[RFC PATCH v6] media: add v4l2 subdev driver for S5K4ECGX sensor

[RFC PATCH v6] media: add v4l2 subdev driver for S5K4ECGX sensor

[Sangwook Lee]

This patch adds driver for S5K4ECGX sensor with embedded ISP SoC,
S5K4ECGX, which is a 5M CMOS Image sensor from Samsung
The driver implements preview mode of the S5K4ECGX sensor.
capture (snapshot) operation, face detection are missing now.
Following controls are supported:
contrast/saturation/brightness/sharpness

Signed-off-by: Sangwook Lee <sangwook.lee@linaro.org>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
---
Changes since v5:
- deleted dummy lines
- fixed pointer errors in handling firmware
- updated comments
- added le32_to_cpu,le16_to_cpu

Changes since v4:
- replaced register tables with the function from Sylwester
- updated firmware parsing function with CRC32 check
  firmware generator from user space:
  git://git.linaro.org/people/sangwook/fimc-v4l2-app.git

Changes since v3:
- used request_firmware to configure initial settings
- added parsing functions to read initial settings
- updated regulator API
- reduced preview setting tables by experiment

Changes since v2:
- added GPIO (reset/stby) and regulators
- updated I2C read/write, based on s5k6aa datasheet
- fixed set_fmt errors
- reduced register tables a bit
- removed vmalloc

Changes since v1:
- fixed s_stream(0) when it called twice
- changed mutex_X position to be used when strictly necessary
- add additional s_power(0) in case that error happens
- update more accurate debugging statements
- remove dummy else

 drivers/media/i2c/Kconfig    |    7 +
 drivers/media/i2c/Makefile   |    1 +
 drivers/media/i2c/s5k4ecgx.c | 1011 ++++++++++++++++++++++++++++++++++++++++++
 include/media/s5k4ecgx.h     |   37 ++
 4 files changed, 1056 insertions(+)
 create mode 100644 drivers/media/i2c/s5k4ecgx.c
 create mode 100644 include/media/s5k4ecgx.h

diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index 9a5a059..55b3bbb 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -484,6 +484,13 @@ config VIDEO_S5K6AA
 	  This is a V4L2 sensor-level driver for Samsung S5K6AA(FX) 1.3M
 	  camera sensor with an embedded SoC image signal processor.
 
+config VIDEO_S5K4ECGX
+        tristate "Samsung S5K4ECGX sensor support"
+        depends on I2C && VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API
+        ---help---
+          This is a V4L2 sensor-level driver for Samsung S5K4ECGX 5M
+          camera sensor with an embedded SoC image signal processor.
+
 source "drivers/media/i2c/smiapp/Kconfig"
 
