[PATCH v4 1/2] gpio: add TI SN65HVS885 spi industrial input serializer driver

[PATCH v4 1/2] gpio: add TI SN65HVS885 spi industrial input serializer driver

[Sean Nyekjaer]

Simple gpiolib driver for TI SN65HVS885 industrial input serializer.
The TI SN65HVS885 only support inputs.

Signed-off-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
Reviewed-by: Martin Hundebøll <martin.hundeboll@prevas.dk>
---
Changes since v3:
- none

Changes since v2:
- Wrong SPI mode. The correct mode is MODE 0

 drivers/gpio/Kconfig           |   9 ++-
 drivers/gpio/Makefile          |   1 +
 drivers/gpio/gpio-sn65hvs885.c | 144 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 152 insertions(+), 2 deletions(-)
 create mode 100644 drivers/gpio/gpio-sn65hvs885.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index cb212eb..d320f50 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1018,6 +1018,13 @@ config GPIO_MC33880
 	  SPI driver for Freescale MC33880 high-side/low-side switch.
 	  This provides GPIO interface supporting inputs and outputs.
 
+config GPIO_SN65HVS885
+        tristate "Texas Instruments sn65hvs885 input serializer 8-bit shift register"
+        depends on SPI_MASTER && OF
+        help
+          Driver for Texas Instruments sn65hvs885 input serializer.
+          This provides a GPIO interface supporting inputs.
+
 endmenu
 
 menu "SPI or I2C GPIO expanders"
@@ -1031,8 +1038,6 @@ config GPIO_MCP23S08
 	  This provides a GPIO interface supporting inputs and outputs.
 	  The I2C versions of the chips can be used as interrupt-controller.
 
-endmenu
-
 menu "USB GPIO expanders"
 	depends on USB
 
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 548e9b5..db7d035 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -120,3 +120,4 @@ obj-$(CONFIG_GPIO_XTENSA)	+= gpio-xtensa.o
 obj-$(CONFIG_GPIO_ZEVIO)	+= gpio-zevio.o
 obj-$(CONFIG_GPIO_ZYNQ)		+= gpio-zynq.o
 obj-$(CONFIG_GPIO_ZX)		+= gpio-zx.o
+obj-$(CONFIG_GPIO_SN65HVS885)	+= gpio-sn65hvs885.o
diff --git a/drivers/gpio/gpio-sn65hvs885.c b/drivers/gpio/gpio-sn65hvs885.c
new file mode 100644
index 0000000..6dceecc
--- /dev/null
+++ b/drivers/gpio/gpio-sn65hvs885.c
@@ -0,0 +1,144 @@
+/*
+ * Copyright (C) 2015 Sean Nyekjaer, Prevas
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
+
+#define SN65HVS885_NUMBER_GPIOS	8
+
+struct sn65hvs885_chip {
+	struct gpio_chip gpio_chip;
+	int latch_gpio;
+	struct mutex lock;	/* protect from simultaneous accesses */
+};
+
+static struct sn65hvs885_chip *sn65hvs885_gpio_to_chip(struct gpio_chip *gc)
+{
+	return container_of(gc, struct sn65hvs885_chip, gpio_chip);
+}
+
+static int sn65hvs885_get_value(struct gpio_chip *gc, unsigned offset)
+{
+	struct sn65hvs885_chip *chip = sn65hvs885_gpio_to_chip(gc);
+	struct spi_device *spi = to_spi_device(chip->gpio_chip.dev);
+	int ret;
+	u8 pin = offset % SN65HVS885_NUMBER_GPIOS;
+	u8 d8;
+	struct spi_transfer t = {
+		.rx_buf = &d8,
+		.len = 1,
+	};
+
+	if (gpio_is_valid(chip->latch_gpio)) {
+		gpio_set_value_cansleep(chip->latch_gpio, 0);
+		gpio_set_value_cansleep(chip->latch_gpio, 1);
+	}
+
+	mutex_lock(&chip->lock);
+	spi_sync_transfer(spi, &t, 1);
+	mutex_unlock(&chip->lock);
+	ret = (d8 >> pin) & 0x1;
+
+	return ret;
+}
+
+static int sn65hvs885_probe(struct spi_device *spi)
+{
+	struct sn65hvs885_chip *chip;
+	int ret;
+
+	spi->bits_per_word = 8;
+
+	ret = spi_setup(spi);
+	if (ret < 0)
+		return ret;
+
+	chip = devm_kzalloc(&spi->dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	spi_set_drvdata(spi, chip);
+
+	chip->gpio_chip.label = spi->modalias;
+	chip->gpio_chip.get = sn65hvs885_get_value;
+	chip->gpio_chip.base = -1;
+	chip->gpio_chip.ngpio = SN65HVS885_NUMBER_GPIOS;
+	chip->gpio_chip.can_sleep = true;
+	chip->gpio_chip.dev = &spi->dev;
+	chip->gpio_chip.owner = THIS_MODULE;
+
+	mutex_init(&chip->lock);
+
+	chip->latch_gpio = of_get_named_gpio(spi->dev.of_node, "latch-gpio", 0);
+	if (chip->latch_gpio < 0) {
+		dev_err(&spi->dev, "latch-gpio property not found\n");
+		return -ENODEV;
+	}
+
+	if (gpio_is_valid(chip->latch_gpio)) {
+		ret = devm_gpio_request_one(&spi->dev,
+					    chip->latch_gpio,
+					    GPIOF_OUT_INIT_HIGH, "gpio-latch");
+		if (ret) {
+			dev_err(&spi->dev, "unable to get latch gpio\n");
+			return -ENODEV;
+		}
+	}
+
+	ret = gpiochip_add(&chip->gpio_chip);
+
+	if (ret != 0) {
+		mutex_destroy(&chip->lock);
+		devm_gpio_free(&spi->dev, chip->latch_gpio);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int sn65hvs885_remove(struct spi_device *spi)
+{
+	struct sn65hvs885_chip *chip = spi_get_drvdata(spi);
+
+	devm_gpio_free(&spi->dev, chip->latch_gpio);
+
+	gpiochip_remove(&chip->gpio_chip);
+
+	mutex_destroy(&chip->lock);
+
+	return 0;
+}
+
+static const struct spi_device_id sn65hvs885_id[] = {
+	{"sn65hvs885", 0},
+	{}
+};
+
+MODULE_DEVICE_TABLE(spi, sn65hvs885_id);
+
+static struct spi_driver sn65hvs885_driver = {
+	.driver = {
+		   .name = "sn65hvs885",
+		   .owner = THIS_MODULE,
+		   },
+	.probe = sn65hvs885_probe,
+	.remove = sn65hvs885_remove,
+	.id_table = sn65hvs885_id,
+};
+
+module_spi_driver(sn65hvs885_driver);
+
+MODULE_AUTHOR("Sean Nyekjaer <sean.nyekjaer@prevas.dk>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("sn65hvs885 Industrial input serializer");
-- 
2.7.0

