[PATCH 2/2] media: Add a driver for the ov7251 camera sensor

[Todor Tomov <todor.tomov@linaro.org>]

The ov7251 sensor is a 1/7.5-Inch B&W VGA (640x480) CMOS Digital Image
Sensor from Omnivision.

The driver supports the following modes:
- 640x480 30fps
- 640x480 60fps
- 640x480 90fps

Output format is MIPI RAW 10.

The driver supports configuration via user controls for:
- exposure and gain;
- horizontal and vertical flip;
- test pattern.

Signed-off-by: Todor Tomov <todor.tomov@linaro.org>
---
 drivers/media/i2c/Kconfig  |   13 +
 drivers/media/i2c/Makefile |    1 +
 drivers/media/i2c/ov7251.c | 1523 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1537 insertions(+)
 create mode 100644 drivers/media/i2c/ov7251.c

diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index 9f18cd2..bfa9aab 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -645,6 +645,19 @@ config VIDEO_OV5670
 	  To compile this driver as a module, choose M here: the
 	  module will be called ov5670.
 
+config VIDEO_OV7251
+	tristate "OmniVision OV7251 sensor support"
+	depends on OF
+	depends on I2C && VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API
+	depends on MEDIA_CAMERA_SUPPORT
+	select V4L2_FWNODE
+	---help---
+	  This is a Video4Linux2 sensor-level driver for the OmniVision
+	  OV7251 camera.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ov7251.
+
 config VIDEO_OV7640
 	tristate "OmniVision OV7640 sensor support"
 	depends on I2C && VIDEO_V4L2
diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
index c0f94cd..be6b3d3 100644
--- a/drivers/media/i2c/Makefile
+++ b/drivers/media/i2c/Makefile
@@ -66,6 +66,7 @@ obj-$(CONFIG_VIDEO_OV5645) += ov5645.o
 obj-$(CONFIG_VIDEO_OV5647) += ov5647.o
 obj-$(CONFIG_VIDEO_OV5670) += ov5670.o
 obj-$(CONFIG_VIDEO_OV6650) += ov6650.o
+obj-$(CONFIG_VIDEO_OV7251) += ov7251.o
 obj-$(CONFIG_VIDEO_OV7640) += ov7640.o
 obj-$(CONFIG_VIDEO_OV7670) += ov7670.o
 obj-$(CONFIG_VIDEO_OV7740) += ov7740.o
diff --git a/drivers/media/i2c/ov7251.c b/drivers/media/i2c/ov7251.c
new file mode 100644
index 0000000..f217177
--- /dev/null
+++ b/drivers/media/i2c/ov7251.c
@@ -0,0 +1,1523 @@
+/*
+ * Driver for the OV7251 camera sensor.
+ *
+ * Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2017-2018, Linaro Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only 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.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_graph.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-fwnode.h>
+#include <media/v4l2-subdev.h>
+
+#define OV7251_VOLTAGE_ANALOG               2800000
+#define OV7251_VOLTAGE_DIGITAL_CORE         1500000
+#define OV7251_VOLTAGE_DIGITAL_IO           1800000
+
+#define OV7251_SC_MODE_SELECT		0x0100
+#define OV7251_SC_MODE_SELECT_SW_STANDBY	0x0
+#define OV7251_SC_MODE_SELECT_STREAMING		0x1
+
+#define OV7251_CHIP_ID_HIGH		0x300a
+#define		OV7251_CHIP_ID_HIGH_BYTE	0x77
+#define OV7251_CHIP_ID_LOW		0x300b
+#define		OV7251_CHIP_ID_LOW_BYTE		0x50
+#define OV7251_SC_GP_IO_IN1		0x3029
+#define OV7251_AEC_EXPO_0		0x3500
+#define OV7251_AEC_EXPO_1		0x3501
+#define OV7251_AEC_EXPO_2		0x3502
+#define OV7251_AEC_AGC_ADJ_0		0x350a
+#define OV7251_AEC_AGC_ADJ_1		0x350b
+#define OV7251_TIMING_FORMAT1		0x3820
+#define		OV7251_SENSOR_VFLIP		BIT(2)
+#define OV7251_TIMING_FORMAT2		0x3821
+#define		OV7251_SENSOR_MIRROR		BIT(2)
+#define OV7251_PRE_ISP_00		0x5e00
+#define		OV7251_TEST_PATTERN_BAR_ENABLE	BIT(7)
+
+struct reg_value {
+	u16 reg;
+	u8 val;
+};
+
+struct ov7251_mode_info {
+	u32 width;
+	u32 height;
+	const struct reg_value *data;
+	u32 data_size;
+	u32 pixel_clock;
+	u32 link_freq;
+	u16 exposure_max;
+	u16 exposure_def;
+	struct v4l2_fract timeperframe;
+};
+
+struct ov7251 {
+	struct i2c_client *i2c_client;
+	struct device *dev;
+	struct v4l2_subdev sd;
+	struct media_pad pad;
+	struct v4l2_fwnode_endpoint ep;
+	struct v4l2_mbus_framefmt fmt;
+	struct v4l2_rect crop;
+	struct clk *xclk;
+
+	struct regulator *io_regulator;
+	struct regulator *core_regulator;
+	struct regulator *analog_regulator;
+
+	const struct ov7251_mode_info *current_mode;
+
+	struct v4l2_ctrl_handler ctrls;
+	struct v4l2_ctrl *pixel_clock;
+	struct v4l2_ctrl *link_freq;
+	struct v4l2_ctrl *exposure;
+	struct v4l2_ctrl *gain;
+
+	/* Cached register values */
+	u8 aec_pk_manual;
+	u8 pre_isp_00;
+	u8 timing_format1;
+	u8 timing_format2;
+
+	struct mutex power_lock; /* lock to protect power state */
+	int power_count;
+
+	struct gpio_desc *enable_gpio;
+};
+
+static inline struct ov7251 *to_ov7251(struct v4l2_subdev *sd)
+{
+	return container_of(sd, struct ov7251, sd);
+}
+
+static const struct reg_value ov7251_global_init_setting[] = {
+	{ 0x0103, 0x01 },
+	{ 0x303b, 0x02 },
+};
+
+static const struct reg_value ov7251_setting_vga_30fps[] = {
+	{ 0x3005, 0x00 },
+	{ 0x3012, 0xc0 },
+	{ 0x3013, 0xd2 },
+	{ 0x3014, 0x04 },
+	{ 0x3016, 0xf0 },
