Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758195AbYJXXLB (ORCPT ); Fri, 24 Oct 2008 19:11:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752839AbYJXXKB (ORCPT ); Fri, 24 Oct 2008 19:10:01 -0400 Received: from az33egw02.freescale.net ([192.88.158.103]:43927 "EHLO az33egw02.freescale.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752889AbYJXXJ6 (ORCPT ); Fri, 24 Oct 2008 19:09:58 -0400 From: Trent Piepho To: linux-kernel@vger.kernel.org Cc: Trent Piepho , linuxppc-dev@ozlabs.org, Anton Vorontsov , Richard Purdie , Sean MacLennan , Wolfram Sang , Grant Likely Subject: [PATCH 4/4] leds: Let GPIO LEDs keep their current state Date: Fri, 24 Oct 2008 16:09:01 -0700 Message-Id: <1224889741-4167-4-git-send-email-tpiepho@freescale.com> X-Mailer: git-send-email 1.5.4.1 In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4549 Lines: 115 Let GPIO LEDs get their initial value from whatever the current state of the GPIO line is. On some systems the LEDs are put into some state by the firmware or hardware before Linux boots, and it is desired to have them keep this state which is otherwise unknown to Linux. This requires that the underlying GPIO driver support reading the value of output GPIOs. Some drivers support this and some do not. The platform data for the platform device binding gets a new field 'keep_state' which turns this on. keep_state overrides default_state. For the OpenFirmware bindings, the "default-state" property gains a new allowable setting "keep". Signed-off-by: Trent Piepho --- Documentation/powerpc/dts-bindings/gpio/led.txt | 16 ++++++++++++---- drivers/leds/leds-gpio.c | 12 ++++++++---- include/linux/leds.h | 3 ++- 3 files changed, 22 insertions(+), 9 deletions(-) diff --git a/Documentation/powerpc/dts-bindings/gpio/led.txt b/Documentation/powerpc/dts-bindings/gpio/led.txt index 544ded7..918bf9f 100644 --- a/Documentation/powerpc/dts-bindings/gpio/led.txt +++ b/Documentation/powerpc/dts-bindings/gpio/led.txt @@ -21,10 +21,12 @@ LED sub-node properties: "ide-disk" - LED indicates disk activity "timer" - LED flashes at a fixed, configurable rate - default-state: (optional) The initial state of the LED. Valid - values are "on" and "off". If the LED is already on or off and the - default-state property is set the to same value, then no glitch - should be produced where the LED momentarily turns off (or on). - The default is off if this property is not present. + values are "on", "off", and "keep". If the LED is already on or off + and the default-state property is set the to same value, then no + glitch should be produced where the LED momentarily turns off (or + on). The "keep" setting will keep the LED at whatever its current + state is, without producing a glitch. The default is off if this + property is not present. Examples: @@ -35,6 +37,12 @@ leds { gpios = <&mcu_pio 0 1>; /* Active low */ linux,default-trigger = "ide-disk"; }; + + fault { + gpios = <&mcu_pio 1 0>; + /* Keep LED on if BIOS detected hardware fault */ + default-state = "keep"; + }; }; run-control { diff --git a/drivers/leds/leds-gpio.c b/drivers/leds/leds-gpio.c index 0dbad87..bb2a234 100644 --- a/drivers/leds/leds-gpio.c +++ b/drivers/leds/leds-gpio.c @@ -76,7 +76,7 @@ static int __devinit create_gpio_led(const struct gpio_led *template, struct gpio_led_data *led_dat, struct device *parent, int (*blink_set)(unsigned, unsigned long *, unsigned long *)) { - int ret; + int ret, state; ret = gpio_request(template->gpio, template->name); if (ret < 0) @@ -92,10 +92,13 @@ static int __devinit create_gpio_led(const struct gpio_led *template, led_dat->cdev.blink_set = gpio_blink_set; } led_dat->cdev.brightness_set = gpio_led_set; - led_dat->cdev.brightness = template->default_state ? LED_FULL : LED_OFF; + if (template->keep_state) + state = !!gpio_get_value(led_dat->gpio) ^ led_dat->active_low; + else + state = template->default_state; + led_dat->cdev.brightness = state ? LED_FULL : LED_OFF; - gpio_direction_output(led_dat->gpio, - led_dat->active_low ^ template->default_state); + gpio_direction_output(led_dat->gpio, led_dat->active_low ^ state); INIT_WORK(&led_dat->work, gpio_led_work); @@ -266,6 +269,7 @@ static int __devinit of_gpio_leds_probe(struct of_device *ofdev, of_get_property(child, "linux,default-trigger", NULL); state = of_get_property(child, "default-state", NULL); led.default_state = state && !strcmp(state, "on"); + led.keep_state = state && !strcmp(state, "keep"); ret = create_gpio_led(&led, &pdata->led_data[pdata->num_leds++], &ofdev->dev, NULL); diff --git a/include/linux/leds.h b/include/linux/leds.h index caa3987..c51b625 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -138,7 +138,8 @@ struct gpio_led { const char *default_trigger; unsigned gpio; u8 active_low; - u8 default_state; + u8 default_state; /* 0 = off, 1 = on */ + u8 keep_state; /* overrides default_state */ }; struct gpio_led_platform_data { -- 1.5.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/