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[PATCH v4 2/2] gpio: sn65hvs885: Add DT binding documentation

[Sean Nyekjaer]

Signed-off-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
---
Changes since v3:
- Added gpio-controller and gpio cells flags

 Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt | 11 +++++++++++
 1 file changed, 11 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt

diff --git a/Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt b/Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt
new file mode 100644
index 0000000..6d99c9e
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt
@@ -0,0 +1,11 @@
+* TI SN65HVS885 digital-input serializer
+
+Example:
+	sn65hvs885@3 {
+		compatible = "sn65hvs885";
+		spi-max-frequency = <10000000>;
+		reg = <0>;
+		gpio-controller;
+		#gpio-cells = <1>;
+	};
+
-- 
2.7.0

Re: [PATCH v4 2/2] gpio: sn65hvs885: Add DT binding documentation

[Rob Herring]

On Thu, Jan 21, 2016 at 07:41:36AM +0100, Sean Nyekjaer wrote:
> Signed-off-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
> ---
> Changes since v3:
> - Added gpio-controller and gpio cells flags
> 
>  Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt
> 
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt b/Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt
> new file mode 100644
> index 0000000..6d99c9e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt
> @@ -0,0 +1,11 @@
> +* TI SN65HVS885 digital-input serializer
> +
> +Example:

The example does not serve as documentation. You need to list the 
properties and allowed values, required vs. optional, and point to 
common bindings you are using as appropriate (i.e. gpio).

> +	sn65hvs885@3 {
> +		compatible = "sn65hvs885";

Also, this needs a vendor prefix, so "ti,sn65hvs885".

> +		spi-max-frequency = <10000000>;
> +		reg = <0>;
> +		gpio-controller;
> +		#gpio-cells = <1>;
> +	};
> +
> -- 
> 2.7.0
> 
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