mtd: nand: gpio: make nCE GPIO optional

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=44dd182861f99f04171256f29b9dc51940757e5d
Commit:     44dd182861f99f04171256f29b9dc51940757e5d
Parent:     01eb9ae1aeaf776653a861bb38aaa816a911da58
Author:     Christophe Leroy <christophe.leroy at c-s.fr>
AuthorDate: Fri Feb 10 15:01:10 2017 +0100
Committer:  Boris Brezillon <boris.brezillon at free-electrons.com>
CommitDate: Thu Mar 16 10:34:27 2017 +0100

    mtd: nand: gpio: make nCE GPIO optional
    
    On some hardware, the nCE signal is wired to the ChipSelect associated
    to bus address of the NAND, so it is automatically driven during the
    memory access and it is not managed by a GPIO.
    
    Signed-off-by: Christophe Leroy <christophe.leroy at c-s.fr>
    Reviewed-by: Marek Vasut <marek.vasut at gmail.com>
    Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
---
 drivers/mtd/nand/gpio.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/nand/gpio.c b/drivers/mtd/nand/gpio.c
index 0d24857..85294f1 100644
--- a/drivers/mtd/nand/gpio.c
+++ b/drivers/mtd/nand/gpio.c
@@ -78,7 +78,9 @@ static void gpio_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
 	gpio_nand_dosync(gpiomtd);
 
 	if (ctrl & NAND_CTRL_CHANGE) {
-		gpio_set_value(gpiomtd->plat.gpio_nce, !(ctrl & NAND_NCE));
+		if (gpio_is_valid(gpiomtd->plat.gpio_nce))
+			gpio_set_value(gpiomtd->plat.gpio_nce,
+				       !(ctrl & NAND_NCE));
 		gpio_set_value(gpiomtd->plat.gpio_cle, !!(ctrl & NAND_CLE));
 		gpio_set_value(gpiomtd->plat.gpio_ale, !!(ctrl & NAND_ALE));
 		gpio_nand_dosync(gpiomtd);
@@ -201,7 +203,8 @@ static int gpio_nand_remove(struct platform_device *pdev)
 
 	if (gpio_is_valid(gpiomtd->plat.gpio_nwp))
 		gpio_set_value(gpiomtd->plat.gpio_nwp, 0);
-	gpio_set_value(gpiomtd->plat.gpio_nce, 1);
+	if (gpio_is_valid(gpiomtd->plat.gpio_nce))
+		gpio_set_value(gpiomtd->plat.gpio_nce, 1);
 
 	return 0;
 }
@@ -239,10 +242,13 @@ static int gpio_nand_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_nce, "NAND NCE");
-	if (ret)
-		return ret;
-	gpio_direction_output(gpiomtd->plat.gpio_nce, 1);
+	if (gpio_is_valid(gpiomtd->plat.gpio_nce)) {
+		ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_nce,
+					"NAND NCE");
+		if (ret)
+			return ret;
+		gpio_direction_output(gpiomtd->plat.gpio_nce, 1);
+	}
 
 	if (gpio_is_valid(gpiomtd->plat.gpio_nwp)) {
 		ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_nwp,