 comment "Flash devices"
diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
index 088a460..a720812 100644
--- a/drivers/media/i2c/Makefile
+++ b/drivers/media/i2c/Makefile
@@ -55,6 +55,7 @@ obj-$(CONFIG_VIDEO_MT9V032) += mt9v032.o
 obj-$(CONFIG_VIDEO_SR030PC30)	+= sr030pc30.o
 obj-$(CONFIG_VIDEO_NOON010PC30)	+= noon010pc30.o
 obj-$(CONFIG_VIDEO_S5K6AA)	+= s5k6aa.o
+obj-$(CONFIG_VIDEO_S5K4ECGX)	+= s5k4ecgx.o
 obj-$(CONFIG_VIDEO_ADP1653)	+= adp1653.o
 obj-$(CONFIG_VIDEO_AS3645A)	+= as3645a.o
 obj-$(CONFIG_VIDEO_SMIAPP_PLL)	+= smiapp-pll.o
diff --git a/drivers/media/i2c/s5k4ecgx.c b/drivers/media/i2c/s5k4ecgx.c
new file mode 100644
index 0000000..66107c8
--- /dev/null
+++ b/drivers/media/i2c/s5k4ecgx.c
@@ -0,0 +1,1011 @@
+/*
+ * Driver for s5k4ecgx (5MP Camera) from Samsung
+ * a quarter-inch optical format 1.4 micron 5 megapixel (Mp)
+ * CMOS image sensor.
+ *
+ * Copyright (C) 2012, Linaro, Sangwook Lee <sangwook.lee@linaro.org>
+ * Copyright (C) 2012, Insignal Co,. Ltd,  Homin Lee <suapapa@insignal.co.kr>
+ *
+ * Based on s5k6aa, noon010pc30 driver
+ * Copyright (C) 2011, Samsung Electronics Co., Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/crc32.h>
+#include <linux/ctype.h>
+#include <linux/delay.h>
+#include <linux/firmware.h>
+#include <linux/gpio.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+#include <media/media-entity.h>
+#include <media/s5k4ecgx.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-mediabus.h>
+#include <media/v4l2-subdev.h>
+
+static int debug;
+module_param(debug, int, 0644);
+
+#define S5K4ECGX_DRIVER_NAME		"s5k4ecgx"
+#define S5K4ECGX_FIRMWARE		"s5k4ecgx.bin"
+
+/* Firmware revision information */
+#define REG_FW_REVISION			0x700001a6
+#define REG_FW_VERSION			0x700001a4
+#define S5K4ECGX_REVISION_1_1		0x11
+#define S5K4ECGX_FW_VERSION		0x4ec0
+
+/* General purpose parameters */
+#define REG_USER_BRIGHTNESS		0x7000022c
+#define REG_USER_CONTRAST		0x7000022e
+#define REG_USER_SATURATION		0x70000230
+
+#define REG_G_NEW_CFG_SYNC		0x7000024a
+#define REG_G_PREV_IN_WIDTH		0x70000250
+#define REG_G_PREV_IN_HEIGHT		0x70000252
+#define REG_G_PREV_IN_XOFFS		0x70000254
+#define REG_G_PREV_IN_YOFFS		0x70000256
+#define REG_G_CAP_IN_WIDTH		0x70000258
+#define REG_G_CAP_IN_HEIGHT		0x7000025a
+#define REG_G_CAP_IN_XOFFS		0x7000025c
+#define REG_G_CAP_IN_YOFFS		0x7000025e
+#define REG_G_INPUTS_CHANGE_REQ		0x70000262
+#define REG_G_ACTIVE_PREV_CFG		0x70000266
+#define REG_G_PREV_CFG_CHG		0x70000268
+#define REG_G_PREV_OPEN_AFTER_CH	0x7000026a
+
+/* Preview context register sets. n = 0...4. */
+#define PREG(n, x)			((n) * 0x30 + (x))
+#define REG_P_OUT_WIDTH(n)		PREG(n, 0x700002a6)
+#define REG_P_OUT_HEIGHT(n)		PREG(n, 0x700002a8)
+#define REG_P_FMT(n)			PREG(n, 0x700002aa)
+#define REG_P_PVI_MASK(n)		PREG(n, 0x700002b4)
+#define REG_P_FR_TIME_TYPE(n)		PREG(n, 0x700002be)
+#define  FR_TIME_DYNAMIC		0
+#define  FR_TIME_FIXED			1
+#define  FR_TIME_FIXED_ACCURATE		2
+#define REG_P_FR_TIME_Q_TYPE(n)		PREG(n, 0x700002c0)
+#define  FR_TIME_Q_DYNAMIC		0
+#define  FR_TIME_Q_BEST_FRRATE		1
+#define  FR_TIME_Q_BEST_QUALITY		2
+
+/* Frame period in 0.1 ms units */
+#define REG_P_MAX_FR_TIME(n)		PREG(n, 0x700002c2)
+#define REG_P_MIN_FR_TIME(n)		PREG(n, 0x700002c4)
+#define  US_TO_FR_TIME(__t)		((__t) / 100)
+#define REG_P_PREV_MIRROR(n)		PREG(n, 0x700002d0)
+#define REG_P_CAP_MIRROR(n)		PREG(n, 0x700002d2)
+
+#define REG_G_PREVZOOM_IN_WIDTH		0x70000494
+#define REG_G_PREVZOOM_IN_HEIGHT	0x70000496
+#define REG_G_PREVZOOM_IN_XOFFS		0x70000498
+#define REG_G_PREVZOOM_IN_YOFFS		0x7000049a
+#define REG_G_CAPZOOM_IN_WIDTH		0x7000049c
+#define REG_G_CAPZOOM_IN_HEIGHT		0x7000049e
+#define REG_G_CAPZOOM_IN_XOFFS		0x700004a0
+#define REG_G_CAPZOOM_IN_YOFFS		0x700004a2
+
+/* n = 0...4 */
+#define REG_USER_SHARPNESS(n)		(0x70000a28 + (n) * 0xb6)
+
+/* Reduce sharpness range for user space API */
+#define SHARPNESS_DIV			8208
+#define TOK_TERM			0xffffffff
+
+/*
+ * FIXME: This is copied from s5k6aa, because of no information
+ * in the S5K4ECGX datasheet.
+ * H/W register Interface (0xd0000000 - 0xd0000fff)
+ */
+#define AHB_MSB_ADDR_PTR		0xfcfc
+#define GEN_REG_OFFSH			0xd000
+#define REG_CMDWR_ADDRH			0x0028
+#define REG_CMDWR_ADDRL			0x002a
+#define REG_CMDRD_ADDRH			0x002c
+#define REG_CMDRD_ADDRL			0x002e
+#define REG_CMDBUF0_ADDR		0x0f12
+
+struct s5k4ecgx_frmsize {
+	struct v4l2_frmsize_discrete size;
+	/* Fixed sensor matrix crop rectangle */
+	struct v4l2_rect input_window;
+};
+
+struct regval_list {
+	u32 addr;
+	u16 val;
+};
+
+/*
+ * TODO: currently only preview is supported and snapshot (capture)
+ * is not implemented yet
+ */
+static const struct s5k4ecgx_frmsize s5k4ecgx_prev_sizes[] = {