+	{ 0x3017, 0xf0 },
+	{ 0x3018, 0xf0 },
+	{ 0x301a, 0xf0 },
+	{ 0x301b, 0xf0 },
+	{ 0x301c, 0xf0 },
+	{ 0x3023, 0x05 },
+	{ 0x3037, 0xf0 },
+	{ 0x3098, 0x04 }, /* pll2 pre divider */
+	{ 0x3099, 0x28 }, /* pll2 multiplier */
+	{ 0x309a, 0x05 }, /* pll2 sys divider */
+	{ 0x309b, 0x04 }, /* pll2 adc divider */
+	{ 0x309d, 0x00 }, /* pll2 divider */
+	{ 0x30b0, 0x0a }, /* pll1 pix divider */
+	{ 0x30b1, 0x01 }, /* pll1 divider */
+	{ 0x30b3, 0x64 }, /* pll1 multiplier */
+	{ 0x30b4, 0x03 }, /* pll1 pre divider */
+	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
+	{ 0x3106, 0xda },
+	{ 0x3503, 0x07 },
+	{ 0x3509, 0x10 },
+	{ 0x3600, 0x1c },
+	{ 0x3602, 0x62 },
+	{ 0x3620, 0xb7 },
+	{ 0x3622, 0x04 },
+	{ 0x3626, 0x21 },
+	{ 0x3627, 0x30 },
+	{ 0x3630, 0x44 },
+	{ 0x3631, 0x35 },
+	{ 0x3634, 0x60 },
+	{ 0x3636, 0x00 },
+	{ 0x3662, 0x01 },
+	{ 0x3663, 0x70 },
+	{ 0x3664, 0x50 },
+	{ 0x3666, 0x0a },
+	{ 0x3669, 0x1a },
+	{ 0x366a, 0x00 },
+	{ 0x366b, 0x50 },
+	{ 0x3673, 0x01 },
+	{ 0x3674, 0xff },
+	{ 0x3675, 0x03 },
+	{ 0x3705, 0xc1 },
+	{ 0x3709, 0x40 },
+	{ 0x373c, 0x08 },
+	{ 0x3742, 0x00 },
+	{ 0x3757, 0xb3 },
+	{ 0x3788, 0x00 },
+	{ 0x37a8, 0x01 },
+	{ 0x37a9, 0xc0 },
+	{ 0x3800, 0x00 },
+	{ 0x3801, 0x04 },
+	{ 0x3802, 0x00 },
+	{ 0x3803, 0x04 },
+	{ 0x3804, 0x02 },
+	{ 0x3805, 0x8b },
+	{ 0x3806, 0x01 },
+	{ 0x3807, 0xeb },
+	{ 0x3808, 0x02 }, /* width high */
+	{ 0x3809, 0x80 }, /* width low */
+	{ 0x380a, 0x01 }, /* height high */
+	{ 0x380b, 0xe0 }, /* height low */
+	{ 0x380c, 0x03 }, /* total horiz timing high */
+	{ 0x380d, 0xa0 }, /* total horiz timing low */
+	{ 0x380e, 0x06 }, /* total vertical timing high */
+	{ 0x380f, 0xbc }, /* total vertical timing low */
+	{ 0x3810, 0x00 },
+	{ 0x3811, 0x04 },
+	{ 0x3812, 0x00 },
+	{ 0x3813, 0x05 },
+	{ 0x3814, 0x11 },
+	{ 0x3815, 0x11 },
+	{ 0x3820, 0x40 },
+	{ 0x3821, 0x00 },
+	{ 0x382f, 0x0e },
+	{ 0x3832, 0x00 },
+	{ 0x3833, 0x05 },
+	{ 0x3834, 0x00 },
+	{ 0x3835, 0x0c },
+	{ 0x3837, 0x00 },
+	{ 0x3b80, 0x00 },
+	{ 0x3b81, 0xa5 },
+	{ 0x3b82, 0x10 },
+	{ 0x3b83, 0x00 },
+	{ 0x3b84, 0x08 },
+	{ 0x3b85, 0x00 },
+	{ 0x3b86, 0x01 },
+	{ 0x3b87, 0x00 },
+	{ 0x3b88, 0x00 },
+	{ 0x3b89, 0x00 },
+	{ 0x3b8a, 0x00 },
+	{ 0x3b8b, 0x05 },
+	{ 0x3b8c, 0x00 },
+	{ 0x3b8d, 0x00 },
+	{ 0x3b8e, 0x00 },
+	{ 0x3b8f, 0x1a },
+	{ 0x3b94, 0x05 },
+	{ 0x3b95, 0xf2 },
+	{ 0x3b96, 0x40 },
+	{ 0x3c00, 0x89 },
+	{ 0x3c01, 0x63 },
+	{ 0x3c02, 0x01 },
+	{ 0x3c03, 0x00 },
+	{ 0x3c04, 0x00 },
+	{ 0x3c05, 0x03 },
+	{ 0x3c06, 0x00 },
+	{ 0x3c07, 0x06 },
+	{ 0x3c0c, 0x01 },
+	{ 0x3c0d, 0xd0 },
+	{ 0x3c0e, 0x02 },
+	{ 0x3c0f, 0x0a },
+	{ 0x4001, 0x42 },
+	{ 0x4004, 0x04 },
+	{ 0x4005, 0x00 },
+	{ 0x404e, 0x01 },
+	{ 0x4300, 0xff },
+	{ 0x4301, 0x00 },
+	{ 0x4315, 0x00 },
+	{ 0x4501, 0x48 },
+	{ 0x4600, 0x00 },
+	{ 0x4601, 0x4e },
+	{ 0x4801, 0x0f },
+	{ 0x4806, 0x0f },
+	{ 0x4819, 0xaa },
+	{ 0x4823, 0x3e },
+	{ 0x4837, 0x19 },
+	{ 0x4a0d, 0x00 },
+	{ 0x4a47, 0x7f },
+	{ 0x4a49, 0xf0 },
+	{ 0x4a4b, 0x30 },
+	{ 0x5000, 0x85 },
+	{ 0x5001, 0x80 },
+};
+
+static const struct reg_value ov7251_setting_vga_60fps[] = {
+	{ 0x3005, 0x00 },
+	{ 0x3012, 0xc0 },
+	{ 0x3013, 0xd2 },
+	{ 0x3014, 0x04 },
+	{ 0x3016, 0x10 },
+	{ 0x3017, 0x00 },
+	{ 0x3018, 0x00 },
+	{ 0x301a, 0x00 },
+	{ 0x301b, 0x00 },
+	{ 0x301c, 0x00 },
+	{ 0x3023, 0x05 },
+	{ 0x3037, 0xf0 },
+	{ 0x3098, 0x04 }, /* pll2 pre divider */
+	{ 0x3099, 0x28 }, /* pll2 multiplier */
+	{ 0x309a, 0x05 }, /* pll2 sys divider */
+	{ 0x309b, 0x04 }, /* pll2 adc divider */
+	{ 0x309d, 0x00 }, /* pll2 divider */
+	{ 0x30b0, 0x0a }, /* pll1 pix divider */
+	{ 0x30b1, 0x01 }, /* pll1 divider */
+	{ 0x30b3, 0x64 }, /* pll1 multiplier */
+	{ 0x30b4, 0x03 }, /* pll1 pre divider */
+	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
+	{ 0x3106, 0xda },
+	{ 0x3503, 0x07 },
+	{ 0x3509, 0x10 },
+	{ 0x3600, 0x1c },
+	{ 0x3602, 0x62 },
+	{ 0x3620, 0xb7 },
+	{ 0x3622, 0x04 },
+	{ 0x3626, 0x21 },
+	{ 0x3627, 0x30 },
+	{ 0x3630, 0x44 },
+	{ 0x3631, 0x35 },
+	{ 0x3634, 0x60 },
+	{ 0x3636, 0x00 },
+	{ 0x3662, 0x01 },
+	{ 0x3663, 0x70 },
+	{ 0x3664, 0x50 },
+	{ 0x3666, 0x0a },
+	{ 0x3669, 0x1a },
+	{ 0x366a, 0x00 },
+	{ 0x366b, 0x50 },
+	{ 0x3673, 0x01 },
+	{ 0x3674, 0xff },
+	{ 0x3675, 0x03 },
+	{ 0x3705, 0xc1 },
+	{ 0x3709, 0x40 },
+	{ 0x373c, 0x08 },
+	{ 0x3742, 0x00 },
+	{ 0x3757, 0xb3 },
+	{ 0x3788, 0x00 },
+	{ 0x37a8, 0x01 },
+	{ 0x37a9, 0xc0 },
+	{ 0x3800, 0x00 },
+	{ 0x3801, 0x04 },
+	{ 0x3802, 0x00 },
+	{ 0x3803, 0x04 },
+	{ 0x3804, 0x02 },
+	{ 0x3805, 0x8b },
+	{ 0x3806, 0x01 },
+	{ 0x3807, 0xeb },
+	{ 0x3808, 0x02 }, /* width high */
+	{ 0x3809, 0x80 }, /* width low */
+	{ 0x380a, 0x01 }, /* height high */
+	{ 0x380b, 0xe0 }, /* height low */
+	{ 0x380c, 0x03 }, /* total horiz timing high */
+	{ 0x380d, 0xa0 }, /* total horiz timing low */
+	{ 0x380e, 0x03 }, /* total vertical timing high */
+	{ 0x380f, 0x5c }, /* total vertical timing low */
