gpiolib: Support 'gpio-reserved-ranges' property
Some qcom platforms make some GPIOs or pins unavailable for use by
non-secure operating systems, and thus reading or writing the registers
for those pins will cause access control issues. Add support for a DT
property to describe the set of GPIOs that are available for use so that
higher level OSes are able to know what pins to avoid reading/writing.
Non-DT platforms can add support by directly updating the
chip->valid_mask.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Tested-by: Timur Tabi <timur@codeaurora.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index 84e5a9d..ed81d9a 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -511,6 +511,28 @@ void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
}
EXPORT_SYMBOL(of_mm_gpiochip_remove);
+static void of_gpiochip_init_valid_mask(struct gpio_chip *chip)
+{
+ int len, i;
+ u32 start, count;
+ struct device_node *np = chip->of_node;
+
+ len = of_property_count_u32_elems(np, "gpio-reserved-ranges");
+ if (len < 0 || len % 2 != 0)
+ return;
+
+ for (i = 0; i < len; i += 2) {
+ of_property_read_u32_index(np, "gpio-reserved-ranges",
+ i, &start);
+ of_property_read_u32_index(np, "gpio-reserved-ranges",
+ i + 1, &count);
+ if (start >= chip->ngpio || start + count >= chip->ngpio)
+ continue;
+
+ bitmap_clear(chip->valid_mask, start, count);
+ }
+};
+
#ifdef CONFIG_PINCTRL
static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
{
@@ -615,6 +637,8 @@ int of_gpiochip_add(struct gpio_chip *chip)
if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS)
return -EINVAL;
+ of_gpiochip_init_valid_mask(chip);
+
status = of_gpiochip_add_pin_range(chip);
if (status)
return status;