+	{
+		.size = { 176, 144 },
+		.input_window = { 0x00, 0x00, 0x928, 0x780 },
+	}, {
+		.size = { 352, 288 },
+		.input_window = { 0x00, 0x00, 0x928, 0x780 },
+	}, {
+		.size = { 640, 480 },
+		.input_window = { 0x00, 0x00, 0xa00, 0x780 },
+	}, {
+		.size = { 720, 480 },
+		.input_window = { 0x00, 0x00, 0xa00, 0x6a8 },
+	}
+};
+
+#define S5K4ECGX_NUM_PREV ARRAY_SIZE(s5k4ecgx_prev_sizes)
+
+struct s5k4ecgx_pixfmt {
+	enum v4l2_mbus_pixelcode code;
+	u32 colorspace;
+	/* REG_TC_PCFG_Format register value */
+	u16 reg_p_format;
+};
+
+/* By default value, output from sensor will be YUV422 0-255 */
+static const struct s5k4ecgx_pixfmt s5k4ecgx_formats[] = {
+	{ V4L2_MBUS_FMT_YUYV8_2X8, V4L2_COLORSPACE_JPEG, 5 },
+};
+
+static const char * const s5k4ecgx_supply_names[] = {
+	/*
+	 * Usually 2.8V is used for analog power (vdda)
+	 * and digital IO (vddio, vddd_core)
+	 */
+	"vdda",
+	"vddio",
+	"vddcore",
+	"vddreg", /* The internal s5k4ecgx regulator's supply (1.8V) */
+};
+
+#define S5K4ECGX_NUM_SUPPLIES ARRAY_SIZE(s5k4ecgx_supply_names)
+
+enum s5k4ecgx_gpio_id {
+	STBY,
+	RST,
+	GPIO_NUM,
+};
+
+struct s5k4ecgx {
+	struct v4l2_subdev sd;
+	struct media_pad pad;
+	struct v4l2_ctrl_handler handler;
+
+	struct s5k4ecgx_platform_data *pdata;
+	const struct s5k4ecgx_pixfmt *curr_pixfmt;
+	const struct s5k4ecgx_frmsize *curr_frmsize;
+	struct mutex lock;
+	u8 streaming;
+	u8 set_params;
+
+	struct regulator_bulk_data supplies[S5K4ECGX_NUM_SUPPLIES];
+	struct s5k4ecgx_gpio gpio[GPIO_NUM];
+};
+
+static inline struct s5k4ecgx *to_s5k4ecgx(struct v4l2_subdev *sd)
+{
+	return container_of(sd, struct s5k4ecgx, sd);
+}
+
+static int s5k4ecgx_i2c_read(struct i2c_client *client, u16 addr, u16 *val)
+{
+	u8 wbuf[2] = { addr >> 8, addr & 0xff };
+	struct i2c_msg msg[2];
+	u8 rbuf[2];
+	int ret;
+
+	msg[0].addr = client->addr;
+	msg[0].flags = 0;
+	msg[0].len = 2;
+	msg[0].buf = wbuf;
+
+	msg[1].addr = client->addr;
+	msg[1].flags = I2C_M_RD;
+	msg[1].len = 2;
+	msg[1].buf = rbuf;
+
+	ret = i2c_transfer(client->adapter, msg, 2);
+	*val = be16_to_cpu(*((u16 *)rbuf));
+
+	v4l2_dbg(4, debug, client, "i2c_read: 0x%04X : 0x%04x\n", addr, *val);
+
+	return ret == 2 ? 0 : ret;
+}
+
+static int s5k4ecgx_i2c_write(struct i2c_client *client, u16 addr, u16 val)
+{
+	u8 buf[4] = { addr >> 8, addr & 0xff, val >> 8, val & 0xff };
+
+	int ret = i2c_master_send(client, buf, 4);
+	v4l2_dbg(4, debug, client, "i2c_write: 0x%04x : 0x%04x\n", addr, val);
+
+	return ret == 4 ? 0 : ret;
+}
+
+static int s5k4ecgx_write(struct i2c_client *client, u32 addr, u16 val)
+{
+	u16 high = addr >> 16, low = addr & 0xffff;
+	int ret;
+
+	v4l2_dbg(3, debug, client, "write: 0x%08x : 0x%04x\n", addr, val);
+	ret = s5k4ecgx_i2c_write(client, REG_CMDWR_ADDRH, high);
+	if (!ret)
+		ret = s5k4ecgx_i2c_write(client, REG_CMDWR_ADDRL, low);
+	if (!ret)
+		ret = s5k4ecgx_i2c_write(client, REG_CMDBUF0_ADDR, val);
+
+	return ret;
+}
+
+static int s5k4ecgx_read(struct i2c_client *client, u32 addr, u16 *val)
+{
+	u16 high = addr >> 16, low =  addr & 0xffff;
+	int ret;
+
+	ret = s5k4ecgx_i2c_write(client, REG_CMDRD_ADDRH, high);
+	if (!ret)
+		ret = s5k4ecgx_i2c_write(client, REG_CMDRD_ADDRL, low);
+	if (!ret)
+		ret = s5k4ecgx_i2c_read(client, REG_CMDBUF0_ADDR, val);
+	if (!ret)
+		dev_err(&client->dev, "Failed to execute read command\n");
+
+	return ret;
+}
+
+static int s5k4ecgx_read_fw_ver(struct v4l2_subdev *sd)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(sd);
+	u16 hw_rev, fw_ver = 0;
+	int ret;
+
+	ret = s5k4ecgx_read(client, REG_FW_VERSION, &fw_ver);
+	if (ret < 0 || fw_ver != S5K4ECGX_FW_VERSION) {
+		v4l2_err(sd, "FW version check failed!\n");
+		return -ENODEV;
+	}
+
+	ret = s5k4ecgx_read(client, REG_FW_REVISION, &hw_rev);
+	if (ret < 0)
+		return ret;
+
+	v4l2_info(sd, "chip found FW ver: 0x%x, HW rev: 0x%x\n",
+						fw_ver, hw_rev);
+	return 0;
+}
+
+static int s5k4ecgx_set_ahb_address(struct v4l2_subdev *sd)
+{
+	int ret;
+	struct i2c_client *client = v4l2_get_subdevdata(sd);
+
+	/* Set APB peripherals start address */
+	ret = s5k4ecgx_i2c_write(client, AHB_MSB_ADDR_PTR, GEN_REG_OFFSH);
+	if (ret)
+		return ret;
+	/*
+	 * FIXME: This is copied from s5k6aa, because of no information
+	 * in s5k4ecgx's datasheet.
+	 * sw_reset is activated to put device into idle status
+	 */
+	ret = s5k4ecgx_i2c_write(client, 0x0010, 0x0001);
+	if (ret)
+		return ret;
+
+	ret = s5k4ecgx_i2c_write(client, 0x1030, 0x0000);
+	if (ret)
+		return ret;
+	/* Halt ARM CPU */
+	return s5k4ecgx_i2c_write(client, 0x0014, 0x0001);
+}
+
+#define FW_CRC_SIZE 4
+#define FW_HEAD 6
+/* Register address, value are 4, 2 bytes */
+#define FW_RECORD_SIZE 6
+/*
+ * Firmware has the following format:
+ * <total number of records (4-bytes + 2-bytes padding) N >, < record 0 >,
+ * < record N - 1 >, < CRC32-CCITT (4-bytes) >, CRC32(4 bytes)
+ * where "record" is a 4-byte register address followed by 2-byte
+ * register value (little endian)
+ */
+static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
+{
+	const struct firmware *fw;
+	int err, i, regs_num;
+	struct i2c_client *client = v4l2_get_subdevdata(sd);
+	u16 val;
+	u32 addr, crc, crc_file, addr_inc = 0;
+
+	err = request_firmware(&fw, S5K4ECGX_FIRMWARE, sd->v4l2_dev->dev);
+	if (err) {
+		v4l2_err(sd, "Failed to read firmware %s\n", S5K4ECGX_FIRMWARE);
+		return err;
+	}
+	regs_num = *(u32 *)(fw->data);
+	v4l2_dbg(3, debug, sd, "FW: %s size %d register sets %d\n",
+		 S5K4ECGX_FIRMWARE, fw->size, regs_num);
+	regs_num++; /* Add header */
+	if (fw->size != regs_num * FW_RECORD_SIZE + FW_CRC_SIZE) {
+		err = -EINVAL;
+		goto fw_out;
+	}
+	crc_file = *(u32 *)(fw->data + regs_num * FW_RECORD_SIZE);
+	crc = crc32_le(~0, fw->data, regs_num * FW_RECORD_SIZE);
+	if (crc != crc_file) {
+		v4l2_err(sd, "FW: invalid crc (%#x:%#x)\n", crc, crc_file);
+		err = -EINVAL;
+		goto fw_out;
+	}
+	for (i = 1; i < regs_num; i++) {
+		addr = le32_to_cpu(*(u32 *)(fw->data + i * FW_RECORD_SIZE));
+		val = le16_to_cpu(*(u16 *)(fw->data + i * FW_RECORD_SIZE + 4));
+		if (addr - addr_inc != 2)
+			err = s5k4ecgx_write(client, addr, val);
+		else
+			err = s5k4ecgx_i2c_write(client, REG_CMDBUF0_ADDR, val);
+		if (err)
+			break;
+		addr_inc = addr;
+	}
+fw_out:
+	release_firmware(fw);
+
+	return err;
+}
+
+/* Set preview and capture input window */
+static int s5k4ecgx_set_input_window(struct i2c_client *c,
+				     const struct v4l2_rect *r)
+{
+	int ret;
+
+	ret = s5k4ecgx_write(c, REG_G_PREV_IN_WIDTH, r->width);
+	if (!ret)
+		ret = s5k4ecgx_write(c, REG_G_PREV_IN_HEIGHT, r->height);
+	if (!ret)
+		ret = s5k4ecgx_write(c, REG_G_PREV_IN_XOFFS, r->left);
+	if (!ret)
+		ret = s5k4ecgx_write(c, REG_G_PREV_IN_YOFFS, r->top);
+	if (!ret)
+		ret = s5k4ecgx_write(c, REG_G_CAP_IN_WIDTH, r->width);
+	if (!ret)
+		ret = s5k4ecgx_write(c, REG_G_CAP_IN_HEIGHT, r->height);
+	if (!ret)
+		ret = s5k4ecgx_write(c, REG_G_CAP_IN_XOFFS, r->left);
+	if (!ret)
+		ret = s5k4ecgx_write(c, REG_G_CAP_IN_YOFFS, r->top);
+
+	return ret;
+}
+
+/* Set preview and capture zoom input window */
+static int s5k4ecgx_set_zoom_window(struct i2c_client *c,
+				    const struct v4l2_rect *r)
+{
+	int ret;
+
+	ret = s5k4ecgx_write(c, REG_G_PREVZOOM_IN_WIDTH, r->width);
+	if (!ret)
+		ret = s5k4ecgx_write(c, REG_G_PREVZOOM_IN_HEIGHT, r->height);
+	if (!ret)
+		ret = s5k4ecgx_write(c, REG_G_PREVZOOM_IN_XOFFS, r->left);
+	if (!ret)
+		ret = s5k4ecgx_write(c, REG_G_PREVZOOM_IN_YOFFS, r->top);
+	if (!ret)
+		ret = s5k4ecgx_write(c, REG_G_CAPZOOM_IN_WIDTH, r->width);
+	if (!ret)
+		ret = s5k4ecgx_write(c, REG_G_CAPZOOM_IN_HEIGHT, r->height);
+	if (!ret)
+		ret = s5k4ecgx_write(c, REG_G_CAPZOOM_IN_XOFFS, r->left);
+	if (!ret)
+		ret = s5k4ecgx_write(c, REG_G_CAPZOOM_IN_YOFFS, r->top);
+
+	return ret;
+}
+
+static int s5k4ecgx_set_output_framefmt(struct s5k4ecgx *priv)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&priv->sd);
+	int ret;
+
+	ret = s5k4ecgx_write(client, REG_P_OUT_WIDTH(0),
+			     priv->curr_frmsize->size.width);
+	if (!ret)
+		ret = s5k4ecgx_write(client, REG_P_OUT_HEIGHT(0),
+				     priv->curr_frmsize->size.height);
+	if (!ret)
+		ret = s5k4ecgx_write(client, REG_P_FMT(0),
+				     priv->curr_pixfmt->reg_p_format);
+	return ret;
+}
+
+static int s5k4ecgx_init_sensor(struct v4l2_subdev *sd)
+{
+	int ret;
+
+	ret = s5k4ecgx_set_ahb_address(sd);
+	/* The delay is from manufacturer's settings */
+	msleep(100);
+
+	if (!ret)
+		ret = s5k4ecgx_load_firmware(sd);
+	if (ret)
+		v4l2_err(sd, "Failed to write initial settings\n");
+
+	return ret;
+}
+
+static int s5k4ecgx_gpio_set_value(struct s5k4ecgx *priv, int id, u32 val)
+{
+	if (!gpio_is_valid(priv->gpio[id].gpio))
+		return 0;
+	gpio_set_value(priv->gpio[id].gpio, val);
+
+	return 1;
+}
+
+static int __s5k4ecgx_power_on(struct s5k4ecgx *priv)
+{
+	int ret;
+
+	ret = regulator_bulk_enable(S5K4ECGX_NUM_SUPPLIES, priv->supplies);
+	if (ret)
+		return ret;
+	usleep_range(30, 50);
+
+	/* The polarity of STBY is controlled by TSP */
+	if (s5k4ecgx_gpio_set_value(priv, STBY, priv->gpio[STBY].level))
+		usleep_range(30, 50);
+
+	if (s5k4ecgx_gpio_set_value(priv, RST, priv->gpio[RST].level))
+		usleep_range(30, 50);
+
+	return 0;
+}
+
+static int __s5k4ecgx_power_off(struct s5k4ecgx *priv)
+{
+	if (s5k4ecgx_gpio_set_value(priv, RST, !priv->gpio[RST].level))
+		usleep_range(30, 50);
+
+	if (s5k4ecgx_gpio_set_value(priv, STBY, !priv->gpio[STBY].level))
