Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2037 insertions, 0 deletions

diff --git a/drivers/media/i2c/imx274.c b/drivers/media/i2c/imx274.c
new file mode 100644
index 000000000..0fe8b8692
--- /dev/null
+++ b/drivers/media/i2c/imx274.c
@@ -0,0 +1,2037 @@
+/*
+ * imx274.c - IMX274 CMOS Image Sensor driver
+ *
+ * Copyright (C) 2017, Leopard Imaging, Inc.
+ *
+ * Leon Luo <leonl@leopardimaging.com>
+ * Edwin Zou <edwinz@leopardimaging.com>
+ * Luca Ceresoli <luca@lucaceresoli.net>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_gpio.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/v4l2-mediabus.h>
+#include <linux/videodev2.h>
+
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-subdev.h>
+
+/*
+ * See "SHR, SVR Setting" in datasheet
+ */
+#define IMX274_DEFAULT_FRAME_LENGTH		(4550)
+#define IMX274_MAX_FRAME_LENGTH			(0x000fffff)
+
+/*
+ * See "Frame Rate Adjustment" in datasheet
+ */
+#define IMX274_PIXCLK_CONST1			(72000000)
+#define IMX274_PIXCLK_CONST2			(1000000)
+
+/*
+ * The input gain is shifted by IMX274_GAIN_SHIFT to get
+ * decimal number. The real gain is
+ * (float)input_gain_value / (1 << IMX274_GAIN_SHIFT)
+ */
+#define IMX274_GAIN_SHIFT			(8)
+#define IMX274_GAIN_SHIFT_MASK			((1 << IMX274_GAIN_SHIFT) - 1)
+
+/*
+ * See "Analog Gain" and "Digital Gain" in datasheet
+ * min gain is 1X
+ * max gain is calculated based on IMX274_GAIN_REG_MAX
+ */
+#define IMX274_GAIN_REG_MAX			(1957)
+#define IMX274_MIN_GAIN				(0x01 << IMX274_GAIN_SHIFT)
+#define IMX274_MAX_ANALOG_GAIN			((2048 << IMX274_GAIN_SHIFT)\
+					/ (2048 - IMX274_GAIN_REG_MAX))
+#define IMX274_MAX_DIGITAL_GAIN			(8)
+#define IMX274_DEF_GAIN				(20 << IMX274_GAIN_SHIFT)
+#define IMX274_GAIN_CONST			(2048) /* for gain formula */
+
+/*
+ * 1 line time in us = (HMAX / 72), minimal is 4 lines
+ */
+#define IMX274_MIN_EXPOSURE_TIME		(4 * 260 / 72)
+
+#define IMX274_DEFAULT_MODE			IMX274_BINNING_OFF
+#define IMX274_MAX_WIDTH			(3840)
+#define IMX274_MAX_HEIGHT			(2160)
+#define IMX274_MAX_FRAME_RATE			(120)
+#define IMX274_MIN_FRAME_RATE			(5)
+#define IMX274_DEF_FRAME_RATE			(60)
+
+/*
+ * register SHR is limited to (SVR value + 1) x VMAX value - 4
+ */
+#define IMX274_SHR_LIMIT_CONST			(4)
+
+/*
+ * Min and max sensor reset delay (microseconds)
+ */
+#define IMX274_RESET_DELAY1			(2000)
+#define IMX274_RESET_DELAY2			(2200)
+
+/*
+ * shift and mask constants
+ */
+#define IMX274_SHIFT_8_BITS			(8)
+#define IMX274_SHIFT_16_BITS			(16)
+#define IMX274_MASK_LSB_2_BITS			(0x03)
+#define IMX274_MASK_LSB_3_BITS			(0x07)
+#define IMX274_MASK_LSB_4_BITS			(0x0f)
+#define IMX274_MASK_LSB_8_BITS			(0x00ff)
+
+#define DRIVER_NAME "IMX274"
+
+/*
+ * IMX274 register definitions
+ */
+#define IMX274_SHR_REG_MSB			0x300D /* SHR */
+#define IMX274_SHR_REG_LSB			0x300C /* SHR */
+#define IMX274_SVR_REG_MSB			0x300F /* SVR */
+#define IMX274_SVR_REG_LSB			0x300E /* SVR */
+#define IMX274_HTRIM_EN_REG			0x3037
+#define IMX274_HTRIM_START_REG_LSB		0x3038
+#define IMX274_HTRIM_START_REG_MSB		0x3039
+#define IMX274_HTRIM_END_REG_LSB		0x303A
+#define IMX274_HTRIM_END_REG_MSB		0x303B
+#define IMX274_VWIDCUTEN_REG			0x30DD
+#define IMX274_VWIDCUT_REG_LSB			0x30DE
+#define IMX274_VWIDCUT_REG_MSB			0x30DF
+#define IMX274_VWINPOS_REG_LSB			0x30E0
+#define IMX274_VWINPOS_REG_MSB			0x30E1
+#define IMX274_WRITE_VSIZE_REG_LSB		0x3130
+#define IMX274_WRITE_VSIZE_REG_MSB		0x3131
+#define IMX274_Y_OUT_SIZE_REG_LSB		0x3132
+#define IMX274_Y_OUT_SIZE_REG_MSB		0x3133
+#define IMX274_VMAX_REG_1			0x30FA /* VMAX, MSB */
+#define IMX274_VMAX_REG_2			0x30F9 /* VMAX */
+#define IMX274_VMAX_REG_3			0x30F8 /* VMAX, LSB */
+#define IMX274_HMAX_REG_MSB			0x30F7 /* HMAX */
+#define IMX274_HMAX_REG_LSB			0x30F6 /* HMAX */
+#define IMX274_ANALOG_GAIN_ADDR_LSB		0x300A /* ANALOG GAIN LSB */
+#define IMX274_ANALOG_GAIN_ADDR_MSB		0x300B /* ANALOG GAIN MSB */
+#define IMX274_DIGITAL_GAIN_REG			0x3012 /* Digital Gain */
+#define IMX274_VFLIP_REG			0x301A /* VERTICAL FLIP */
+#define IMX274_TEST_PATTERN_REG			0x303D /* TEST PATTERN */
+#define IMX274_STANDBY_REG			0x3000 /* STANDBY */
+
+#define IMX274_TABLE_WAIT_MS			0
+#define IMX274_TABLE_END			1
+
+/*
+ * imx274 I2C operation related structure
+ */
+struct reg_8 {
+	u16 addr;
+	u8 val;
+};
+
+static const struct regmap_config imx274_regmap_config = {
+	.reg_bits = 16,
+	.val_bits = 8,
+	.cache_type = REGCACHE_RBTREE,
+};
+
+enum imx274_binning {
+	IMX274_BINNING_OFF,
+	IMX274_BINNING_2_1,
+	IMX274_BINNING_3_1,
+};
+
+/*
+ * Parameters for each imx274 readout mode.
+ *
+ * These are the values to configure the sensor in one of the
+ * implemented modes.
