[PATCH v4 4/4] Input: atmel_mxt_ts - add support for poweroff-sleep

[Stefan Eichenberger <eichest@gmail.com>]

From: Stefan Eichenberger <stefan.eichenberger@toradex.com>

Add support for poweroff-sleep to the Atmel maXTouch driver. This allows
us to power off the input device entirely and only power it on when it
is opened. This will also automatically power it off when we suspend the
system.

Signed-off-by: Stefan Eichenberger <stefan.eichenberger@toradex.com>
---
 drivers/input/touchscreen/atmel_mxt_ts.c | 71 +++++++++++++++++++-----
 1 file changed, 57 insertions(+), 14 deletions(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 7c807d1f1f9b..f92808be3f5b 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -317,6 +317,7 @@ struct mxt_data {
 	struct gpio_desc *reset_gpio;
 	struct gpio_desc *wake_gpio;
 	bool use_retrigen_workaround;
+	bool poweroff_sleep;
 
 	/* Cached parameters from object table */
 	u16 T5_address;
@@ -2277,6 +2278,19 @@ static void mxt_config_cb(const struct firmware *cfg, void *ctx)
 	release_firmware(cfg);
 }
 
+static int mxt_initialize_after_resume(struct mxt_data *data)
+{
+	const struct firmware *fw;
+
+	mxt_acquire_irq(data);
+
+	firmware_request_nowarn(&fw, MXT_CFG_NAME, &data->client->dev);
+
+	mxt_config_cb(fw, data);
+
+	return 0;
+}
+
 static void mxt_debug_init(struct mxt_data *data);
 
 static int mxt_device_register(struct mxt_data *data)
@@ -2341,17 +2355,23 @@ static int mxt_initialize(struct mxt_data *data)
 	if (error)
 		return error;
 
-	error = mxt_acquire_irq(data);
-	if (error)
-		return error;
+	if (data->poweroff_sleep) {
+		error = mxt_device_register(data);
+		if (error)
+			return error;
+	} else {
+		error = mxt_acquire_irq(data);
+		if (error)
+			return error;
 
-	error = request_firmware_nowait(THIS_MODULE, true, MXT_CFG_NAME,
-					&client->dev, GFP_KERNEL, data,
-					mxt_config_cb);
-	if (error) {
-		dev_err(&client->dev, "Failed to invoke firmware loader: %d\n",
-			error);
-		return error;
+		error = request_firmware_nowait(THIS_MODULE, true, MXT_CFG_NAME,
+						&client->dev, GFP_KERNEL, data,
+						mxt_config_cb);
+		if (error) {
+			dev_err(&client->dev, "Failed to invoke firmware loader: %d\n",
+				error);
+			return error;
+		}
 	}
 
 	return 0;
@@ -3089,6 +3109,9 @@ static ssize_t mxt_update_fw_store(struct device *dev,
 	struct mxt_data *data = dev_get_drvdata(dev);
 	int error;
 
+	if (data->poweroff_sleep && !data->in_bootloader)
+		mxt_power_on(data);
+
 	error = mxt_load_fw(dev, MXT_FW_NAME);
 	if (error) {
 		dev_err(dev, "The firmware update failed(%d)\n", error);
@@ -3101,6 +3124,9 @@ static ssize_t mxt_update_fw_store(struct device *dev,
 			return error;
 	}
 
+	if (data->poweroff_sleep && !data->in_bootloader)
+		mxt_power_off(data);
+
 	return count;
 }
 
@@ -3123,7 +3149,12 @@ static const struct attribute_group mxt_attr_group = {
 
 static void mxt_start(struct mxt_data *data)
 {
-	mxt_wakeup_toggle(data->client, true, false);
+	if (data->poweroff_sleep) {
+		mxt_power_on(data);
+		mxt_initialize_after_resume(data);
+	} else {
+		mxt_wakeup_toggle(data->client, true, false);
+	}
 
 	switch (data->suspend_mode) {
 	case MXT_SUSPEND_T9_CTRL:
@@ -3160,7 +3191,12 @@ static void mxt_stop(struct mxt_data *data)
 		break;
 	}
 
-	mxt_wakeup_toggle(data->client, false, false);
+	if (data->poweroff_sleep) {
+		disable_irq(data->irq);
+		mxt_power_off(data);
+	} else {
+		mxt_wakeup_toggle(data->client, false, false);
+	}
 }
 
 static int mxt_input_open(struct input_dev *dev)
@@ -3357,6 +3393,8 @@ static int mxt_probe(struct i2c_client *client)
 	if (error)
 		return error;
 
+	data->poweroff_sleep = device_property_read_bool(&client->dev,
+							 "atmel,poweroff-sleep");
 	/*
 	 * Controllers like mXT1386 have a dedicated WAKE line that could be
 	 * connected to a GPIO or to I2C SCL pin, or permanently asserted low.
@@ -3387,6 +3425,9 @@ static int mxt_probe(struct i2c_client *client)
 		goto err_free_object;
 	}
 
+	if (data->poweroff_sleep && !data->in_bootloader)
+		mxt_power_off(data);
+
 	return 0;
 
 err_free_object:
@@ -3406,7 +3447,8 @@ static void mxt_remove(struct i2c_client *client)
 	sysfs_remove_group(&client->dev.kobj, &mxt_attr_group);
 	mxt_free_input_device(data);
 	mxt_free_object_table(data);
-	mxt_power_off(data);
+	if (!data->poweroff_sleep)
+		mxt_power_off(data);
 }
 
 static int mxt_suspend(struct device *dev)
@@ -3439,7 +3481,8 @@ static int mxt_resume(struct device *dev)
 	if (!input_dev)
 		return 0;
 
-	enable_irq(data->irq);
+	if (!data->poweroff_sleep)
+		enable_irq(data->irq);
 
 	mutex_lock(&input_dev->mutex);
 
-- 
2.40.1