[PATCH] spi: Retire legacy GPIO handling

[PATCH] spi: Retire legacy GPIO handling

[Linus Walleij]

All drivers using GPIOs as chip select have been rewritten to use
GPIO descriptors passing the ->use_gpio_descriptors flag. Retire
the code and fields used by the legacy GPIO API.

Do not drop the ->use_gpio_descriptors flag: it now only indicates
that we want to use GPIOs in addition to native chip selects.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
As far as I can tell all prerequisite patches are in
the SPI tree, the patch is a bit invasive so look
close at it. It builds fine in my tests.
---
 drivers/spi/spi.c       | 125 +++++++++-------------------------------
 include/linux/spi/spi.h |  14 +----
 2 files changed, 30 insertions(+), 109 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 4599b121d744..9afb159d6053 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -18,7 +18,6 @@
 #include <linux/mod_devicetable.h>
 #include <linux/spi/spi.h>
 #include <linux/spi/spi-mem.h>
-#include <linux/of_gpio.h>
 #include <linux/gpio/consumer.h>
 #include <linux/pm_runtime.h>
 #include <linux/pm_domain.h>
@@ -549,7 +548,6 @@ static struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
 	spi->dev.parent = &ctlr->dev;
 	spi->dev.bus = &spi_bus_type;
 	spi->dev.release = spidev_release;
-	spi->cs_gpio = -ENOENT;
 	spi->mode = ctlr->buswidth_override_bits;
 
 	spin_lock_init(&spi->statistics.lock);
@@ -612,11 +610,8 @@ static int __spi_add_device(struct spi_device *spi)
 		return -ENODEV;
 	}
 
-	/* Descriptors take precedence */
 	if (ctlr->cs_gpiods)
 		spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
-	else if (ctlr->cs_gpios)
-		spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
 
 	/*
 	 * Drivers may modify this initial i/o setup, but will
@@ -945,39 +940,30 @@ static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
 	spi->controller->last_cs_enable = enable;
 	spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
 
-	if ((spi->cs_gpiod || gpio_is_valid(spi->cs_gpio) ||
-	    !spi->controller->set_cs_timing) && !activate) {
+	if ((spi->cs_gpiod || !spi->controller->set_cs_timing) && !activate) {
 		spi_delay_exec(&spi->cs_hold, NULL);
 	}
 
 	if (spi->mode & SPI_CS_HIGH)
 		enable = !enable;
 
-	if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) {
+	if (spi->cs_gpiod) {
 		if (!(spi->mode & SPI_NO_CS)) {
-			if (spi->cs_gpiod) {
-				/*
-				 * Historically ACPI has no means of the GPIO polarity and
-				 * thus the SPISerialBus() resource defines it on the per-chip
-				 * basis. In order to avoid a chain of negations, the GPIO
-				 * polarity is considered being Active High. Even for the cases
-				 * when _DSD() is involved (in the updated versions of ACPI)
-				 * the GPIO CS polarity must be defined Active High to avoid
-				 * ambiguity. That's why we use enable, that takes SPI_CS_HIGH
-				 * into account.
-				 */
-				if (has_acpi_companion(&spi->dev))
-					gpiod_set_value_cansleep(spi->cs_gpiod, !enable);
-				else
-					/* Polarity handled by GPIO library */
-					gpiod_set_value_cansleep(spi->cs_gpiod, activate);
-			} else {
-				/*
-				 * Invert the enable line, as active low is
-				 * default for SPI.
-				 */
-				gpio_set_value_cansleep(spi->cs_gpio, !enable);
-			}
+			/*
+			 * Historically ACPI has no means of the GPIO polarity and
+			 * thus the SPISerialBus() resource defines it on the per-chip
+			 * basis. In order to avoid a chain of negations, the GPIO
+			 * polarity is considered being Active High. Even for the cases
+			 * when _DSD() is involved (in the updated versions of ACPI)
+			 * the GPIO CS polarity must be defined Active High to avoid
+			 * ambiguity. That's why we use enable, that takes SPI_CS_HIGH
+			 * into account.
+			 */
+			if (has_acpi_companion(&spi->dev))
+				gpiod_set_value_cansleep(spi->cs_gpiod, !enable);
+			else
+				/* Polarity handled by GPIO library */
+				gpiod_set_value_cansleep(spi->cs_gpiod, activate);
 		}
 		/* Some SPI masters need both GPIO CS & slave_select */
 		if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
@@ -987,8 +973,7 @@ static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
 		spi->controller->set_cs(spi, !enable);
 	}
 