+ *
+ * @init_regs: registers to initialize the mode
+ * @bin_ratio: downscale factor (e.g. 3 for 3:1 binning)
+ * @min_frame_len: Minimum frame length for each mode (see "Frame Rate
+ *                 Adjustment (CSI-2)" in the datasheet)
+ * @min_SHR: Minimum SHR register value (see "Shutter Setting (CSI-2)" in the
+ *           datasheet)
+ * @max_fps: Maximum frames per second
+ * @nocpiop: Number of clocks per internal offset period (see "Integration Time
+ *           in Each Readout Drive Mode (CSI-2)" in the datasheet)
+ */
+struct imx274_frmfmt {
+	const struct reg_8 *init_regs;
+	unsigned int bin_ratio;
+	int min_frame_len;
+	int min_SHR;
+	int max_fps;
+	int nocpiop;
+};
+
+/*
+ * imx274 test pattern related structure
+ */
+enum {
+	TEST_PATTERN_DISABLED = 0,
+	TEST_PATTERN_ALL_000H,
+	TEST_PATTERN_ALL_FFFH,
+	TEST_PATTERN_ALL_555H,
+	TEST_PATTERN_ALL_AAAH,
+	TEST_PATTERN_VSP_5AH, /* VERTICAL STRIPE PATTERN 555H/AAAH */
+	TEST_PATTERN_VSP_A5H, /* VERTICAL STRIPE PATTERN AAAH/555H */
+	TEST_PATTERN_VSP_05H, /* VERTICAL STRIPE PATTERN 000H/555H */
+	TEST_PATTERN_VSP_50H, /* VERTICAL STRIPE PATTERN 555H/000H */
+	TEST_PATTERN_VSP_0FH, /* VERTICAL STRIPE PATTERN 000H/FFFH */
+	TEST_PATTERN_VSP_F0H, /* VERTICAL STRIPE PATTERN FFFH/000H */
+	TEST_PATTERN_H_COLOR_BARS,
+	TEST_PATTERN_V_COLOR_BARS,
+};
+
+static const char * const tp_qmenu[] = {
+	"Disabled",
+	"All 000h Pattern",
+	"All FFFh Pattern",
+	"All 555h Pattern",
+	"All AAAh Pattern",
+	"Vertical Stripe (555h / AAAh)",
+	"Vertical Stripe (AAAh / 555h)",
+	"Vertical Stripe (000h / 555h)",
+	"Vertical Stripe (555h / 000h)",
+	"Vertical Stripe (000h / FFFh)",
+	"Vertical Stripe (FFFh / 000h)",
+	"Horizontal Color Bars",
+	"Vertical Color Bars",
+};
+
+/*
+ * All-pixel scan mode (10-bit)
+ * imx274 mode1(refer to datasheet) register configuration with
+ * 3840x2160 resolution, raw10 data and mipi four lane output
+ */
+static const struct reg_8 imx274_mode1_3840x2160_raw10[] = {
+	{0x3004, 0x01},
+	{0x3005, 0x01},
+	{0x3006, 0x00},
+	{0x3007, 0xa2},
+
+	{0x3018, 0xA2}, /* output XVS, HVS */
+
+	{0x306B, 0x05},
+	{0x30E2, 0x01},
+
+	{0x30EE, 0x01},
+	{0x3342, 0x0A},
+	{0x3343, 0x00},
+	{0x3344, 0x16},
+	{0x3345, 0x00},
+	{0x33A6, 0x01},
+	{0x3528, 0x0E},
+	{0x3554, 0x1F},
+	{0x3555, 0x01},
+	{0x3556, 0x01},
+	{0x3557, 0x01},
+	{0x3558, 0x01},
+	{0x3559, 0x00},
+	{0x355A, 0x00},
+	{0x35BA, 0x0E},
+	{0x366A, 0x1B},
+	{0x366B, 0x1A},
+	{0x366C, 0x19},
+	{0x366D, 0x17},
+	{0x3A41, 0x08},
+
+	{IMX274_TABLE_END, 0x00}
+};
+
+/*
+ * Horizontal/vertical 2/2-line binning
+ * (Horizontal and vertical weightedbinning, 10-bit)
+ * imx274 mode3(refer to datasheet) register configuration with
+ * 1920x1080 resolution, raw10 data and mipi four lane output
+ */
+static const struct reg_8 imx274_mode3_1920x1080_raw10[] = {
+	{0x3004, 0x02},
+	{0x3005, 0x21},
+	{0x3006, 0x00},
+	{0x3007, 0xb1},
+
+	{0x3018, 0xA2}, /* output XVS, HVS */
+
+	{0x306B, 0x05},
+	{0x30E2, 0x02},
+
+	{0x30EE, 0x01},
+	{0x3342, 0x0A},
+	{0x3343, 0x00},
+	{0x3344, 0x1A},
+	{0x3345, 0x00},
+	{0x33A6, 0x01},
+	{0x3528, 0x0E},
+	{0x3554, 0x00},
+	{0x3555, 0x01},
+	{0x3556, 0x01},
+	{0x3557, 0x01},
+	{0x3558, 0x01},
+	{0x3559, 0x00},
+	{0x355A, 0x00},
+	{0x35BA, 0x0E},
+	{0x366A, 0x1B},
+	{0x366B, 0x1A},
+	{0x366C, 0x19},
+	{0x366D, 0x17},
+	{0x3A41, 0x08},
+
+	{IMX274_TABLE_END, 0x00}
+};
+
+/*
+ * Vertical 2/3 subsampling binning horizontal 3 binning
+ * imx274 mode5(refer to datasheet) register configuration with
+ * 1280x720 resolution, raw10 data and mipi four lane output
+ */
+static const struct reg_8 imx274_mode5_1280x720_raw10[] = {
+	{0x3004, 0x03},
+	{0x3005, 0x31},
+	{0x3006, 0x00},
+	{0x3007, 0xa9},
+
+	{0x3018, 0xA2}, /* output XVS, HVS */
+
+	{0x306B, 0x05},
+	{0x30E2, 0x03},
+
+	{0x30EE, 0x01},
+	{0x3342, 0x0A},
+	{0x3343, 0x00},
+	{0x3344, 0x1B},
+	{0x3345, 0x00},
+	{0x33A6, 0x01},
+	{0x3528, 0x0E},
+	{0x3554, 0x00},
+	{0x3555, 0x01},
+	{0x3556, 0x01},
+	{0x3557, 0x01},
+	{0x3558, 0x01},
+	{0x3559, 0x00},
+	{0x355A, 0x00},
+	{0x35BA, 0x0E},
+	{0x366A, 0x1B},
+	{0x366B, 0x19},
+	{0x366C, 0x17},
+	{0x366D, 0x17},
+	{0x3A41, 0x04},
+
+	{IMX274_TABLE_END, 0x00}
+};
+
+/*
+ * imx274 first step register configuration for
+ * starting stream
+ */
+static const struct reg_8 imx274_start_1[] = {
+	{IMX274_STANDBY_REG, 0x12},
+	{IMX274_TABLE_END, 0x00}
+};
+
+/*
+ * imx274 second step register configuration for
+ * starting stream
+ */
+static const struct reg_8 imx274_start_2[] = {
+	{0x3120, 0xF0}, /* clock settings */
+	{0x3121, 0x00}, /* clock settings */
+	{0x3122, 0x02}, /* clock settings */
+	{0x3129, 0x9C}, /* clock settings */
+	{0x312A, 0x02}, /* clock settings */
+	{0x312D, 0x02}, /* clock settings */
+
+	{0x310B, 0x00},
+
+	/* PLSTMG */
+	{0x304C, 0x00}, /* PLSTMG01 */
+	{0x304D, 0x03},
+	{0x331C, 0x1A},
+	{0x331D, 0x00},
+	{0x3502, 0x02},
+	{0x3529, 0x0E},
+	{0x352A, 0x0E},
+	{0x352B, 0x0E},
+	{0x3538, 0x0E},
+	{0x3539, 0x0E},
+	{0x3553, 0x00},
+	{0x357D, 0x05},
+	{0x357F, 0x05},
+	{0x3581, 0x04},
+	{0x3583, 0x76},
+	{0x3587, 0x01},
+	{0x35BB, 0x0E},
+	{0x35BC, 0x0E},
+	{0x35BD, 0x0E},
+	{0x35BE, 0x0E},
+	{0x35BF, 0x0E},
+	{0x366E, 0x00},
+	{0x366F, 0x00},
+	{0x3670, 0x00},
+	{0x3671, 0x00},
+
+	/* PSMIPI */
+	{0x3304, 0x32}, /* PSMIPI1 */
+	{0x3305, 0x00},
+	{0x3306, 0x32},
+	{0x3307, 0x00},
+	{0x3590, 0x32},
+	{0x3591, 0x00},
+	{0x3686, 0x32},
+	{0x3687, 0x00},
+
+	{IMX274_TABLE_END, 0x00}
+};
+
+/*
+ * imx274 third step register configuration for
+ * starting stream
+ */
+static const struct reg_8 imx274_start_3[] = {
+	{IMX274_STANDBY_REG, 0x00},
+	{0x303E, 0x02}, /* SYS_MODE = 2 */
+	{IMX274_TABLE_END, 0x00}
+};
+
+/*
+ * imx274 forth step register configuration for
+ * starting stream
+ */
+static const struct reg_8 imx274_start_4[] = {
+	{0x30F4, 0x00},
+	{0x3018, 0xA2}, /* XHS VHS OUTUPT */
+	{IMX274_TABLE_END, 0x00}
+};
+
+/*
+ * imx274 register configuration for stoping stream
+ */
+static const struct reg_8 imx274_stop[] = {
+	{IMX274_STANDBY_REG, 0x01},
+	{IMX274_TABLE_END, 0x00}
+};
+
+/*
+ * imx274 disable test pattern register configuration
+ */
+static const struct reg_8 imx274_tp_disabled[] = {
+	{0x303C, 0x00},
+	{0x377F, 0x00},
+	{0x3781, 0x00},
+	{0x370B, 0x00},
+	{IMX274_TABLE_END, 0x00}
+};
+
+/*
+ * imx274 test pattern register configuration
+ * reg 0x303D defines the test pattern modes
+ */
+static const struct reg_8 imx274_tp_regs[] = {
+	{0x303C, 0x11},
+	{0x370E, 0x01},
+	{0x377F, 0x01},
+	{0x3781, 0x01},
+	{0x370B, 0x11},
+	{IMX274_TABLE_END, 0x00}
+};
+
+/* nocpiop happens to be the same number for the implemented modes */
+static const struct imx274_frmfmt imx274_formats[] = {
+	{
+		/* mode 1, 4K */
+		.bin_ratio = 1,
+		.init_regs = imx274_mode1_3840x2160_raw10,
+		.min_frame_len = 4550,
+		.min_SHR = 12,
+		.max_fps = 60,
+		.nocpiop = 112,
+	},
+	{
+		/* mode 3, 1080p */
+		.bin_ratio = 2,
+		.init_regs = imx274_mode3_1920x1080_raw10,
+		.min_frame_len = 2310,
+		.min_SHR = 8,
+		.max_fps = 120,
+		.nocpiop = 112,
+	},
+	{
+		/* mode 5, 720p */
+		.bin_ratio = 3,
+		.init_regs = imx274_mode5_1280x720_raw10,
+		.min_frame_len = 2310,
+		.min_SHR = 8,
