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authorMyungJoo Ham <myungjoo.ham@samsung.com>2012-04-20 14:16:23 +0900
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-04-20 09:22:02 -0700
commitbe48308a24c7651bf968b561dbd590edb8166d62 (patch)
tree7b7e7d49976f592171bdb75ea286d7b083946e64 /drivers/extcon
parentde55d8716ac50a356cea736c29bb7db5ac3d0190 (diff)
downloadlinux-be48308a24c7651bf968b561dbd590edb8166d62.tar.bz2
Extcon: support generic GPIO extcon driver
The generic GPIO extcon driver (an external connector device based on GPIO control) and imported from Android kernel. switch: switch class and GPIO drivers. (splitted) Author: Mike Lockwood <lockwood@android.com> switch: gpio: Don't call request_irq with interrupts disabled Author: Arve Hjønnevåg <arve@android.com> switch_gpio: Add missing #include <linux/interrupt.h> Author: Mike Lockwood <lockwood@android.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> -- Changed from v7: - Style updates mentioned by Stephen Boyd and Mark Brown Changed from v5: - Splitted at v5 from the main extcon patch. - Added debounce time for irq handlers. - Use request_any_context_irq instead of request_irq - User needs to specify irq flags for GPIO interrupts (was fixed to IRQF_TRIGGER_LOW before) - Use module_platform_driver(). Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/extcon')
-rw-r--r--drivers/extcon/Kconfig7
-rw-r--r--drivers/extcon/Makefile1
-rw-r--r--drivers/extcon/extcon_gpio.c169
3 files changed, 177 insertions, 0 deletions
diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
index 7932e1bd9b02..85cecff36db3 100644
--- a/drivers/extcon/Kconfig
+++ b/drivers/extcon/Kconfig
@@ -14,4 +14,11 @@ if EXTCON
comment "Extcon Device Drivers"
+config EXTCON_GPIO
+ tristate "GPIO extcon support"
+ depends on GENERIC_GPIO
+ help
+ Say Y here to enable GPIO based extcon support. Note that GPIO
+ extcon supports single state per extcon instance.
+
endif # MULTISTATE_SWITCH
diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile
index 6bc69214fcd7..2c46d4176d18 100644
--- a/drivers/extcon/Makefile
+++ b/drivers/extcon/Makefile
@@ -3,3 +3,4 @@
#
obj-$(CONFIG_EXTCON) += extcon_class.o
+obj-$(CONFIG_EXTCON_GPIO) += extcon_gpio.o
diff --git a/drivers/extcon/extcon_gpio.c b/drivers/extcon/extcon_gpio.c
new file mode 100644
index 000000000000..5c0f08506f93
--- /dev/null
+++ b/drivers/extcon/extcon_gpio.c
@@ -0,0 +1,169 @@
+/*
+ * drivers/extcon/extcon_gpio.c
+ *
+ * Single-state GPIO extcon driver based on extcon class
+ *
+ * Copyright (C) 2008 Google, Inc.
