[media] as3645a: Add driver for LED flash controller

This patch adds the driver for the as3645a LED flash controller. This
controller supports a high power led in flash and torch modes and an
indicator light, sometimes also called privacy light.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Nayden Kanchev <nkanchev@mm-sol.com>
Signed-off-by: Tuukka Toivonen <tuukkat76@gmail.com>
Signed-off-by: Antti Koskipaa <antti.koskipaa@gmail.com>
Signed-off-by: Stanimir Varbanov <svarbanov@mm-sol.com>
Signed-off-by: Vimarsh Zutshi <vimarsh.zutshi@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
Signed-off-by: Mika Westerberg <ext-mika.1.westerberg@nokia.com>
Signed-off-by: David Cohen <dacohen@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

3 files changed, 912 insertions, 0 deletions

diff --git a/drivers/media/video/Kconfig b/drivers/media/video/Kconfig
index 4e8a0c4..0e4d241 100644
--- a/drivers/media/video/Kconfig
+++ b/drivers/media/video/Kconfig
@@ -533,6 +533,13 @@ config VIDEO_ADP1653
 	  This is a driver for the ADP1653 flash controller. It is used for
 	  example in Nokia N900.
 
+config VIDEO_AS3645A
+	tristate "AS3645A flash driver support"
+	depends on I2C && VIDEO_V4L2 && MEDIA_CONTROLLER
+	---help---
+	  This is a driver for the AS3645A and LM3555 flash controllers. It has
+	  build in control for flash, torch and indicator LEDs.
+
 comment "Video improvement chips"
 
 config VIDEO_UPD64031A
diff --git a/drivers/media/video/Makefile b/drivers/media/video/Makefile
index ddeaa6c..86aabd6 100644
--- a/drivers/media/video/Makefile
+++ b/drivers/media/video/Makefile
@@ -74,6 +74,7 @@ obj-$(CONFIG_VIDEO_NOON010PC30)	+= noon010pc30.o
 obj-$(CONFIG_VIDEO_M5MOLS)	+= m5mols/
 obj-$(CONFIG_VIDEO_S5K6AA)	+= s5k6aa.o
 obj-$(CONFIG_VIDEO_ADP1653)	+= adp1653.o
+obj-$(CONFIG_VIDEO_AS3645A)	+= as3645a.o
 
 obj-$(CONFIG_SOC_CAMERA_IMX074)		+= imx074.o
 obj-$(CONFIG_SOC_CAMERA_MT9M001)	+= mt9m001.o
diff --git a/drivers/media/video/as3645a.c b/drivers/media/video/as3645a.c
new file mode 100644
index 0000000..ec859a5
--- /dev/null
+++ b/drivers/media/video/as3645a.c
@@ -0,0 +1,904 @@
+/*
+ * drivers/media/video/as3645a.c - AS3645A and LM3555 flash controllers driver
+ *
+ * Copyright (C) 2008-2011 Nokia Corporation
+ * Copyright (c) 2011, Intel Corporation.
+ *
+ * Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+ * TODO:
+ * - Check hardware FSTROBE control when sensor driver add support for this
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+
+#include <media/as3645a.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-device.h>
+
+#define AS_TIMER_MS_TO_CODE(t)			(((t) - 100) / 50)
+#define AS_TIMER_CODE_TO_MS(c)			(50 * (c) + 100)
+
+/* Register definitions */
+
+/* Read-only Design info register: Reset state: xxxx 0001 */
+#define AS_DESIGN_INFO_REG			0x00
+#define AS_DESIGN_INFO_FACTORY(x)		(((x) >> 4))
+#define AS_DESIGN_INFO_MODEL(x)			((x) & 0x0f)
+
+/* Read-only Version control register: Reset state: 0000 0000
+ * for first engineering samples
+ */
+#define AS_VERSION_CONTROL_REG			0x01
+#define AS_VERSION_CONTROL_RFU(x)		(((x) >> 4))
+#define AS_VERSION_CONTROL_VERSION(x)		((x) & 0x0f)
+
+/* Read / Write	(Indicator and timer register): Reset state: 0000 1111 */
+#define AS_INDICATOR_AND_TIMER_REG		0x02
+#define AS_INDICATOR_AND_TIMER_TIMEOUT_SHIFT	0
+#define AS_INDICATOR_AND_TIMER_VREF_SHIFT	4
+#define AS_INDICATOR_AND_TIMER_INDICATOR_SHIFT	6
+
+/* Read / Write	(Current set register): Reset state: 0110 1001 */
+#define AS_CURRENT_SET_REG			0x03
+#define AS_CURRENT_ASSIST_LIGHT_SHIFT		0