+		.max_fps = 120,
+		.nocpiop = 112,
+	},
+};
+
+/*
+ * struct imx274_ctrls - imx274 ctrl structure
+ * @handler: V4L2 ctrl handler structure
+ * @exposure: Pointer to expsure ctrl structure
+ * @gain: Pointer to gain ctrl structure
+ * @vflip: Pointer to vflip ctrl structure
+ * @test_pattern: Pointer to test pattern ctrl structure
+ */
+struct imx274_ctrls {
+	struct v4l2_ctrl_handler handler;
+	struct v4l2_ctrl *exposure;
+	struct v4l2_ctrl *gain;
+	struct v4l2_ctrl *vflip;
+	struct v4l2_ctrl *test_pattern;
+};
+
+/*
+ * struct stim274 - imx274 device structure
+ * @sd: V4L2 subdevice structure
+ * @pad: Media pad structure
+ * @client: Pointer to I2C client
+ * @ctrls: imx274 control structure
+ * @crop: rect to be captured
+ * @compose: compose rect, i.e. output resolution
+ * @format: V4L2 media bus frame format structure
+ *          (width and height are in sync with the compose rect)
+ * @frame_rate: V4L2 frame rate structure
+ * @regmap: Pointer to regmap structure
+ * @reset_gpio: Pointer to reset gpio
+ * @lock: Mutex structure
+ * @mode: Parameters for the selected readout mode
+ */
+struct stimx274 {
+	struct v4l2_subdev sd;
+	struct media_pad pad;
+	struct i2c_client *client;
+	struct imx274_ctrls ctrls;
+	struct v4l2_rect crop;
+	struct v4l2_mbus_framefmt format;
+	struct v4l2_fract frame_interval;
+	struct regmap *regmap;
+	struct gpio_desc *reset_gpio;
+	struct mutex lock; /* mutex lock for operations */
+	const struct imx274_frmfmt *mode;
+};
+
+#define IMX274_ROUND(dim, step, flags)			\
+	((flags) & V4L2_SEL_FLAG_GE			\
+	 ? roundup((dim), (step))			\
+	 : ((flags) & V4L2_SEL_FLAG_LE			\
+	    ? rounddown((dim), (step))			\
+	    : rounddown((dim) + (step) / 2, (step))))
+
+/*
+ * Function declaration
+ */
+static int imx274_set_gain(struct stimx274 *priv, struct v4l2_ctrl *ctrl);
+static int imx274_set_exposure(struct stimx274 *priv, int val);
+static int imx274_set_vflip(struct stimx274 *priv, int val);
+static int imx274_set_test_pattern(struct stimx274 *priv, int val);
+static int imx274_set_frame_interval(struct stimx274 *priv,
+				     struct v4l2_fract frame_interval);
+
+static inline void msleep_range(unsigned int delay_base)
+{
+	usleep_range(delay_base * 1000, delay_base * 1000 + 500);
+}
+
+/*
+ * v4l2_ctrl and v4l2_subdev related operations
+ */
+static inline struct v4l2_subdev *ctrl_to_sd(struct v4l2_ctrl *ctrl)
+{
+	return &container_of(ctrl->handler,
+			     struct stimx274, ctrls.handler)->sd;
+}
+
+static inline struct stimx274 *to_imx274(struct v4l2_subdev *sd)
+{
+	return container_of(sd, struct stimx274, sd);
+}
+
+/*
+ * Writing a register table
+ *
+ * @priv: Pointer to device
+ * @table: Table containing register values (with optional delays)
+ *
+ * This is used to write register table into sensor's reg map.
+ *
+ * Return: 0 on success, errors otherwise
+ */
+static int imx274_write_table(struct stimx274 *priv, const struct reg_8 table[])
+{
+	struct regmap *regmap = priv->regmap;
+	int err = 0;
+	const struct reg_8 *next;
+	u8 val;
+
+	int range_start = -1;
+	int range_count = 0;
+	u8 range_vals[16];
+	int max_range_vals = ARRAY_SIZE(range_vals);
+
+	for (next = table;; next++) {
+		if ((next->addr != range_start + range_count) ||
+		    (next->addr == IMX274_TABLE_END) ||
+		    (next->addr == IMX274_TABLE_WAIT_MS) ||
+		    (range_count == max_range_vals)) {
+			if (range_count == 1)
+				err = regmap_write(regmap,
+						   range_start, range_vals[0]);
+			else if (range_count > 1)
+				err = regmap_bulk_write(regmap, range_start,
+							&range_vals[0],
+							range_count);
+			else
+				err = 0;
+
+			if (err)
+				return err;
+
+			range_start = -1;
+			range_count = 0;
+
+			/* Handle special address values */
+			if (next->addr == IMX274_TABLE_END)
+				break;
+
+			if (next->addr == IMX274_TABLE_WAIT_MS) {
+				msleep_range(next->val);
+				continue;
+			}
+		}
+
+		val = next->val;
+
+		if (range_start == -1)
+			range_start = next->addr;
+
+		range_vals[range_count++] = val;
+	}
+	return 0;
+}
+
+static inline int imx274_read_reg(struct stimx274 *priv, u16 addr, u8 *val)
+{
+	unsigned int uint_val;
+	int err;
+
+	err = regmap_read(priv->regmap, addr, &uint_val);
+	if (err)
+		dev_err(&priv->client->dev,
+			"%s : i2c read failed, addr = %x\n", __func__, addr);
+	else
+		dev_dbg(&priv->client->dev,
+			"%s : addr 0x%x, val=0x%x\n", __func__,
+			addr, uint_val);
+
+	*val = uint_val;
+	return err;
+}
+
+static inline int imx274_write_reg(struct stimx274 *priv, u16 addr, u8 val)
+{
+	int err;
+
+	err = regmap_write(priv->regmap, addr, val);
+	if (err)
+		dev_err(&priv->client->dev,
+			"%s : i2c write failed, %x = %x\n", __func__,
+			addr, val);
+	else
+		dev_dbg(&priv->client->dev,
+			"%s : addr 0x%x, val=0x%x\n", __func__,
+			addr, val);
+	return err;
+}
+
+/**
+ * Write a multibyte register.
+ *
+ * Uses a bulk write where possible.
+ *
+ * @priv: Pointer to device structure
+ * @addr: Address of the LSB register.  Other registers must be
+ *        consecutive, least-to-most significant.
+ * @val: Value to be written to the register (cpu endianness)
+ * @nbytes: Number of bits to write (range: [1..3])
+ */
+static int imx274_write_mbreg(struct stimx274 *priv, u16 addr, u32 val,
+			      size_t nbytes)
+{
+	__le32 val_le = cpu_to_le32(val);
+	int err;
+
+	err = regmap_bulk_write(priv->regmap, addr, &val_le, nbytes);
+	if (err)
+		dev_err(&priv->client->dev,
+			"%s : i2c bulk write failed, %x = %x (%zu bytes)\n",
+			__func__, addr, val, nbytes);
+	else
+		dev_dbg(&priv->client->dev,
+			"%s : addr 0x%x, val=0x%x (%zu bytes)\n",
+			__func__, addr, val, nbytes);
+	return err;
+}
+
+/*
+ * Set mode registers to start stream.
+ * @priv: Pointer to device structure
+ *
+ * Return: 0 on success, errors otherwise
+ */
+static int imx274_mode_regs(struct stimx274 *priv)
+{
+	int err = 0;
+
+	err = imx274_write_table(priv, imx274_start_1);
+	if (err)
+		return err;
+
+	err = imx274_write_table(priv, imx274_start_2);
+	if (err)
+		return err;
+
+	err = imx274_write_table(priv, priv->mode->init_regs);
+
+	return err;
+}
+
+/*
+ * imx274_start_stream - Function for starting stream per mode index
+ * @priv: Pointer to device structure
+ *
+ * Return: 0 on success, errors otherwise
+ */
+static int imx274_start_stream(struct stimx274 *priv)
+{
+	int err = 0;
+
+	/*
+	 * Refer to "Standby Cancel Sequence when using CSI-2" in
+	 * imx274 datasheet, it should wait 10ms or more here.
+	 * give it 1 extra ms for margin
+	 */
+	msleep_range(11);
+	err = imx274_write_table(priv, imx274_start_3);
+	if (err)
+		return err;
+
+	/*
+	 * Refer to "Standby Cancel Sequence when using CSI-2" in
+	 * imx274 datasheet, it should wait 7ms or more here.
+	 * give it 1 extra ms for margin
+	 */
+	msleep_range(8);
+	err = imx274_write_table(priv, imx274_start_4);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+/*
+ * imx274_reset - Function called to reset the sensor
+ * @priv: Pointer to device structure
+ * @rst: Input value for determining the sensor's end state after reset
+ *
+ * Set the senor in reset and then
+ * if rst = 0, keep it in reset;
+ * if rst = 1, bring it out of reset.
