linux-kernel - Re: [PATCH] gpio: stmpe: Add DT support for stmpe gpio

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Date:	Fri, 23 Nov 2012 10:34:00 +0000
From:	Lee Jones <lee.jones@...aro.org>
To:	Viresh Kumar <viresh.kumar@...aro.org>
Cc:	linus.walleij@...aro.org, grant.likely@...retlab.ca,
	devicetree-discuss@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
	spear-devel@...t.st.com,
	Vipul Kumar Samar <vipulkumar.samar@...com>
Subject: Re: [PATCH] gpio: stmpe: Add DT support for stmpe gpio

On Fri, 23 Nov 2012, Viresh Kumar wrote:

> From: Vipul Kumar Samar <vipulkumar.samar@...com>
> 
> This patch allows the STMPE GPIO driver to be successfully probed and
> initialised when Device Tree support is enabled. Bindings are mentioned in
> Documentation too.
> 
> Signed-off-by: Vipul Kumar Samar <vipulkumar.samar@...com>
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> ---
>  Documentation/devicetree/bindings/gpio/gpio-stmpe.txt | 18 ++++++++++++++++++
>  drivers/gpio/gpio-stmpe.c                             | 15 ++++++++++++---
>  drivers/mfd/stmpe.c                                   |  2 ++
>  3 files changed, 32 insertions(+), 3 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/gpio/gpio-stmpe.txt
> 
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-stmpe.txt b/Documentation/devicetree/bindings/gpio/gpio-stmpe.txt
> new file mode 100644
> index 0000000..7f010e0
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/gpio-stmpe.txt
> @@ -0,0 +1,18 @@
> +STMPE gpio
> +----------
> +
> +Required properties:
> + - compatible: "st,stmpe-gpio"
> +
> +Optional properties:
> + - norequest-mask: bitmask specifying which GPIOs should _not_ be requestable
> +   due to different usage (e.g. touch, keypad)
> +
> +Node name must be stmpe_gpio and should be child node of stmpe node to which it
> +belongs.
> +
> +Example:
> +	stmpe_gpio {
> +		compatible = "st,stmpe-gpio";
> +		st,norequest-mask = <0x20>;	//gpio 5 can't be used
> +	};
> diff --git a/drivers/gpio/gpio-stmpe.c b/drivers/gpio/gpio-stmpe.c
> index dce3472..91455d4 100644
> --- a/drivers/gpio/gpio-stmpe.c
> +++ b/drivers/gpio/gpio-stmpe.c
> @@ -12,6 +12,7 @@
>  #include <linux/gpio.h>
>  #include <linux/irq.h>
>  #include <linux/interrupt.h>
> +#include <linux/of.h>
>  #include <linux/mfd/stmpe.h>
>  
>  /*
> @@ -304,6 +305,7 @@ static void stmpe_gpio_irq_remove(struct stmpe_gpio *stmpe_gpio)
>  static int __devinit stmpe_gpio_probe(struct platform_device *pdev)
>  {
>  	struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
> +	struct device_node *np = pdev->dev.of_node;
>  	struct stmpe_gpio_platform_data *pdata;
>  	struct stmpe_gpio *stmpe_gpio;
>  	int ret;
> @@ -321,12 +323,19 @@ static int __devinit stmpe_gpio_probe(struct platform_device *pdev)
>  
>  	stmpe_gpio->dev = &pdev->dev;
>  	stmpe_gpio->stmpe = stmpe;
> -	stmpe_gpio->norequest_mask = pdata ? pdata->norequest_mask : 0;
> -
>  	stmpe_gpio->chip = template_chip;
>  	stmpe_gpio->chip.ngpio = stmpe->num_gpios;
>  	stmpe_gpio->chip.dev = &pdev->dev;
> -	stmpe_gpio->chip.base = pdata ? pdata->gpio_base : -1;

Why have you deleted this?

> +
> +	if (pdata) {
> +		stmpe_gpio->norequest_mask = pdata->norequest_mask;
> +		stmpe_gpio->chip.base = pdata->gpio_base;

Then added this?

> +	} else {
> +		stmpe_gpio->chip.base = -1;

And this?

Just leave the top line in and it saves you lots of complecations.

> +		if (np)
> +			of_property_read_u32(np, "st,norequest-mask",
> +					&pdata->norequest_mask);

Can you explain to me what this does?

> +	}
>  
>  	if (irq >= 0)
>  		stmpe_gpio->irq_base = stmpe->irq_base + STMPE_INT_GPIO(0);
> diff --git a/drivers/mfd/stmpe.c b/drivers/mfd/stmpe.c
> index e2c0dda..c757ac3 100644
> --- a/drivers/mfd/stmpe.c
> +++ b/drivers/mfd/stmpe.c
> @@ -298,12 +298,14 @@ static struct resource stmpe_gpio_resources[] = {
>  
>  static struct mfd_cell stmpe_gpio_cell = {
>  	.name		= "stmpe-gpio",
> +	.of_compatible	= "st,stmpe-gpio",

There's no need for any of the STMPE to have their own compatible
string, as they are MFD devices. They are registered as platform
devices from the MFD subsystem.

>  	.resources	= stmpe_gpio_resources,
>  	.num_resources	= ARRAY_SIZE(stmpe_gpio_resources),
>  };
>  
>  static struct mfd_cell stmpe_gpio_cell_noirq = {
>  	.name		= "stmpe-gpio",
> +	.of_compatible	= "st,stmpe-gpio",
>  	/* gpio cell resources consist of an irq only so no resources here */
>  };
>  
> -- 
> 1.7.12.rc2.18.g61b472e
> 

-- 
Lee Jones
Linaro ST-Ericsson Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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