+	{ 0x3810, 0x00 },
+	{ 0x3811, 0x04 },
+	{ 0x3812, 0x00 },
+	{ 0x3813, 0x05 },
+	{ 0x3814, 0x11 },
+	{ 0x3815, 0x11 },
+	{ 0x3820, 0x40 },
+	{ 0x3821, 0x00 },
+	{ 0x382f, 0x0e },
+	{ 0x3832, 0x00 },
+	{ 0x3833, 0x05 },
+	{ 0x3834, 0x00 },
+	{ 0x3835, 0x0c },
+	{ 0x3837, 0x00 },
+	{ 0x3b80, 0x00 },
+	{ 0x3b81, 0xa5 },
+	{ 0x3b82, 0x10 },
+	{ 0x3b83, 0x00 },
+	{ 0x3b84, 0x08 },
+	{ 0x3b85, 0x00 },
+	{ 0x3b86, 0x01 },
+	{ 0x3b87, 0x00 },
+	{ 0x3b88, 0x00 },
+	{ 0x3b89, 0x00 },
+	{ 0x3b8a, 0x00 },
+	{ 0x3b8b, 0x05 },
+	{ 0x3b8c, 0x00 },
+	{ 0x3b8d, 0x00 },
+	{ 0x3b8e, 0x00 },
+	{ 0x3b8f, 0x1a },
+	{ 0x3b94, 0x05 },
+	{ 0x3b95, 0xf2 },
+	{ 0x3b96, 0x40 },
+	{ 0x3c00, 0x89 },
+	{ 0x3c01, 0x63 },
+	{ 0x3c02, 0x01 },
+	{ 0x3c03, 0x00 },
+	{ 0x3c04, 0x00 },
+	{ 0x3c05, 0x03 },
+	{ 0x3c06, 0x00 },
+	{ 0x3c07, 0x06 },
+	{ 0x3c0c, 0x01 },
+	{ 0x3c0d, 0xd0 },
+	{ 0x3c0e, 0x02 },
+	{ 0x3c0f, 0x0a },
+	{ 0x4001, 0x42 },
+	{ 0x4004, 0x04 },
+	{ 0x4005, 0x00 },
+	{ 0x404e, 0x01 },
+	{ 0x4300, 0xff },
+	{ 0x4301, 0x00 },
+	{ 0x4315, 0x00 },
+	{ 0x4501, 0x48 },
+	{ 0x4600, 0x00 },
+	{ 0x4601, 0x4e },
+	{ 0x4801, 0x0f },
+	{ 0x4806, 0x0f },
+	{ 0x4819, 0xaa },
+	{ 0x4823, 0x3e },
+	{ 0x4837, 0x19 },
+	{ 0x4a0d, 0x00 },
+	{ 0x4a47, 0x7f },
+	{ 0x4a49, 0xf0 },
+	{ 0x4a4b, 0x30 },
+	{ 0x5000, 0x85 },
+	{ 0x5001, 0x80 },
+};
+
+static const struct reg_value ov7251_setting_vga_90fps[] = {
+	{ 0x3005, 0x00 },
+	{ 0x3012, 0xc0 },
+	{ 0x3013, 0xd2 },
+	{ 0x3014, 0x04 },
+	{ 0x3016, 0x10 },
+	{ 0x3017, 0x00 },
+	{ 0x3018, 0x00 },
+	{ 0x301a, 0x00 },
+	{ 0x301b, 0x00 },
+	{ 0x301c, 0x00 },
+	{ 0x3023, 0x05 },
+	{ 0x3037, 0xf0 },
+	{ 0x3098, 0x04 }, /* pll2 pre divider */
+	{ 0x3099, 0x28 }, /* pll2 multiplier */
+	{ 0x309a, 0x05 }, /* pll2 sys divider */
+	{ 0x309b, 0x04 }, /* pll2 adc divider */
+	{ 0x309d, 0x00 }, /* pll2 divider */
+	{ 0x30b0, 0x0a }, /* pll1 pix divider */
+	{ 0x30b1, 0x01 }, /* pll1 divider */
+	{ 0x30b3, 0x64 }, /* pll1 multiplier */
+	{ 0x30b4, 0x03 }, /* pll1 pre divider */
+	{ 0x30b5, 0x05 }, /* pll1 mipi divider */
+	{ 0x3106, 0xda },
+	{ 0x3503, 0x07 },
+	{ 0x3509, 0x10 },
+	{ 0x3600, 0x1c },
+	{ 0x3602, 0x62 },
+	{ 0x3620, 0xb7 },
+	{ 0x3622, 0x04 },
+	{ 0x3626, 0x21 },
+	{ 0x3627, 0x30 },
+	{ 0x3630, 0x44 },
+	{ 0x3631, 0x35 },
+	{ 0x3634, 0x60 },
+	{ 0x3636, 0x00 },
+	{ 0x3662, 0x01 },
+	{ 0x3663, 0x70 },
+	{ 0x3664, 0x50 },
+	{ 0x3666, 0x0a },
+	{ 0x3669, 0x1a },
+	{ 0x366a, 0x00 },
+	{ 0x366b, 0x50 },
+	{ 0x3673, 0x01 },
+	{ 0x3674, 0xff },
+	{ 0x3675, 0x03 },
+	{ 0x3705, 0xc1 },
+	{ 0x3709, 0x40 },
+	{ 0x373c, 0x08 },
+	{ 0x3742, 0x00 },
+	{ 0x3757, 0xb3 },
+	{ 0x3788, 0x00 },
+	{ 0x37a8, 0x01 },
+	{ 0x37a9, 0xc0 },
+	{ 0x3800, 0x00 },
+	{ 0x3801, 0x04 },
+	{ 0x3802, 0x00 },
+	{ 0x3803, 0x04 },
+	{ 0x3804, 0x02 },
+	{ 0x3805, 0x8b },
+	{ 0x3806, 0x01 },
+	{ 0x3807, 0xeb },
+	{ 0x3808, 0x02 }, /* width high */
+	{ 0x3809, 0x80 }, /* width low */
+	{ 0x380a, 0x01 }, /* height high */
+	{ 0x380b, 0xe0 }, /* height low */
+	{ 0x380c, 0x03 }, /* total horiz timing high */
+	{ 0x380d, 0xa0 }, /* total horiz timing low */
+	{ 0x380e, 0x02 }, /* total vertical timing high */
+	{ 0x380f, 0x3c }, /* total vertical timing low */
+	{ 0x3810, 0x00 },
+	{ 0x3811, 0x04 },
+	{ 0x3812, 0x00 },
+	{ 0x3813, 0x05 },
+	{ 0x3814, 0x11 },
+	{ 0x3815, 0x11 },
+	{ 0x3820, 0x40 },
+	{ 0x3821, 0x00 },
+	{ 0x382f, 0x0e },
+	{ 0x3832, 0x00 },
+	{ 0x3833, 0x05 },
+	{ 0x3834, 0x00 },
+	{ 0x3835, 0x0c },
+	{ 0x3837, 0x00 },
+	{ 0x3b80, 0x00 },
+	{ 0x3b81, 0xa5 },
+	{ 0x3b82, 0x10 },
+	{ 0x3b83, 0x00 },
+	{ 0x3b84, 0x08 },
+	{ 0x3b85, 0x00 },
+	{ 0x3b86, 0x01 },
+	{ 0x3b87, 0x00 },
+	{ 0x3b88, 0x00 },
+	{ 0x3b89, 0x00 },
+	{ 0x3b8a, 0x00 },
+	{ 0x3b8b, 0x05 },
+	{ 0x3b8c, 0x00 },
+	{ 0x3b8d, 0x00 },
+	{ 0x3b8e, 0x00 },
+	{ 0x3b8f, 0x1a },
+	{ 0x3b94, 0x05 },
+	{ 0x3b95, 0xf2 },
+	{ 0x3b96, 0x40 },
+	{ 0x3c00, 0x89 },
+	{ 0x3c01, 0x63 },
+	{ 0x3c02, 0x01 },
+	{ 0x3c03, 0x00 },
+	{ 0x3c04, 0x00 },
+	{ 0x3c05, 0x03 },
+	{ 0x3c06, 0x00 },
+	{ 0x3c07, 0x06 },
+	{ 0x3c0c, 0x01 },
+	{ 0x3c0d, 0xd0 },
+	{ 0x3c0e, 0x02 },
+	{ 0x3c0f, 0x0a },
+	{ 0x4001, 0x42 },
+	{ 0x4004, 0x04 },
+	{ 0x4005, 0x00 },
+	{ 0x404e, 0x01 },
+	{ 0x4300, 0xff },
+	{ 0x4301, 0x00 },
+	{ 0x4315, 0x00 },
+	{ 0x4501, 0x48 },
+	{ 0x4600, 0x00 },
+	{ 0x4601, 0x4e },
+	{ 0x4801, 0x0f },
+	{ 0x4806, 0x0f },
+	{ 0x4819, 0xaa },
+	{ 0x4823, 0x3e },
+	{ 0x4837, 0x19 },
+	{ 0x4a0d, 0x00 },
+	{ 0x4a47, 0x7f },
+	{ 0x4a49, 0xf0 },
+	{ 0x4a4b, 0x30 },
+	{ 0x5000, 0x85 },
+	{ 0x5001, 0x80 },
+};
+
+static const s64 link_freq[] = {
+	240000000,
+};
+
+static const struct ov7251_mode_info ov7251_mode_info_data[] = {
+	{
+		.width = 640,
+		.height = 480,
+		.data = ov7251_setting_vga_30fps,
+		.data_size = ARRAY_SIZE(ov7251_setting_vga_30fps),
+		.pixel_clock = 48000000,
+		.link_freq = 0, /* an index in link_freq[] */
+		.exposure_max = 1704,