+ *
+ */
+static void imx274_reset(struct stimx274 *priv, int rst)
+{
+	gpiod_set_value_cansleep(priv->reset_gpio, 0);
+	usleep_range(IMX274_RESET_DELAY1, IMX274_RESET_DELAY2);
+	gpiod_set_value_cansleep(priv->reset_gpio, !!rst);
+	usleep_range(IMX274_RESET_DELAY1, IMX274_RESET_DELAY2);
+}
+
+/**
+ * imx274_s_ctrl - This is used to set the imx274 V4L2 controls
+ * @ctrl: V4L2 control to be set
+ *
+ * This function is used to set the V4L2 controls for the imx274 sensor.
+ *
+ * Return: 0 on success, errors otherwise
+ */
+static int imx274_s_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct v4l2_subdev *sd = ctrl_to_sd(ctrl);
+	struct stimx274 *imx274 = to_imx274(sd);
+	int ret = -EINVAL;
+
+	dev_dbg(&imx274->client->dev,
+		"%s : s_ctrl: %s, value: %d\n", __func__,
+		ctrl->name, ctrl->val);
+
+	switch (ctrl->id) {
+	case V4L2_CID_EXPOSURE:
+		dev_dbg(&imx274->client->dev,
+			"%s : set V4L2_CID_EXPOSURE\n", __func__);
+		ret = imx274_set_exposure(imx274, ctrl->val);
+		break;
+
+	case V4L2_CID_GAIN:
+		dev_dbg(&imx274->client->dev,
+			"%s : set V4L2_CID_GAIN\n", __func__);
+		ret = imx274_set_gain(imx274, ctrl);
+		break;
+
+	case V4L2_CID_VFLIP:
+		dev_dbg(&imx274->client->dev,
+			"%s : set V4L2_CID_VFLIP\n", __func__);
+		ret = imx274_set_vflip(imx274, ctrl->val);
+		break;
+
+	case V4L2_CID_TEST_PATTERN:
+		dev_dbg(&imx274->client->dev,
+			"%s : set V4L2_CID_TEST_PATTERN\n", __func__);
+		ret = imx274_set_test_pattern(imx274, ctrl->val);
+		break;
+	}
+
+	return ret;
+}
+
+static int imx274_binning_goodness(struct stimx274 *imx274,
+				   int w, int ask_w,
+				   int h, int ask_h, u32 flags)
+{
+	struct device *dev = &imx274->client->dev;
+	const int goodness = 100000;
+	int val = 0;
+
+	if (flags & V4L2_SEL_FLAG_GE) {
+		if (w < ask_w)
+			val -= goodness;
+		if (h < ask_h)
+			val -= goodness;
+	}
+
+	if (flags & V4L2_SEL_FLAG_LE) {
+		if (w > ask_w)
+			val -= goodness;
+		if (h > ask_h)
+			val -= goodness;
+	}
+
+	val -= abs(w - ask_w);
+	val -= abs(h - ask_h);
+
+	dev_dbg(dev, "%s: ask %dx%d, size %dx%d, goodness %d\n",
+		__func__, ask_w, ask_h, w, h, val);
+
+	return val;
+}
+
+/**
+ * Helper function to change binning and set both compose and format.
+ *
+ * We have two entry points to change binning: set_fmt and
+ * set_selection(COMPOSE). Both have to compute the new output size
+ * and set it in both the compose rect and the frame format size. We
+ * also need to do the same things after setting cropping to restore
+ * 1:1 binning.
+ *
+ * This function contains the common code for these three cases, it
+ * has many arguments in order to accommodate the needs of all of
+ * them.
+ *
+ * Must be called with imx274->lock locked.
+ *
+ * @imx274: The device object
+ * @cfg:    The pad config we are editing for TRY requests
+ * @which:  V4L2_SUBDEV_FORMAT_ACTIVE or V4L2_SUBDEV_FORMAT_TRY from the caller
+ * @width:  Input-output parameter: set to the desired width before
+ *          the call, contains the chosen value after returning successfully
+ * @height: Input-output parameter for height (see @width)
+ * @flags:  Selection flags from struct v4l2_subdev_selection, or 0 if not
+ *          available (when called from set_fmt)
+ */
+static int __imx274_change_compose(struct stimx274 *imx274,
+				   struct v4l2_subdev_pad_config *cfg,
+				   u32 which,
+				   u32 *width,
+				   u32 *height,
+				   u32 flags)
+{
+	struct device *dev = &imx274->client->dev;
+	const struct v4l2_rect *cur_crop;
+	struct v4l2_mbus_framefmt *tgt_fmt;
+	unsigned int i;
+	const struct imx274_frmfmt *best_mode = &imx274_formats[0];
+	int best_goodness = INT_MIN;
+
+	if (which == V4L2_SUBDEV_FORMAT_TRY) {
+		cur_crop = &cfg->try_crop;
+		tgt_fmt = &cfg->try_fmt;
+	} else {
+		cur_crop = &imx274->crop;
+		tgt_fmt = &imx274->format;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(imx274_formats); i++) {
+		unsigned int ratio = imx274_formats[i].bin_ratio;
+
+		int goodness = imx274_binning_goodness(
+			imx274,
+			cur_crop->width / ratio, *width,
+			cur_crop->height / ratio, *height,
+			flags);
+
+		if (goodness >= best_goodness) {
+			best_goodness = goodness;
+			best_mode = &imx274_formats[i];
+		}
+	}
+
+	*width = cur_crop->width / best_mode->bin_ratio;
+	*height = cur_crop->height / best_mode->bin_ratio;
+
+	if (which == V4L2_SUBDEV_FORMAT_ACTIVE)
+		imx274->mode = best_mode;
+
+	dev_dbg(dev, "%s: selected %u:1 binning\n",
+		__func__, best_mode->bin_ratio);
+
+	tgt_fmt->width = *width;
+	tgt_fmt->height = *height;
+	tgt_fmt->field = V4L2_FIELD_NONE;
+
+	return 0;
+}
+
+/**
+ * imx274_get_fmt - Get the pad format
+ * @sd: Pointer to V4L2 Sub device structure
+ * @cfg: Pointer to sub device pad information structure
+ * @fmt: Pointer to pad level media bus format
+ *
+ * This function is used to get the pad format information.
+ *
+ * Return: 0 on success
+ */
+static int imx274_get_fmt(struct v4l2_subdev *sd,
+			  struct v4l2_subdev_pad_config *cfg,
+			  struct v4l2_subdev_format *fmt)
+{
+	struct stimx274 *imx274 = to_imx274(sd);
+
+	mutex_lock(&imx274->lock);
+	fmt->format = imx274->format;
+	mutex_unlock(&imx274->lock);
+	return 0;
+}
+
+/**
+ * imx274_set_fmt - This is used to set the pad format
+ * @sd: Pointer to V4L2 Sub device structure
+ * @cfg: Pointer to sub device pad information structure
+ * @format: Pointer to pad level media bus format
+ *
+ * This function is used to set the pad format.
+ *
+ * Return: 0 on success
+ */
+static int imx274_set_fmt(struct v4l2_subdev *sd,
+			  struct v4l2_subdev_pad_config *cfg,
+			  struct v4l2_subdev_format *format)
+{
+	struct v4l2_mbus_framefmt *fmt = &format->format;
+	struct stimx274 *imx274 = to_imx274(sd);
+	int err = 0;
+
+	mutex_lock(&imx274->lock);
+
+	err = __imx274_change_compose(imx274, cfg, format->which,
+				      &fmt->width, &fmt->height, 0);
+
+	if (err)
+		goto out;
+
+	/*
+	 * __imx274_change_compose already set width and height in the
+	 * applicable format, but we need to keep all other format
+	 * values, so do a full copy here
+	 */
+	fmt->field = V4L2_FIELD_NONE;
+	if (format->which == V4L2_SUBDEV_FORMAT_TRY)
+		cfg->try_fmt = *fmt;
+	else
+		imx274->format = *fmt;
+
+out:
+	mutex_unlock(&imx274->lock);
+
+	return err;
+}
+
+static int imx274_get_selection(struct v4l2_subdev *sd,
+				struct v4l2_subdev_pad_config *cfg,
+				struct v4l2_subdev_selection *sel)
+{
+	struct stimx274 *imx274 = to_imx274(sd);
+	const struct v4l2_rect *src_crop;
+	const struct v4l2_mbus_framefmt *src_fmt;
+	int ret = 0;
+
+	if (sel->pad != 0)
+		return -EINVAL;
+
+	if (sel->target == V4L2_SEL_TGT_CROP_BOUNDS) {
+		sel->r.left = 0;
+		sel->r.top = 0;
+		sel->r.width = IMX274_MAX_WIDTH;
+		sel->r.height = IMX274_MAX_HEIGHT;
+		return 0;
+	}
+
+	if (sel->which == V4L2_SUBDEV_FORMAT_TRY) {
+		src_crop = &cfg->try_crop;
+		src_fmt = &cfg->try_fmt;
+	} else {
+		src_crop = &imx274->crop;
+		src_fmt = &imx274->format;
+	}
+
+	mutex_lock(&imx274->lock);
+
+	switch (sel->target) {
+	case V4L2_SEL_TGT_CROP:
+		sel->r = *src_crop;
+		break;
+	case V4L2_SEL_TGT_COMPOSE_BOUNDS:
+		sel->r.top = 0;
+		sel->r.left = 0;
+		sel->r.width = src_crop->width;
+		sel->r.height = src_crop->height;
+		break;
+	case V4L2_SEL_TGT_COMPOSE:
+		sel->r.top = 0;
+		sel->r.left = 0;
+		sel->r.width = src_fmt->width;
+		sel->r.height = src_fmt->height;
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	mutex_unlock(&imx274->lock);
+
+	return ret;
+}
+
+static int imx274_set_selection_crop(struct stimx274 *imx274,
+				     struct v4l2_subdev_pad_config *cfg,
+				     struct v4l2_subdev_selection *sel)
+{
+	struct v4l2_rect *tgt_crop;
+	struct v4l2_rect new_crop;
+	bool size_changed;
+
+	/*
+	 * h_step could be 12 or 24 depending on the binning. But we
+	 * won't know the binning until we choose the mode later in
+	 * __imx274_change_compose(). Thus let's be safe and use the
+	 * most conservative value in all cases.
