Until now the Exynos-SoC was the only Samsung-SoC supporting the GPIOs
via the device tree. This patch implements dt-support for the
s3c24xx arches.
The controllers contain only 3 cells, as the underlying gpio controller
does not support controlling the drive strength on a gpio level.
Tested with the gpio-keys driver on a s3c2416 based machine.
Signed-off-by: Heiko Stuebner <heiko@xxxxxxxxx>
Reviewed-by: Thomas Abraham <thomas.abraham@xxxxxxxxxx>
---
changes since v1:
update bindings documentation to address SoC specific issues
.../devicetree/bindings/gpio/gpio-samsung.txt | 43 +++++++++++++
drivers/gpio/gpio-samsung.c | 63 ++++++++++++++++++++
2 files changed, 106 insertions(+), 0 deletions(-)
diff --git a/Documentation/devicetree/bindings/gpio/gpio-samsung.txt b/Documentation/devicetree/bindings/gpio/gpio-samsung.txt
index 5375625..f1e5dfe 100644
--- a/Documentation/devicetree/bindings/gpio/gpio-samsung.txt
+++ b/Documentation/devicetree/bindings/gpio/gpio-samsung.txt
@@ -39,3 +39,46 @@ Example:
#gpio-cells = <4>;
gpio-controller;
};
+
+
+Samsung S3C24XX GPIO Controller
+
+Required properties:
+- compatible: Compatible property value should be "samsung,s3c24xx-gpio".
+
+- reg: Physical base address of the controller and length of memory mapped
+ region.
+
+- #gpio-cells: Should be 3. 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]
+ [flags and pull up/down]
+
+ Values for gpio specifier:
+ - Pin number: depending on the controller a number from 0 up to 15.
+ - Mux function: Depending on the SoC and the gpio bank the gpio can be set
+ as input, output or a special function
+ - Flags and Pull Up/Down: the values to use differ for the individual SoCs
+ example S3C2416/S3C2450:
+ 0 - Pull Up/Down Disabled.
+ 1 - Pull Down Enabled.
+ 2 - Pull Up Enabled.
+ Bit 16 (0x00010000) - Input is active low.
+ Consult the user manual for the correct values of Mux and Pull Up/Down.
+
+- gpio-controller: Specifies that the node is a gpio controller.
+- #address-cells: should be 1.
+- #size-cells: should be 1.
+
+Example:
+
+ gpa: gpio-controller@56000000 {
+ #address-cells = <1>;
+ #size-cells = <1>;
+ compatible = "samsung,s3c24xx-gpio";
+ reg = <0x56000000 0x10>;
+ #gpio-cells = <3>;
+ gpio-controller;
+ };
diff --git a/drivers/gpio/gpio-samsung.c b/drivers/gpio/gpio-samsung.c
index ba126cc..54f6663 100644
--- a/drivers/gpio/gpio-samsung.c
+++ b/drivers/gpio/gpio-samsung.c
@@ -938,6 +938,67 @@ static void __init samsung_gpiolib_add(struct samsung_gpio_chip *chip)
s3c_gpiolib_track(chip);
}
+#if defined(CONFIG_PLAT_S3C24XX) && defined(CONFIG_OF)
+static int s3c24xx_gpio_xlate(struct gpio_chip *gc,
+ const struct of_phandle_args *gpiospec, u32 *flags)
+{
+ unsigned int pin;
+
+ if (WARN_ON(gc->of_gpio_n_cells < 3))
+ return -EINVAL;
+
+ if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
+ return -EINVAL;
+
+ if (gpiospec->args[0] > gc->ngpio)
+ return -EINVAL;
+
+ pin = gc->base + gpiospec->args[0];
+
+ if (s3c_gpio_cfgpin(pin, S3C_GPIO_SFN(gpiospec->args[1])))
+ pr_warn("gpio_xlate: failed to set pin function\n");
+ if (s3c_gpio_setpull(pin, gpiospec->args[2] & 0xffff))
+ pr_warn("gpio_xlate: failed to set pin pull up/down\n");
+
+ if (flags)
+ *flags = gpiospec->args[2] >> 16;
+
+ return gpiospec->args[0];
+}
+
+static const struct of_device_id s3c24xx_gpio_dt_match[] __initdata = {
+ { .compatible = "samsung,s3c24xx-gpio", },
+ {}
+};
+
+static __init void s3c24xx_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,
+ s3c24xx_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 = 3;
+ gc->of_xlate = s3c24xx_gpio_xlate;
+}
+#elif defined(CONFIG_PLAT_S3C24XX)
+static __init void s3c24xx_gpiolib_attach_ofnode(struct samsung_gpio_chip *chip,
+ u64 base, u64 offset)
+{
+ return;
+}
+#endif /* defined(CONFIG_PLAT_S3C24XX) && defined(CONFIG_OF) */
+
static void __init s3c24xx_gpiolib_add_chips(struct samsung_gpio_chip *chip,
int nr_chips, void __iomem *base)
{
@@ -962,6 +1023,8 @@ static void __init s3c24xx_gpiolib_add_chips(struct samsung_gpio_chip *chip,
gc->direction_output = samsung_gpiolib_2bit_output;
samsung_gpiolib_add(chip);
+
+ s3c24xx_gpiolib_attach_ofnode(chip, S3C24XX_PA_GPIO, i * 0x10);
}
}
--
1.7.2.3
--
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