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[PATCH] mtd: nand: gpio: make nCE GPIO optional

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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@c-s.fr>
---
 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,
-- 
2.10.1

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[PATCH] mtd: nand: gpio: make nCE GPIO optional Christophe Leroy <christophe.leroy@c-s.fr> - 2017-02-10 15:30 +0100
  Re: [PATCH] mtd: nand: gpio: make nCE GPIO optional Marek Vasut <marek.vasut@gmail.com> - 2017-02-10 16:20 +0100
  Re: [PATCH] mtd: nand: gpio: make nCE GPIO optional Boris Brezillon <boris.brezillon@free-electrons.com> - 2017-02-13 11:40 +0100
    Re: [PATCH] mtd: nand: gpio: make nCE GPIO optional Christophe LEROY <christophe.leroy@c-s.fr> - 2017-02-13 14:00 +0100
      Re: [PATCH] mtd: nand: gpio: make nCE GPIO optional Boris Brezillon <boris.brezillon@free-electrons.com> - 2017-02-13 14:30 +0100

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