+	 */
+	const u32 h_step = 24;
+
+	new_crop.width = min_t(u32,
+			       IMX274_ROUND(sel->r.width, h_step, sel->flags),
+			       IMX274_MAX_WIDTH);
+
+	/* Constraint: HTRIMMING_END - HTRIMMING_START >= 144 */
+	if (new_crop.width < 144)
+		new_crop.width = 144;
+
+	new_crop.left = min_t(u32,
+			      IMX274_ROUND(sel->r.left, h_step, 0),
+			      IMX274_MAX_WIDTH - new_crop.width);
+
+	new_crop.height = min_t(u32,
+				IMX274_ROUND(sel->r.height, 2, sel->flags),
+				IMX274_MAX_HEIGHT);
+
+	new_crop.top = min_t(u32, IMX274_ROUND(sel->r.top, 2, 0),
+			     IMX274_MAX_HEIGHT - new_crop.height);
+
+	sel->r = new_crop;
+
+	if (sel->which == V4L2_SUBDEV_FORMAT_TRY)
+		tgt_crop = &cfg->try_crop;
+	else
+		tgt_crop = &imx274->crop;
+
+	mutex_lock(&imx274->lock);
+
+	size_changed = (new_crop.width != tgt_crop->width ||
+			new_crop.height != tgt_crop->height);
+
+	/* __imx274_change_compose needs the new size in *tgt_crop */
+	*tgt_crop = new_crop;
+
+	/* if crop size changed then reset the output image size */
+	if (size_changed)
+		__imx274_change_compose(imx274, cfg, sel->which,
+					&new_crop.width, &new_crop.height,
+					sel->flags);
+
+	mutex_unlock(&imx274->lock);
+
+	return 0;
+}
+
+static int imx274_set_selection(struct v4l2_subdev *sd,
+				struct v4l2_subdev_pad_config *cfg,
+				struct v4l2_subdev_selection *sel)
+{
+	struct stimx274 *imx274 = to_imx274(sd);
+
+	if (sel->pad != 0)
+		return -EINVAL;
+
+	if (sel->target == V4L2_SEL_TGT_CROP)
+		return imx274_set_selection_crop(imx274, cfg, sel);
+
+	if (sel->target == V4L2_SEL_TGT_COMPOSE) {
+		int err;
+
+		mutex_lock(&imx274->lock);
+		err =  __imx274_change_compose(imx274, cfg, sel->which,
+					       &sel->r.width, &sel->r.height,
+					       sel->flags);
+		mutex_unlock(&imx274->lock);
+
+		/*
+		 * __imx274_change_compose already set width and
+		 * height in set->r, we still need to set top-left
+		 */
+		if (!err) {
+			sel->r.top = 0;
+			sel->r.left = 0;
+		}
+
+		return err;
+	}
+
+	return -EINVAL;
+}
+
+static int imx274_apply_trimming(struct stimx274 *imx274)
+{
+	u32 h_start;
+	u32 h_end;
+	u32 hmax;
+	u32 v_cut;
+	s32 v_pos;
+	u32 write_v_size;
+	u32 y_out_size;
+	int err;
+
+	h_start = imx274->crop.left + 12;
+	h_end = h_start + imx274->crop.width;
+
+	/* Use the minimum allowed value of HMAX */
+	/* Note: except in mode 1, (width / 16 + 23) is always < hmax_min */
+	/* Note: 260 is the minimum HMAX in all implemented modes */
+	hmax = max_t(u32, 260, (imx274->crop.width) / 16 + 23);
+
+	/* invert v_pos if VFLIP */
+	v_pos = imx274->ctrls.vflip->cur.val ?
+		(-imx274->crop.top / 2) : (imx274->crop.top / 2);
+	v_cut = (IMX274_MAX_HEIGHT - imx274->crop.height) / 2;
+	write_v_size = imx274->crop.height + 22;
+	y_out_size   = imx274->crop.height + 14;
+
+	err = imx274_write_mbreg(imx274, IMX274_HMAX_REG_LSB, hmax, 2);
+	if (!err)
+		err = imx274_write_mbreg(imx274, IMX274_HTRIM_EN_REG, 1, 1);
+	if (!err)
+		err = imx274_write_mbreg(imx274, IMX274_HTRIM_START_REG_LSB,
+					 h_start, 2);
+	if (!err)
+		err = imx274_write_mbreg(imx274, IMX274_HTRIM_END_REG_LSB,
+					 h_end, 2);
+	if (!err)
+		err = imx274_write_mbreg(imx274, IMX274_VWIDCUTEN_REG, 1, 1);
+	if (!err)
+		err = imx274_write_mbreg(imx274, IMX274_VWIDCUT_REG_LSB,
+					 v_cut, 2);
+	if (!err)
+		err = imx274_write_mbreg(imx274, IMX274_VWINPOS_REG_LSB,
+					 v_pos, 2);
+	if (!err)
+		err = imx274_write_mbreg(imx274, IMX274_WRITE_VSIZE_REG_LSB,
+					 write_v_size, 2);
+	if (!err)
+		err = imx274_write_mbreg(imx274, IMX274_Y_OUT_SIZE_REG_LSB,
+					 y_out_size, 2);
+
+	return err;
+}
+
+/**
+ * imx274_g_frame_interval - Get the frame interval
+ * @sd: Pointer to V4L2 Sub device structure
+ * @fi: Pointer to V4l2 Sub device frame interval structure
+ *
+ * This function is used to get the frame interval.
+ *
+ * Return: 0 on success
+ */
+static int imx274_g_frame_interval(struct v4l2_subdev *sd,
+				   struct v4l2_subdev_frame_interval *fi)
+{
+	struct stimx274 *imx274 = to_imx274(sd);
+
+	fi->interval = imx274->frame_interval;
+	dev_dbg(&imx274->client->dev, "%s frame rate = %d / %d\n",
+		__func__, imx274->frame_interval.numerator,
+		imx274->frame_interval.denominator);
+
+	return 0;
+}
+
+/**
+ * imx274_s_frame_interval - Set the frame interval
+ * @sd: Pointer to V4L2 Sub device structure
+ * @fi: Pointer to V4l2 Sub device frame interval structure
+ *
+ * This function is used to set the frame intervavl.
+ *
+ * Return: 0 on success
+ */
+static int imx274_s_frame_interval(struct v4l2_subdev *sd,
+				   struct v4l2_subdev_frame_interval *fi)
+{
+	struct stimx274 *imx274 = to_imx274(sd);
+	struct v4l2_ctrl *ctrl = imx274->ctrls.exposure;
+	int min, max, def;
+	int ret;
+
+	mutex_lock(&imx274->lock);
+	ret = imx274_set_frame_interval(imx274, fi->interval);
+
+	if (!ret) {
+		fi->interval = imx274->frame_interval;
+
+		/*
+		 * exposure time range is decided by frame interval
+		 * need to update it after frame interval changes
+		 */
+		min = IMX274_MIN_EXPOSURE_TIME;
+		max = fi->interval.numerator * 1000000
+			/ fi->interval.denominator;
+		def = max;
+		if (__v4l2_ctrl_modify_range(ctrl, min, max, 1, def)) {
+			dev_err(&imx274->client->dev,
+				"Exposure ctrl range update failed\n");
+			goto unlock;
+		}
+
+		/* update exposure time accordingly */
+		imx274_set_exposure(imx274, ctrl->val);
+
+		dev_dbg(&imx274->client->dev, "set frame interval to %uus\n",
+			fi->interval.numerator * 1000000
+			/ fi->interval.denominator);
+	}
+
+unlock:
+	mutex_unlock(&imx274->lock);
+
+	return ret;
+}
+
+/**
+ * imx274_load_default - load default control values
+ * @priv: Pointer to device structure
+ *
+ * Return: 0 on success, errors otherwise
+ */
+static int imx274_load_default(struct stimx274 *priv)
+{
+	int ret;
+
+	/* load default control values */
+	priv->frame_interval.numerator = 1;
+	priv->frame_interval.denominator = IMX274_DEF_FRAME_RATE;
+	priv->ctrls.exposure->val = 1000000 / IMX274_DEF_FRAME_RATE;
+	priv->ctrls.gain->val = IMX274_DEF_GAIN;
+	priv->ctrls.vflip->val = 0;
+	priv->ctrls.test_pattern->val = TEST_PATTERN_DISABLED;
+
+	/* update frame rate */
+	ret = imx274_set_frame_interval(priv,
+					priv->frame_interval);
+	if (ret)
+		return ret;
+
+	/* update exposure time */
+	ret = v4l2_ctrl_s_ctrl(priv->ctrls.exposure, priv->ctrls.exposure->val);
+	if (ret)
+		return ret;
+
+	/* update gain */
+	ret = v4l2_ctrl_s_ctrl(priv->ctrls.gain, priv->ctrls.gain->val);
+	if (ret)
+		return ret;
+
+	/* update vflip */
+	ret = v4l2_ctrl_s_ctrl(priv->ctrls.vflip, priv->ctrls.vflip->val);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+/**
+ * imx274_s_stream - It is used to start/stop the streaming.