+#define AS_CURRENT_LED_DET_ON			(1 << 3)
+#define AS_CURRENT_FLASH_CURRENT_SHIFT		4
+
+/* Read / Write	(Control register): Reset state: 1011 0100 */
+#define AS_CONTROL_REG				0x04
+#define AS_CONTROL_MODE_SETTING_SHIFT		0
+#define AS_CONTROL_STROBE_ON			(1 << 2)
+#define AS_CONTROL_OUT_ON			(1 << 3)
+#define AS_CONTROL_EXT_TORCH_ON			(1 << 4)
+#define AS_CONTROL_STROBE_TYPE_EDGE		(0 << 5)
+#define AS_CONTROL_STROBE_TYPE_LEVEL		(1 << 5)
+#define AS_CONTROL_COIL_PEAK_SHIFT		6
+
+/* Read only (D3 is read / write) (Fault and info): Reset state: 0000 x000 */
+#define AS_FAULT_INFO_REG			0x05
+#define AS_FAULT_INFO_INDUCTOR_PEAK_LIMIT	(1 << 1)
+#define AS_FAULT_INFO_INDICATOR_LED		(1 << 2)
+#define AS_FAULT_INFO_LED_AMOUNT		(1 << 3)
+#define AS_FAULT_INFO_TIMEOUT			(1 << 4)
+#define AS_FAULT_INFO_OVER_TEMPERATURE		(1 << 5)
+#define AS_FAULT_INFO_SHORT_CIRCUIT		(1 << 6)
+#define AS_FAULT_INFO_OVER_VOLTAGE		(1 << 7)
+
+/* Boost register */
+#define AS_BOOST_REG				0x0d
+#define AS_BOOST_CURRENT_DISABLE		(0 << 0)
+#define AS_BOOST_CURRENT_ENABLE			(1 << 0)
+
+/* Password register is used to unlock boost register writing */
+#define AS_PASSWORD_REG				0x0f
+#define AS_PASSWORD_UNLOCK_VALUE		0x55
+
+enum as_mode {
+	AS_MODE_EXT_TORCH = 0 << AS_CONTROL_MODE_SETTING_SHIFT,
+	AS_MODE_INDICATOR = 1 << AS_CONTROL_MODE_SETTING_SHIFT,
+	AS_MODE_ASSIST = 2 << AS_CONTROL_MODE_SETTING_SHIFT,
+	AS_MODE_FLASH = 3 << AS_CONTROL_MODE_SETTING_SHIFT,
+};
+
+/*
+ * struct as3645a
+ *
+ * @subdev:		V4L2 subdev
+ * @pdata:		Flash platform data
+ * @power_lock:		Protects power_count
+ * @power_count:	Power reference count
+ * @led_mode:		V4L2 flash LED mode
+ * @timeout:		Flash timeout in microseconds
+ * @flash_current:	Flash current (0=200mA ... 15=500mA). Maximum
+ *			values are 400mA for two LEDs and 500mA for one LED.
+ * @assist_current:	Torch/Assist light current (0=20mA, 1=40mA ... 7=160mA)
+ * @indicator_current:	Indicator LED current (0=0mA, 1=2.5mA ... 4=10mA)
+ * @strobe_source:	Flash strobe source (software or external)
+ */
+struct as3645a {
+	struct v4l2_subdev subdev;
+	const struct as3645a_platform_data *pdata;
+
+	struct mutex power_lock;
+	int power_count;
+
+	/* Controls */
+	struct v4l2_ctrl_handler ctrls;
+
+	enum v4l2_flash_led_mode led_mode;
+	unsigned int timeout;
+	u8 flash_current;
+	u8 assist_current;
+	u8 indicator_current;
+	enum v4l2_flash_strobe_source strobe_source;
+};
+
+#define to_as3645a(sd) container_of(sd, struct as3645a, subdev)
+
+/* Return negative errno else zero on success */
+static int as3645a_write(struct as3645a *flash, u8 addr, u8 val)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&flash->subdev);
+	int rval;
+
+	rval = i2c_smbus_write_byte_data(client, addr, val);
+
+	dev_dbg(&client->dev, "Write Addr:%02X Val:%02X %s\n", addr, val,
+		rval < 0 ? "fail" : "ok");
+
+	return rval;
+}
+
+/* Return negative errno else a data byte received from the device. */
+static int as3645a_read(struct as3645a *flash, u8 addr)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&flash->subdev);
+	int rval;
+
+	rval = i2c_smbus_read_byte_data(client, addr);
+
+	dev_dbg(&client->dev, "Read Addr:%02X Val:%02X %s\n", addr, rval,
+		rval < 0 ? "fail" : "ok");
+
+	return rval;
+}
+
+/* -----------------------------------------------------------------------------
+ * Hardware configuration and trigger
+ */
+
+/*
+ * as3645a_set_config - Set flash configuration registers
+ * @flash: The flash
+ *
+ * Configure the hardware with flash, assist and indicator currents, as well as
+ * flash timeout.
