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dm: gpio: Add better functions to request GPIOs

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At present U-Boot sort-of supports the standard way of reading GPIOs from
device tree nodes, but the support is incomplete, a bit clunky and only
works for GPIO bindings where #gpio-cells is 2.

Add new functions to request GPIOs, taking full account of the device
tree binding. These permit requesting a GPIO with a simple call like:

   gpio_request_by_name(dev, "cd-gpios", 0, &desc, GPIOD_IS_IN);

This will request the GPIO, looking at the device's node which might be
this, for example:

   cd-gpios = <&gpio TEGRA_GPIO(B, 3) GPIO_ACTIVE_LOW>;

The GPIO will be set to input mode in this case and polarity will be
honoured by the GPIO calls.

It is also possible to request and free a list of GPIOs.

Signed-off-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Simon Glass 2015-01-05 20:05:29 -07:00
parent 0dac4d51f5
commit 3669e0e759
5 changed files with 461 additions and 4 deletions
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20
drivers/gpio/sandbox.c
View file

@ -8,6 +8,7 @@
#include <fdtdec.h>
#include <malloc.h>
#include <asm/gpio.h>
#include <dt-bindings/gpio/gpio.h>
DECLARE_GLOBAL_DATA_PTR;
@ -130,12 +131,31 @@ static int sb_gpio_get_function(struct udevice *dev, unsigned offset)
return GPIOF_INPUT;
}
static int sb_gpio_xlate(struct udevice *dev, struct gpio_desc *desc,
struct fdtdec_phandle_args *args)
{
desc->offset = args->args[0];
if (args->args_count < 2)
return 0;
if (args->args[1] & GPIO_ACTIVE_LOW)
desc->flags |= GPIOD_ACTIVE_LOW;
if (args->args[1] & 2)
desc->flags |= GPIOD_IS_IN;
if (args->args[1] & 4)
desc->flags |= GPIOD_IS_OUT;
if (args->args[1] & 8)
desc->flags |= GPIOD_IS_OUT_ACTIVE;
return 0;
}
static const struct dm_gpio_ops gpio_sandbox_ops = {
.direction_input = sb_gpio_direction_input,
.direction_output = sb_gpio_direction_output,
.get_value = sb_gpio_get_value,
.set_value = sb_gpio_set_value,
.get_function = sb_gpio_get_function,
.xlate = sb_gpio_xlate,
};
static int sandbox_gpio_ofdata_to_platdata(struct udevice *dev)