[PATCH v2 1/3] power: Add simple poweroff-gpio driver
Andrew Lunn
andrew at lunn.ch
Wed Nov 14 02:44:43 EST 2012
From: Jamie Lentin <jm at lentin.co.uk>
Given appropriate devicetree bindings, this driver registers a
pm_power_off function to set a GPIO line high/low to power down
your board.
Signed-off-by: Jamie Lentin <jm at lentin.co.uk>
Signed-off-by: Andrew Lunn <andrew at lunn.ch>
---
.../devicetree/bindings/gpio/gpio-poweroff.txt | 22 ++++
drivers/power/Kconfig | 3 +
drivers/power/Makefile | 1 +
drivers/power/reset/Kconfig | 15 +++
drivers/power/reset/Makefile | 1 +
drivers/power/reset/gpio-poweroff.c | 129 ++++++++++++++++++++
6 files changed, 171 insertions(+)
create mode 100644 Documentation/devicetree/bindings/gpio/gpio-poweroff.txt
create mode 100644 drivers/power/reset/Kconfig
create mode 100644 drivers/power/reset/Makefile
create mode 100644 drivers/power/reset/gpio-poweroff.c
diff --git a/Documentation/devicetree/bindings/gpio/gpio-poweroff.txt b/Documentation/devicetree/bindings/gpio/gpio-poweroff.txt
new file mode 100644
index 0000000..558cdf3
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-poweroff.txt
@@ -0,0 +1,22 @@
+GPIO line that should be set high/low to power off a device
+
+Required properties:
+- compatible : should be "gpio-poweroff".
+- gpios : The GPIO to set high/low, see "gpios property" in
+ Documentation/devicetree/bindings/gpio/gpio.txt. If the pin should be
+ low to power down the board set it to "Active Low", otherwise set
+ gpio to "Active High".
+
+Optional properties:
+- input : Initially configure the GPIO line as an input. Only reconfigure
+ it to an output when the pm_power_off function is called. If this optional
+ 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 */
+};
diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 49a8939..b1d956d 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -335,6 +335,9 @@ config AB8500_BATTERY_THERM_ON_BATCTRL
help
Say Y to enable battery temperature measurements using
thermistor connected on BATCTRL ADC.
+
+source "drivers/power/reset/Kconfig"
+
endif # POWER_SUPPLY
source "drivers/power/avs/Kconfig"
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index b949cf8..f1d99f4 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -49,3 +49,4 @@ obj-$(CONFIG_CHARGER_MAX8997) += max8997_charger.o
obj-$(CONFIG_CHARGER_MAX8998) += max8998_charger.o
obj-$(CONFIG_POWER_AVS) += avs/
obj-$(CONFIG_CHARGER_SMB347) += smb347-charger.o
+obj-$(CONFIG_POWER_RESET) += reset/
diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
new file mode 100644
index 0000000..6461b48
--- /dev/null
+++ b/drivers/power/reset/Kconfig
@@ -0,0 +1,15 @@
+menuconfig POWER_RESET
+ bool "Board level reset or power off"
+ help
+ Provides a number of drivers which either reset a complete board
+ or shut it down, by manipulating the main power supply on the board.
+
+ Say Y here to enable board reset and power off
+
+config POWER_RESET_GPIO
+ bool "GPIO power-off driver"
+ depends on OF_GPIO && POWER_RESET
+ help
+ This driver supports turning off your board via a GPIO line.
+ If your board needs a GPIO high/low to power down, say Y and
+ create a binding in your devicetree.
diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
new file mode 100644
index 0000000..751488a
--- /dev/null
+++ b/drivers/power/reset/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o
diff --git a/drivers/power/reset/gpio-poweroff.c b/drivers/power/reset/gpio-poweroff.c
new file mode 100644
index 0000000..101ad57
--- /dev/null
+++ b/drivers/power/reset/gpio-poweroff.c
@@ -0,0 +1,129 @@
+/*
+ * Toggles a GPIO pin to power down a device
+ *
+ * Jamie Lentin <jm at lentin.co.uk>
+ * Andrew Lunn <andrew at lunn.ch>
+ *
+ * Copyright (C) 2012 Jamie Lentin
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/of_platform.h>
+#include <linux/of_gpio.h>
+#include <linux/module.h>
+
+/*
+ * Hold configuration here, cannot be more than one instance of the driver
+ * since pm_power_off itself is global.
+ */
+static int gpio_num = -1;
+static int gpio_active_low;
+
+static void gpio_poweroff_do_poweroff(void)
+{
+ BUG_ON(gpio_num == -1);
+
+ /* drive it active */
+ gpio_direction_output(gpio_num, !gpio_active_low);
+ mdelay(100);
+ /* rising edge or drive inactive */
+ gpio_set_value(gpio_num, gpio_active_low);
+ mdelay(100);
+ /* falling edge */
+ gpio_set_value(gpio_num, !gpio_active_low);
+
+ /* give it some time */
+ mdelay(100);
+
+ WARN_ON(1);
+}
+
+static int __devinit gpio_poweroff_probe(struct platform_device *pdev)
+{
+ enum of_gpio_flags flags;
+ bool input = false;
+ int ret;
+
+ /* If a pm_power_off function has already been added, leave it alone */
+ if (pm_power_off != NULL) {
+ pr_err("%s: pm_power_off function already registered",
+ __func__);
+ return -EBUSY;
+ }
+
+ 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;
+ }
+ gpio_active_low = flags & OF_GPIO_ACTIVE_LOW;
+
+ if (of_get_property(pdev->dev.of_node, "input", NULL))
+ input = true;
+
+ ret = gpio_request(gpio_num, "poweroff-gpio");
+ if (ret) {
+ pr_err("%s: Could not get GPIO %d", __func__, gpio_num);
+ return ret;
+ }
+ if (input) {
+ if (gpio_direction_input(gpio_num)) {
+ pr_err("Could not set direction of GPIO %d to input",
+ gpio_num);
+ goto err;
+ }
+ } else {
+ if (gpio_direction_output(gpio_num, gpio_active_low)) {
+ pr_err("Could not set direction of GPIO %d", gpio_num);
+ goto err;
+ }
+ }
+
+ pm_power_off = &gpio_poweroff_do_poweroff;
+ return 0;
+
+err:
+ gpio_free(gpio_num);
+ return -ENODEV;
+}
+
+static int __devexit gpio_poweroff_remove(struct platform_device *pdev)
+{
+ if (gpio_num != -1)
+ gpio_free(gpio_num);
+ if (pm_power_off == &gpio_poweroff_do_poweroff)
+ pm_power_off = NULL;
+
+ return 0;
+}
+
+static const struct of_device_id of_gpio_poweroff_match[] = {
+ { .compatible = "gpio-poweroff", },
+ {},
+};
+
+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,
+ },
+};
+
+module_platform_driver(gpio_poweroff_driver);
+
+MODULE_AUTHOR("Jamie Lentin <jm at lentin.co.uk>");
+MODULE_DESCRIPTION("GPIO poweroff driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:poweroff-gpio");
--
1.7.10.4
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