-	if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio) ||
-	    !spi->controller->set_cs_timing) {
+	if (spi->cs_gpiod || !spi->controller->set_cs_timing) {
 		if (activate)
 			spi_delay_exec(&spi->cs_setup, NULL);
 		else
@@ -2729,46 +2714,6 @@ struct spi_controller *__devm_spi_alloc_controller(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(__devm_spi_alloc_controller);
 
-#ifdef CONFIG_OF
-static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
-{
-	int nb, i, *cs;
-	struct device_node *np = ctlr->dev.of_node;
-
-	if (!np)
-		return 0;
-
-	nb = of_gpio_named_count(np, "cs-gpios");
-	ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
-
-	/* Return error only for an incorrectly formed cs-gpios property */
-	if (nb == 0 || nb == -ENOENT)
-		return 0;
-	else if (nb < 0)
-		return nb;
-
-	cs = devm_kcalloc(&ctlr->dev, ctlr->num_chipselect, sizeof(int),
-			  GFP_KERNEL);
-	ctlr->cs_gpios = cs;
-
-	if (!ctlr->cs_gpios)
-		return -ENOMEM;
-
-	for (i = 0; i < ctlr->num_chipselect; i++)
-		cs[i] = -ENOENT;
-
-	for (i = 0; i < nb; i++)
-		cs[i] = of_get_named_gpio(np, "cs-gpios", i);
-
-	return 0;
-}
-#else
-static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
-{
-	return 0;
-}
-#endif
-
 /**
  * spi_get_gpio_descs() - grab chip select GPIOs for the master
  * @ctlr: The SPI master to grab GPIO descriptors for
@@ -2953,22 +2898,15 @@ int spi_register_controller(struct spi_controller *ctlr)
 	 */
 	dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
 
-	if (!spi_controller_is_slave(ctlr)) {
-		if (ctlr->use_gpio_descriptors) {
-			status = spi_get_gpio_descs(ctlr);
-			if (status)
-				goto free_bus_id;
-			/*
-			 * A controller using GPIO descriptors always
-			 * supports SPI_CS_HIGH if need be.
-			 */
-			ctlr->mode_bits |= SPI_CS_HIGH;
-		} else {
-			/* Legacy code path for GPIOs from DT */
-			status = of_spi_get_gpio_numbers(ctlr);
-			if (status)
-				goto free_bus_id;
-		}
+	if (!spi_controller_is_slave(ctlr) && ctlr->use_gpio_descriptors) {
+		status = spi_get_gpio_descs(ctlr);
+		if (status)
+			goto free_bus_id;
+		/*
+		 * A controller using GPIO descriptors always
+		 * supports SPI_CS_HIGH if need be.
+		 */
+		ctlr->mode_bits |= SPI_CS_HIGH;
 	}
 
 	/*
@@ -3457,12 +3395,6 @@ int spi_setup(struct spi_device *spi)
 	 */
 	bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD |
 				 SPI_NO_TX | SPI_NO_RX);
-	/*
-	 * Nothing prevents from working with active-high CS in case if it
-	 * is driven by GPIO.
-	 */
-	if (gpio_is_valid(spi->cs_gpio))
-		bad_bits &= ~SPI_CS_HIGH;
 	ugly_bits = bad_bits &
 		    (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
 		     SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
@@ -3588,8 +3520,7 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
 	 * cs_change is set for each transfer.
 	 */
 	if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
-					  spi->cs_gpiod ||
-					  gpio_is_valid(spi->cs_gpio))) {
+					  spi->cs_gpiod)) {
 		size_t maxsize;
 		int ret;
 
