On Fri, Feb 5, 2010 at 1:32 PM, Anton Vorontsov
<avoront...@ru.mvista.com> wrote:
> This patch implements GPIOLIB notifier hooks, and thus makes device-enabled
> GPIO chips (i.e. the ones that have gpio_chip->dev specified) automatically
> attached to the OpenFirmware subsystem. Which means that now we can handle
> I2C and SPI GPIO chips almost* transparently.
>
> * "Almost" because some chips still require platform data, and for these
> chips OF-glue is still needed, though with this support the glue will
> be much smaller.
>
> Signed-off-by: Anton Vorontsov <avoront...@ru.mvista.com>
> ---
> drivers/of/gpio.c | 100
> +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 100 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/of/gpio.c b/drivers/of/gpio.c
> index 12c4af0..9d8df77 100644
> --- a/drivers/of/gpio.c
> +++ b/drivers/of/gpio.c
> @@ -13,6 +13,7 @@
>
> #include <linux/kernel.h>
> #include <linux/errno.h>
> +#include <linux/notifier.h>
> #include <linux/io.h>
> #include <linux/of.h>
> #include <linux/of_gpio.h>
> @@ -236,3 +237,102 @@ err0:
> return ret;
> }
> EXPORT_SYMBOL(of_mm_gpiochip_add);
> +
> +/**
> + * of_gpiochip_register_simple - Register a chip with the OF GPIO subsystem
> + * @chip pointer to a GPIO chip
> + * @np: device node to register the GPIO chip with
> + *
> + * This function registers a GPIO chip with the OF infrastructure. It is
> + * assumed that the chip was previsously allocated and added to a generic
> + * GPIOLIB framework (using gpiochip_add() function).
> + *
> + * The `simple' name means that the chip is using simple two-cells scheme for
> + * the gpio-specifier.
> + */
> +static int of_gpiochip_register_simple(struct gpio_chip *chip,
> + struct device_node *np)
> +{
> + struct of_gpio_chip *of_gc;
> +
> + if (np->data) {
> + WARN_ON(1);
> + return -EBUSY;
> + }
> +
> + of_gc = kzalloc(sizeof(*of_gc), GFP_KERNEL);
> + if (!of_gc)
> + return -ENOMEM;
> +
> + of_gc->gpio_cells = 2;
> + of_gc->xlate = of_gpio_simple_xlate;
> + of_gc->chip = chip;
One concern.
How does an OF-aware GPIO driver override these settings? What is to
be done when a GPIO chip requires a different xlate hook? Or a
different number of gpio_cells?
g.
--
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
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