RE: [PATCH v2] gpio/samsung: Add device tree support for Exynos4

[Kukjin Kim <kgene.kim@samsung.com>]

Thomas Abraham wrote:
> 
> As gpio chips get registered, a device tree node which represents the
> gpio chip is searched and attached to it. A translate function is also
> provided to convert the gpio specifier into actual platform settings
> for pin function selection, pull up/down and driver strength settings.
> 
> Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
> Acked-by: Grant Likely <grant.likely@secretlab.ca>
> ---
> Changes since v1:
> - As suggested by Rob and Grant, the gpio controller node lookup is based
>   on the base address of the gpio controller instead of the unique
>   per-controller compatible property value.
> 
> This patch is based on the following tree and branch.
> git://git.linaro.org/git/people/arnd/arm-soc.git  branch: for-next
> 
>  .../devicetree/bindings/gpio/gpio-samsung.txt      |   40 ++++++++++++
>  drivers/gpio/gpio-samsung.c                        |   66
> ++++++++++++++++++++
>  2 files changed, 106 insertions(+), 0 deletions(-)
>  create mode 100644
Documentation/devicetree/bindings/gpio/gpio-samsung.txt
> 
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-samsung.txt
> b/Documentation/devicetree/bindings/gpio/gpio-samsung.txt
> new file mode 100644
> index 0000000..c143058
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/gpio-samsung.txt
> @@ -0,0 +1,40 @@
> +Samsung Exynos4 GPIO Controller
> +
> +Required properties:
> +- compatible: Compatible property value should be
"samsung,exynos4-gpio>".
> +
> +- reg: Physical base address of the controller and length of memory
mapped
> +  region.
> +
> +- #gpio-cells: Should be 4. The syntax of the gpio specifier used by
client nodes
> +  should be the following with values derived from the SoC user manual.
> +     <[phandle of the gpio controller node]
> +      [pin number within the gpio controller]
> +      [mux function]
> +      [pull up/down]
> +      [drive strength]>
> +
> +  Values for gpio specifier:
> +  - Pin number: is a value between 0 to 7.
> +  - Pull Up/Down: 0 - Pull Up/Down Disabled.
> +                  1 - Pull Down Enabled.
> +                  3 - Pull Up Enabled.
> +  - Drive Strength: 0 - 1x,
> +                    1 - 3x,
> +                    2 - 2x,
> +                    3 - 4x
> +
> +- gpio-controller: Specifies that the node is a gpio controller.
> +- #address-cells: should be 1.
> +- #size-cells: should be 1.
> +
> +Example:
> +
> +	gpa0: gpio-controller@11400000 {
> +		#address-cells = <1>;
> +		#size-cells = <1>;
> +		compatible = "samsung,exynos4-gpio";
> +		reg = <0x11400000 0x20>;
> +		#gpio-cells = <4>;
> +		gpio-controller;
> +	};
> diff --git a/drivers/gpio/gpio-samsung.c b/drivers/gpio/gpio-samsung.c
> index 8662518..0140756 100644
> --- a/drivers/gpio/gpio-samsung.c
> +++ b/drivers/gpio/gpio-samsung.c
> @@ -24,6 +24,9 @@
>  #include <linux/interrupt.h>
>  #include <linux/sysdev.h>
>  #include <linux/ioport.h>
> +#include <linux/of.h>
> +#include <linux/slab.h>
> +#include <linux/of_address.h>
> 
>  #include <asm/irq.h>
> 
> @@ -2374,6 +2377,63 @@ static struct samsung_gpio_chip exynos4_gpios_3[] =
> {
>  #endif
>  };
> 
> +#if defined(CONFIG_ARCH_EXYNOS4) && defined(CONFIG_OF)
> +int exynos4_gpio_xlate(struct gpio_chip *gc, struct device_node *np,