+ * @sd: V4L2 Sub device
+ * @on: Flag (True / False)
+ *
+ * This function controls the start or stop of streaming for the
+ * imx274 sensor.
+ *
+ * Return: 0 on success, errors otherwise
+ */
+static int imx274_s_stream(struct v4l2_subdev *sd, int on)
+{
+	struct stimx274 *imx274 = to_imx274(sd);
+	int ret = 0;
+
+	dev_dbg(&imx274->client->dev, "%s : %s, mode index = %td\n", __func__,
+		on ? "Stream Start" : "Stream Stop",
+		imx274->mode - &imx274_formats[0]);
+
+	mutex_lock(&imx274->lock);
+
+	if (on) {
+		/* load mode registers */
+		ret = imx274_mode_regs(imx274);
+		if (ret)
+			goto fail;
+
+		ret = imx274_apply_trimming(imx274);
+		if (ret)
+			goto fail;
+
+		/*
+		 * update frame rate & expsoure. if the last mode is different,
+		 * HMAX could be changed. As the result, frame rate & exposure
+		 * are changed.
+		 * gain is not affected.
+		 */
+		ret = imx274_set_frame_interval(imx274,
+						imx274->frame_interval);
+		if (ret)
+			goto fail;
+
+		/* update exposure time */
+		ret = __v4l2_ctrl_s_ctrl(imx274->ctrls.exposure,
+					 imx274->ctrls.exposure->val);
+		if (ret)
+			goto fail;
+
+		/* start stream */
+		ret = imx274_start_stream(imx274);
+		if (ret)
+			goto fail;
+	} else {
+		/* stop stream */
+		ret = imx274_write_table(imx274, imx274_stop);
+		if (ret)
+			goto fail;
+	}
+
+	mutex_unlock(&imx274->lock);
+	dev_dbg(&imx274->client->dev, "%s : Done\n", __func__);
+	return 0;
+
+fail:
+	mutex_unlock(&imx274->lock);
+	dev_err(&imx274->client->dev, "s_stream failed\n");
+	return ret;
+}
+
+/*
+ * imx274_get_frame_length - Function for obtaining current frame length
+ * @priv: Pointer to device structure
+ * @val: Pointer to obainted value
+ *
+ * frame_length = vmax x (svr + 1), in unit of hmax.
+ *
+ * Return: 0 on success
+ */
+static int imx274_get_frame_length(struct stimx274 *priv, u32 *val)
+{
+	int err;
+	u16 svr;
+	u32 vmax;
+	u8 reg_val[3];
+
+	/* svr */
+	err = imx274_read_reg(priv, IMX274_SVR_REG_LSB, &reg_val[0]);
+	if (err)
+		goto fail;
+
+	err = imx274_read_reg(priv, IMX274_SVR_REG_MSB, &reg_val[1]);
+	if (err)
+		goto fail;
+
+	svr = (reg_val[1] << IMX274_SHIFT_8_BITS) + reg_val[0];
+
+	/* vmax */
+	err = imx274_read_reg(priv, IMX274_VMAX_REG_3, &reg_val[0]);
+	if (err)
+		goto fail;
+
+	err = imx274_read_reg(priv, IMX274_VMAX_REG_2, &reg_val[1]);
+	if (err)
+		goto fail;
+
+	err = imx274_read_reg(priv, IMX274_VMAX_REG_1, &reg_val[2]);
+	if (err)
+		goto fail;
+
+	vmax = ((reg_val[2] & IMX274_MASK_LSB_3_BITS) << IMX274_SHIFT_16_BITS)
+		+ (reg_val[1] << IMX274_SHIFT_8_BITS) + reg_val[0];
+
+	*val = vmax * (svr + 1);
+
+	return 0;
+
+fail:
+	dev_err(&priv->client->dev, "%s error = %d\n", __func__, err);
+	return err;
+}
+
+static int imx274_clamp_coarse_time(struct stimx274 *priv, u32 *val,
+				    u32 *frame_length)
+{
+	int err;
+
+	err = imx274_get_frame_length(priv, frame_length);
+	if (err)
+		return err;
+
+	if (*frame_length < priv->mode->min_frame_len)
+		*frame_length =  priv->mode->min_frame_len;
+
+	*val = *frame_length - *val; /* convert to raw shr */
+	if (*val > *frame_length - IMX274_SHR_LIMIT_CONST)
+		*val = *frame_length - IMX274_SHR_LIMIT_CONST;
+	else if (*val < priv->mode->min_SHR)
+		*val = priv->mode->min_SHR;
+
+	return 0;
+}
+
+/*
+ * imx274_set_digital gain - Function called when setting digital gain
+ * @priv: Pointer to device structure
+ * @dgain: Value of digital gain.
+ *
+ * Digital gain has only 4 steps: 1x, 2x, 4x, and 8x
+ *
+ * Return: 0 on success
+ */
+static int imx274_set_digital_gain(struct stimx274 *priv, u32 dgain)
+{
+	u8 reg_val;
+
+	reg_val = ffs(dgain);
+
+	if (reg_val)
+		reg_val--;
+
+	reg_val = clamp(reg_val, (u8)0, (u8)3);
+
+	return imx274_write_reg(priv, IMX274_DIGITAL_GAIN_REG,
+				reg_val & IMX274_MASK_LSB_4_BITS);
+}
+
+/*
+ * imx274_set_gain - Function called when setting gain
+ * @priv: Pointer to device structure
+ * @val: Value of gain. the real value = val << IMX274_GAIN_SHIFT;
+ * @ctrl: v4l2 control pointer
+ *
+ * Set the gain based on input value.
+ * The caller should hold the mutex lock imx274->lock if necessary
+ *
+ * Return: 0 on success
+ */
+static int imx274_set_gain(struct stimx274 *priv, struct v4l2_ctrl *ctrl)
+{
+	int err;
+	u32 gain, analog_gain, digital_gain, gain_reg;
+
+	gain = (u32)(ctrl->val);
+
+	dev_dbg(&priv->client->dev,
+		"%s : input gain = %d.%d\n", __func__,
+		gain >> IMX274_GAIN_SHIFT,
+		((gain & IMX274_GAIN_SHIFT_MASK) * 100) >> IMX274_GAIN_SHIFT);
+
+	if (gain > IMX274_MAX_DIGITAL_GAIN * IMX274_MAX_ANALOG_GAIN)
+		gain = IMX274_MAX_DIGITAL_GAIN * IMX274_MAX_ANALOG_GAIN;
+	else if (gain < IMX274_MIN_GAIN)
+		gain = IMX274_MIN_GAIN;
+
+	if (gain <= IMX274_MAX_ANALOG_GAIN)
+		digital_gain = 1;
+	else if (gain <= IMX274_MAX_ANALOG_GAIN * 2)
+		digital_gain = 2;
+	else if (gain <= IMX274_MAX_ANALOG_GAIN * 4)
+		digital_gain = 4;
+	else
+		digital_gain = IMX274_MAX_DIGITAL_GAIN;
+
+	analog_gain = gain / digital_gain;
+
+	dev_dbg(&priv->client->dev,
+		"%s : digital gain = %d, analog gain = %d.%d\n",
+		__func__, digital_gain, analog_gain >> IMX274_GAIN_SHIFT,
+		((analog_gain & IMX274_GAIN_SHIFT_MASK) * 100)
+		>> IMX274_GAIN_SHIFT);
+
+	err = imx274_set_digital_gain(priv, digital_gain);
+	if (err)
+		goto fail;
+
+	/* convert to register value, refer to imx274 datasheet */
+	gain_reg = (u32)IMX274_GAIN_CONST -
+		(IMX274_GAIN_CONST << IMX274_GAIN_SHIFT) / analog_gain;
+	if (gain_reg > IMX274_GAIN_REG_MAX)
+		gain_reg = IMX274_GAIN_REG_MAX;
+
+	err = imx274_write_mbreg(priv, IMX274_ANALOG_GAIN_ADDR_LSB, gain_reg,
+				 2);
+	if (err)
+		goto fail;
+
+	if (IMX274_GAIN_CONST - gain_reg == 0) {
+		err = -EINVAL;
+		goto fail;
+	}
+
+	/* convert register value back to gain value */
+	ctrl->val = (IMX274_GAIN_CONST << IMX274_GAIN_SHIFT)
+			/ (IMX274_GAIN_CONST - gain_reg) * digital_gain;
+
+	dev_dbg(&priv->client->dev,
+		"%s : GAIN control success, gain_reg = %d, new gain = %d\n",
+		__func__, gain_reg, ctrl->val);
+
+	return 0;
+
+fail:
+	dev_err(&priv->client->dev, "%s error = %d\n", __func__, err);
+	return err;
+}
+
+/*
+ * imx274_set_coarse_time - Function called when setting SHR value
+ * @priv: Pointer to device structure
+ * @val: Value for exposure time in number of line_length, or [HMAX]
+ *
+ * Set SHR value based on input value.
