Input: atmel_mxt_ts - add regulator control support

Allow the driver to optionally manage enabling/disable power to the touch
controller itself. If the regulators are not present then use the deep
sleep power mode instead.

For a correct power on sequence, it is required that we have control over
the RESET line.

Signed-off-by: Nick Dyer <[email protected]>
Acked-by: Benson Leung <[email protected]>
Acked-by: Yufeng Shen <[email protected]>

Documentation/devicetree/bindings/input/atmel,maxtouch.txt

@@ -22,6 +22,14 @@ Optional properties for main touchpad device:
     experiment to determine which bit corresponds to which input. Use
     KEY_RESERVED for unused padding values.
 
+- atmel,suspend-mode: Select method used to suspend:
+    MXT_SUSPEND_DEEP_SLEEP - use T7 to suspend the device into deep sleep
+    MXT_SUSPEND_T9_CTRL - use T9.CTRL to turn off touch processing
+    MXT_SUSPEND_REGULATOR - use regulators to power down device during suspend
+    Definitions are in <dt-bindings/input/atmel_mxt_ts.h>.
+
+- atmel,reset-gpio: Configure RESET GPIO. Required for regulator support.
+
 Example:
 
 	touch@4b {

MAINTAINERS

@@ -2055,6 +2055,7 @@ S:	Supported
 F:	Documentation/devicetree/bindings/input/atmel,maxtouch.txt
 F:	drivers/input/touchscreen/atmel_mxt_ts.c
 F:	include/linux/platform_data/atmel_mxt_ts.h
+F:	include/dt-bindings/input/atmel_mxt_ts.h
 
 ATTO EXPRESSSAS SAS/SATA RAID SCSI DRIVER
 M:	Bradley Grove <[email protected]>

drivers/input/touchscreen/atmel_mxt_ts.c

@@ -27,8 +27,11 @@
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/of.h>
+#include <linux/of_gpio.h>
 #include <linux/slab.h>
 #include <asm/unaligned.h>
+#include <linux/regulator/consumer.h>
+#include <linux/gpio.h>
 
 /* Firmware files */
 #define MXT_FW_NAME		"maxtouch.fw"
@@ -186,6 +189,9 @@ enum t100_type {
 #define MXT_CRC_TIMEOUT		1000	/* msec */
 #define MXT_FW_RESET_TIME	3000	/* msec */
 #define MXT_FW_CHG_TIMEOUT	300	/* msec */
+#define MXT_REGULATOR_DELAY	150	/* msec */
+#define MXT_CHG_DELAY	        100	/* msec */
+#define MXT_POWERON_DELAY	150	/* msec */
 
 /* Command to unlock bootloader */
 #define MXT_UNLOCK_CMD_MSB	0xaa
@@ -271,6 +277,8 @@ struct mxt_data {
 	u8 stylus_aux_pressure;
 	u8 stylus_aux_peak;
 	bool use_retrigen_workaround;
+	struct regulator *reg_vdd;
+	struct regulator *reg_avdd;
 
 	/* Cached parameters from object table */
 	u16 T5_address;
@@ -1997,6 +2005,90 @@ static int mxt_read_info_block(struct mxt_data *data)
 	return error;
 }
 
+static void mxt_regulator_enable(struct mxt_data *data)
+{
+	int error;
+
+	if (!data->reg_vdd || !data->reg_avdd)
+		return;
+
+	gpio_set_value(data->pdata->gpio_reset, 0);
+
+	error = regulator_enable(data->reg_vdd);
+	if (error)
+		return;
+
+	error = regulator_enable(data->reg_avdd);
+	if (error)
+		return;
+
+	/*
+	 * According to maXTouch power sequencing specification, RESET line
+	 * must be kept low until some time after regulators come up to
+	 * voltage
+	 */
+	msleep(MXT_REGULATOR_DELAY);
+	gpio_set_value(data->pdata->gpio_reset, 1);
+	msleep(MXT_CHG_DELAY);
+
+retry_wait:
+	reinit_completion(&data->bl_completion);
+	data->in_bootloader = true;
+	error = mxt_wait_for_completion(data, &data->bl_completion,
+					MXT_POWERON_DELAY);
+	if (error == -EINTR)
+		goto retry_wait;
+
+	data->in_bootloader = false;
+}
+
+static void mxt_regulator_disable(struct mxt_data *data)
+{
+	if (!data->reg_vdd || !data->reg_avdd)
+		return;
+
+	regulator_disable(data->reg_vdd);
+	regulator_disable(data->reg_avdd);
+}
+
+static int mxt_probe_regulators(struct mxt_data *data)
+{
+	struct device *dev = &data->client->dev;
+	int error;
+
+	/* Must have reset GPIO to use regulator support */
+	if (!gpio_is_valid(data->pdata->gpio_reset)) {
+		error = -EINVAL;
+		goto fail;
+	}
+
+	data->reg_vdd = regulator_get(dev, "vdd");
+	if (IS_ERR(data->reg_vdd)) {
+		error = PTR_ERR(data->reg_vdd);
+		dev_err(dev, "Error %d getting vdd regulator\n", error);
+		goto fail;
+	}
+
+	data->reg_avdd = regulator_get(dev, "avdd");
+	if (IS_ERR(data->reg_avdd)) {
+		error = PTR_ERR(data->reg_avdd);
+		dev_err(dev, "Error %d getting avdd regulator\n", error);
+		goto fail_release;
+	}
+
+	mxt_regulator_enable(data);
+
+	dev_dbg(dev, "Initialised regulators\n");
+	return 0;
+
+fail_release:
+	regulator_put(data->reg_vdd);
+fail:
+	data->reg_vdd = NULL;
+	data->reg_avdd = NULL;
+	return error;
+}
+
 static int mxt_read_t9_resolution(struct mxt_data *data)
 {
 	struct i2c_client *client = data->client;
@@ -2609,7 +2701,12 @@ static int mxt_load_fw(struct device *dev, const char *fn)
 		goto release_firmware;
 