+		usleep_range(30, 50);
+
+	priv->streaming = 0;
+
+	return regulator_bulk_disable(S5K4ECGX_NUM_SUPPLIES, priv->supplies);
+}
+
+/* Find nearest matching image pixel size. */
+static int s5k4ecgx_try_frame_size(struct v4l2_mbus_framefmt *mf,
+				  const struct s5k4ecgx_frmsize **size)
+{
+	unsigned int min_err = ~0;
+	int i = ARRAY_SIZE(s5k4ecgx_prev_sizes);
+	const struct s5k4ecgx_frmsize *fsize = &s5k4ecgx_prev_sizes[0],
+		*match = NULL;
+
+	while (i--) {
+		int err = abs(fsize->size.width - mf->width)
+				+ abs(fsize->size.height - mf->height);
+		if (err < min_err) {
+			min_err = err;
+			match = fsize;
+		}
+		fsize++;
+	}
+	if (match) {
+		mf->width  = match->size.width;
+		mf->height = match->size.height;
+		if (size)
+			*size = match;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int s5k4ecgx_enum_mbus_code(struct v4l2_subdev *sd,
+				   struct v4l2_subdev_fh *fh,
+				   struct v4l2_subdev_mbus_code_enum *code)
+{
+	if (code->index >= ARRAY_SIZE(s5k4ecgx_formats))
+		return -EINVAL;
+	code->code = s5k4ecgx_formats[code->index].code;
+
+	return 0;
+}
+
+static int s5k4ecgx_get_fmt(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh,
+			   struct v4l2_subdev_format *fmt)
+{
+	struct s5k4ecgx *priv = to_s5k4ecgx(sd);
+	struct v4l2_mbus_framefmt *mf;
+
+	if (fmt->which == V4L2_SUBDEV_FORMAT_TRY) {
+		if (fh) {
+			mf = v4l2_subdev_get_try_format(fh, 0);
+			fmt->format = *mf;
+		}
+		return 0;
+	}
+
+	mf = &fmt->format;
+
+	mutex_lock(&priv->lock);
+	mf->width = priv->curr_frmsize->size.width;
+	mf->height = priv->curr_frmsize->size.height;
+	mf->code = priv->curr_pixfmt->code;
+	mf->colorspace = priv->curr_pixfmt->colorspace;
+	mf->field = V4L2_FIELD_NONE;
+	mutex_unlock(&priv->lock);
+
+	return 0;
+}
+
+static const struct s5k4ecgx_pixfmt *s5k4ecgx_try_fmt(struct v4l2_subdev *sd,
+					    struct v4l2_mbus_framefmt *mf)
+{
+	int i = ARRAY_SIZE(s5k4ecgx_formats);
+
+	while (--i)
+		if (mf->code == s5k4ecgx_formats[i].code)
+			break;
+	mf->code = s5k4ecgx_formats[i].code;
+
+	return &s5k4ecgx_formats[i];
+}
+
+static int s5k4ecgx_set_fmt(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh,
+			    struct v4l2_subdev_format *fmt)
+{
+	struct s5k4ecgx *priv = to_s5k4ecgx(sd);
+	const struct s5k4ecgx_frmsize *fsize = NULL;
+	const struct s5k4ecgx_pixfmt *pf;
+	struct v4l2_mbus_framefmt *mf;
+	int ret = 0;
+
+	pf = s5k4ecgx_try_fmt(sd, &fmt->format);
+	s5k4ecgx_try_frame_size(&fmt->format, &fsize);
+	fmt->format.colorspace = V4L2_COLORSPACE_JPEG;
+
+	if (fmt->which == V4L2_SUBDEV_FORMAT_TRY) {
+		if (fh) {
+			mf = v4l2_subdev_get_try_format(fh, 0);
+			*mf = fmt->format;
+		}
+		return 0;
+	}
+
+	mutex_lock(&priv->lock);
+	if (!priv->streaming) {
+		priv->curr_frmsize = fsize;
+		priv->curr_pixfmt = pf;
+		priv->set_params = 1;
+	} else {
+		ret = -EBUSY;
+	}
+	mutex_unlock(&priv->lock);
+
+	return ret;
+}
+
+static const struct v4l2_subdev_pad_ops s5k4ecgx_pad_ops = {
+	.enum_mbus_code	= s5k4ecgx_enum_mbus_code,
+	.get_fmt	= s5k4ecgx_get_fmt,
+	.set_fmt	= s5k4ecgx_set_fmt,
+};
+
+/*
+ * V4L2 subdev controls
+ */
+static int s5k4ecgx_s_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct v4l2_subdev *sd = &container_of(ctrl->handler, struct s5k4ecgx,
+						handler)->sd;
+	struct i2c_client *client = v4l2_get_subdevdata(sd);
+	struct s5k4ecgx *priv = to_s5k4ecgx(sd);
+	unsigned int i;
+	int err = 0;
+
+	v4l2_dbg(1, debug, sd, "ctrl: 0x%x, value: %d\n", ctrl->id, ctrl->val);
+
+	mutex_lock(&priv->lock);
+	switch (ctrl->id) {
+	case V4L2_CID_CONTRAST:
+		err = s5k4ecgx_write(client, REG_USER_CONTRAST, ctrl->val);
+		break;
+
+	case V4L2_CID_SATURATION:
+		err = s5k4ecgx_write(client, REG_USER_SATURATION, ctrl->val);
+		break;
+
+	case V4L2_CID_SHARPNESS:
+		/* TODO: Revisit, is this setting for all presets ? */
+		for (i = 0; i < 4 && !err; i++)
+			err = s5k4ecgx_write(client, REG_USER_SHARPNESS(i),
+					     ctrl->val * SHARPNESS_DIV);
+		break;
+
+	case V4L2_CID_BRIGHTNESS:
+		err = s5k4ecgx_write(client, REG_USER_BRIGHTNESS, ctrl->val);
+		break;
+	}
+	mutex_unlock(&priv->lock);
+	if (err < 0)
+		v4l2_err(sd, "Failed to write s_ctrl err %d\n", err);
+
+	return err;
+}
+
+static const struct v4l2_ctrl_ops s5k4ecgx_ctrl_ops = {
+	.s_ctrl = s5k4ecgx_s_ctrl,
+};
+
+/*
+ * Reading s5k4ecgx version information
+ */
+static int s5k4ecgx_registered(struct v4l2_subdev *sd)
+{
+	int ret;
+	struct s5k4ecgx *priv = to_s5k4ecgx(sd);
+
+	mutex_lock(&priv->lock);
+	ret = __s5k4ecgx_power_on(priv);
+	if (!ret) {
+		ret = s5k4ecgx_read_fw_ver(sd);
+		__s5k4ecgx_power_off(priv);
+	}
+	mutex_unlock(&priv->lock);
+
+	return ret;
+}
+
+/*
+ * V4L2 subdev internal operations
+ */
