spi: npcm-pspi: Convert to use GPIO descriptors

The Nuvoton PSPI driver already uses the core to handle GPIO
chip selects but is using the old GPIO number method and
retrieveing the GPIOs in the probe() call.

Switch it over to using GPIO descriptors saving a bunch of
code and modernizing it.

Compile tested med ARMv7 multiplatform config augmented
with the Nuvoton arch and this driver.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Tomer Maimon <tmaimon77@gmail.com>
Link: https://lore.kernel.org/r/20200625225759.273911-1-linus.walleij@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-npcm-pspi.c

@@ -10,8 +10,6 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/spi/spi.h>
-#include <linux/gpio.h>
-#include <linux/of_gpio.h>
 #include <linux/reset.h>
 
 #include <asm/unaligned.h>
@@ -344,16 +342,9 @@ static int npcm_pspi_probe(struct platform_device *pdev)
 	struct npcm_pspi *priv;
 	struct spi_master *master;
 	unsigned long clk_hz;
-	struct device_node *np = pdev->dev.of_node;
-	int num_cs, i;
-	int csgpio;
 	int irq;
 	int ret;
 
-	num_cs = of_gpio_named_count(np, "cs-gpios");
-	if (num_cs < 0)
-		return num_cs;
-
 	master = spi_alloc_master(&pdev->dev, sizeof(*priv));
 	if (!master)
 		return -ENOMEM;
@@ -418,24 +409,7 @@ static int npcm_pspi_probe(struct platform_device *pdev)
 		npcm_pspi_prepare_transfer_hardware;
 	master->unprepare_transfer_hardware =
 		npcm_pspi_unprepare_transfer_hardware;
-	master->num_chipselect = num_cs;
-
-	for (i = 0; i < num_cs; i++) {
-		csgpio = of_get_named_gpio(np, "cs-gpios", i);
-		if (csgpio < 0) {
-			dev_err(&pdev->dev, "failed to get csgpio#%u\n", i);
-			goto out_disable_clk;
-		}
-		dev_dbg(&pdev->dev, "csgpio#%u = %d\n", i, csgpio);
-		ret = devm_gpio_request_one(&pdev->dev, csgpio,
-					    GPIOF_OUT_INIT_HIGH, DRIVER_NAME);
-		if (ret < 0) {
-			dev_err(&pdev->dev,
-				"failed to configure csgpio#%u %d\n"
-				, i, csgpio);
-			goto out_disable_clk;
-		}
-	}
+	master->use_gpio_descriptors = true;
 
 	/* set to default clock rate */
 	npcm_pspi_set_baudrate(priv, NPCM_PSPI_DEFAULT_CLK);