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Subject[PATCH v2 2/3] gpiolib-of: Support 'reserved-gpio-ranges' property
Date
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.

For now, we plumb this into the gpiochip irq APIs so that
GPIO/pinctrl drivers can use the gpiochip_irqchip_irq_valid() to
test validity of GPIOs.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---

Or this can move into a dedicated API and not be tied to the irq code.
Something like of_gpiochip_init_valid_mask?

drivers/gpio/gpiolib-of.c | 28 ++++++++++++++++++++++++++++
drivers/gpio/gpiolib.c | 9 +++++++++
2 files changed, 37 insertions(+)

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index 564bb7a31da4..194b3306ef74 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -498,6 +498,32 @@ void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
}
EXPORT_SYMBOL(of_mm_gpiochip_remove);

+#ifdef CONFIG_GPIOLIB_IRQCHIP
+static void of_gpiochip_init_irq_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, "reserved-gpio-ranges");
+ if (len < 0 || len % 2 != 0)
+ return;
+
+ for (i = 0; i < len; i += 2) {
+ of_property_read_u32_index(np, "reserved-gpio-ranges",
+ i, &start);
+ of_property_read_u32_index(np, "reserved-gpio-ranges",
+ i + 1, &count);
+ if (start >= chip->ngpio || start + count >= chip->ngpio)
+ continue;
+
+ bitmap_clear(chip->irq.valid_mask, start, count);
+ }
+};
+#else
+static void of_gpiochip_init_irq_valid_mask(struct gpio_chip *chip) { }
+#endif
+
#ifdef CONFIG_PINCTRL
static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
{
@@ -602,6 +628,8 @@ int of_gpiochip_add(struct gpio_chip *chip)
if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS)
return -EINVAL;

+ of_gpiochip_init_irq_valid_mask(chip);
+
status = of_gpiochip_add_pin_range(chip);
if (status)
return status;
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 930676ec9847..8483850463e6 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1483,6 +1483,15 @@ static struct gpio_chip *find_chip_by_name(const char *name)

static int gpiochip_irqchip_init_valid_mask(struct gpio_chip *gpiochip)
{
+#ifdef CONFIG_OF_GPIO
+ int size;
+ struct device_node *np = gpiochip->of_node;
+
+ size = of_property_count_u32_elems(np, "reserved-gpio-ranges");
+ if (size > 0 && size % 2 == 0)
+ gpiochip->irq.need_valid_mask = true;
+#endif
+
if (!gpiochip->irq.need_valid_mask)
return 0;

--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
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