On 27 August 2012 13:31, Heiko Stübner <heiko@xxxxxxxxx> wrote: > Hi Thomas, > > thanks for your review: > > Am Montag, 27. August 2012, 06:20:49 schrieb Thomas Abraham: >> Hi Heiko, >> >> On 26 August 2012 03:23, Heiko Stübner <heiko@xxxxxxxxx> wrote: >> > 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> >> > --- >> > >> > .../devicetree/bindings/gpio/gpio-samsung.txt | 38 ++++++++++++ >> > drivers/gpio/gpio-samsung.c | 63 >> > ++++++++++++++++++++ 2 files changed, 101 insertions(+), 0 deletions(-) >> > >> > diff --git a/Documentation/devicetree/bindings/gpio/gpio-samsung.txt >> > b/Documentation/devicetree/bindings/gpio/gpio-samsung.txt index >> > 5375625..ce6a7d4 100644 >> > --- a/Documentation/devicetree/bindings/gpio/gpio-samsung.txt >> > +++ b/Documentation/devicetree/bindings/gpio/gpio-samsung.txt >> > >> > @@ -39,3 +39,41 @@ Example: >> > #gpio-cells = <4>; >> > gpio-controller; >> > >> > }; >> > >> > + >> > + >> > +Samsung S3C24XX GPIO Controller >> > + >> > +Required properties: >> > +- compatible: Compatible property value should be >> > "samsung,s3c24xx-gpio". >> >> This is debatable, but I would choose to be specific here and use >> "samsing,s3c2416-gpio". For instance, SoC's in s3c24xx family have >> differing value for pull none/down/up. > > Hmmm, but the logic to drive the gpio controller is the same for all arches. > The only difference is the number to use for the different pull up/down > settings. So I think the "samsung,s3c24xx-gpio" is ok but the documentation > should simply reflect the different pull settings. Ok. > > >> > + >> > +- 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. >> > + - Flags and Pull Up/Down: 0 - Pull Up/Down Disabled. >> > + 1 - Pull Down Enabled. >> > + 3 - Pull Up Enabled. >> >> As per s3c2416 user manual, 2 is used for Pull Up and 3 is listed as >> reserved value. Any particular reason to use 3 here for pull up and >> not 2 as per the user manual? > > Sorry, copy and paste error :-) Ok. > > >> > + Bit 16 (0x00010000) - Input is active low. >> > + >> > +- gpio-controller: Specifies that the node is a gpio controller. >> > +- #address-cells: should be 1. >> > +- #size-cells: should be 1. >> >> It would be informative to add information about the 'mux function' >> cell here as well. Specifically, on how to handle the banks that have >> an extended GPxSEL register that allow additional pin function >> selection. > > Will add a mux function description. > > Until now I've never realised the existence of the GPxSEL registers, so thanks > for the pointer :-). > > But is this used in the driver at all? All the setcfg/getcfg functions in > gpio-samsung.c only handle the GPxCON registers - I haven't found code to > handle the GPxSEL registers at all. So my guess is that this was never > implemented - or that I'm blind ;-) . You are right, there is no code that is handling the GPxCON registers. Thanks, Thomas. > > >> > + >> > +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 a150d2e..80a2817 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 >> >> Overall, this is patch looks fine. >> >> Reviewed-by: Thomas Abraham <thomas.abraham@xxxxxxxxxx> > > > Heiko -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html