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 <nick.dyer@itdev.co.uk>
Acked-by: Benson Leung <bleung@chromium.org>
Acked-by: Yufeng Shen <miletus@chromium.org>
[cyrille.pitchen@atmel.com: adapt original patch to mainline]
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
[eugen.hristev@microchip.com: adapt original patch to 4.14]
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>

Author: ndyer

drivers/input/touchscreen/atmel_mxt_ts.c

@@ -27,9 +27,12 @@
 #include <linux/input/mt.h>
 #include <linux/interrupt.h>
 #include <linux/of.h>
+#include <linux/of_gpio.h>
 #include <linux/slab.h>
 #include <linux/gpio/consumer.h>
 #include <asm/unaligned.h>
+#include <linux/regulator/consumer.h>
+#include <linux/gpio.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-ioctl.h>
 #include <media/videobuf2-v4l2.h>
@@ -198,6 +201,9 @@ 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
@@ -301,6 +307,8 @@ struct mxt_data {
 	u8 num_touchids;
 	u8 multitouch;
 	struct t7_config t7_cfg;
+	struct regulator *reg_vdd;
+	struct regulator *reg_avdd;
 	struct mxt_dbg dbg;
 	struct gpio_desc *reset_gpio;
 
@@ -2086,6 +2094,84 @@ static void mxt_config_cb(const struct firmware *cfg, void *ctx)
 	release_firmware(cfg);
 }
 
+static void mxt_regulator_enable(struct mxt_data *data)
+{
+	int error;
+
+	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)
+{
+	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_vdd)) {
+		error = PTR_ERR(data->reg_vdd);
+		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_initialize(struct mxt_data *data)
 {
 	struct i2c_client *client = data->client;
@@ -2765,7 +2851,12 @@ 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;
 	}
 
@@ -2931,12 +3022,6 @@ static void mxt_start(struct mxt_data *data)
 	if (!data->suspended || data->in_bootloader)
 		return;
 
-	/*
-	 * Discard any touch messages still in message buffer
-	 * from before chip went to sleep
-	 */
-	mxt_process_messages_until_invalid(data);
-
 	switch (data->pdata->suspend_mode) {
 	case MXT_SUSPEND_T9_CTRL:
 		mxt_soft_reset(data);
@@ -2947,16 +3032,28 @@ 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:
+		/*
+		 * Discard any touch messages still in message buffer
+		 * from before chip went to sleep
+		 */
+		mxt_process_messages_until_invalid(data);
+
 		mxt_set_t7_power_cfg(data, MXT_POWER_CFG_RUN);
 
 		/* Recalibrate since chip has been in deep sleep */
 		mxt_t6_command(data, MXT_COMMAND_CALIBRATE, 1, false);
+
+		mxt_acquire_irq(data);
 		break;
 	}
 
-	mxt_acquire_irq(data);
 	data->suspended = false;
 }
 
@@ -2965,22 +3062,29 @@ static void mxt_stop(struct mxt_data *data)
 	if (data->suspended || data->in_bootloader)
 		return;
 
-	disable_irq(data->irq);
-
 	switch (data->pdata->suspend_mode) {
 	case MXT_SUSPEND_T9_CTRL:
 		/* Touch disable */
 		mxt_write_object(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);
+
 		mxt_set_t7_power_cfg(data, MXT_POWER_CFG_DEEPSLEEP);
+
+		mxt_reset_slots(data);
 		break;
 	}
 
-	mxt_reset_slots(data);
 	data->suspended = true;
 }
 
@@ -3015,6 +3119,9 @@ 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);
 
@@ -3033,7 +3140,7 @@ 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;
 }
@@ -3252,7 +3359,15 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
 		data->in_bootloader = false;
 	}
 
-	disable_irq(client->irq);
+	if (pdata->suspend_mode == MXT_SUSPEND_REGULATOR) {
+		error = mxt_probe_regulators(data);
+		if (error)
+			return error;
+
+		disable_irq(data->irq);
+	}
+
+	disable_irq(data->irq);
 
 	error = mxt_initialize(data);
 	if (error) {
@@ -3285,6 +3400,8 @@ static int mxt_remove(struct i2c_client *client)
 
 	disable_irq(data->irq);
 	sysfs_remove_group(&client->dev.kobj, &mxt_attr_group);
+	regulator_put(data->reg_avdd);
+	regulator_put(data->reg_vdd);
 	mxt_free_input_device(data);
 	mxt_free_object_table(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 <nick.dyer@itdev.co.uk>
+ *
+ * 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

@@ -14,18 +14,15 @@
 #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 {
 	unsigned long irqflags;
 	u8 t19_num_keys;
 	const unsigned int *t19_keymap;
 	enum mxt_suspend_mode suspend_mode;
+	unsigned long gpio_reset;
 };
 
 #endif /* __LINUX_PLATFORM_DATA_ATMEL_MXT_TS_H */