pinctrl: add a pin_base for sparse gpio-ranges

This patch enables mapping a base offset of gpio ranges with
a pin offset even if does'nt matched. A base of pinctrl_gpio_range
means a base offset of gpio. However, we cannot convert gpio to pin
number for sparse gpio ranges just only using a gpio base offset.
We can convert a gpio to real pin number(even if not matched) using
a new pin_base which means a base pin offset of requested gpio range.
Now, the pin control subsystem passes the pin base offset to the
pinmux driver.

For example, let's assume below two gpio ranges in the system.

static struct pinctrl_gpio_range gpio_range_a = {
    .name = "chip a",
    .id = 0,
    .base = 32,
    .pin_base = 32,
    .npins = 16,
    .gc = &chip_a;
};

static struct pinctrl_gpio_range gpio_range_b = {
    .name = "chip b",
    .id = 0,
    .base = 48,
    .pin_base = 64,
    .npins = 8,
    .gc = &chip_b;
};

We can calucalate a exact pin ranges even if doesn't matched with gpio ranges.

chip a:
    gpio-range : [32 .. 47]
    pin-range  : [32 .. 47]
chip b:
    gpio-range : [48 .. 55]
    pin-range  : [64 .. 71]

Signed-off-by: Chanho Park <chanho61.park@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c
index ee3aba78c3dd..92aa13ee2208 100644
--- a/drivers/pinctrl/pinmux.c
+++ b/drivers/pinctrl/pinmux.c
@@ -229,7 +229,7 @@ int pinmux_request_gpio(unsigned gpio)
                 return -EINVAL;
 
         /* Convert to the pin controllers number space */
-        pin = gpio - range->base;
+        pin = gpio - range->base + range->pin_base;
 
         /* Conjure some name stating what chip and pin this is taken by */
         snprintf(gpiostr, 15, "%s:%d", range->name, gpio);
@@ -263,7 +263,7 @@ void pinmux_free_gpio(unsigned gpio)
                 return;
 
         /* Convert to the pin controllers number space */
-        pin = gpio - range->base;
+        pin = gpio - range->base + range->pin_base;
 
         func = pin_free(pctldev, pin, range);
         kfree(func);