT) &
BCM2835_AUX_SPI_STAT_TX_FULL))) {
bcm2835aux_wr_fifo(bs);
- ret = IRQ_HANDLED;
}
+}
- /* and check if we have reached "done" */
- while (bs->rx_len &&
- (!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT) &
- BCM2835_AUX_SPI_STAT_BUSY))) {
- bcm2835aux_rd_fifo(bs);
- ret = IRQ_HANDLED;
- }
+static irqreturn_t bcm2835aux_spi_interrupt(int irq, void *dev_id)
+{
+ struct spi_master *master = dev_id;
+ struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
+
+ /* IRQ may be shared, so return if our interrupts are disabled */
+ if (!(bcm2835aux_rd(bs, BCM2835_AUX_SPI_CNTL1) &
+ (BCM2835_AUX_SPI_CNTL1_TXEMPTY | BCM2835_AUX_SPI_CNTL1_IDLE)))
+ return IRQ_NONE;
+
+ /* do common fifo handling */
+ bcm2835aux_spi_transfer_helper(bs);
if (!bs->tx_len) {
/* disable tx fifo empty interrupt */
@@ -226,8 +257,7 @@
complete(&master->xfer_completion);
}
- /* and return */
- return ret;
+ return IRQ_HANDLED;
}
static int __bcm2835aux_spi_transfer_one_irq(struct spi_master *master,
@@ -251,6 +281,9 @@
{
struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
+ /* update statistics */
+ bs->count_transfer_irq++;
+
/* fill in registers and fifos before enabling interrupts */
bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1]);
bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL0, bs->cntl[0]);
@@ -273,35 +306,22 @@
{
struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
unsigned long timeout;
- u32 stat;
+
+ /* update statistics */
+ bs->count_transfer_polling++;
/* configure spi */
bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL1, bs->cntl[1]);
bcm2835aux_wr(bs, BCM2835_AUX_SPI_CNTL0, bs->cntl[0]);
- /* set the timeout */
- timeout = jiffies + BCM2835_AUX_SPI_POLLING_JIFFIES;
+ /* set the timeout to at least 2 jiffies */
+ timeout = jiffies + 2 + HZ * polling_limit_us / 1000000;
/* loop until finished the transfer */
while (bs->rx_len) {
- /* read status */
- stat = bcm2835aux_rd(bs, BCM2835_AUX_SPI_STAT);
- /* fill in tx fifo with remaining data */
- if ((bs->tx_len) && (!(stat & BCM2835_AUX_SPI_STAT_TX_FULL))) {
- bcm2835aux_wr_fifo(bs);
- continue;
- }
-
- /* read data from fifo for both cases */
- if (!(stat & BCM2835_AUX_SPI_STAT_RX_EMPTY)) {
- bcm2835aux_rd_fifo(bs);
- continue;
- }
- if (!(stat & BCM2835_AUX_SPI_STAT_BUSY)) {
- bcm2835aux_rd_fifo(bs);
- continue;
- }
+ /* do common fifo handling */
+ bcm2835aux_spi_transfer_helper(bs);
/* there is still data pending to read check the timeout */
if (bs->rx_len && time_after(jiffies, timeout)) {
@@ -310,6 +330,7 @@
jiffies - timeout,
bs->tx_len, bs->rx_len);
/* forward to interrupt handler */
+ bs->count_transfer_irq_after_poll++;
return __bcm2835aux_spi_transfer_one_irq(master,
spi, tfr);
}
@@ -324,8 +345,8 @@
struct spi_transfer *tfr)
{
struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
- unsigned long spi_hz, clk_hz, speed;
- unsigned long spi_used_hz;
+ unsigned long spi_hz, clk_hz, speed, spi_used_hz;
+ unsigned long hz_per_byte, byte_limit;
/* calculate the registers to handle
*
@@ -369,14 +390,15 @@
* of Hz per byte per polling limit. E.g., we can transfer 1 byte in
* 30 µs per 300,000 Hz of bus clock.