+ *
+ * Return: 0 on success
+ */
+static int imx274_set_coarse_time(struct stimx274 *priv, u32 *val)
+{
+	int err;
+	u32 coarse_time, frame_length;
+
+	coarse_time = *val;
+
+	/* convert exposure_time to appropriate SHR value */
+	err = imx274_clamp_coarse_time(priv, &coarse_time, &frame_length);
+	if (err)
+		goto fail;
+
+	err = imx274_write_mbreg(priv, IMX274_SHR_REG_LSB, coarse_time, 2);
+	if (err)
+		goto fail;
+
+	*val = frame_length - coarse_time;
+	return 0;
+
+fail:
+	dev_err(&priv->client->dev, "%s error = %d\n", __func__, err);
+	return err;
+}
+
+/*
+ * imx274_set_exposure - Function called when setting exposure time
+ * @priv: Pointer to device structure
+ * @val: Variable for exposure time, in the unit of micro-second
+ *
+ * Set exposure time based on input value.
+ * The caller should hold the mutex lock imx274->lock if necessary
+ *
+ * Return: 0 on success
+ */
+static int imx274_set_exposure(struct stimx274 *priv, int val)
+{
+	int err;
+	u16 hmax;
+	u8 reg_val[2];
+	u32 coarse_time; /* exposure time in unit of line (HMAX)*/
+
+	dev_dbg(&priv->client->dev,
+		"%s : EXPOSURE control input = %d\n", __func__, val);
+
+	/* step 1: convert input exposure_time (val) into number of 1[HMAX] */
+
+	/* obtain HMAX value */
+	err = imx274_read_reg(priv, IMX274_HMAX_REG_LSB, &reg_val[0]);
+	if (err)
+		goto fail;
+	err = imx274_read_reg(priv, IMX274_HMAX_REG_MSB, &reg_val[1]);
+	if (err)
+		goto fail;
+	hmax = (reg_val[1] << IMX274_SHIFT_8_BITS) + reg_val[0];
+	if (hmax == 0) {
+		err = -EINVAL;
+		goto fail;
+	}
+
+	coarse_time = (IMX274_PIXCLK_CONST1 / IMX274_PIXCLK_CONST2 * val
+			- priv->mode->nocpiop) / hmax;
+
+	/* step 2: convert exposure_time into SHR value */
+
+	/* set SHR */
+	err = imx274_set_coarse_time(priv, &coarse_time);
+	if (err)
+		goto fail;
+
+	priv->ctrls.exposure->val =
+			(coarse_time * hmax + priv->mode->nocpiop)
+			/ (IMX274_PIXCLK_CONST1 / IMX274_PIXCLK_CONST2);
+
+	dev_dbg(&priv->client->dev,
+		"%s : EXPOSURE control success\n", __func__);
+	return 0;
+
+fail:
+	dev_err(&priv->client->dev, "%s error = %d\n", __func__, err);
+
+	return err;
+}
+
+/*
+ * imx274_set_vflip - Function called when setting vertical flip
+ * @priv: Pointer to device structure
+ * @val: Value for vflip setting
+ *
+ * Set vertical flip based on input value.
+ * val = 0: normal, no vertical flip
+ * val = 1: vertical flip enabled
+ * The caller should hold the mutex lock imx274->lock if necessary
+ *
+ * Return: 0 on success
+ */
+static int imx274_set_vflip(struct stimx274 *priv, int val)
+{
+	int err;
+
+	err = imx274_write_reg(priv, IMX274_VFLIP_REG, val);
+	if (err) {
+		dev_err(&priv->client->dev, "VFLIP control error\n");
+		return err;
+	}
+
+	dev_dbg(&priv->client->dev,
+		"%s : VFLIP control success\n", __func__);
+
+	return 0;
+}
+
+/*
+ * imx274_set_test_pattern - Function called when setting test pattern
+ * @priv: Pointer to device structure
+ * @val: Variable for test pattern
+ *
+ * Set to different test patterns based on input value.
+ *
+ * Return: 0 on success
+ */
+static int imx274_set_test_pattern(struct stimx274 *priv, int val)
+{
+	int err = 0;
+
+	if (val == TEST_PATTERN_DISABLED) {
+		err = imx274_write_table(priv, imx274_tp_disabled);
+	} else if (val <= TEST_PATTERN_V_COLOR_BARS) {
+		err = imx274_write_reg(priv, IMX274_TEST_PATTERN_REG, val - 1);
+		if (!err)
+			err = imx274_write_table(priv, imx274_tp_regs);
+	} else {
+		err = -EINVAL;
+	}
+
+	if (!err)
+		dev_dbg(&priv->client->dev,
+			"%s : TEST PATTERN control success\n", __func__);
+	else
+		dev_err(&priv->client->dev, "%s error = %d\n", __func__, err);
+
+	return err;
+}
+
+/*
+ * imx274_set_frame_length - Function called when setting frame length
+ * @priv: Pointer to device structure
+ * @val: Variable for frame length (= VMAX, i.e. vertical drive period length)
+ *
+ * Set frame length based on input value.
+ *
+ * Return: 0 on success
+ */
+static int imx274_set_frame_length(struct stimx274 *priv, u32 val)
+{
+	int err;
+	u32 frame_length;
+
+	dev_dbg(&priv->client->dev, "%s : input length = %d\n",
+		__func__, val);
+
+	frame_length = (u32)val;
+
+	err = imx274_write_mbreg(priv, IMX274_VMAX_REG_3, frame_length, 3);
+	if (err)
+		goto fail;
+
+	return 0;
+
+fail:
+	dev_err(&priv->client->dev, "%s error = %d\n", __func__, err);
+	return err;
+}
+
+/*
+ * imx274_set_frame_interval - Function called when setting frame interval
+ * @priv: Pointer to device structure
+ * @frame_interval: Variable for frame interval
+ *
+ * Change frame interval by updating VMAX value
+ * The caller should hold the mutex lock imx274->lock if necessary
+ *
+ * Return: 0 on success
+ */
+static int imx274_set_frame_interval(struct stimx274 *priv,
+				     struct v4l2_fract frame_interval)
+{
+	int err;
+	u32 frame_length, req_frame_rate;
+	u16 svr;
+	u16 hmax;
+	u8 reg_val[2];
+
+	dev_dbg(&priv->client->dev, "%s: input frame interval = %d / %d",
+		__func__, frame_interval.numerator,
+		frame_interval.denominator);
+
+	if (frame_interval.numerator == 0 || frame_interval.denominator == 0) {
+		frame_interval.denominator = IMX274_DEF_FRAME_RATE;
+		frame_interval.numerator = 1;
+	}
+
+	req_frame_rate = (u32)(frame_interval.denominator
+				/ frame_interval.numerator);
+
+	/* boundary check */
+	if (req_frame_rate > priv->mode->max_fps) {
+		frame_interval.numerator = 1;
+		frame_interval.denominator = priv->mode->max_fps;
+	} else if (req_frame_rate < IMX274_MIN_FRAME_RATE) {
+		frame_interval.numerator = 1;
+		frame_interval.denominator = IMX274_MIN_FRAME_RATE;
+	}
+
+	/*
+	 * VMAX = 1/frame_rate x 72M / (SVR+1) / HMAX
+	 * frame_length (i.e. VMAX) = (frame_interval) x 72M /(SVR+1) / HMAX
+	 */
+
+	/* SVR */
+	err = imx274_read_reg(priv, IMX274_SVR_REG_LSB, &reg_val[0]);
+	if (err)
+		goto fail;
+	err = imx274_read_reg(priv, IMX274_SVR_REG_MSB, &reg_val[1]);
+	if (err)
+		goto fail;
+	svr = (reg_val[1] << IMX274_SHIFT_8_BITS) + reg_val[0];
+	dev_dbg(&priv->client->dev,
+		"%s : register SVR = %d\n", __func__, svr);
+
+	/* HMAX */
+	err = imx274_read_reg(priv, IMX274_HMAX_REG_LSB, &reg_val[0]);
+	if (err)
+		goto fail;
+	err = imx274_read_reg(priv, IMX274_HMAX_REG_MSB, &reg_val[1]);
+	if (err)
+		goto fail;
+	hmax = (reg_val[1] << IMX274_SHIFT_8_BITS) + reg_val[0];
+	dev_dbg(&priv->client->dev,