+static int s5k4ecgx_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
+{
+	struct v4l2_mbus_framefmt *mf = v4l2_subdev_get_try_format(fh, 0);
+
+	mf->width = s5k4ecgx_prev_sizes[0].size.width;
+	mf->height = s5k4ecgx_prev_sizes[0].size.height;
+	mf->code = s5k4ecgx_formats[0].code;
+	mf->colorspace = V4L2_COLORSPACE_JPEG;
+	mf->field = V4L2_FIELD_NONE;
+
+	return 0;
+}
+
+static const struct v4l2_subdev_internal_ops s5k4ecgx_subdev_internal_ops = {
+	.registered = s5k4ecgx_registered,
+	.open = s5k4ecgx_open,
+};
+
+static int s5k4ecgx_s_power(struct v4l2_subdev *sd, int on)
+{
+	struct s5k4ecgx *priv = to_s5k4ecgx(sd);
+	int ret;
+
+	v4l2_dbg(1, debug, sd, "Switching %s\n", on ? "on" : "off");
+
+	if (on) {
+		ret = __s5k4ecgx_power_on(priv);
+		if (ret < 0)
+			return ret;
+		/* Time to stabilize sensor */
+		msleep(100);
+		ret = s5k4ecgx_init_sensor(sd);
+		if (ret < 0)
+			__s5k4ecgx_power_off(priv);
+		else
+			priv->set_params = 1;
+	} else {
+		ret = __s5k4ecgx_power_off(priv);
+	}
+
+	return 0;
+}
+
+static int s5k4ecgx_log_status(struct v4l2_subdev *sd)
+{
+	v4l2_ctrl_handler_log_status(sd->ctrl_handler, sd->name);
+
+	return 0;
+}
+
+static const struct v4l2_subdev_core_ops s5k4ecgx_core_ops = {
+	.s_power	= s5k4ecgx_s_power,
+	.log_status	= s5k4ecgx_log_status,
+};
+
+static int __s5k4ecgx_s_stream(struct s5k4ecgx *priv, int on)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&priv->sd);
+	const struct v4l2_rect *crop_rect = &priv->curr_frmsize->input_window;
+	int ret = 0;
+
+	/* TODO: Add s_stream(0) handling */
+
+	if (!on || !priv->set_params)
+		return 0;
+
+	ret = s5k4ecgx_set_input_window(client, crop_rect);
+	if (!ret)
+		ret = s5k4ecgx_set_zoom_window(client, crop_rect);
+	if (!ret)
+		ret = s5k4ecgx_write(client, REG_G_INPUTS_CHANGE_REQ, 1);
+	if (!ret)
+		ret = s5k4ecgx_write(client, 0x70000a1e, 0x28);
+	if (!ret)
+		ret = s5k4ecgx_write(client, 0x70000ad4, 0x3c);
+	if (!ret)
+		ret = s5k4ecgx_set_output_framefmt(priv);
+	if (!ret)
+		ret = s5k4ecgx_write(client, REG_P_PVI_MASK(0), 0x52);
+	if (!ret)
+		ret = s5k4ecgx_write(client, REG_P_FR_TIME_TYPE(0),
+				     FR_TIME_DYNAMIC);
+	if (!ret)
+		ret = s5k4ecgx_write(client, REG_P_FR_TIME_Q_TYPE(0),
+				     FR_TIME_Q_BEST_FRRATE);
+	if (!ret)
+		ret = s5k4ecgx_write(client,  REG_P_MIN_FR_TIME(0),
+				     US_TO_FR_TIME(33300));
+	if (!ret)
+		ret = s5k4ecgx_write(client, REG_P_MAX_FR_TIME(0),
+				     US_TO_FR_TIME(66600));
+	if (!ret)
+		ret = s5k4ecgx_write(client, REG_P_PREV_MIRROR(0), 0);
+	if (!ret)
+		ret = s5k4ecgx_write(client, REG_P_CAP_MIRROR(0), 0);
+	if (!ret)
+		ret = s5k4ecgx_write(client, REG_G_ACTIVE_PREV_CFG, 0);
+	if (!ret)
+		ret = s5k4ecgx_write(client, REG_G_PREV_OPEN_AFTER_CH, 1);
+	if (!ret)
+		ret = s5k4ecgx_write(client, REG_G_NEW_CFG_SYNC, 1);
+	if (!ret)
+		ret = s5k4ecgx_write(client, REG_G_PREV_CFG_CHG, 1);
+	if (!ret)
+		priv->set_params = 0;
+
+	return ret;
+}
+
+static int s5k4ecgx_s_stream(struct v4l2_subdev *sd, int on)
+{
+	struct s5k4ecgx *priv = to_s5k4ecgx(sd);
+	int ret = 0;
+
+	v4l2_dbg(1, debug, sd, "Turn streaming %s\n", on ? "on" : "off");
+
+	mutex_lock(&priv->lock);
+	if (on) {
+		/* Ignore if s_stream is called twice */
+		if (priv->streaming == !on) {
+			ret = __s5k4ecgx_s_stream(priv, on);
+			if (!ret)
+				priv->streaming = on & 1;
+		}
+	}
+	mutex_unlock(&priv->lock);
+
+	return ret;
+}
+
+static const struct v4l2_subdev_video_ops s5k4ecgx_video_ops = {
+	.s_stream = s5k4ecgx_s_stream,
+};
+
+static const struct v4l2_subdev_ops s5k4ecgx_ops = {
+	.core = &s5k4ecgx_core_ops,
+	.pad = &s5k4ecgx_pad_ops,
+	.video = &s5k4ecgx_video_ops,
+};
+
+/*
+ * GPIO setup
+ */
+static int s5k4ecgx_config_gpio(int nr, int val, const char *name)
+{
+	unsigned long flags = val ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
+	int ret;
+
+	if (!gpio_is_valid(nr))
+		return 0;
+	ret = gpio_request_one(nr, flags, name);
+	if (!ret)
+		gpio_export(nr, 0);
+
+	return ret;
+}
+
+static void s5k4ecgx_free_gpios(struct s5k4ecgx *priv)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(priv->gpio); i++) {
+		if (!gpio_is_valid(priv->gpio[i].gpio))
+			continue;
+		gpio_free(priv->gpio[i].gpio);
+		priv->gpio[i].gpio = -EINVAL;
+	}
+}
+
+static int s5k4ecgx_config_gpios(struct s5k4ecgx *priv,
+				  const struct s5k4ecgx_platform_data *pdata)
+{
+	const struct s5k4ecgx_gpio *gpio = &pdata->gpio_stby;
+	int ret;
+
+	priv->gpio[STBY].gpio = -EINVAL;
+	priv->gpio[RST].gpio  = -EINVAL;
+
+	ret = s5k4ecgx_config_gpio(gpio->gpio, gpio->level, "S5K4ECGX_STBY");
+
+	if (ret) {
+		s5k4ecgx_free_gpios(priv);
+		return ret;
+	}
+	priv->gpio[STBY] = *gpio;
+	if (gpio_is_valid(gpio->gpio))