+ *
+ * Return 0 on success, or a negative error code if an I2C communication error
+ * occurred.
+ */
+static int as3645a_set_config(struct as3645a *flash)
+{
+	int ret;
+	u8 val;
+
+	val = (flash->flash_current << AS_CURRENT_FLASH_CURRENT_SHIFT)
+	    | (flash->assist_current << AS_CURRENT_ASSIST_LIGHT_SHIFT)
+	    | AS_CURRENT_LED_DET_ON;
+
+	ret = as3645a_write(flash, AS_CURRENT_SET_REG, val);
+	if (ret < 0)
+		return ret;
+
+	val = AS_TIMER_MS_TO_CODE(flash->timeout / 1000)
+		    << AS_INDICATOR_AND_TIMER_TIMEOUT_SHIFT;
+
+	val |= (flash->pdata->vref << AS_INDICATOR_AND_TIMER_VREF_SHIFT)
+	    |  ((flash->indicator_current ? flash->indicator_current - 1 : 0)
+		 << AS_INDICATOR_AND_TIMER_INDICATOR_SHIFT);
+
+	return as3645a_write(flash, AS_INDICATOR_AND_TIMER_REG, val);
+}
+
+/*
+ * as3645a_set_control - Set flash control register
+ * @flash: The flash
+ * @mode: Desired output mode
+ * @on: Desired output state
+ *
+ * Configure the hardware with output mode and state.
+ *
+ * Return 0 on success, or a negative error code if an I2C communication error
+ * occurred.
+ */
+static int
+as3645a_set_control(struct as3645a *flash, enum as_mode mode, bool on)
+{
+	u8 reg;
+
+	/* Configure output parameters and operation mode. */
+	reg = (flash->pdata->peak << AS_CONTROL_COIL_PEAK_SHIFT)
+	    | (on ? AS_CONTROL_OUT_ON : 0)
+	    | mode;
+
+	if (flash->led_mode == V4L2_FLASH_LED_MODE_FLASH &&
+	    flash->strobe_source == V4L2_FLASH_STROBE_SOURCE_EXTERNAL) {
+		reg |= AS_CONTROL_STROBE_TYPE_LEVEL
+		    |  AS_CONTROL_STROBE_ON;
+	}
+
+	return as3645a_write(flash, AS_CONTROL_REG, reg);
+}
+
+/*
+ * as3645a_set_output - Configure output and operation mode
+ * @flash: Flash controller
+ * @strobe: Strobe the flash (only valid in flash mode)
+ *
+ * Turn the LEDs output on/off and set the operation mode based on the current
+ * parameters.
+ *
+ * The AS3645A can't control the indicator LED independently of the flash/torch
+ * LED. If the flash controller is in V4L2_FLASH_LED_MODE_NONE mode, set the
+ * chip to indicator mode. Otherwise set it to assist light (torch) or flash
+ * mode.
+ *
+ * In indicator and assist modes, turn the output on/off based on the indicator
+ * and torch currents. In software strobe flash mode, turn the output on/off
+ * based on the strobe parameter.