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 7ab3fed7b804..04b09b98d9a8 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -136,9 +136,6 @@ extern int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer);
  *	for driver coldplugging, and in uevents used for hotplugging
  * @driver_override: If the name of a driver is written to this attribute, then
  *	the device will bind to the named driver and only the named driver.
- * @cs_gpio: LEGACY: gpio number of the chipselect line (optional, -ENOENT when
- *	not using a GPIO line) use cs_gpiod in new drivers by opting in on
- *	the spi_master.
  * @cs_gpiod: gpio descriptor of the chipselect line (optional, NULL when
  *	not using a GPIO line)
  * @word_delay: delay to be inserted between consecutive
@@ -185,7 +182,6 @@ struct spi_device {
 	void			*controller_data;
 	char			modalias[SPI_NAME_SIZE];
 	const char		*driver_override;
-	int			cs_gpio;	/* LEGACY: chip select gpio */
 	struct gpio_desc	*cs_gpiod;	/* chip select gpio desc */
 	struct spi_delay	word_delay; /* inter-word delay */
 	/* CS delays */
@@ -417,17 +413,12 @@ extern struct spi_device *spi_new_ancillary_device(struct spi_device *spi, u8 ch
  *	     controller has native support for memory like operations.
  * @unprepare_message: undo any work done by prepare_message().
  * @slave_abort: abort the ongoing transfer request on an SPI slave controller
- * @cs_gpios: LEGACY: array of GPIO descs to use as chip select lines; one per
- *	CS number. Any individual value may be -ENOENT for CS lines that
- *	are not GPIOs (driven by the SPI controller itself). Use the cs_gpiods
- *	in new drivers.
  * @cs_gpiods: Array of GPIO descs to use as chip select lines; one per CS
  *	number. Any individual value may be NULL for CS lines that
  *	are not GPIOs (driven by the SPI controller itself).
  * @use_gpio_descriptors: Turns on the code in the SPI core to parse and grab
- *	GPIO descriptors rather than using global GPIO numbers grabbed by the
- *	driver. This will fill in @cs_gpiods and @cs_gpios should not be used,
- *	and SPI devices will have the cs_gpiod assigned rather than cs_gpio.
+ *	GPIO descriptors. This will fill in @cs_gpiods and SPI devices will have
+ *	the cs_gpiod assigned if a GPIO line is found for the chipselect.
  * @unused_native_cs: When cs_gpiods is used, spi_register_controller() will
  *	fill in this field with the first unused native CS, to be used by SPI
  *	controller drivers that need to drive a native CS when using GPIO CS.
@@ -641,7 +632,6 @@ struct spi_controller {
 	const struct spi_controller_mem_ops *mem_ops;
 
 	/* gpio chip select */
-	int			*cs_gpios;
 	struct gpio_desc	**cs_gpiods;
 	bool			use_gpio_descriptors;
 	s8			unused_native_cs;
-- 
2.34.1

Re: [PATCH] spi: Retire legacy GPIO handling

[Mark Brown]

On Fri, 11 Feb 2022 00:19:54 +0100, Linus Walleij wrote:
> All drivers using GPIOs as chip select have been rewritten to use
> GPIO descriptors passing the ->use_gpio_descriptors flag. Retire
> the code and fields used by the legacy GPIO API.
> 
> Do not drop the ->use_gpio_descriptors flag: it now only indicates
> that we want to use GPIOs in addition to native chip selects.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next

Thanks!

[1/1] spi: Retire legacy GPIO handling
      commit: f48dc6b9664963107e500aecfc2f4df27dc5afb6

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark