From 7ebc194d0fd4bb0fc8c7aca4b500b5b24e733267 Mon Sep 17 00:00:00 2001
From: Fabio Estevam <fabio.estevam@nxp.com>
Date: Mon, 7 Aug 2017 09:41:50 -0300
Subject: [PATCH] gpio: 74x164: Introduce 'enable-gpios' property
74HC595 has an /OE (output enable) pin that can be controlled by a GPIO.
Introduce an optional property called 'enable-gpios' that allows
controlling the /OE pin.
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
Documentation/devicetree/bindings/gpio/gpio-74x164.txt | 3 +++
drivers/gpio/gpio-74x164.c | 10 ++++++++++
2 files changed, 13 insertions(+)
diff --git a/Documentation/devicetree/bindings/gpio/gpio-74x164.txt b/Documentation/devicetree/bindings/gpio/gpio-74x164.txt
index ce1b2231bf5db..2a97553d8d76d 100644
--- a/Documentation/devicetree/bindings/gpio/gpio-74x164.txt
+++ b/Documentation/devicetree/bindings/gpio/gpio-74x164.txt
@@ -12,6 +12,9 @@ Required properties:
1 = active low
- registers-number: Number of daisy-chained shift registers
+Optional properties:
+- enable-gpios: GPIO connected to the OE (Output Enable) pin.
+
Example:
gpio5: gpio5@0 {
diff --git a/drivers/gpio/gpio-74x164.c b/drivers/gpio/gpio-74x164.c
index a6607faf2fdf8..6b535ec858cc3 100644
--- a/drivers/gpio/gpio-74x164.c
+++ b/drivers/gpio/gpio-74x164.c
@@ -9,6 +9,7 @@
* published by the Free Software Foundation.
*/
+#include <linux/gpio/consumer.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/spi/spi.h>
@@ -31,6 +32,7 @@ struct gen_74x164_chip {
* numbering, store the bytes in reverse order.
*/
u8 buffer[0];
+ struct gpio_desc *gpiod_oe;
};
static int __gen_74x164_write_config(struct gen_74x164_chip *chip)
@@ -126,6 +128,13 @@ static int gen_74x164_probe(struct spi_device *spi)
if (!chip)
return -ENOMEM;
+ chip->gpiod_oe = devm_gpiod_get_optional(&spi->dev, "enable",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(chip->gpiod_oe))
+ return PTR_ERR(chip->gpiod_oe);
+
+ gpiod_set_value_cansleep(chip->gpiod_oe, 1);
+
spi_set_drvdata(spi, chip);
chip->gpio_chip.label = spi->modalias;
@@ -164,6 +173,7 @@ static int gen_74x164_remove(struct spi_device *spi)
{
struct gen_74x164_chip *chip = spi_get_drvdata(spi);
+ gpiod_set_value_cansleep(chip->gpiod_oe, 0);
gpiochip_remove(&chip->gpio_chip);
mutex_destroy(&chip->lock);
--
2.30.2