+ */
+static int as3645a_set_output(struct as3645a *flash, bool strobe)
+{
+	enum as_mode mode;
+	bool on;
+
+	switch (flash->led_mode) {
+	case V4L2_FLASH_LED_MODE_NONE:
+		on = flash->indicator_current != 0;
+		mode = AS_MODE_INDICATOR;
+		break;
+	case V4L2_FLASH_LED_MODE_TORCH:
+		on = true;
+		mode = AS_MODE_ASSIST;
+		break;
+	case V4L2_FLASH_LED_MODE_FLASH:
+		on = strobe;
+		mode = AS_MODE_FLASH;
+		break;
+	default:
+		BUG();
+	}
+
+	/* Configure output parameters and operation mode. */
+	return as3645a_set_control(flash, mode, on);
+}
+
+/* -----------------------------------------------------------------------------
+ * V4L2 controls
+ */
+
+static int as3645a_is_active(struct as3645a *flash)
+{
+	int ret;
+
+	ret = as3645a_read(flash, AS_CONTROL_REG);
+	return ret < 0 ? ret : !!(ret & AS_CONTROL_OUT_ON);
+}
+
+static int as3645a_read_fault(struct as3645a *flash)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&flash->subdev);
+	int rval;
+
+	/* NOTE: reading register clear fault status */
+	rval = as3645a_read(flash, AS_FAULT_INFO_REG);
+	if (rval < 0)
+		return rval;
+
+	if (rval & AS_FAULT_INFO_INDUCTOR_PEAK_LIMIT)
+		dev_dbg(&client->dev, "Inductor Peak limit fault\n");
+
+	if (rval & AS_FAULT_INFO_INDICATOR_LED)
+		dev_dbg(&client->dev, "Indicator LED fault: "
+			"Short circuit or open loop\n");
+
+	dev_dbg(&client->dev, "%u connected LEDs\n",
+		rval & AS_FAULT_INFO_LED_AMOUNT ? 2 : 1);
+
+	if (rval & AS_FAULT_INFO_TIMEOUT)
+		dev_dbg(&client->dev, "Timeout fault\n");
+
+	if (rval & AS_FAULT_INFO_OVER_TEMPERATURE)
+		dev_dbg(&client->dev, "Over temperature fault\n");
+
+	if (rval & AS_FAULT_INFO_SHORT_CIRCUIT)
+		dev_dbg(&client->dev, "Short circuit fault\n");
+
+	if (rval & AS_FAULT_INFO_OVER_VOLTAGE)
+		dev_dbg(&client->dev, "Over voltage fault: "
+			"Indicates missing capacitor or open connection\n");
+
+	return rval;
+}
+
+static int as3645a_get_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct as3645a *flash =
+		container_of(ctrl->handler, struct as3645a, ctrls);
+	struct i2c_client *client = v4l2_get_subdevdata(&flash->subdev);
+	int value;
+
+	switch (ctrl->id) {
+	case V4L2_CID_FLASH_FAULT:
+		value = as3645a_read_fault(flash);
+		if (value < 0)
+			return value;
+
+		ctrl->cur.val = 0;
+		if (value & AS_FAULT_INFO_SHORT_CIRCUIT)
+			ctrl->cur.val |= V4L2_FLASH_FAULT_SHORT_CIRCUIT;
+		if (value & AS_FAULT_INFO_OVER_TEMPERATURE)
+			ctrl->cur.val |= V4L2_FLASH_FAULT_OVER_TEMPERATURE;
+		if (value & AS_FAULT_INFO_TIMEOUT)
+			ctrl->cur.val |= V4L2_FLASH_FAULT_TIMEOUT;
+		if (value & AS_FAULT_INFO_OVER_VOLTAGE)
+			ctrl->cur.val |= V4L2_FLASH_FAULT_OVER_VOLTAGE;
+		if (value & AS_FAULT_INFO_INDUCTOR_PEAK_LIMIT)
+			ctrl->cur.val |= V4L2_FLASH_FAULT_OVER_CURRENT;
+		if (value & AS_FAULT_INFO_INDICATOR_LED)
+			ctrl->cur.val |= V4L2_FLASH_FAULT_INDICATOR;
+		break;
+
+	case V4L2_CID_FLASH_STROBE_STATUS:
+		if (flash->led_mode != V4L2_FLASH_LED_MODE_FLASH) {
+			ctrl->cur.val = 0;
+			break;
+		}
+
+		value = as3645a_is_active(flash);
+		if (value < 0)
+			return value;
+
+		ctrl->cur.val = value;
+		break;
+	}
+
+	dev_dbg(&client->dev, "G_CTRL %08x:%d\n", ctrl->id, ctrl->cur.val);
+
+	return 0;
+}
+
+static int as3645a_set_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct as3645a *flash =
+		container_of(ctrl->handler, struct as3645a, ctrls);
+	struct i2c_client *client = v4l2_get_subdevdata(&flash->subdev);
+	int ret;
+
+	dev_dbg(&client->dev, "S_CTRL %08x:%d\n", ctrl->id, ctrl->val);
+
+	/* If a control that doesn't apply to the current mode is modified,
+	 * we store the value and return immediately. The setting will be
+	 * applied when the LED mode is changed. Otherwise we apply the setting
+	 * immediately.
