gpio: Add bitmask to block requests to unavailable stmpe GPIOs

GPIOs on these controller are multi-functional. If you decided to use
some of them e.g. as input channels for the ADC, you surely don't want
those pins to be reassigned as simple GPIOs (which may be triggered even
from userspace via 'export'). Same for the touchscreen controller pins.
Since knowledge about the hardware is needed to decide which GPIOs to
reserve, let this bitmask be inside platform_data and provide some
defines to assist potential users.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Rabin Vincent <rabin.vincent@stericsson.com>
Cc: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/gpio/stmpe-gpio.c b/drivers/gpio/stmpe-gpio.c
index 4e1f1b9d5e67..65b996083918 100644
--- a/drivers/gpio/stmpe-gpio.c
+++ b/drivers/gpio/stmpe-gpio.c
@@ -30,6 +30,7 @@ struct stmpe_gpio {
         struct mutex irq_lock;
 
         int irq_base;
+        unsigned norequest_mask;
 
         /* Caches of interrupt control registers for bus_lock */
         u8 regs[CACHE_NR_REGS][CACHE_NR_BANKS];
@@ -103,6 +104,9 @@ static int stmpe_gpio_request(struct gpio_chip *chip, unsigned offset)
         struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(chip);
         struct stmpe *stmpe = stmpe_gpio->stmpe;
 
+        if (stmpe_gpio->norequest_mask & (1 << offset))
+                return -EINVAL;
+
         return stmpe_set_altfunc(stmpe, 1 << offset, STMPE_BLOCK_GPIO);
 }
 
@@ -302,6 +306,7 @@ static int __devinit stmpe_gpio_probe(struct platform_device *pdev)
 
         stmpe_gpio->dev = &pdev->dev;
         stmpe_gpio->stmpe = stmpe;
+        stmpe_gpio->norequest_mask = pdata ? pdata->norequest_mask : 0;
 
         stmpe_gpio->chip = template_chip;
         stmpe_gpio->chip.ngpio = stmpe->num_gpios;