+		.exposure_def = 504,
+		.timeperframe = {
+			.numerator = 100,
+			.denominator = 3000
+		}
+	},
+	{
+		.width = 640,
+		.height = 480,
+		.data = ov7251_setting_vga_60fps,
+		.data_size = ARRAY_SIZE(ov7251_setting_vga_60fps),
+		.pixel_clock = 48000000,
+		.link_freq = 0, /* an index in link_freq[] */
+		.exposure_max = 840,
+		.exposure_def = 504,
+		.timeperframe = {
+			.numerator = 100,
+			.denominator = 6014
+		}
+	},
+	{
+		.width = 640,
+		.height = 480,
+		.data = ov7251_setting_vga_90fps,
+		.data_size = ARRAY_SIZE(ov7251_setting_vga_90fps),
+		.pixel_clock = 48000000,
+		.link_freq = 0, /* an index in link_freq[] */
+		.exposure_max = 552,
+		.exposure_def = 504,
+		.timeperframe = {
+			.numerator = 100,
+			.denominator = 9043
+		}
+	},
+};
+
+static int ov7251_regulators_enable(struct ov7251 *ov7251)
+{
+	int ret;
+
+	ret = regulator_enable(ov7251->io_regulator);
+	if (ret < 0) {
+		dev_err(ov7251->dev, "set io voltage failed\n");
+		return ret;
+	}
+
+	ret = regulator_enable(ov7251->analog_regulator);
+	if (ret) {
+		dev_err(ov7251->dev, "set analog voltage failed\n");
+		goto err_disable_io;
+	}
+
+	ret = regulator_enable(ov7251->core_regulator);
+	if (ret) {
+		dev_err(ov7251->dev, "set core voltage failed\n");
+		goto err_disable_analog;
+	}
+
+	return 0;
+
+err_disable_analog:
+	regulator_disable(ov7251->analog_regulator);
+err_disable_io:
+	regulator_disable(ov7251->io_regulator);
+
+	return ret;
+}
+
+static void ov7251_regulators_disable(struct ov7251 *ov7251)
+{
+	int ret;
+
+	ret = regulator_disable(ov7251->core_regulator);
+	if (ret < 0)
+		dev_err(ov7251->dev, "core regulator disable failed\n");
+
+	ret = regulator_disable(ov7251->analog_regulator);
+	if (ret < 0)
+		dev_err(ov7251->dev, "analog regulator disable failed\n");
+
+	ret = regulator_disable(ov7251->io_regulator);
+	if (ret < 0)
+		dev_err(ov7251->dev, "io regulator disable failed\n");
+}
+
+static int ov7251_write_reg(struct ov7251 *ov7251, u16 reg, u8 val)
+{
+	u8 regbuf[3];
+	int ret;
+
+	regbuf[0] = reg >> 8;
+	regbuf[1] = reg & 0xff;
+	regbuf[2] = val;
+
+	ret = i2c_master_send(ov7251->i2c_client, regbuf, 3);
+	if (ret < 0) {
+		dev_err(ov7251->dev, "%s: write reg error %d: reg=%x, val=%x\n",
+			__func__, ret, reg, val);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int ov7251_read_reg(struct ov7251 *ov7251, u16 reg, u8 *val)
+{
+	u8 regbuf[2];
+	int ret;
+
+	regbuf[0] = reg >> 8;
+	regbuf[1] = reg & 0xff;
+
+	ret = i2c_master_send(ov7251->i2c_client, regbuf, 2);
+	if (ret < 0) {
+		dev_err(ov7251->dev, "%s: write reg error %d: reg=%x\n",
+			__func__, ret, reg);
+		return ret;
+	}
+
+	ret = i2c_master_recv(ov7251->i2c_client, val, 1);
+	if (ret < 0) {
+		dev_err(ov7251->dev, "%s: read reg error %d: reg=%x\n",
+			__func__, ret, reg);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int ov7251_set_exposure(struct ov7251 *ov7251, s32 exposure)
+{
+	int ret;
+
+	ret = ov7251_write_reg(ov7251, OV7251_AEC_EXPO_0,
+			       (exposure & 0xf000) >> 12);
+	if (ret < 0)
+		return ret;
+
+	ret = ov7251_write_reg(ov7251, OV7251_AEC_EXPO_1,
+			       (exposure & 0x0ff0) >> 4);
+	if (ret < 0)
+		return ret;
+
+	return ov7251_write_reg(ov7251, OV7251_AEC_EXPO_2,
+				(exposure & 0x000f) << 4);
+}
+
+static int ov7251_set_gain(struct ov7251 *ov7251, s32 gain)
+{
+	int ret;
+
+	ret = ov7251_write_reg(ov7251, OV7251_AEC_AGC_ADJ_0,
+			       (gain & 0x0300) >> 8);
+	if (ret < 0)
+		return ret;
+
+	return ov7251_write_reg(ov7251, OV7251_AEC_AGC_ADJ_1, gain & 0xff);
+}
+
+static int ov7251_set_register_array(struct ov7251 *ov7251,
+				     const struct reg_value *settings,
+				     unsigned int num_settings)
+{
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < num_settings; ++i, ++settings) {
+		ret = ov7251_write_reg(ov7251, settings->reg, settings->val);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int ov7251_set_power_on(struct ov7251 *ov7251)
+{
+	int ret;
+
+	ret = ov7251_regulators_enable(ov7251);
+	if (ret < 0) {
+		return ret;
+	}
+
+	ret = clk_prepare_enable(ov7251->xclk);
+	if (ret < 0) {
+		dev_err(ov7251->dev, "clk prepare enable failed\n");
+		ov7251_regulators_disable(ov7251);
+		return ret;
+	}
+
+	gpiod_set_value_cansleep(ov7251->enable_gpio, 1);
+
+	usleep_range(3000, 4000); /* 65536 / 24MHz = 2.73ms */
+
+	return 0;
+}
+
+static void ov7251_set_power_off(struct ov7251 *ov7251)
+{
+	clk_disable_unprepare(ov7251->xclk);
+	gpiod_set_value_cansleep(ov7251->enable_gpio, 0);
+	ov7251_regulators_disable(ov7251);
+}
+
+static int ov7251_s_power(struct v4l2_subdev *sd, int on)
+{
+	struct ov7251 *ov7251 = to_ov7251(sd);
+	int ret = 0;
+
+	mutex_lock(&ov7251->power_lock);
+
+	/* If the power count is modified from 0 to != 0 or from != 0 to 0,
+	 * update the power state.
+	 */
+	if (ov7251->power_count == !on) {
+		if (on) {
+			ret = ov7251_set_power_on(ov7251);