+	 */
+
+	switch (ctrl->id) {
+	case V4L2_CID_FLASH_LED_MODE:
+		if (flash->indicator_current)
+			return -EBUSY;
+
+		ret = as3645a_set_config(flash);
+		if (ret < 0)
+			return ret;
+
+		flash->led_mode = ctrl->val;
+		return as3645a_set_output(flash, false);
+
+	case V4L2_CID_FLASH_STROBE_SOURCE:
+		flash->strobe_source = ctrl->val;
+
+		/* Applies to flash mode only. */
+		if (flash->led_mode != V4L2_FLASH_LED_MODE_FLASH)
+			break;
+
+		return as3645a_set_output(flash, false);
+
+	case V4L2_CID_FLASH_STROBE:
+		if (flash->led_mode != V4L2_FLASH_LED_MODE_FLASH)
+			return -EBUSY;
+
+		return as3645a_set_output(flash, true);
+
+	case V4L2_CID_FLASH_STROBE_STOP:
+		if (flash->led_mode != V4L2_FLASH_LED_MODE_FLASH)
+			return -EBUSY;
+
+		return as3645a_set_output(flash, false);
+
+	case V4L2_CID_FLASH_TIMEOUT:
+		flash->timeout = ctrl->val;
+
+		/* Applies to flash mode only. */
+		if (flash->led_mode != V4L2_FLASH_LED_MODE_FLASH)
+			break;
+
+		return as3645a_set_config(flash);
+
+	case V4L2_CID_FLASH_INTENSITY:
+		flash->flash_current = (ctrl->val - AS3645A_FLASH_INTENSITY_MIN)
+				     / AS3645A_FLASH_INTENSITY_STEP;
+
+		/* Applies to flash mode only. */
+		if (flash->led_mode != V4L2_FLASH_LED_MODE_FLASH)
+			break;
+
+		return as3645a_set_config(flash);
+
+	case V4L2_CID_FLASH_TORCH_INTENSITY:
+		flash->assist_current =
+			(ctrl->val - AS3645A_TORCH_INTENSITY_MIN)
+			/ AS3645A_TORCH_INTENSITY_STEP;
+
+		/* Applies to torch mode only. */
+		if (flash->led_mode != V4L2_FLASH_LED_MODE_TORCH)
+			break;
+
+		return as3645a_set_config(flash);
+
+	case V4L2_CID_FLASH_INDICATOR_INTENSITY:
+		if (flash->led_mode != V4L2_FLASH_LED_MODE_NONE)
+			return -EBUSY;
+
+		flash->indicator_current =
+			(ctrl->val - AS3645A_INDICATOR_INTENSITY_MIN)
+			/ AS3645A_INDICATOR_INTENSITY_STEP;
+
+		ret = as3645a_set_config(flash);
+		if (ret < 0)
+			return ret;
+
+		if ((ctrl->val == 0) == (ctrl->cur.val == 0))
+			break;
+
+		return as3645a_set_output(flash, false);
+	}
+
+	return 0;
+}
+
+static const struct v4l2_ctrl_ops as3645a_ctrl_ops = {
+	.g_volatile_ctrl = as3645a_get_ctrl,
+	.s_ctrl = as3645a_set_ctrl,
+};
+
+/* -----------------------------------------------------------------------------
+ * V4L2 subdev core operations
+ */
+
+/* Put device into know state. */
+static int as3645a_setup(struct as3645a *flash)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&flash->subdev);
+	int ret;
+
+	/* clear errors */
+	ret = as3645a_read(flash, AS_FAULT_INFO_REG);
+	if (ret < 0)
+		return ret;
+
+	dev_dbg(&client->dev, "Fault info: %02x\n", ret);
+
+	ret = as3645a_set_config(flash);
+	if (ret < 0)
+		return ret;
+
+	ret = as3645a_set_output(flash, false);
+	if (ret < 0)
+		return ret;
+
+	/* read status */
+	ret = as3645a_read_fault(flash);
+	if (ret < 0)
+		return ret;
+
+	dev_dbg(&client->dev, "AS_INDICATOR_AND_TIMER_REG: %02x\n",
+		as3645a_read(flash, AS_INDICATOR_AND_TIMER_REG));
+	dev_dbg(&client->dev, "AS_CURRENT_SET_REG: %02x\n",
+		as3645a_read(flash, AS_CURRENT_SET_REG));
+	dev_dbg(&client->dev, "AS_CONTROL_REG: %02x\n",
+		as3645a_read(flash, AS_CONTROL_REG));
+
+	return ret & ~AS_FAULT_INFO_LED_AMOUNT ? -EIO : 0;
+}
+
+static int __as3645a_set_power(struct as3645a *flash, int on)
+{
+	int ret;
+
+	if (!on)
+		as3645a_set_control(flash, AS_MODE_EXT_TORCH, false);
+
+	if (flash->pdata->set_power) {
+		ret = flash->pdata->set_power(&flash->subdev, on);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (!on)
+		return 0;
+
+	ret = as3645a_setup(flash);
+	if (ret < 0) {
+		if (flash->pdata->set_power)
+			flash->pdata->set_power(&flash->subdev, 0);
+	}
+
+	return ret;
+}
+
+static int as3645a_set_power(struct v4l2_subdev *sd, int on)
+{
+	struct as3645a *flash = to_as3645a(sd);
+	int ret = 0;
+
+	mutex_lock(&flash->power_lock);
+
+	if (flash->power_count == !on) {
+		ret = __as3645a_set_power(flash, !!on);
+		if (ret < 0)
+			goto done;
+	}
+
+	flash->power_count += on ? 1 : -1;
+	WARN_ON(flash->power_count < 0);
+
+done:
+	mutex_unlock(&flash->power_lock);
+	return ret;
+}
+
+static int as3645a_registered(struct v4l2_subdev *sd)
+{
+	struct as3645a *flash = to_as3645a(sd);
+	struct i2c_client *client = v4l2_get_subdevdata(sd);
+	int rval, man, model, rfu, version;
+	const char *vendor;
+
+	/* Power up the flash driver and read manufacturer ID, model ID, RFU
+	 * and version.
+	 */
+	rval = as3645a_set_power(&flash->subdev, 1);
+	if (rval < 0)
+		return rval;
+
+	rval = as3645a_read(flash, AS_DESIGN_INFO_REG);
+	if (rval < 0)
+		goto power_off;
+
+	man = AS_DESIGN_INFO_FACTORY(rval);
+	model = AS_DESIGN_INFO_MODEL(rval);
+
+	rval = as3645a_read(flash, AS_VERSION_CONTROL_REG);
+	if (rval < 0)
+		goto power_off;
+
+	rfu = AS_VERSION_CONTROL_RFU(rval);
+	version = AS_VERSION_CONTROL_VERSION(rval);
+
+	/* Verify the chip model and version. */
+	if (model != 0x01 || rfu != 0x00) {
+		dev_err(&client->dev, "AS3645A not detected "
+			"(model %d rfu %d)\n", model, rfu);
+		rval = -ENODEV;
+		goto power_off;
+	}
+
+	switch (man) {
+	case 1:
+		vendor = "AMS, Austria Micro Systems";
+		break;
+	case 2:
+		vendor = "ADI, Analog Devices Inc.";
+		break;
+	case 3:
+		vendor = "NSC, National Semiconductor";
+		break;
+	case 4:
+		vendor = "NXP";
+		break;
+	case 5:
+		vendor = "TI, Texas Instrument";
+		break;
+	default:
+		vendor = "Unknown";
+	}
+
+	dev_info(&client->dev, "Chip vendor: %s (%d) Version: %d\n", vendor,
+		 man, version);
+
+	rval = as3645a_write(flash, AS_PASSWORD_REG, AS_PASSWORD_UNLOCK_VALUE);
+	if (rval < 0)
+		goto power_off;
+
+	rval = as3645a_write(flash, AS_BOOST_REG, AS_BOOST_CURRENT_DISABLE);
+	if (rval < 0)
+		goto power_off;
+
+	/* Setup default values. This makes sure that the chip is in a known
+	 * state, in case the power rail can't be controlled.
+	 */
+	rval = as3645a_setup(flash);
+
+power_off:
+	as3645a_set_power(&flash->subdev, 0);
+
+	return rval;
+}
+
+static int as3645a_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+	return as3645a_set_power(sd, 1);
+}
+
+static int as3645a_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+	return as3645a_set_power(sd, 0);
+}
+
+static const struct v4l2_subdev_core_ops as3645a_core_ops = {
+	.s_power		= as3645a_set_power,
+};
+
+static const struct v4l2_subdev_ops as3645a_ops = {
+	.core = &as3645a_core_ops,
+};
+
+static const struct v4l2_subdev_internal_ops as3645a_internal_ops = {
+	.registered = as3645a_registered,
+	.open = as3645a_open,
+	.close = as3645a_close,
+};
+
+/* -----------------------------------------------------------------------------
+ *  I2C driver
+ */
+#ifdef CONFIG_PM
+
+static int as3645a_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct v4l2_subdev *subdev = i2c_get_clientdata(client);
+	struct as3645a *flash = to_as3645a(subdev);
+	int rval;
+
+	if (flash->power_count == 0)
+		return 0;
+
+	rval = __as3645a_set_power(flash, 0);
+
+	dev_dbg(&client->dev, "Suspend %s\n", rval < 0 ? "failed" : "ok");
+
+	return rval;
+}
+
+static int as3645a_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct v4l2_subdev *subdev = i2c_get_clientdata(client);
+	struct as3645a *flash = to_as3645a(subdev);
+	int rval;
+
+	if (flash->power_count == 0)
+		return 0;
+
+	rval = __as3645a_set_power(flash, 1);
+
+	dev_dbg(&client->dev, "Resume %s\n", rval < 0 ? "fail" : "ok");
+
+	return rval;
+}
+
+#else
+
+#define as3645a_suspend	NULL
+#define as3645a_resume	NULL
+
+#endif /* CONFIG_PM */
+
+/*
+ * as3645a_init_controls - Create controls
+ * @flash: The flash
+ *
+ * The number of LEDs reported in platform data is used to compute default
+ * limits. Parameters passed through platform data can override those limits.