 	if (data->suspended) {
-		enable_irq(data->irq);
+		if (data->pdata->suspend_mode == MXT_SUSPEND_REGULATOR)
+			mxt_regulator_enable(data);
+
+		if (data->pdata->suspend_mode == MXT_SUSPEND_DEEP_SLEEP)
+			enable_irq(data->irq);
+
 		data->suspended = false;
 	}
 
@@ -2817,6 +2914,11 @@ static void mxt_start(struct mxt_data *data)
 				MXT_TOUCH_MULTI_T9, MXT_T9_CTRL, 0x83);
 		break;
 
+	case MXT_SUSPEND_REGULATOR:
+		enable_irq(data->irq);
+		mxt_regulator_enable(data);
+		break;
+
 	case MXT_SUSPEND_DEEP_SLEEP:
 	default:
 		/*
@@ -2849,6 +2951,12 @@ static void mxt_stop(struct mxt_data *data)
 				MXT_TOUCH_MULTI_T9, MXT_T9_CTRL, 0);
 		break;
 
+	case MXT_SUSPEND_REGULATOR:
+		disable_irq(data->irq);
+		mxt_regulator_disable(data);
+		mxt_reset_slots(data);
+		break;
+
 	case MXT_SUSPEND_DEEP_SLEEP:
 	default:
 		disable_irq(data->irq);
@@ -2893,6 +3001,9 @@ static const struct mxt_platform_data *mxt_parse_dt(struct i2c_client *client)
 	if (!pdata)
 		return ERR_PTR(-ENOMEM);
 
+	pdata->gpio_reset = of_get_named_gpio_flags(np, "atmel,reset-gpio",
+						    0, NULL);
+
 	if (of_find_property(np, "linux,gpio-keymap", &proplen)) {
 		pdata->t19_num_keys = proplen / sizeof(u32);
 
@@ -2911,7 +3022,7 @@ static const struct mxt_platform_data *mxt_parse_dt(struct i2c_client *client)
 		pdata->t19_keymap = keymap;
 	}
 
-	pdata->suspend_mode = MXT_SUSPEND_DEEP_SLEEP;
+	of_property_read_u32(np, "atmel,suspend-mode", &pdata->suspend_mode);
 
 	return pdata;
 }
@@ -3100,7 +3211,13 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		goto err_free_mem;
 	}
 
-	disable_irq(client->irq);
+	if (pdata->suspend_mode == MXT_SUSPEND_REGULATOR) {
+		error = mxt_probe_regulators(data);
+		if (error)
+			goto err_free_irq;
+	}
+
+	disable_irq(data->irq);
 
 	error = sysfs_create_group(&client->dev.kobj, &mxt_fw_attr_group);
 	if (error) {
@@ -3129,6 +3246,8 @@ static int mxt_remove(struct i2c_client *client)
 	sysfs_remove_group(&client->dev.kobj, &mxt_fw_attr_group);
 	mxt_sysfs_remove(data);
 	free_irq(data->irq, data);
+	regulator_put(data->reg_avdd);
+	regulator_put(data->reg_vdd);
 	mxt_free_input_device(data);
 	mxt_free_object_table(data);
 	kfree(data);

include/dt-bindings/input/atmel_mxt_ts.h

@@ -0,0 +1,22 @@
+/*
+ * Atmel maXTouch Touchscreen driver
+ *
+ * Copyright (C) 2015 Atmel Corporation
+ * Author: Nick Dyer <[email protected]>
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ */
+
+#ifndef __DT_BINDINGS_ATMEL_MXT_TS_H
+#define __DT_BINDINGS_ATMEL_MXT_TS_H
+
+enum mxt_suspend_mode {
+	MXT_SUSPEND_DEEP_SLEEP = 0,
+	MXT_SUSPEND_T9_CTRL = 1,
+	MXT_SUSPEND_REGULATOR = 2,
+};
+
+#endif /* __DT_BINDINGS_ATMEL_MXT_TS_H */

include/linux/platform_data/atmel_mxt_ts.h

@@ -14,11 +14,7 @@
 #define __LINUX_PLATFORM_DATA_ATMEL_MXT_TS_H
 
 #include <linux/types.h>
-
-enum mxt_suspend_mode {
-	MXT_SUSPEND_DEEP_SLEEP	= 0,
-	MXT_SUSPEND_T9_CTRL	= 1,
-};
+#include <dt-bindings/input/atmel_mxt_ts.h>
 
 /* The platform data for the Atmel maXTouch touchscreen driver */
 struct mxt_platform_data {
@@ -28,6 +24,7 @@ struct mxt_platform_data {
 	enum mxt_suspend_mode suspend_mode;
 	int t15_num_keys;
 	const unsigned int *t15_keymap;
+	unsigned long gpio_reset;
 };
 
 #endif /* __LINUX_PLATFORM_DATA_ATMEL_MXT_TS_H */