+		"%s : register HMAX = %d\n", __func__, hmax);
+
+	if (hmax == 0 || frame_interval.denominator == 0) {
+		err = -EINVAL;
+		goto fail;
+	}
+
+	frame_length = IMX274_PIXCLK_CONST1 / (svr + 1) / hmax
+					* frame_interval.numerator
+					/ frame_interval.denominator;
+
+	err = imx274_set_frame_length(priv, frame_length);
+	if (err)
+		goto fail;
+
+	priv->frame_interval = frame_interval;
+	return 0;
+
+fail:
+	dev_err(&priv->client->dev, "%s error = %d\n", __func__, err);
+	return err;
+}
+
+static const struct v4l2_subdev_pad_ops imx274_pad_ops = {
+	.get_fmt = imx274_get_fmt,
+	.set_fmt = imx274_set_fmt,
+	.get_selection = imx274_get_selection,
+	.set_selection = imx274_set_selection,
+};
+
+static const struct v4l2_subdev_video_ops imx274_video_ops = {
+	.g_frame_interval = imx274_g_frame_interval,
+	.s_frame_interval = imx274_s_frame_interval,
+	.s_stream = imx274_s_stream,
+};
+
+static const struct v4l2_subdev_ops imx274_subdev_ops = {
+	.pad = &imx274_pad_ops,
+	.video = &imx274_video_ops,
+};
+
+static const struct v4l2_ctrl_ops imx274_ctrl_ops = {
+	.s_ctrl	= imx274_s_ctrl,
+};
+
+static const struct of_device_id imx274_of_id_table[] = {
+	{ .compatible = "sony,imx274" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, imx274_of_id_table);
+
+static const struct i2c_device_id imx274_id[] = {
+	{ "IMX274", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, imx274_id);
+
+static int imx274_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct v4l2_subdev *sd;
+	struct stimx274 *imx274;
+	int ret;
+
+	/* initialize imx274 */
+	imx274 = devm_kzalloc(&client->dev, sizeof(*imx274), GFP_KERNEL);
+	if (!imx274)
+		return -ENOMEM;
+
+	mutex_init(&imx274->lock);
+
+	/* initialize format */
+	imx274->mode = &imx274_formats[IMX274_DEFAULT_MODE];
+	imx274->crop.width = IMX274_MAX_WIDTH;
+	imx274->crop.height = IMX274_MAX_HEIGHT;
+	imx274->format.width = imx274->crop.width / imx274->mode->bin_ratio;
+	imx274->format.height = imx274->crop.height / imx274->mode->bin_ratio;
+	imx274->format.field = V4L2_FIELD_NONE;
+	imx274->format.code = MEDIA_BUS_FMT_SRGGB10_1X10;
+	imx274->format.colorspace = V4L2_COLORSPACE_SRGB;
+	imx274->frame_interval.numerator = 1;
+	imx274->frame_interval.denominator = IMX274_DEF_FRAME_RATE;
+
+	/* initialize regmap */
+	imx274->regmap = devm_regmap_init_i2c(client, &imx274_regmap_config);
+	if (IS_ERR(imx274->regmap)) {
+		dev_err(&client->dev,
+			"regmap init failed: %ld\n", PTR_ERR(imx274->regmap));
+		ret = -ENODEV;
+		goto err_regmap;
+	}
+
+	/* initialize subdevice */
+	imx274->client = client;
+	sd = &imx274->sd;
+	v4l2_i2c_subdev_init(sd, client, &imx274_subdev_ops);
+	strlcpy(sd->name, DRIVER_NAME, sizeof(sd->name));
+	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE | V4L2_SUBDEV_FL_HAS_EVENTS;
+
+	/* initialize subdev media pad */
+	imx274->pad.flags = MEDIA_PAD_FL_SOURCE;
+	sd->entity.function = MEDIA_ENT_F_CAM_SENSOR;
+	ret = media_entity_pads_init(&sd->entity, 1, &imx274->pad);
+	if (ret < 0) {
+		dev_err(&client->dev,
+			"%s : media entity init Failed %d\n", __func__, ret);
+		goto err_regmap;
+	}
+
+	/* initialize sensor reset gpio */
+	imx274->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
+						     GPIOD_OUT_HIGH);
+	if (IS_ERR(imx274->reset_gpio)) {
+		if (PTR_ERR(imx274->reset_gpio) != -EPROBE_DEFER)
+			dev_err(&client->dev, "Reset GPIO not setup in DT");
+		ret = PTR_ERR(imx274->reset_gpio);
+		goto err_me;
+	}
+
+	/* pull sensor out of reset */
+	imx274_reset(imx274, 1);
+
+	/* initialize controls */
+	ret = v4l2_ctrl_handler_init(&imx274->ctrls.handler, 2);
+	if (ret < 0) {
+		dev_err(&client->dev,
+			"%s : ctrl handler init Failed\n", __func__);
+		goto err_me;
+	}
+
+	imx274->ctrls.handler.lock = &imx274->lock;
+
+	/* add new controls */
+	imx274->ctrls.test_pattern = v4l2_ctrl_new_std_menu_items(
+		&imx274->ctrls.handler, &imx274_ctrl_ops,
+		V4L2_CID_TEST_PATTERN,
+		ARRAY_SIZE(tp_qmenu) - 1, 0, 0, tp_qmenu);
+
+	imx274->ctrls.gain = v4l2_ctrl_new_std(
+		&imx274->ctrls.handler,
+		&imx274_ctrl_ops,
+		V4L2_CID_GAIN, IMX274_MIN_GAIN,
+		IMX274_MAX_DIGITAL_GAIN * IMX274_MAX_ANALOG_GAIN, 1,
+		IMX274_DEF_GAIN);
+
+	imx274->ctrls.exposure = v4l2_ctrl_new_std(
+		&imx274->ctrls.handler,
+		&imx274_ctrl_ops,
+		V4L2_CID_EXPOSURE, IMX274_MIN_EXPOSURE_TIME,
+		1000000 / IMX274_DEF_FRAME_RATE, 1,
+		IMX274_MIN_EXPOSURE_TIME);
+
+	imx274->ctrls.vflip = v4l2_ctrl_new_std(
+		&imx274->ctrls.handler,
+		&imx274_ctrl_ops,
+		V4L2_CID_VFLIP, 0, 1, 1, 0);
+
+	imx274->sd.ctrl_handler = &imx274->ctrls.handler;
+	if (imx274->ctrls.handler.error) {
+		ret = imx274->ctrls.handler.error;
+		goto err_ctrls;
+	}
+
+	/* setup default controls */
+	ret = v4l2_ctrl_handler_setup(&imx274->ctrls.handler);
+	if (ret) {
+		dev_err(&client->dev,
+			"Error %d setup default controls\n", ret);
+		goto err_ctrls;
+	}
+
+	/* load default control values */
+	ret = imx274_load_default(imx274);
+	if (ret) {
+		dev_err(&client->dev,
+			"%s : imx274_load_default failed %d\n",
+			__func__, ret);
+		goto err_ctrls;
+	}
+
+	/* register subdevice */
+	ret = v4l2_async_register_subdev(sd);
+	if (ret < 0) {
+		dev_err(&client->dev,
+			"%s : v4l2_async_register_subdev failed %d\n",
+			__func__, ret);
+		goto err_ctrls;
+	}
+
+	dev_info(&client->dev, "imx274 : imx274 probe success !\n");
+	return 0;
+
+err_ctrls:
+	v4l2_ctrl_handler_free(&imx274->ctrls.handler);
+err_me:
+	media_entity_cleanup(&sd->entity);
+err_regmap:
+	mutex_destroy(&imx274->lock);
+	return ret;
+}
+
+static int imx274_remove(struct i2c_client *client)
+{
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct stimx274 *imx274 = to_imx274(sd);
+
+	/* stop stream */
+	imx274_write_table(imx274, imx274_stop);
+
+	v4l2_async_unregister_subdev(sd);
+	v4l2_ctrl_handler_free(&imx274->ctrls.handler);
+	media_entity_cleanup(&sd->entity);
+	mutex_destroy(&imx274->lock);
+	return 0;
+}
+
+static struct i2c_driver imx274_i2c_driver = {
+	.driver = {
+		.name	= DRIVER_NAME,
+		.of_match_table	= imx274_of_id_table,
+	},
+	.probe		= imx274_probe,
+	.remove		= imx274_remove,
+	.id_table	= imx274_id,
+};
+
+module_i2c_driver(imx274_i2c_driver);
+
+MODULE_AUTHOR("Leon Luo <leonl@leopardimaging.com>");
+MODULE_DESCRIPTION("IMX274 CMOS Image Sensor driver");
+MODULE_LICENSE("GPL v2");