El 14/01/2015 a las 6:32, Alexandre Courbot escribió: > On Wed, Dec 17, 2014 at 7:41 AM, Álvaro Fernández Rojas > <[email protected]> wrote: >> Add DT support while keeping legacy support. >> >> Signed-off-by: Álvaro Fernández Rojas <[email protected]> >> --- >> diff --git a/drivers/gpio/gpio-generic.c b/drivers/gpio/gpio-generic.c > > There is no documentation for these new bindings?
Actually, I was waiting for this patch (by [email protected]) to be accepted before: "[PATCH v1 5/5] gpio: document basic mmio gpio library". Anyway, I will add documentation on the next version of this patch. > >> index 16f6115..9792783 100644 >> --- a/drivers/gpio/gpio-generic.c >> +++ b/drivers/gpio/gpio-generic.c >> @@ -61,6 +61,9 @@ o ` ~~~~\___/~~~~ ` >> controller in FPGA is ,.` >> #include <linux/platform_device.h> >> #include <linux/mod_devicetable.h> >> #include <linux/basic_mmio_gpio.h> >> +#include <linux/of.h> >> +#include <linux/of_device.h> >> +#include <linux/of_gpio.h> >> >> static void bgpio_write8(void __iomem *reg, unsigned long data) >> { >> @@ -488,8 +491,58 @@ static void __iomem *bgpio_map(struct platform_device >> *pdev, >> return ret; >> } >> >> +#ifdef CONFIG_OF >> +static const struct of_device_id bgpio_dt_ids[] = { >> + { .compatible = "basic-mmio-gpio" }, >> +}; >> +MODULE_DEVICE_TABLE(of, bgpio_dt_ids); >> + >> +static int bgpio_probe_dt(struct platform_device *pdev) >> +{ >> + u32 tmp; >> + struct bgpio_pdata *pdata; >> + struct device_node *np; >> + >> + np = pdev->dev.of_node; >> + if (!np) >> + return 0; >> + >> + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); >> + if (!pdata) >> + return -ENOMEM; >> + >> + pdata->label = dev_name(&pdev->dev); >> + pdata->base = -1; >> + if (of_find_property(np, "byte-be", NULL)) { >> + pdata->flags |= BGPIOF_BIG_ENDIAN_BYTE_ORDER; >> + } >> + if (of_find_property(np, "bit-be", NULL)) { >> + pdata->flags |= BGPIOF_BIG_ENDIAN; >> + } >> + if (of_find_property(np, "regset-nr", NULL)) { >> + pdata->flags |= BGPIOF_UNREADABLE_REG_SET; >> + } >> + if (of_find_property(np, "regdir-nr", NULL)) { >> + pdata->flags |= BGPIOF_UNREADABLE_REG_DIR; >> + } >> + if (!of_property_read_u32(np, "num-gpios", &tmp)) { >> + pdata->ngpio = tmp; >> + } > > I don't think this is acceptable. gpio-generic is designed to be used > as a framework for other drivers to build upon. These drivers should > have their own compatible strings, which should be enough to infer all > the properties you defined here. > gpio-generic is not only designed as a framework for other drivers, it can also be used directly by registering the driver through platform device (basic-mmio-gpio/basic-mmio-gpio-be). My intention is to make it DT compatible as a generic driver, which can be used for different hardware, by selecting different DT properties as configuration. > Device Tree identifies hardware precisely (vendor and model), and this > new binding is just not that. You *could* however have a very simple > driver that associates compatible strings to static tables containing > the values of the properties you wanted to see passed through the DT, > and have one single driver that covers many mmio-based GPIO devices. > But I'm afraid "basic-mmio-gpio" is *way* to vague to describe > hardware. > I don't think making a new driver mapping different compatible strings to static tables containing the values of the properties passed through DT is a sane way of doing it, since it will require multiple combinations to cover all the possibilites. My plan is to be able to do something like this (btw, I actually tested this patch on BCM63xx and works perfectly): gpio-controller@10000084 { compatible = "basic-mmio-gpio", "brcm,brcm6368"; reg = <0x10000084 0x4>, <0x1000008c 0x4>; reg-names = "dirout", "dat"; num-gpios = <32>; byte-be; gpio-controller; #gpio-cells = <2>; }; And for other hardware you could do: gpio-controller@10000180 { compatible = "basic-mmio-gpio", "foo,bar"; reg = <0x10000180 0x4>, <0x10000184 0x4>, <0x10000188 0x4>; reg-names = "dirin", "dirout", "dat"; num-gpios = <20>; bit-be; byte-be; regdir-nr; gpio-controller; #gpio-cells = <2>; }; This way you wouldn't need to add a wrapper for each specific hardware using basic-mmio-gpio, and you would save time by using the generic driver. Regards, Álvaro. -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