> +			 const void *gpio_spec, u32 *flags)
> +{
> +	const __be32 *gpio = gpio_spec;
> +	const u32 n = be32_to_cpup(gpio);
> +	unsigned int pin = gc->base + be32_to_cpu(gpio[0]);
> +
> +	if (gc->of_gpio_n_cells < 4) {
> +		WARN_ON(1);
> +		return -EINVAL;
> +	}
> +
> +	if (n > gc->ngpio)
> +		return -EINVAL;
> +
> +	s3c_gpio_cfgpin(pin, S3C_GPIO_SFN(be32_to_cpu(gpio[1])));
> +	s3c_gpio_setpull(pin, be32_to_cpu(gpio[2]));
> +	s5p_gpio_set_drvstr(pin, be32_to_cpu(gpio[3]));
> +	return n;
> +}
> +
> +static const struct of_device_id exynos4_gpio_dt_match[] __initdata = {
> +	{ .compatible = "samsung,exynos4-gpio", },
> +	{}
> +};
> +
> +static __init void exynos4_gpiolib_attach_ofnode(struct samsung_gpio_chip
> *chip,
> +						u64 base, u64 offset)
> +{
> +	struct gpio_chip *gc =  &chip->chip;
> +	u64 address;
> +
> +	if (!of_have_populated_dt())
> +		return;
> +
> +	address = (chip->base) ? (base + ((u32)chip->base & 0xfff)) :
> +			(base + offset);
> +
> +	gc->of_node = of_find_matching_node_by_address(NULL,
> +			exynos4_gpio_dt_match, address);
> +	if (!gc->of_node) {
> +		pr_info("gpio: device tree node not found for gpio
controller"
> +			" with base address %08llx\n", address);
> +		return;
> +	}
> +	gc->of_gpio_n_cells = 4;
> +	gc->of_xlate = exynos4_gpio_xlate;
> +}
> +#else
> +static __init void exynos4_gpiolib_attach_ofnode(struct samsung_gpio_chip
> *chip,
> +						u64 base, u64 offset)
> +{
> +	return;
> +}
> +#endif /* defined(CONFIG_ARCH_EXYNOS4) && defined(CONFIG_OF) */
> +
>  /* TODO: cleanup soc_is_* */
>  static __init int samsung_gpiolib_init(void)
>  {
> @@ -2455,6 +2515,8 @@ static __init int samsung_gpiolib_init(void)
>  				chip->config = &exynos4_gpio_cfg;
>  				chip->group = group++;
>  			}
> +			exynos4_gpiolib_attach_ofnode(chip,
> +					EXYNOS4_PA_GPIO1, i * 0x20);
>  		}
>  		samsung_gpiolib_add_4bit_chips(exynos4_gpios_1, nr_chips,
> S5P_VA_GPIO1);
> 
> @@ -2467,6 +2529,8 @@ static __init int samsung_gpiolib_init(void)
>  				chip->config = &exynos4_gpio_cfg;
>  				chip->group = group++;
>  			}
> +			exynos4_gpiolib_attach_ofnode(chip,
> +					EXYNOS4_PA_GPIO2, i * 0x20);
>  		}
>  		samsung_gpiolib_add_4bit_chips(exynos4_gpios_2, nr_chips,
> S5P_VA_GPIO2);
> 
> @@ -2479,6 +2543,8 @@ static __init int samsung_gpiolib_init(void)
>  				chip->config = &exynos4_gpio_cfg;
>  				chip->group = group++;
>  			}
> +			exynos4_gpiolib_attach_ofnode(chip,
> +					EXYNOS4_PA_GPIO3, i * 0x20);
>  		}
>  		samsung_gpiolib_add_4bit_chips(exynos4_gpios_3, nr_chips,
> S5P_VA_GPIO3);
> 
> --
> 1.7.4.4

Thomas,

Happens following build error.

drivers/gpio/gpio-samsung.c: In function 'samsung_gpiolib_init':
drivers/gpio/gpio-samsung.c:2519: error: 'EXYNOS4_PA_GPIO1' undeclared
(first use in this function)
drivers/gpio/gpio-samsung.c:2519: error: (Each undeclared identifier is
reported only once
drivers/gpio/gpio-samsung.c:2519: error: for each function it appears in.)
drivers/gpio/gpio-samsung.c:2533: error: 'EXYNOS4_PA_GPIO2' undeclared
(first use in this function)
drivers/gpio/gpio-samsung.c:2547: error: 'EXYNOS4_PA_GPIO3' undeclared
(first use in this function)

Thanks.

Best regards,
Kgene.
--
Kukjin Kim <kgene.kim@samsung.com>, Senior Engineer,
SW Solution Development Team, Samsung Electronics Co., Ltd.