+ * Author: Mike Lockwood <lockwood@android.com>
+ *
+ * Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon
+ * (originally switch class is supported)
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+*/
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/extcon.h>
+#include <linux/workqueue.h>
+#include <linux/gpio.h>
+#include <linux/extcon.h>
+#include <linux/extcon/extcon_gpio.h>
+
+struct gpio_extcon_data {
+ struct extcon_dev edev;
+ unsigned gpio;
+ const char *state_on;
+ const char *state_off;
+ int irq;
+ struct delayed_work work;
+ unsigned long debounce_jiffies;
+};
+
+static void gpio_extcon_work(struct work_struct *work)
+{
+ int state;
+ struct gpio_extcon_data *data =
+ container_of(to_delayed_work(work), struct gpio_extcon_data,
+ work);
+
+ state = gpio_get_value(data->gpio);
+ extcon_set_state(&data->edev, state);
+}
+
+static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
+{
+ struct gpio_extcon_data *extcon_data = dev_id;
+
+ schedule_delayed_work(&extcon_data->work,
+ extcon_data->debounce_jiffies);
+ return IRQ_HANDLED;
+}
+
+static ssize_t extcon_gpio_print_state(struct extcon_dev *edev, char *buf)
+{
+ struct gpio_extcon_data *extcon_data =
+ container_of(edev, struct gpio_extcon_data, edev);
+ const char *state;
+ if (extcon_get_state(edev))
+ state = extcon_data->state_on;
+ else
+ state = extcon_data->state_off;
+
+ if (state)
+ return sprintf(buf, "%s\n", state);
+ return -EINVAL;
+}
+
+static int __devinit gpio_extcon_probe(struct platform_device *pdev)
+{
+ struct gpio_extcon_platform_data *pdata = pdev->dev.platform_data;
+ struct gpio_extcon_data *extcon_data;
+ int ret = 0;
+
+ if (!pdata)
+ return -EBUSY;
+ if (!pdata->irq_flags) {
+ dev_err(&pdev->dev, "IRQ flag is not specified.\n");
+ return -EINVAL;
+ }
+
+ extcon_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_extcon_data),
+ GFP_KERNEL);
+ if (!extcon_data)
+ return -ENOMEM;
+
+ extcon_data->edev.name = pdata->name;
+ extcon_data->gpio = pdata->gpio;
+ extcon_data->state_on = pdata->state_on;
+ extcon_data->state_off = pdata->state_off;
+ if (pdata->state_on && pdata->state_off)
+ extcon_data->edev.print_state = extcon_gpio_print_state;
+ extcon_data->debounce_jiffies = msecs_to_jiffies(pdata->debounce);
+
+ ret = extcon_dev_register(&extcon_data->edev, &pdev->dev);
+ if (ret < 0)
+ goto err_extcon_dev_register;
+
+ ret = gpio_request_one(extcon_data->gpio, GPIOF_DIR_IN, pdev->name);
+ if (ret < 0)
+ goto err_request_gpio;
+
+ INIT_DELAYED_WORK(&extcon_data->work, gpio_extcon_work);
+
+ extcon_data->irq = gpio_to_irq(extcon_data->gpio);
+ if (extcon_data->irq < 0) {
+ ret = extcon_data->irq;
+ goto err_detect_irq_num_failed;
+ }
+
+ ret = request_any_context_irq(extcon_data->irq, gpio_irq_handler,
+ pdata->irq_flags, pdev->name,
+ extcon_data);
+ if (ret < 0)
+ goto err_request_irq;
+
+ /* Perform initial detection */
+ gpio_extcon_work(&extcon_data->work.work);
+
+ return 0;
+
+err_request_irq:
+err_detect_irq_num_failed:
+ gpio_free(extcon_data->gpio);
+err_request_gpio:
+ extcon_dev_unregister(&extcon_data->edev);
+err_extcon_dev_register:
+ devm_kfree(&pdev->dev, extcon_data);
+
+ return ret;
+}
+
+static int __devexit gpio_extcon_remove(struct platform_device *pdev)
+{
+ struct gpio_extcon_data *extcon_data = platform_get_drvdata(pdev);
+
+ cancel_delayed_work_sync(&extcon_data->work);
+ gpio_free(extcon_data->gpio);
+ extcon_dev_unregister(&extcon_data->edev);
+ devm_kfree(&pdev->dev, extcon_data);
+
+ return 0;
+}
+
+static struct platform_driver gpio_extcon = {
+ .probe = gpio_extcon_probe,
+ .remove = __devexit_p(gpio_extcon_remove),
+ .driver = {
+ .name = "extcon-gpio",
+ .owner = THIS_MODULE,
+ },
+};
+
+module_platform_driver(gpio_extcon);
+
+MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
+MODULE_DESCRIPTION("GPIO extcon driver");
+MODULE_LICENSE("GPL");