[PATCHv3 1/2] gpio: add TI SN65HVS885 spi industrial input serializer driver

[PATCHv3 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 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

--
To unsubscribe from this list: send the line "unsubscribe linux-gpio" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCHv3 2/2] gpio: sn65hvs885: Add DT binding documentation

[Sean Nyekjaer]

Signed-off-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
---
 Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt | 9 +++++++++
 1 file changed, 9 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..56679ac
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt
@@ -0,0 +1,9 @@
+* TI SN65HVS885 digital-input serializer
+
+Example:
+	sn65hvs885@3 {
+		compatible = "sn65hvs885";
+		spi-max-frequency = <10000000>;
+		reg = <0>;
+	};
+
-- 
2.7.0

Re: [PATCHv3 2/2] gpio: sn65hvs885: Add DT binding documentation

[Rob Herring]

On Tue, Jan 19, 2016 at 11:22:20AM +0100, Sean Nyekjaer wrote:
> Signed-off-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
> ---
>  Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt | 9 +++++++++
>  1 file changed, 9 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..56679ac
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt
> @@ -0,0 +1,9 @@
> +* TI SN65HVS885 digital-input serializer
> +
> +Example:
> +	sn65hvs885@3 {
> +		compatible = "sn65hvs885";
> +		spi-max-frequency = <10000000>;
> +		reg = <0>;

What about all the standard gpio controller properties?

> +	};
> +
> -- 
> 2.7.0
> 
> --
> To unsubscribe from this list: send the line "unsubscribe devicetree" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCHv3 2/2] gpio: sn65hvs885: Add DT binding documentation

[Sean Nyekjær]

Hi

Yes i need to add the gpio-controller and #gpio-cells. But i'm not 
exactly sure what gpio-cells means and its difficult to find in 
documentation.

I found this in the documentation:
#gpio-cells: The first cell is the GPIO number and the second cell is 
used to specify the GPIO polarity.

This device only supports inputs so the gpio-cells option needs to be 
<1>  or ??
#gpio-cells = <1>;

/Sean

On 2016-01-19 18:20, Rob Herring wrote:
> On Tue, Jan 19, 2016 at 11:22:20AM +0100, Sean Nyekjaer wrote:
>> Signed-off-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
>> ---
>>   Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt | 9 +++++++++
>>   1 file changed, 9 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..56679ac
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt
>> @@ -0,0 +1,9 @@
>> +* TI SN65HVS885 digital-input serializer
>> +
>> +Example:
>> +	sn65hvs885@3 {
>> +		compatible = "sn65hvs885";
>> +		spi-max-frequency = <10000000>;
>> +		reg = <0>;
> What about all the standard gpio controller properties?
>
>> +	};
>> +
>> -- 
>> 2.7.0
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe devicetree" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCHv3 2/2] gpio: sn65hvs885: Add DT binding documentation

[Rob Herring]

On Wed, Jan 20, 2016 at 6:45 AM, Sean Nyekjær <sean.nyekjaer@prevas.dk> wrote:
> Hi
>
> Yes i need to add the gpio-controller and #gpio-cells. But i'm not exactly
> sure what gpio-cells means and its difficult to find in documentation.

#*-cells are standard properties that a producer sets for clients to
describe their connection and are necessary to know how to parse
properties such as *-gpios in this case.

> I found this in the documentation:
> #gpio-cells: The first cell is the GPIO number and the second cell is used
> to specify the GPIO polarity.
>
> This device only supports inputs so the gpio-cells option needs to be <1>
> or ??
> #gpio-cells = <1>;

Most controllers use 2 even if 2nd field is unused. You can use the
2nd field for inputs too. For example, specify that a detect line is
active high or low for detect.

Rob

>
> /Sean
>
>
> On 2016-01-19 18:20, Rob Herring wrote:
>>
>> On Tue, Jan 19, 2016 at 11:22:20AM +0100, Sean Nyekjaer wrote:
>>>
>>> Signed-off-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
>>> ---
>>>   Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt | 9
>>> +++++++++
>>>   1 file changed, 9 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..56679ac
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/gpio/gpio-sn65hvs885.txt
>>> @@ -0,0 +1,9 @@
>>> +* TI SN65HVS885 digital-input serializer
>>> +
>>> +Example:
>>> +       sn65hvs885@3 {
>>> +               compatible = "sn65hvs885";
>>> +               spi-max-frequency = <10000000>;
>>> +               reg = <0>;
>>
>> What about all the standard gpio controller properties?
>>
>>> +       };
>>> +
>>> --
>>> 2.7.0
>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe devicetree" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe devicetree" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-gpio" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html