+		gpio_set_value(gpio->gpio, 0);
+
+	gpio = &pdata->gpio_reset;
+
+	ret = s5k4ecgx_config_gpio(gpio->gpio, gpio->level, "S5K4ECGX_RST");
+	if (ret) {
+		s5k4ecgx_free_gpios(priv);
+		return ret;
+	}
+	priv->gpio[RST] = *gpio;
+	if (gpio_is_valid(gpio->gpio))
+		gpio_set_value(gpio->gpio, 0);
+
+	return 0;
+}
+
+static int s5k4ecgx_init_v4l2_ctrls(struct s5k4ecgx *priv)
+{
+	const struct v4l2_ctrl_ops *ops = &s5k4ecgx_ctrl_ops;
+	struct v4l2_ctrl_handler *hdl = &priv->handler;
+	int ret;
+
+	ret =  v4l2_ctrl_handler_init(hdl, 4);
+	if (ret)
+		return ret;
+
+	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_BRIGHTNESS, -208, 127, 1, 0);
+	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_CONTRAST, -127, 127, 1, 0);
+	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_SATURATION, -127, 127, 1, 0);
+
+	/* Sharpness default is 24612, and then (24612/SHARPNESS_DIV) = 2 */
+	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_SHARPNESS, -32704/SHARPNESS_DIV,
+			  24612/SHARPNESS_DIV, 1, 2);
+	if (hdl->error) {
+		ret = hdl->error;
+		v4l2_ctrl_handler_free(hdl);
+		return ret;
+	}
+	priv->sd.ctrl_handler = hdl;
+
+	return 0;
+};
+
+static int s5k4ecgx_probe(struct i2c_client *client,
+			  const struct i2c_device_id *id)
+{
+	int	ret, i;
+	struct v4l2_subdev *sd;
+	struct s5k4ecgx *priv;
+	struct s5k4ecgx_platform_data *pdata = client->dev.platform_data;
+
+	if (pdata == NULL) {
+		dev_err(&client->dev, "platform data is missing!\n");
+		return -EINVAL;
+	}
+	priv = devm_kzalloc(&client->dev, sizeof(struct s5k4ecgx), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	mutex_init(&priv->lock);
+	priv->streaming = 0;
+
+	sd = &priv->sd;
+	/* Registering subdev */
+	v4l2_i2c_subdev_init(sd, client, &s5k4ecgx_ops);
+	strlcpy(sd->name, S5K4ECGX_DRIVER_NAME, sizeof(sd->name));
+
+	sd->internal_ops = &s5k4ecgx_subdev_internal_ops;
+	/* Support v4l2 sub-device user space API */
+	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
+
+	priv->pad.flags = MEDIA_PAD_FL_SOURCE;
+	sd->entity.type = MEDIA_ENT_T_V4L2_SUBDEV_SENSOR;
+	ret = media_entity_init(&sd->entity, 1, &priv->pad, 0);
+	if (ret)
+		return ret;
+
+	ret = s5k4ecgx_config_gpios(priv, pdata);
+	if (ret) {
+		dev_err(&client->dev, "Failed to set gpios\n");
+		goto out_err1;
+	}
+	for (i = 0; i < S5K4ECGX_NUM_SUPPLIES; i++)
+		priv->supplies[i].supply = s5k4ecgx_supply_names[i];
+
+	ret = devm_regulator_bulk_get(&client->dev, S5K4ECGX_NUM_SUPPLIES,
+				 priv->supplies);
+	if (ret) {
+		dev_err(&client->dev, "Failed to get regulators\n");
+		goto out_err2;
+	}
+	ret = s5k4ecgx_init_v4l2_ctrls(priv);
+	if (ret)
+		goto out_err2;
+
+	priv->curr_pixfmt = &s5k4ecgx_formats[0];
+	priv->curr_frmsize = &s5k4ecgx_prev_sizes[0];
+
+	return 0;
+
+out_err2:
+	s5k4ecgx_free_gpios(priv);
+out_err1:
+	media_entity_cleanup(&priv->sd.entity);
+
+	return ret;
+}
+
+static int s5k4ecgx_remove(struct i2c_client *client)
+{
+	struct v4l2_subdev *sd = i2c_get_clientdata(client);
+	struct s5k4ecgx *priv = to_s5k4ecgx(sd);
+
+	mutex_destroy(&priv->lock);
+	v4l2_device_unregister_subdev(sd);
+	v4l2_ctrl_handler_free(&priv->handler);
+	media_entity_cleanup(&sd->entity);
+
+	return 0;
+}
+
+static const struct i2c_device_id s5k4ecgx_id[] = {
+	{ S5K4ECGX_DRIVER_NAME, 0 },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, s5k4ecgx_id);
+
+static struct i2c_driver v4l2_i2c_driver = {
+	.driver = {
+		.owner	= THIS_MODULE,
+		.name = S5K4ECGX_DRIVER_NAME,
+	},
+	.probe = s5k4ecgx_probe,
+	.remove = s5k4ecgx_remove,
+	.id_table = s5k4ecgx_id,
+};
+
+module_i2c_driver(v4l2_i2c_driver);
+
+MODULE_DESCRIPTION("Samsung S5K4ECGX 5MP SOC camera");
+MODULE_AUTHOR("Sangwook Lee <sangwook.lee@linaro.org>");
+MODULE_AUTHOR("Seok-Young Jang <quartz.jang@samsung.com>");
+MODULE_LICENSE("GPL");
+MODULE_FIRMWARE(S5K4ECGX_FIRMWARE);
diff --git a/include/media/s5k4ecgx.h b/include/media/s5k4ecgx.h
new file mode 100644
index 0000000..90c1be7
--- /dev/null
+++ b/include/media/s5k4ecgx.h
@@ -0,0 +1,37 @@
+/*
+ * S5K4ECGX image sensor header file
+ *
+ * Copyright (C) 2012, Linaro
+ * Copyright (C) 2012, Samsung Electronics Co., Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef S5K4ECGX_H
+#define S5K4ECGX_H
+
+/**
+ * struct s5k4ecgx_gpio - data structure describing a GPIO
+ * @gpio : GPIO number
+ * @level: indicates active state of the @gpio
+ */
+struct s5k4ecgx_gpio {
+	int gpio;
+	int level;
+};
+
+/**
+ * struct ss5k4ecgx_platform_data- s5k4ecgx driver platform data
+ * @gpio_reset:	 GPIO driving RESET pin
+ * @gpio_stby :	 GPIO driving STBY pin
+ */
+
+struct s5k4ecgx_platform_data {
+	struct s5k4ecgx_gpio gpio_reset;
+	struct s5k4ecgx_gpio gpio_stby;
+};
+
+#endif /* S5K4ECGX_H */
-- 
1.7.9.5