+			if (ret < 0)
+				goto exit;
+
+			ret = ov7251_set_register_array(ov7251,
+					ov7251_global_init_setting,
+					ARRAY_SIZE(ov7251_global_init_setting));
+			if (ret < 0) {
+				dev_err(ov7251->dev,
+					"could not set init registers\n");
+				ov7251_set_power_off(ov7251);
+				goto exit;
+			}
+		} else {
+			ov7251_set_power_off(ov7251);
+		}
+	}
+
+	/* Update the power count. */
+	ov7251->power_count += on ? 1 : -1;
+	WARN_ON(ov7251->power_count < 0);
+
+exit:
+	mutex_unlock(&ov7251->power_lock);
+
+	return ret;
+}
+
+static int ov7251_set_hflip(struct ov7251 *ov7251, s32 value)
+{
+	u8 val = ov7251->timing_format2;
+	int ret;
+
+	if (value)
+		val |= OV7251_SENSOR_MIRROR;
+	else
+		val &= ~OV7251_SENSOR_MIRROR;
+
+	ret = ov7251_write_reg(ov7251, OV7251_TIMING_FORMAT2, val);
+	if (!ret)
+		ov7251->timing_format2 = val;
+
+	return ret;
+}
+
+static int ov7251_set_vflip(struct ov7251 *ov7251, s32 value)
+{
+	u8 val = ov7251->timing_format1;
+	int ret;
+
+	if (value)
+		val |= OV7251_SENSOR_VFLIP;
+	else
+		val &= ~OV7251_SENSOR_VFLIP;
+
+	ret = ov7251_write_reg(ov7251, OV7251_TIMING_FORMAT1, val);
+	if (!ret)
+		ov7251->timing_format1 = val;
+
+	return ret;
+}
+
+static int ov7251_set_test_pattern(struct ov7251 *ov7251, s32 value)
+{
+	u8 val = ov7251->pre_isp_00;
+	int ret;
+
+	if (value)
+		val |= OV7251_TEST_PATTERN_BAR_ENABLE;
+	else
+		val &= ~OV7251_TEST_PATTERN_BAR_ENABLE;
+
+	ret = ov7251_write_reg(ov7251, OV7251_PRE_ISP_00, val);
+	if (!ret)
+		ov7251->pre_isp_00 = val;
+
+	return ret;
+}
+
+static const char * const ov7251_test_pattern_menu[] = {
+	"Disabled",
+	"Vertical Patern Bars",
+};
+
+static int ov7251_s_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct ov7251 *ov7251 = container_of(ctrl->handler,
+					     struct ov7251, ctrls);
+	int ret;
+
+	mutex_lock(&ov7251->power_lock);
+	if (!ov7251->power_count) {
+		mutex_unlock(&ov7251->power_lock);
+		return 0;
+	}
+
+	switch (ctrl->id) {
+	case V4L2_CID_EXPOSURE:
+		ret = ov7251_set_exposure(ov7251, ctrl->val);
+		break;
+	case V4L2_CID_GAIN:
+		ret = ov7251_set_gain(ov7251, ctrl->val);
+		break;
+	case V4L2_CID_TEST_PATTERN:
+		ret = ov7251_set_test_pattern(ov7251, ctrl->val);
+		break;
+	case V4L2_CID_HFLIP:
+		ret = ov7251_set_hflip(ov7251, ctrl->val);
+		break;
+	case V4L2_CID_VFLIP:
+		ret = ov7251_set_vflip(ov7251, ctrl->val);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	mutex_unlock(&ov7251->power_lock);
+
+	return ret;
+}
+
+static const struct v4l2_ctrl_ops ov7251_ctrl_ops = {
+	.s_ctrl = ov7251_s_ctrl,
+};
+
+static int ov7251_enum_mbus_code(struct v4l2_subdev *sd,
+				 struct v4l2_subdev_pad_config *cfg,
+				 struct v4l2_subdev_mbus_code_enum *code)
+{
+	if (code->index > 0)
+		return -EINVAL;
+
+	code->code = MEDIA_BUS_FMT_SBGGR10_1X10;
+
+	return 0;
+}
+
+static int ov7251_enum_frame_size(struct v4l2_subdev *subdev,
+				  struct v4l2_subdev_pad_config *cfg,
+				  struct v4l2_subdev_frame_size_enum *fse)
+{
+	if (fse->code != MEDIA_BUS_FMT_SBGGR10_1X10)
+		return -EINVAL;
+
+	if (fse->index >= ARRAY_SIZE(ov7251_mode_info_data))
+		return -EINVAL;
+
+	fse->min_width = ov7251_mode_info_data[fse->index].width;
+	fse->max_width = ov7251_mode_info_data[fse->index].width;
+	fse->min_height = ov7251_mode_info_data[fse->index].height;
+	fse->max_height = ov7251_mode_info_data[fse->index].height;
+
+	return 0;
+}
+
+static int ov7251_enum_frame_ival(struct v4l2_subdev *subdev,
+				  struct v4l2_subdev_pad_config *cfg,
+				  struct v4l2_subdev_frame_interval_enum *fie)
+{
+	int index = fie->index;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ov7251_mode_info_data); i++) {
+		if (fie->width != ov7251_mode_info_data[i].width ||
+		    fie->height != ov7251_mode_info_data[i].height)
+			continue;
+
+		if (index-- == 0) {
+			fie->interval = ov7251_mode_info_data[i].timeperframe;
+			return 0;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static struct v4l2_mbus_framefmt *
+__ov7251_get_pad_format(struct ov7251 *ov7251,
+			struct v4l2_subdev_pad_config *cfg,
+			unsigned int pad,
+			enum v4l2_subdev_format_whence which)
+{
+	switch (which) {
+	case V4L2_SUBDEV_FORMAT_TRY:
+		return v4l2_subdev_get_try_format(&ov7251->sd, cfg, pad);
+	case V4L2_SUBDEV_FORMAT_ACTIVE:
+		return &ov7251->fmt;
+	default:
+		return NULL;
+	}
+}
+
+static int ov7251_get_format(struct v4l2_subdev *sd,
+			     struct v4l2_subdev_pad_config *cfg,
+			     struct v4l2_subdev_format *format)
+{
+	struct ov7251 *ov7251 = to_ov7251(sd);
+
+	format->format = *__ov7251_get_pad_format(ov7251, cfg, format->pad,
+						  format->which);
+	return 0;
+}
+
+static struct v4l2_rect *
+__ov7251_get_pad_crop(struct ov7251 *ov7251, struct v4l2_subdev_pad_config *cfg,
+		      unsigned int pad, enum v4l2_subdev_format_whence which)
+{
+	switch (which) {
+	case V4L2_SUBDEV_FORMAT_TRY:
+		return v4l2_subdev_get_try_crop(&ov7251->sd, cfg, pad);
