MIPS: BCM47XX: Get GPIO pin from nvram configuration

The nvram contains some gpio configuration for boards. It is stored in
a gpio<number>=name format e.g.
gpio8=wps_button
gpio4=robo_reset

This patches adds a function to parse these entries, so other driver
can use it.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5841/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/bcm47xx/nvram.c

@@ -190,3 +190,23 @@ int bcm47xx_nvram_getenv(char *name, char *val, size_t val_len)
 	return -ENOENT;
 }
 EXPORT_SYMBOL(bcm47xx_nvram_getenv);
+
+int bcm47xx_nvram_gpio_pin(const char *name)
+{
+	int i, err;
+	char nvram_var[10];
+	char buf[30];
+
+	for (i = 0; i < 16; i++) {
+		err = snprintf(nvram_var, sizeof(nvram_var), "gpio%i", i);
+		if (err <= 0)
+			continue;
+		err = bcm47xx_nvram_getenv(nvram_var, buf, sizeof(buf));
+		if (err <= 0)
+			continue;
+		if (!strcmp(name, buf))
+			return i;
+	}
+	return -ENOENT;
+}
+EXPORT_SYMBOL(bcm47xx_nvram_gpio_pin);

arch/mips/include/asm/mach-bcm47xx/bcm47xx_nvram.h

@@ -48,4 +48,6 @@ static inline void bcm47xx_nvram_parse_macaddr(char *buf, u8 macaddr[6])
 		printk(KERN_WARNING "Can not parse mac address: %s\n", buf);
 }
 
+int bcm47xx_nvram_gpio_pin(const char *name);
+
 #endif /* __BCM47XX_NVRAM_H */