*/
-#define HZ_PER_BYTE ((9 * 1000000) / BCM2835_AUX_SPI_POLLING_LIMIT_US)
+ hz_per_byte = polling_limit_us ? (9 * 1000000) / polling_limit_us : 0;
+ byte_limit = hz_per_byte ? spi_used_hz / hz_per_byte : 1;
+
/* run in polling mode for short transfers */
- if (tfr->len < spi_used_hz / HZ_PER_BYTE)
+ if (tfr->len < byte_limit)
return bcm2835aux_spi_transfer_one_poll(master, spi, tfr);
/* run in interrupt mode for all others */
return bcm2835aux_spi_transfer_one_irq(master, spi, tfr);
-#undef HZ_PER_BYTE
}
static int bcm2835aux_spi_prepare_message(struct spi_master *master,
@@ -421,24 +443,77 @@
bcm2835aux_spi_reset_hw(bs);
}
+static int bcm2835aux_spi_setup(struct spi_device *spi)
+{
+ int ret;
+
+ /* sanity check for native cs */
+ if (spi->mode & SPI_NO_CS)
+ return 0;
+ if (gpio_is_valid(spi->cs_gpio)) {
+ /* with gpio-cs set the GPIO to the correct level
+ * and as output (in case the dt has the gpio not configured
+ * as output but native cs)
+ */
+ ret = gpio_direction_output(spi->cs_gpio,
+ (spi->mode & SPI_CS_HIGH) ? 0 : 1);
+ if (ret)
+ dev_err(&spi->dev,
+ "could not set gpio %i as output: %i\n",
+ spi->cs_gpio, ret);
+
+ return ret;
+ }
+
+ /* for dt-backwards compatibility: only support native on CS0
+ * known things not supported with broken native CS:
+ * * multiple chip-selects: cs0-cs2 are all
+ * simultaniously asserted whenever there is a transfer
+ * this even includes SPI_NO_CS
+ * * SPI_CS_HIGH: cs are always asserted low
+ * * cs_change: cs is deasserted after each spi_transfer
+ * * cs_delay_usec: cs is always deasserted one SCK cycle
+ * after the last transfer
+ * probably more...
+ */
+ dev_warn(&spi->dev,
+ "Native CS is not supported - please configure cs-gpio in device-tree\n");
+
+ if (spi->chip_select == 0)
+ return 0;
+
+ dev_warn(&spi->dev, "Native CS is not working for cs > 0\n");
+
+ return -EINVAL;
+}
+
static int bcm2835aux_spi_probe(struct platform_device *pdev)
{
struct spi_master *master;
struct bcm2835aux_spi *bs;
- struct resource *res;
unsigned long clk_hz;
int err;
master = spi_alloc_master(&pdev->dev, sizeof(*bs));
- if (!master) {
- dev_err(&pdev->dev, "spi_alloc_master() failed\n");
+ if (!master)
return -ENOMEM;
- }
platform_set_drvdata(pdev, master);
master->mode_bits = (SPI_CPOL | SPI_CS_HIGH | SPI_NO_CS);
master->bits_per_word_mask = SPI_BPW_MASK(8);
- master->num_chipselect = -1;
+ /* even though the driver never officially supported native CS
+ * allow a single native CS for legacy DT support purposes when
+ * no cs-gpio is configured.
+ * Known limitations for native cs are:
+ * * multiple chip-selects: cs0-cs2 are all simultaniously asserted
+ * whenever there is a transfer - this even includes SPI_NO_CS
+ * * SPI_CS_HIGH: is ignores - cs are always asserted low
+ * * cs_change: cs is deasserted after each spi_transfer
+ * * cs_delay_usec: cs is always deasserted one SCK cycle after
+ * a spi_transfer
+ */
+ master->num_chipselect = 1;
+ master->setup = bcm2835aux_spi_setup;
master->transfer_one = bcm2835aux_spi_transfer_one;
master->handle_err = bcm2835aux_spi_handle_err;
master->prepare_message = bcm2835aux_spi_prepare_message;
@@ -448,15 +523,14 @@
bs = spi_master_get_devdata(master);
/* the main area */
- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- bs->regs = devm_ioremap_resource(&pdev->dev, res);
+ bs->regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(bs->regs)) {
err = PTR_ERR(bs->regs);
goto out_master_put;
}
bs->clk = devm_clk_get(&pdev->dev, NULL);
- if ((!bs->clk) || (IS_ERR(bs->clk))) {
+ if (IS_ERR(bs->clk)) {
err = PTR_ERR(bs->clk);
dev_err(&pdev->dev, "could not get clk: %d\n", err);
goto out_master_put;
@@ -464,7 +538,6 @@
bs->irq = platform_get_irq(pdev, 0);
if (bs->irq <= 0) {
- dev_err(&pdev->dev, "could not get IRQ: %d\n", bs->irq);
err = bs->irq ? bs->irq : -ENODEV;
goto out_master_put;
}
@@ -502,6 +575,8 @@
goto out_clk_disable;
}
+ bcm2835aux_debugfs_create(bs, dev_name(&pdev->dev));
+
return 0;
out_clk_disable:
@@ -516,6 +591,8 @@
struct spi_master *master = platform_get_drvdata(pdev);
struct bcm2835aux_spi *bs = spi_master_get_devdata(master);
+ bcm2835aux_debugfs_remove(bs);
+
bcm2835aux_spi_reset_hw(bs);
/* disable the HW block by releasing the clock */
@@ -542,4 +619,4 @@
MODULE_DESCRIPTION("SPI controller driver for Broadcom BCM2835 aux");
MODULE_AUTHOR("Martin Sperl <kernel@martin.sperl.org>");
-MODULE_LICENSE("GPL v2");
+MODULE_LICENSE("GPL");