+ */
+static int as3645a_init_controls(struct as3645a *flash)
+{
+	const struct as3645a_platform_data *pdata = flash->pdata;
+	struct v4l2_ctrl *ctrl;
+	int maximum;
+
+	v4l2_ctrl_handler_init(&flash->ctrls, 10);
+
+	/* V4L2_CID_FLASH_LED_MODE */
+	v4l2_ctrl_new_std_menu(&flash->ctrls, &as3645a_ctrl_ops,
+			       V4L2_CID_FLASH_LED_MODE, 2, ~7,
+			       V4L2_FLASH_LED_MODE_NONE);
+
+	/* V4L2_CID_FLASH_STROBE_SOURCE */
+	v4l2_ctrl_new_std_menu(&flash->ctrls, &as3645a_ctrl_ops,
+			       V4L2_CID_FLASH_STROBE_SOURCE,
+			       pdata->ext_strobe ? 1 : 0,
+			       pdata->ext_strobe ? ~3 : ~1,
+			       V4L2_FLASH_STROBE_SOURCE_SOFTWARE);
+
+	flash->strobe_source = V4L2_FLASH_STROBE_SOURCE_SOFTWARE;
+
+	/* V4L2_CID_FLASH_STROBE */
+	v4l2_ctrl_new_std(&flash->ctrls, &as3645a_ctrl_ops,
+			  V4L2_CID_FLASH_STROBE, 0, 0, 0, 0);
+
+	/* V4L2_CID_FLASH_STROBE_STOP */
+	v4l2_ctrl_new_std(&flash->ctrls, &as3645a_ctrl_ops,
+			  V4L2_CID_FLASH_STROBE_STOP, 0, 0, 0, 0);
+
+	/* V4L2_CID_FLASH_STROBE_STATUS */
+	ctrl = v4l2_ctrl_new_std(&flash->ctrls, &as3645a_ctrl_ops,
+				 V4L2_CID_FLASH_STROBE_STATUS, 0, 1, 1, 1);
+	if (ctrl != NULL)
+		ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE;
+
+	/* V4L2_CID_FLASH_TIMEOUT */
+	maximum = pdata->timeout_max;
+
+	v4l2_ctrl_new_std(&flash->ctrls, &as3645a_ctrl_ops,
+			  V4L2_CID_FLASH_TIMEOUT, AS3645A_FLASH_TIMEOUT_MIN,
+			  maximum, AS3645A_FLASH_TIMEOUT_STEP, maximum);
+
+	flash->timeout = maximum;
+
+	/* V4L2_CID_FLASH_INTENSITY */
+	maximum = pdata->flash_max_current;
+
+	v4l2_ctrl_new_std(&flash->ctrls, &as3645a_ctrl_ops,
+			  V4L2_CID_FLASH_INTENSITY, AS3645A_FLASH_INTENSITY_MIN,
+			  maximum, AS3645A_FLASH_INTENSITY_STEP, maximum);
+
+	flash->flash_current = (maximum - AS3645A_FLASH_INTENSITY_MIN)
+			     / AS3645A_FLASH_INTENSITY_STEP;
+
+	/* V4L2_CID_FLASH_TORCH_INTENSITY */
+	maximum = pdata->torch_max_current;
+
+	v4l2_ctrl_new_std(&flash->ctrls, &as3645a_ctrl_ops,
+			  V4L2_CID_FLASH_TORCH_INTENSITY,
+			  AS3645A_TORCH_INTENSITY_MIN, maximum,
+			  AS3645A_TORCH_INTENSITY_STEP,
+			  AS3645A_TORCH_INTENSITY_MIN);
+
+	flash->assist_current = 0;
+
+	/* V4L2_CID_FLASH_INDICATOR_INTENSITY */
+	v4l2_ctrl_new_std(&flash->ctrls, &as3645a_ctrl_ops,
+			  V4L2_CID_FLASH_INDICATOR_INTENSITY,
+			  AS3645A_INDICATOR_INTENSITY_MIN,
+			  AS3645A_INDICATOR_INTENSITY_MAX,
+			  AS3645A_INDICATOR_INTENSITY_STEP,
+			  AS3645A_INDICATOR_INTENSITY_MIN);
+
+	flash->indicator_current = 0;
+
+	/* V4L2_CID_FLASH_FAULT */
+	ctrl = v4l2_ctrl_new_std(&flash->ctrls, &as3645a_ctrl_ops,
+				 V4L2_CID_FLASH_FAULT, 0,