+	case V4L2_SUBDEV_FORMAT_ACTIVE:
+		return &ov7251->crop;
+	default:
+		return NULL;
+	}
+}
+
+static const struct ov7251_mode_info *
+ov7251_find_mode_by_size(unsigned int width, unsigned int height)
+{
+	unsigned int max_dist_match = (unsigned int) -1;
+	int i, n = 0;
+
+	for (i = 0; i < ARRAY_SIZE(ov7251_mode_info_data); i++) {
+		unsigned int dist = min(width, ov7251_mode_info_data[i].width)
+				* min(height, ov7251_mode_info_data[i].height);
+
+		dist = ov7251_mode_info_data[i].width *
+				ov7251_mode_info_data[i].height +
+			width * height - 2 * dist;
+
+		if (dist < max_dist_match) {
+			n = i;
+			max_dist_match = dist;
+		}
+	}
+
+	return &ov7251_mode_info_data[n];
+}
+
+#define TIMEPERFRAME_AVG_FPS(t)						\
+	(((t).denominator + ((t).numerator >> 1)) / (t).numerator)
+
+static const struct ov7251_mode_info *
+ov7251_find_mode_by_ival(struct ov7251 *ov7251, struct v4l2_fract *timeperframe)
+{
+	const struct ov7251_mode_info *mode = ov7251->current_mode;
+	int fps_req = TIMEPERFRAME_AVG_FPS(*timeperframe);
+	unsigned int max_dist_match = (unsigned int) -1;
+	int i, n = 0;
+
+	for (i = 0; i < ARRAY_SIZE(ov7251_mode_info_data); i++) {
+		unsigned int dist;
+		int fps_tmp;
+
+		if (mode->width != ov7251_mode_info_data[i].width ||
+		    mode->height != ov7251_mode_info_data[i].height)
+			continue;
+
+		fps_tmp = TIMEPERFRAME_AVG_FPS(
+					ov7251_mode_info_data[i].timeperframe);
+
+		if (fps_req > fps_tmp)
+			dist = fps_req - fps_tmp;
+		else
+			dist = fps_tmp - fps_req;
+
+		if (dist < max_dist_match) {
+			n = i;
+			max_dist_match = dist;
+		}
+	}
+
+	return &ov7251_mode_info_data[n];
+}
+
+static int ov7251_set_format(struct v4l2_subdev *sd,
+			     struct v4l2_subdev_pad_config *cfg,
+			     struct v4l2_subdev_format *format)
+{
+	struct ov7251 *ov7251 = to_ov7251(sd);
+	struct v4l2_mbus_framefmt *__format;
+	struct v4l2_rect *__crop;
+	const struct ov7251_mode_info *new_mode;
+	int ret;
+
+	__crop = __ov7251_get_pad_crop(ov7251, cfg, format->pad,
+			format->which);
+
+	new_mode = ov7251_find_mode_by_size(format->format.width,
+					    format->format.height);
+	__crop->width = new_mode->width;
+	__crop->height = new_mode->height;
+
+	if (format->which == V4L2_SUBDEV_FORMAT_ACTIVE) {
+		ret = v4l2_ctrl_s_ctrl_int64(ov7251->pixel_clock,
+					     new_mode->pixel_clock);
+		if (ret < 0)
+			return ret;
+
+		ret = v4l2_ctrl_s_ctrl(ov7251->link_freq,
+				       new_mode->link_freq);
+		if (ret < 0)
+			return ret;
+
+		ret = v4l2_ctrl_modify_range(ov7251->exposure,
+					     1, new_mode->exposure_max,
+					     1, new_mode->exposure_def);
+		if (ret < 0)
+			return ret;
+
+		ret = v4l2_ctrl_s_ctrl(ov7251->exposure,
+				       new_mode->exposure_def);
+		if (ret < 0)
+			return ret;
+
+
+		ret = v4l2_ctrl_s_ctrl(ov7251->gain, 16);
+		if (ret < 0)
+			return ret;
+
+		ov7251->current_mode = new_mode;
+	}
+
+	__format = __ov7251_get_pad_format(ov7251, cfg, format->pad,
+			format->which);
+	__format->width = __crop->width;
+	__format->height = __crop->height;
+	__format->code = MEDIA_BUS_FMT_SBGGR10_1X10;
+	__format->field = V4L2_FIELD_NONE;
+	__format->colorspace = V4L2_COLORSPACE_SRGB;
+
+	format->format = *__format;
+
+	return 0;
+}
+
+static int ov7251_entity_init_cfg(struct v4l2_subdev *subdev,
+				  struct v4l2_subdev_pad_config *cfg)
+{
+	struct v4l2_subdev_format fmt = { 0 };
+
+	fmt.which = cfg ? V4L2_SUBDEV_FORMAT_TRY : V4L2_SUBDEV_FORMAT_ACTIVE;
+	fmt.format.width = 640;
+	fmt.format.height = 480;
+
+	ov7251_set_format(subdev, cfg, &fmt);
+
+	return 0;
+}
+
+static int ov7251_get_selection(struct v4l2_subdev *sd,
+			   struct v4l2_subdev_pad_config *cfg,
+			   struct v4l2_subdev_selection *sel)
+{
+	struct ov7251 *ov7251 = to_ov7251(sd);
+
+	if (sel->target != V4L2_SEL_TGT_CROP)
+		return -EINVAL;
+
+	sel->r = *__ov7251_get_pad_crop(ov7251, cfg, sel->pad,
+					sel->which);
+	return 0;
+}
+
+static int ov7251_s_stream(struct v4l2_subdev *subdev, int enable)
+{
+	struct ov7251 *ov7251 = to_ov7251(subdev);
+	int ret;
+
+	if (enable) {
+		ret = ov7251_set_register_array(ov7251,
+					ov7251->current_mode->data,
+					ov7251->current_mode->data_size);
+		if (ret < 0) {
+			dev_err(ov7251->dev, "could not set mode %dx%d\n",
+				ov7251->current_mode->width,
+				ov7251->current_mode->height);
+			return ret;
+		}
+		ret = v4l2_ctrl_handler_setup(&ov7251->ctrls);
+		if (ret < 0) {
+			dev_err(ov7251->dev, "could not sync v4l2 controls\n");
+			return ret;
+		}
+		ret = ov7251_write_reg(ov7251, OV7251_SC_MODE_SELECT,
+				       OV7251_SC_MODE_SELECT_STREAMING);
+		if (ret < 0)
+			return ret;
+	} else {
+		ret = ov7251_write_reg(ov7251, OV7251_SC_MODE_SELECT,
+				       OV7251_SC_MODE_SELECT_SW_STANDBY);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int ov7251_get_frame_interval(struct v4l2_subdev *subdev,
