spi: mpc512x-psc: Convert to use GPIO descriptors

This driver is already relying on the core to provide
valid GPIO numbers in spi->cs_gpio through
of_spi_get_gpio_numbers(), so we can switch to letting
the core use GPIO descriptors instead.

The driver was assigning a local function to the custom
chipselect callback, but I chose to just open code the
gpiod setting instead, this is easier to read.

The only platform that overrides the cs_control callback
is the mpc832x_rdb.

Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Anatolij Gustschin <agust@denx.de>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20220120002600.216667-1-linus.walleij@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-mpc512x-psc.c

@@ -23,7 +23,6 @@
 #include <linux/clk.h>
 #include <linux/spi/spi.h>
 #include <linux/fsl_devices.h>
-#include <linux/gpio.h>
 #include <asm/mpc52xx_psc.h>
 
 enum {
@@ -128,17 +127,28 @@ static void mpc512x_psc_spi_activate_cs(struct spi_device *spi)
 	out_be32(psc_addr(mps, ccr), ccr);
 	mps->bits_per_word = cs->bits_per_word;
 
-	if (mps->cs_control && gpio_is_valid(spi->cs_gpio))
-		mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 1 : 0);
+	if (cs->gpiod) {
+		if (mps->cs_control)
+			/* boardfile override */
+			mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 1 : 0);
+		else
+			/* gpiolib will deal with the inversion */
+			gpiod_set_value(spi->cs_gpiod, 1);
+	}
 }
 
 static void mpc512x_psc_spi_deactivate_cs(struct spi_device *spi)
 {
 	struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master);
 
-	if (mps->cs_control && gpio_is_valid(spi->cs_gpio))
-		mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 0 : 1);
-
+	if (spi->cs_gpiod) {
+		if (mps->cs_control)
+			/* boardfile override */
+			mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 0 : 1);
+		else
+			/* gpiolib will deal with the inversion */
+			gpiod_set_value(spi->cs_gpiod, 0);
+	}
 }
 
 /* extract and scale size field in txsz or rxsz */
@@ -373,18 +383,6 @@ static int mpc512x_psc_spi_setup(struct spi_device *spi)
 		if (!cs)
 			return -ENOMEM;
 
-		if (gpio_is_valid(spi->cs_gpio)) {
-			ret = gpio_request(spi->cs_gpio, dev_name(&spi->dev));
-			if (ret) {
-				dev_err(&spi->dev, "can't get CS gpio: %d\n",
-					ret);
-				kfree(cs);
-				return ret;
-			}
-			gpio_direction_output(spi->cs_gpio,
-					spi->mode & SPI_CS_HIGH ? 0 : 1);
-		}
-
 		spi->controller_state = cs;
 	}
 
@@ -396,8 +394,6 @@ static int mpc512x_psc_spi_setup(struct spi_device *spi)
 
 static void mpc512x_psc_spi_cleanup(struct spi_device *spi)
 {
-	if (gpio_is_valid(spi->cs_gpio))
-		gpio_free(spi->cs_gpio);
 	kfree(spi->controller_state);
 }
 
@@ -476,11 +472,6 @@ static irqreturn_t mpc512x_psc_spi_isr(int irq, void *dev_id)
 	return IRQ_NONE;
 }
 
-static void mpc512x_spi_cs_control(struct spi_device *spi, bool onoff)
-{
-	gpio_set_value(spi->cs_gpio, onoff);
-}
-
 static int mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr,
 					      u32 size, unsigned int irq)
 {
@@ -500,9 +491,7 @@ static int mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr,
 	mps->type = (int)of_device_get_match_data(dev);
 	mps->irq = irq;
 
-	if (pdata == NULL) {
-		mps->cs_control = mpc512x_spi_cs_control;
-	} else {
+	if (pdata) {
 		mps->cs_control = pdata->cs_control;
 		master->bus_num = pdata->bus_num;
 		master->num_chipselect = pdata->max_chipselect;
@@ -513,6 +502,7 @@ static int mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr,
 	master->prepare_transfer_hardware = mpc512x_psc_spi_prep_xfer_hw;
 	master->transfer_one_message = mpc512x_psc_spi_msg_xfer;
 	master->unprepare_transfer_hardware = mpc512x_psc_spi_unprep_xfer_hw;
+	master->use_gpio_descriptors = true;
 	master->cleanup = mpc512x_psc_spi_cleanup;
 	master->dev.of_node = dev->of_node;