+				 V4L2_FLASH_FAULT_OVER_VOLTAGE |
+				 V4L2_FLASH_FAULT_TIMEOUT |
+				 V4L2_FLASH_FAULT_OVER_TEMPERATURE |
+				 V4L2_FLASH_FAULT_SHORT_CIRCUIT, 0, 0);
+	if (ctrl != NULL)
+		ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE;
+
+	flash->subdev.ctrl_handler = &flash->ctrls;
+
+	return flash->ctrls.error;
+}
+
+static int as3645a_probe(struct i2c_client *client,
+			 const struct i2c_device_id *devid)
+{
+	struct as3645a *flash;
+	int ret;
+
+	if (client->dev.platform_data == NULL)
+		return -ENODEV;
+
+	flash = kzalloc(sizeof(*flash), GFP_KERNEL);
+	if (flash == NULL)
+		return -ENOMEM;
+
+	flash->pdata = client->dev.platform_data;
+
+	v4l2_i2c_subdev_init(&flash->subdev, client, &as3645a_ops);
+	flash->subdev.internal_ops = &as3645a_internal_ops;
+	flash->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+
+	ret = as3645a_init_controls(flash);
+	if (ret < 0)
+		goto done;
+
+	ret = media_entity_init(&flash->subdev.entity, 0, NULL, 0);
+	if (ret < 0)
+		goto done;
+
+	flash->subdev.entity.type = MEDIA_ENT_T_V4L2_SUBDEV_FLASH;
+
+	mutex_init(&flash->power_lock);
+
+	flash->led_mode = V4L2_FLASH_LED_MODE_NONE;
+
+done:
+	if (ret < 0) {
+		v4l2_ctrl_handler_free(&flash->ctrls);
+		kfree(flash);
+	}
+
+	return ret;
+}
+
+static int __exit as3645a_remove(struct i2c_client *client)
+{
+	struct v4l2_subdev *subdev = i2c_get_clientdata(client);
+	struct as3645a *flash = to_as3645a(subdev);
+
+	v4l2_device_unregister_subdev(subdev);
+	v4l2_ctrl_handler_free(&flash->ctrls);
+	media_entity_cleanup(&flash->subdev.entity);
+	mutex_destroy(&flash->power_lock);
+	kfree(flash);
+
+	return 0;
+}
+
+static const struct i2c_device_id as3645a_id_table[] = {
+	{ AS3645A_NAME, 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, as3645a_id_table);
+
+static const struct dev_pm_ops as3645a_pm_ops = {
+	.suspend = as3645a_suspend,
+	.resume = as3645a_resume,
+};
+
+static struct i2c_driver as3645a_i2c_driver = {
+	.driver	= {
+		.name = AS3645A_NAME,
+		.pm   = &as3645a_pm_ops,
+	},
+	.probe	= as3645a_probe,
+	.remove	= __exit_p(as3645a_remove),
+	.id_table = as3645a_id_table,
+};
+
+static int __init as3645a_init(void)
+{
+	int rval;
+
+	rval = i2c_add_driver(&as3645a_i2c_driver);
+	if (rval)
+		pr_err("%s: Failed to register the driver\n", AS3645A_NAME);
+
+	return rval;
+}
+
+static void __exit as3645a_exit(void)
+{
+	i2c_del_driver(&as3645a_i2c_driver);
+}
+
+module_init(as3645a_init);
+module_exit(as3645a_exit);
+
+MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
+MODULE_DESCRIPTION("LED flash driver for AS3645A, LM3555 and their clones");
+MODULE_LICENSE("GPL");