+				     struct v4l2_subdev_frame_interval *fi)
+{
+	struct ov7251 *ov7251 = to_ov7251(subdev);
+
+	fi->interval = ov7251->current_mode->timeperframe;
+
+	return 0;
+}
+
+static int ov7251_set_frame_interval(struct v4l2_subdev *subdev,
+				     struct v4l2_subdev_frame_interval *fi)
+{
+	struct ov7251 *ov7251 = to_ov7251(subdev);
+	const struct ov7251_mode_info *new_mode;
+
+	new_mode = ov7251_find_mode_by_ival(ov7251, &fi->interval);
+
+	if (new_mode != ov7251->current_mode) {
+		int ret;
+
+		ret = v4l2_ctrl_s_ctrl_int64(ov7251->pixel_clock,
+					     new_mode->pixel_clock);
+		if (ret < 0)
+			return ret;
+
+		ret = v4l2_ctrl_s_ctrl(ov7251->link_freq,
+				       new_mode->link_freq);
+		if (ret < 0)
+			return ret;
+
+		ret = v4l2_ctrl_modify_range(ov7251->exposure,
+					     1, new_mode->exposure_max,
+					     1, new_mode->exposure_def);
+		if (ret < 0)
+			return ret;
+
+		ret = v4l2_ctrl_s_ctrl(ov7251->exposure,
+				       new_mode->exposure_def);
+		if (ret < 0)
+			return ret;
+
+		ret = v4l2_ctrl_s_ctrl(ov7251->gain, 16);
+		if (ret < 0)
+			return ret;
+
+		ov7251->current_mode = new_mode;
+	}
+
+	fi->interval = ov7251->current_mode->timeperframe;
+
+	return 0;
+}
+
+static const struct v4l2_subdev_core_ops ov7251_core_ops = {
+	.s_power = ov7251_s_power,
+};
+
+static const struct v4l2_subdev_video_ops ov7251_video_ops = {
+	.s_stream = ov7251_s_stream,
+	.g_frame_interval = ov7251_get_frame_interval,
+	.s_frame_interval = ov7251_set_frame_interval,
+};
+
+static const struct v4l2_subdev_pad_ops ov7251_subdev_pad_ops = {
+	.init_cfg = ov7251_entity_init_cfg,
+	.enum_mbus_code = ov7251_enum_mbus_code,
+	.enum_frame_size = ov7251_enum_frame_size,
+	.enum_frame_interval = ov7251_enum_frame_ival,
+	.get_fmt = ov7251_get_format,
+	.set_fmt = ov7251_set_format,
+	.get_selection = ov7251_get_selection,
+};
+
+static const struct v4l2_subdev_ops ov7251_subdev_ops = {
+	.core = &ov7251_core_ops,
+	.video = &ov7251_video_ops,
+	.pad = &ov7251_subdev_pad_ops,
+};
+
+static int ov7251_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct device_node *endpoint;
+	struct ov7251 *ov7251;
+	u8 chip_id_high, chip_id_low, chip_rev;
+	u32 xclk_freq;
+	int ret;
+
+	ov7251 = devm_kzalloc(dev, sizeof(struct ov7251), GFP_KERNEL);
+	if (!ov7251)
+		return -ENOMEM;
+
+	ov7251->i2c_client = client;
+	ov7251->dev = dev;
+
+	endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
+	if (!endpoint) {
+		dev_err(dev, "endpoint node not found\n");
+		return -EINVAL;
+	}
+
+	ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(endpoint),
+					 &ov7251->ep);
+	if (ret < 0) {
+		dev_err(dev, "parsing endpoint node failed\n");
+		return ret;
+	}
+
+	of_node_put(endpoint);
+
+	if (ov7251->ep.bus_type != V4L2_MBUS_CSI2) {
+		dev_err(dev, "invalid bus type, must be CSI2\n");
+		return -EINVAL;
+	}
+
+	/* get system clock (xclk) */
+	ov7251->xclk = devm_clk_get(dev, "xclk");
+	if (IS_ERR(ov7251->xclk)) {
+		dev_err(dev, "could not get xclk");
+		return PTR_ERR(ov7251->xclk);
+	}
+
+	ret = of_property_read_u32(dev->of_node, "clock-frequency", &xclk_freq);
+	if (ret) {
+		dev_err(dev, "could not get xclk frequency\n");
+		return ret;
+	}
+
+	if (xclk_freq != 24000000) {
+		dev_err(dev, "external clock frequency %u is not supported\n",
+			xclk_freq);
+		return -EINVAL;
+	}
+
+	ret = clk_set_rate(ov7251->xclk, xclk_freq);
+	if (ret) {
+		dev_err(dev, "could not set xclk frequency\n");
+		return ret;
+	}
+
+	ov7251->io_regulator = devm_regulator_get(dev, "vdddo");
+	if (IS_ERR(ov7251->io_regulator)) {
+		dev_err(dev, "cannot get io regulator\n");
+		return PTR_ERR(ov7251->io_regulator);
+	}
+
+	ret = regulator_set_voltage(ov7251->io_regulator,
+				    OV7251_VOLTAGE_DIGITAL_IO,
+				    OV7251_VOLTAGE_DIGITAL_IO);
+	if (ret < 0) {
+		dev_err(dev, "cannot set io voltage\n");
+		return ret;
+	}
+
+	ov7251->core_regulator = devm_regulator_get(dev, "vddd");
+	if (IS_ERR(ov7251->core_regulator)) {
+		dev_err(dev, "cannot get core regulator\n");
+		return PTR_ERR(ov7251->core_regulator);
+	}
+
+	ret = regulator_set_voltage(ov7251->core_regulator,
+				    OV7251_VOLTAGE_DIGITAL_CORE,
+				    OV7251_VOLTAGE_DIGITAL_CORE);
+	if (ret < 0) {
+		dev_err(dev, "cannot set core voltage\n");
+		return ret;
+	}
+
+	ov7251->analog_regulator = devm_regulator_get(dev, "vdda");
+	if (IS_ERR(ov7251->analog_regulator)) {
+		dev_err(dev, "cannot get analog regulator\n");
+		return PTR_ERR(ov7251->analog_regulator);
+	}
+
+	ret = regulator_set_voltage(ov7251->analog_regulator,
+				    OV7251_VOLTAGE_ANALOG,
+				    OV7251_VOLTAGE_ANALOG);
+	if (ret < 0) {
+		dev_err(dev, "cannot set analog voltage\n");
+		return ret;
+	}
+
+	ov7251->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_HIGH);
+	if (IS_ERR(ov7251->enable_gpio)) {
+		dev_err(dev, "cannot get enable gpio\n");
+		return PTR_ERR(ov7251->enable_gpio);
+	}
+
+	mutex_init(&ov7251->power_lock);
