Messages in this thread Patch in this message | | | Date | Sun, 29 Jun 2008 21:59:23 +0200 | From | Martin Michlmayr <> | Subject | Re: LEDs: how to handle gpios that control brightness for all LEDs |
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* Riku Voipio <riku.voipio@iki.fi> [2008-06-28 20:52]: > > I have a device that has various gpios that correspond to the colours > > (blue, red) of various LEDs. They only accept 0/1, not the actual > > brightness. However, there are two other gpios that can be used to > > control the brightness (of all LEDs): gpio V_LED 5V is bright, gpio > > V_LED 3.3V is dimmed and if neither of these two gpios are set, all > > LEDs stay off. > > > Can I simply export these brightness gpios to userland or would it be > > better to handle the brightness setting in the kernel so that setting > > e.g. 100 to a LED would automatically set the V_LED 3.3V gpio and 255 > > would set V_LED 5V. If so, how should this be done? > > There is a enum led_brightness, which defines LED_HALF and LED_FULL. You > would need a custom brightness function. Leds-gpio driver would need to > be extended for it. The main problem with this approach is the > unexpected effect for enduser, that adjusting brighntess of one led > affects all of them.
OK, this sounds to me like I should simply export the gpios that influence the brightness.
> default-on trigger is probably the easiest way.
This works for me, thanks.
New patch below. Any comments Richard?
diff --git a/arch/arm/mach-orion5x/mv2120-setup.c b/arch/arm/mach-orion5x/mv2120-setup.c index d838bdb..0ac5209 100644 --- a/arch/arm/mach-orion5x/mv2120-setup.c +++ b/arch/arm/mach-orion5x/mv2120-setup.c @@ -137,6 +137,50 @@ static struct i2c_board_info __initdata mv2120_i2c_rtc = { .irq = 0, }; +static struct gpio_led mv2120_led_pins[] = { + { + .name = "mv2120:blue:health", + .gpio = 0, + }, + { + .name = "mv2120:red:health", + .gpio = 1, + }, + { + .name = "mv2120:led:bright", + .gpio = 4, + .default_trigger = "default-on", + }, + { + .name = "mv2120:led:dimmed", + .gpio = 5, + }, + { + .name = "mv2120:red:sata0", + .gpio = 8, + .active_low = 1, + }, + { + .name = "mv2120:red:sata1", + .gpio = 9, + .active_low = 1, + }, + +}; + +static struct gpio_led_platform_data mv2120_led_data = { + .leds = mv2120_led_pins, + .num_leds = ARRAY_SIZE(mv2120_led_pins), +}; + +static struct platform_device mv2120_leds = { + .name = "leds-gpio", + .id = -1, + .dev = { + .platform_data = &mv2120_led_data, + } +}; + static void mv2120_power_off(void) { pr_info("%s: triggering power-off...\n", __func__); @@ -172,6 +216,7 @@ static void __init mv2120_init(void) gpio_free(MV2120_GPIO_RTC_IRQ); } i2c_register_board_info(0, &mv2120_i2c_rtc, 1); + platform_device_register(&mv2120_leds); /* register mv2120 specific power-off method */ if (gpio_request(MV2120_GPIO_POWER_OFF, "POWEROFF") != 0 || -- Martin Michlmayr http://www.cyrius.com/
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