gpio_led: add support for inverted polarity

Some GPIO connected LEDs have inverted polarity.
Introduce new config option: CONFIG_GPIO_LED_INVERTED_TABLE for the
specifying the inverted GPIO LEDs list and add support for this in the
gpio_led driver.

Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
Tested-by: Ilya Ledvich <ilya@compulab.co.il>

diff --git a/README b/README
index 7b393b79b34c8ffcaf272f23c7259f15a75585a9..5def773ff5aeb73c4e70f83cbbcd6897c4a07cea 100644 (file)
--- a/README
+++ b/README
@@ -1971,6 +1971,13 @@ CBFS (Coreboot Filesystem) support
                status LED backend implementation. Define CONFIG_GPIO_LED
                to include the gpio_led driver in the U-Boot binary.
 
+               CONFIG_GPIO_LED_INVERTED_TABLE
+               Some GPIO connected LEDs may have inverted polarity in which
+               case the GPIO high value corresponds to LED off state and
+               GPIO low value corresponds to LED on state.
+               In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined
+               with a list of GPIO LEDs that have inverted polarity.
+
 - CAN Support: CONFIG_CAN_DRIVER
 
                Defining CONFIG_CAN_DRIVER enables CAN driver support

diff --git a/drivers/misc/gpio_led.c b/drivers/misc/gpio_led.c
index de2041956b837b1e987156b7277f8840102e6f54..3e95727d798309bf9125f5d0f722334174062b3b 100644 (file)
--- a/drivers/misc/gpio_led.c
+++ b/drivers/misc/gpio_led.c
@@ -9,19 +9,42 @@
 #include <status_led.h>
 #include <asm/gpio.h>
 
+#ifndef CONFIG_GPIO_LED_INVERTED_TABLE
+#define CONFIG_GPIO_LED_INVERTED_TABLE {}
+#endif
+
+static led_id_t gpio_led_inv[] = CONFIG_GPIO_LED_INVERTED_TABLE;
+
+static int gpio_led_gpio_value(led_id_t mask, int state)
+{
+       int i, gpio_value = (state == STATUS_LED_ON);
+
+       for (i = 0; i < ARRAY_SIZE(gpio_led_inv); i++) {
+               if (gpio_led_inv[i] == mask)
+                       gpio_value = !gpio_value;
+       }
+
+       return gpio_value;
+}
+
 void __led_init(led_id_t mask, int state)
 {
+       int gpio_value;
+
        if (gpio_request(mask, "gpio_led") != 0) {
                printf("%s: failed requesting GPIO%lu!\n", __func__, mask);
                return;
        }
 
-       gpio_direction_output(mask, state == STATUS_LED_ON);
+       gpio_value = gpio_led_gpio_value(mask, state);
+       gpio_direction_output(mask, gpio_value);
 }
 
 void __led_set(led_id_t mask, int state)
 {
-       gpio_set_value(mask, state == STATUS_LED_ON);
+       int gpio_value = gpio_led_gpio_value(mask, state);
+
+       gpio_set_value(mask, gpio_value);
 }
 
 void __led_toggle(led_id_t mask)