+
+	v4l2_ctrl_handler_init(&ov7251->ctrls, 7);
+	v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
+			  V4L2_CID_HFLIP, 0, 1, 1, 0);
+	v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
+			  V4L2_CID_VFLIP, 0, 1, 1, 0);
+	ov7251->exposure = v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
+					     V4L2_CID_EXPOSURE, 1, 32, 1, 32);
+	ov7251->gain = v4l2_ctrl_new_std(&ov7251->ctrls, &ov7251_ctrl_ops,
+					 V4L2_CID_GAIN, 16, 1023, 1, 16);
+	v4l2_ctrl_new_std_menu_items(&ov7251->ctrls, &ov7251_ctrl_ops,
+				     V4L2_CID_TEST_PATTERN,
+				     ARRAY_SIZE(ov7251_test_pattern_menu) - 1,
+				     0, 0, ov7251_test_pattern_menu);
+	ov7251->pixel_clock = v4l2_ctrl_new_std(&ov7251->ctrls,
+						&ov7251_ctrl_ops,
+						V4L2_CID_PIXEL_RATE,
+						1, INT_MAX, 1, 1);
+	ov7251->link_freq = v4l2_ctrl_new_int_menu(&ov7251->ctrls,
+						   &ov7251_ctrl_ops,
+						   V4L2_CID_LINK_FREQ,
+						   ARRAY_SIZE(link_freq) - 1,
+						   0, link_freq);
+	if (ov7251->link_freq)
+		ov7251->link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
+
+	ov7251->sd.ctrl_handler = &ov7251->ctrls;
+
+	if (ov7251->ctrls.error) {
+		dev_err(dev, "%s: control initialization error %d\n",
+		       __func__, ov7251->ctrls.error);
+		ret = ov7251->ctrls.error;
+		goto free_ctrl;
+	}
+
+	v4l2_i2c_subdev_init(&ov7251->sd, client, &ov7251_subdev_ops);
+	ov7251->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+	ov7251->pad.flags = MEDIA_PAD_FL_SOURCE;
+	ov7251->sd.dev = &client->dev;
+	ov7251->sd.entity.function = MEDIA_ENT_F_CAM_SENSOR;
+
+	ret = media_entity_pads_init(&ov7251->sd.entity, 1, &ov7251->pad);
+	if (ret < 0) {
+		dev_err(dev, "could not register media entity\n");
+		goto free_ctrl;
+	}
+
+	ret = ov7251_s_power(&ov7251->sd, true);
+	if (ret < 0) {
+		dev_err(dev, "could not power up OV7251\n");
+		goto free_entity;
+	}
+
+	ret = ov7251_read_reg(ov7251, OV7251_CHIP_ID_HIGH, &chip_id_high);
+	if (ret < 0 || chip_id_high != OV7251_CHIP_ID_HIGH_BYTE) {
+		dev_err(dev, "could not read ID high\n");
+		ret = -ENODEV;
+		goto power_down;
+	}
+	ret = ov7251_read_reg(ov7251, OV7251_CHIP_ID_LOW, &chip_id_low);
+	if (ret < 0 || chip_id_low != OV7251_CHIP_ID_LOW_BYTE) {
+		dev_err(dev, "could not read ID low\n");
+		ret = -ENODEV;
+		goto power_down;
+	}
+
+	ret = ov7251_read_reg(ov7251, OV7251_SC_GP_IO_IN1, &chip_rev);
+	if (ret < 0) {
+		dev_err(dev, "could not read revision\n");
+		ret = -ENODEV;
+		goto power_down;
+	}
+	chip_rev >>= 4;
+
+	dev_info(dev, "OV7251 revision %x (%s) detected at address 0x%02x\n",
+		 chip_rev,
+		 chip_rev == 0x4 ? "1A / 1B" :
+		 chip_rev == 0x5 ? "1C / 1D" :
+		 chip_rev == 0x6 ? "1E" :
+		 chip_rev == 0x7 ? "1F" : "unknown",
+		 client->addr);
+
+	ret = ov7251_read_reg(ov7251, OV7251_PRE_ISP_00,
+			      &ov7251->pre_isp_00);
+	if (ret < 0) {
+		dev_err(dev, "could not read test pattern value\n");
+		ret = -ENODEV;
+		goto power_down;
+	}
+
+	ret = ov7251_read_reg(ov7251, OV7251_TIMING_FORMAT1,
+			      &ov7251->timing_format1);
+	if (ret < 0) {
+		dev_err(dev, "could not read vflip value\n");
+		ret = -ENODEV;
+		goto power_down;
+	}
+
+	ret = ov7251_read_reg(ov7251, OV7251_TIMING_FORMAT2,
+			      &ov7251->timing_format2);
+	if (ret < 0) {
+		dev_err(dev, "could not read hflip value\n");
+		ret = -ENODEV;
+		goto power_down;
+	}
+
+	ov7251_s_power(&ov7251->sd, false);
+
+	ret = v4l2_async_register_subdev(&ov7251->sd);
+	if (ret < 0) {
+		dev_err(dev, "could not register v4l2 device\n");
+		goto free_entity;
+	}
+
+	ov7251_entity_init_cfg(&ov7251->sd, NULL);
+
+	return 0;
+
+power_down:
+	ov7251_s_power(&ov7251->sd, false);
+free_entity:
+	media_entity_cleanup(&ov7251->sd.entity);
+free_ctrl:
+	v4l2_ctrl_handler_free(&ov7251->ctrls);
+	mutex_destroy(&ov7251->power_lock);
+
+	return ret;
+}
+
+static int ov7251_remove(struct i2c_client *client)
+{
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct ov7251 *ov7251 = to_ov7251(sd);
+
+	v4l2_async_unregister_subdev(&ov7251->sd);
+	media_entity_cleanup(&ov7251->sd.entity);
+	v4l2_ctrl_handler_free(&ov7251->ctrls);
+	mutex_destroy(&ov7251->power_lock);
+
+	return 0;
+}
+
+static const struct i2c_device_id ov7251_id[] = {
+	{ "ov7251", 0 },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, ov7251_id);
+
+static const struct of_device_id ov7251_of_match[] = {
+	{ .compatible = "ovti,ov7251" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ov7251_of_match);
+
+static struct i2c_driver ov7251_i2c_driver = {
+	.driver = {
+		.of_match_table = of_match_ptr(ov7251_of_match),
+		.name  = "ov7251",
+	},
+	.probe  = ov7251_probe,
+	.remove = ov7251_remove,
+	.id_table = ov7251_id,
+};
+
+module_i2c_driver(ov7251_i2c_driver);
+
+MODULE_DESCRIPTION("Omnivision OV7251 Camera Driver");
+MODULE_AUTHOR("Todor Tomov <todor.tomov@linaro.org>");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4