ARM: at91: gpio: implement request

Configure the pin as pio when requested.

It is needed to configure the pin as PIO at "request time" when we are
using DT. Indeed, the muxing via old AT91 API is not allowed anymore if
we are using the plain gpiolib.
Acked-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NJean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

arch/arm/mach-at91/gpio.c

@@ -46,6 +46,7 @@ struct at91_gpio_chip {
 
 #define to_at91_gpio_chip(c) container_of(c, struct at91_gpio_chip, chip)
 
+static int at91_gpiolib_request(struct gpio_chip *chip, unsigned offset);
 static void at91_gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip);
 static void at91_gpiolib_set(struct gpio_chip *chip, unsigned offset, int val);
 static int at91_gpiolib_get(struct gpio_chip *chip, unsigned offset);
@@ -59,6 +60,7 @@ static int at91_gpiolib_to_irq(struct gpio_chip *chip, unsigned offset);
 	{								\
 		.chip = {						\
 			.label		  = name,			\
+			.request	  = at91_gpiolib_request,	\
 			.direction_input  = at91_gpiolib_direction_input, \
 			.direction_output = at91_gpiolib_direction_output, \
 			.get		  = at91_gpiolib_get,		\
@@ -862,6 +864,16 @@ void __init at91_gpio_irq_setup(void)
 }
 
 /* gpiolib support */
+static int at91_gpiolib_request(struct gpio_chip *chip, unsigned offset)
+{
+	struct at91_gpio_chip *at91_gpio = to_at91_gpio_chip(chip);
+	void __iomem *pio = at91_gpio->regbase;
+	unsigned mask = 1 << offset;
+
+	__raw_writel(mask, pio + PIO_PER);
+	return 0;
+}
+
 static int at91_gpiolib_direction_input(struct gpio_chip *chip,
 					unsigned offset)
 {