Re: [PATCH] gpio: Enable pcf857x GPIO expander for Device Tree

[Archit Taneja <archit@ti.com>]

Hi Linus,

On Thursday 06 June 2013 07:35 PM, Archit Taneja wrote:
> Add code to parse the GPIO expander Device Tree node and extract platform data
> out of it, and populate the struct 'pcf857x_platform_data' maintained by the
> driver. This enables devices to reference the gpio expander from Device Tree.
>
> Add DT binding info in Documentation.

Any comments on this patch?

Thanks,
Archit

>
> CC: Grant Likely <grant.likely@secretlab.ca>
> Signed-off-by: Archit Taneja <archit@ti.com>
> ---
>   .../devicetree/bindings/gpio/gpio-pcf857x.txt      | 44 +++++++++++++++++
>   drivers/gpio/gpio-pcf857x.c                        | 57 ++++++++++++++++++++--
>   2 files changed, 97 insertions(+), 4 deletions(-)
>   create mode 100644 Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt
>
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt b/Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt
> new file mode 100644
> index 0000000..0556512
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt
> @@ -0,0 +1,44 @@
> +PCF857x I2C based GPIO controller bindings
> +
> +Required properties:
> +- compatible:
> +  - "nxp,pca9670" for NXP PCA9670 8 bit I/O expander
> +  - "nxp,pca9672" for NXP PCA9672 8 bit I/O expander with interrupt
> +  - "nxp,pca9674" for NXP PCA9672 8 bit I/O expander with interrupt
> +  - "nxp,pca8574" for NXP PCA8574 8 bit I/O expander with interrupt
> +  - "nxp,pca8575" for NXP PCA8575 16 bit I/O expander with interrupt
> +  - "nxp,pca9671" for NXP PCA9671 16 bit I/O expander
> +  - "nxp,pca9673" for NXP PCA9673 16 bit I/O expander with interrupt
> +  - "nxp,pca9675" for NXP PCA9675 16 bit I/O expander with interrupt
> +  - "ti,pcf8574"  for TI PCF8574 8 bit I/O expander with interrupt
> +  - "ti,pcf8574a" for TI PCF8574A 8 bit I/O expander with interrupt
> +  - "ti,pcf8575"  for TI PCF8575 16 bit I/O expander with interrupt
> +  - "ti,tca9554"  for TI TCA9554 8 bit I/O expander with interrupt
> +  - "maxim,max7328" for MAXIM MAX7328 8 bit I/O expander with interrupt
> +  - "maxim,max7329" for MAXIM MAX7329 8 bit I/O expander with interrupt
> +- gpio-controller : Marks the device node as a GPIO controller.
> +- #gpio-cells : Should be two.
> +  - first cell is the pin number.
> +  - second cell is unused.
> +- interrupt-controller: Mark the device node as an interrupt controller.
> +- #interrupt-cells : Should be two.
> +  - first cell is the GPIO number.
> +  - second cell is unused.
> +- reg: I2C address of the chip.
> +
> +Device speific properties:
> +- n_latch:		optional bit-inverse of initial register value; if
> +			you leave this initialized to zero the driver will act
> +			like the chip was just reset.
> +
> +Example:
> +
> +pcf8575: pcf8575 {
> +	compatible = "ti,pcf8575";
> +	gpio-controller;
> +	#gpio-cells = <2>;
> +	interrupt-controller;
> +	#interrupt-cells = <2>;
> +	reg = <0x20>;
> +	n_latch = <0x0>;
> +};
> diff --git a/drivers/gpio/gpio-pcf857x.c b/drivers/gpio/gpio-pcf857x.c
> index e8faf53..3435790 100644
> --- a/drivers/gpio/gpio-pcf857x.c
> +++ b/drivers/gpio/gpio-pcf857x.c
> @@ -21,6 +21,7 @@
>   #include <linux/kernel.h>
>   #include <linux/slab.h>
>   #include <linux/gpio.h>
> +#include <linux/of.h>
>   #include <linux/i2c.h>
>   #include <linux/i2c/pcf857x.h>
>   #include <linux/interrupt.h>
> @@ -255,17 +256,42 @@ fail:
>
>   /*-------------------------------------------------------------------------*/
>
> +static struct pcf857x_platform_data *of_gpio_pcf857x(struct device *dev)
> +{
> +	struct pcf857x_platform_data *pdata;
> +	int r;
> +
> +	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
> +	if (!pdata)
> +		return NULL;
> +
> +	pdata->gpio_base = -1;
> +
> +	r = of_property_read_u32(dev->of_node, "n_latch", &pdata->n_latch);
> +	if (r) {
> +		dev_dbg(dev, "couldn't find n-latch, use default\n");
> +		pdata->n_latch = 0;
> +	}
> +
> +	return pdata;
> +}
> +
>   static int pcf857x_probe(struct i2c_client *client,
>   			 const struct i2c_device_id *id)
>   {
>   	struct pcf857x_platform_data	*pdata;
> +	struct device_node		*node;
>   	struct pcf857x			*gpio;
>   	int				status;
>
>   	pdata = client->dev.platform_data;
> -	if (!pdata) {
> +	node = client->dev.of_node;
> +
> +	if (!pdata && node)
> +		pdata = of_gpio_pcf857x(&client->dev);
> +
> +	if (!pdata)
>   		dev_dbg(&client->dev, "no platform data\n");
> -	}
>
>   	/* Allocate, initialize, and register this gpio_chip. */
>   	gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
> @@ -420,10 +446,33 @@ static int pcf857x_remove(struct i2c_client *client)
>   	return status;
>   }
>
> +static const struct of_device_id pcf857x_dt_ids[] = {
> +	{ .compatible = "nxp,pca9670", },
> +	{ .compatible = "nxp,pca9672", },
> +	{ .compatible = "nxp,pca9674", },
> +	{ .compatible = "nxp,pca8574", },
> +	{ .compatible = "nxp,pca8575", },
> +	{ .compatible = "nxp,pca9671", },
> +	{ .compatible = "nxp,pca9673", },
> +	{ .compatible = "nxp,pca9675", },
> +
> +	{ .compatible = "ti,pcf8574", },
> +	{ .compatible = "ti,pcf8574a", },
> +	{ .compatible = "ti,pcf8575", },
> +	{ .compatible = "ti,tca9554", },
> +
> +	{ .compatible = "maxim,max7328", },
> +	{ .compatible = "maxim,max7329", },
> +	{ }
> +};
> +
> +MODULE_DEVICE_TABLE(of, pcf857x_dt_ids);
> +
>   static struct i2c_driver pcf857x_driver = {
>   	.driver = {
> -		.name	= "pcf857x",
> -		.owner	= THIS_MODULE,
> +		.name		= "pcf857x",
> +		.owner		= THIS_MODULE,
> +		.of_match_table	= pcf857x_dt_ids,
>   	},
>   	.probe	= pcf857x_probe,
>   	.remove	= pcf857x_remove,
>