diff options
| -rw-r--r-- | Documentation/devicetree/bindings/gpio/gpio-poweroff.txt | 20 | ||||
| -rw-r--r-- | drivers/power/reset/gpio-poweroff.c | 33 |
2 files changed, 32 insertions, 21 deletions
diff --git a/Documentation/devicetree/bindings/gpio/gpio-poweroff.txt b/Documentation/devicetree/bindings/gpio/gpio-poweroff.txt index 558cdf3c9abc..d4eab9227ea4 100644 --- a/Documentation/devicetree/bindings/gpio/gpio-poweroff.txt +++ b/Documentation/devicetree/bindings/gpio/gpio-poweroff.txt @@ -1,4 +1,19 @@ -GPIO line that should be set high/low to power off a device +Driver a GPIO line that can be used to turn the power off. + +The driver supports both level triggered and edge triggered power off. +At driver load time, the driver will request the given gpio line and +install a pm_power_off handler. If the optional properties 'input' is +not found, the GPIO line will be driven in the inactive +state. Otherwise its configured as an input. + +When the pm_power_off is called, the gpio is configured as an output, +and drive active, so triggering a level triggered power off +condition. This will also cause an inactive->active edge condition, so +triggering positive edge triggered power off. After a delay of 100ms, +the GPIO is set to inactive, thus causing an active->inactive edge, +triggering negative edge triggered power off. After another 100ms +delay the GPIO is driver active again. If the power is still on and +the CPU still running after a 3000ms delay, a WARN_ON(1) is emitted. Required properties: - compatible : should be "gpio-poweroff". @@ -13,10 +28,9 @@ Optional properties: property is not specified, the GPIO is initialized as an output in its inactive state. - Examples: gpio-poweroff { compatible = "gpio-poweroff"; - gpios = <&gpio 4 0>; /* GPIO 4 Active Low */ + gpios = <&gpio 4 0>; }; diff --git a/drivers/power/reset/gpio-poweroff.c b/drivers/power/reset/gpio-poweroff.c index 0491e5335d02..adc943b3fc3f 100644 --- a/drivers/power/reset/gpio-poweroff.c +++ b/drivers/power/reset/gpio-poweroff.c @@ -29,15 +29,16 @@ static int gpio_active_low; static void gpio_poweroff_do_poweroff(void) { - BUG_ON(gpio_num == -1); + BUG_ON(!gpio_is_valid(gpio_num)); - /* drive it active */ + /* drive it active, also inactive->active edge */ gpio_direction_output(gpio_num, !gpio_active_low); mdelay(100); - /* rising edge or drive inactive */ + /* drive inactive, also active->inactive edge */ gpio_set_value(gpio_num, gpio_active_low); mdelay(100); - /* falling edge */ + + /* drive it active, also inactive->active edge */ gpio_set_value(gpio_num, !gpio_active_low); /* give it some time */ @@ -60,15 +61,12 @@ static int __devinit gpio_poweroff_probe(struct platform_device *pdev) } gpio_num = of_get_gpio_flags(pdev->dev.of_node, 0, &flags); - if (gpio_num < 0) { - pr_err("%s: Could not get GPIO configuration: %d", - __func__, gpio_num); - return -ENODEV; - } + if (!gpio_is_valid(gpio_num)) + return gpio_num; + gpio_active_low = flags & OF_GPIO_ACTIVE_LOW; - if (of_get_property(pdev->dev.of_node, "input", NULL)) - input = true; + input = of_property_read_bool(pdev->dev.of_node, "input"); ret = gpio_request(gpio_num, "poweroff-gpio"); if (ret) { @@ -98,8 +96,7 @@ err: static int __devexit gpio_poweroff_remove(struct platform_device *pdev) { - if (gpio_num != -1) - gpio_free(gpio_num); + gpio_free(gpio_num); if (pm_power_off == &gpio_poweroff_do_poweroff) pm_power_off = NULL; @@ -115,15 +112,15 @@ static struct platform_driver gpio_poweroff_driver = { .probe = gpio_poweroff_probe, .remove = __devexit_p(gpio_poweroff_remove), .driver = { - .name = "poweroff-gpio", - .owner = THIS_MODULE, - .of_match_table = of_gpio_poweroff_match, - }, + .name = "poweroff-gpio", + .owner = THIS_MODULE, + .of_match_table = of_gpio_poweroff_match, + }, }; module_platform_driver(gpio_poweroff_driver); MODULE_AUTHOR("Jamie Lentin <jm@lentin.co.uk>"); MODULE_DESCRIPTION("GPIO poweroff driver"); -MODULE_LICENSE("GPL"); +MODULE_LICENSE("GPL v2"); MODULE_ALIAS("platform:poweroff-gpio"); |