Re: [RFC PATCH v6] media: add v4l2 subdev driver for S5K4ECGX sensor

[Sylwester Nawrocki]

Hi Sangwook,

On 09/06/2012 05:08 PM, Sangwook Lee wrote:
> This patch adds driver for S5K4ECGX sensor with embedded ISP SoC,
> S5K4ECGX, which is a 5M CMOS Image sensor from Samsung
> The driver implements preview mode of the S5K4ECGX sensor.
> capture (snapshot) operation, face detection are missing now.
> Following controls are supported:
> contrast/saturation/brightness/sharpness
>
> Signed-off-by: Sangwook Lee<sangwook.lee@linaro.org>
> Reviewed-by: Sylwester Nawrocki<s.nawrocki@samsung.com>

Thanks for the update. I've done a few more minor fixes and improved
s_stream() subdev op handling, so it really enables/disables data
stream on the sensor's output. It's pushed to

git://linuxtv.org/snawrocki/media.git samsung_s5k4ecgx

Could you please squash the changes that you are willing to accept
and test if the last patch really does what it is intended to ?

After you send v7 I could add this patch to my tree for v3.7,
unless you want to handle it yourself.

--
Thanks,
Sylwester

Re: [RFC PATCH v6] media: add v4l2 subdev driver for S5K4ECGX sensor

[Francesco Lavra]

Hi,
I'm going to report the (few) things which are also present in
Sylwester's tree.

On 09/06/2012 05:08 PM, Sangwook Lee wrote:
> This patch adds driver for S5K4ECGX sensor with embedded ISP SoC,
> S5K4ECGX, which is a 5M CMOS Image sensor from Samsung
> The driver implements preview mode of the S5K4ECGX sensor.
> capture (snapshot) operation, face detection are missing now.
> Following controls are supported:
> contrast/saturation/brightness/sharpness
> 
> Signed-off-by: Sangwook Lee <sangwook.lee@linaro.org>
> Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>

[snip]

> +static const char * const s5k4ecgx_supply_names[] = {
> +	/*
> +	 * Usually 2.8V is used for analog power (vdda)
> +	 * and digital IO (vddio, vddd_core)

s/vddd_core/vddcore

[snip]

> +static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
> +{
> +	const struct firmware *fw;
> +	int err, i, regs_num;
> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
> +	u16 val;
> +	u32 addr, crc, crc_file, addr_inc = 0;
> +
> +	err = request_firmware(&fw, S5K4ECGX_FIRMWARE, sd->v4l2_dev->dev);
> +	if (err) {
> +		v4l2_err(sd, "Failed to read firmware %s\n", S5K4ECGX_FIRMWARE);
> +		return err;
> +	}
> +	regs_num = *(u32 *)(fw->data);
> +	v4l2_dbg(3, debug, sd, "FW: %s size %d register sets %d\n",
> +		 S5K4ECGX_FIRMWARE, fw->size, regs_num);
> +	regs_num++; /* Add header */
> +	if (fw->size != regs_num * FW_RECORD_SIZE + FW_CRC_SIZE) {
> +		err = -EINVAL;
> +		goto fw_out;
> +	}
> +	crc_file = *(u32 *)(fw->data + regs_num * FW_RECORD_SIZE);

Depending on the value of regs_num, this may result in unaligned access

[snip]

> +static int s5k4ecgx_s_power(struct v4l2_subdev *sd, int on)
> +{
> +	struct s5k4ecgx *priv = to_s5k4ecgx(sd);
> +	int ret;
> +
> +	v4l2_dbg(1, debug, sd, "Switching %s\n", on ? "on" : "off");
> +
> +	if (on) {
> +		ret = __s5k4ecgx_power_on(priv);
> +		if (ret < 0)
> +			return ret;
> +		/* Time to stabilize sensor */
> +		msleep(100);
> +		ret = s5k4ecgx_init_sensor(sd);
> +		if (ret < 0)
> +			__s5k4ecgx_power_off(priv);
> +		else
> +			priv->set_params = 1;
> +	} else {
> +		ret = __s5k4ecgx_power_off(priv);
> +	}
> +
> +	return 0;

return ret;

[snip]

> +static int s5k4ecgx_probe(struct i2c_client *client,
> +			  const struct i2c_device_id *id)
> +{
> +	int	ret, i;
> +	struct v4l2_subdev *sd;
> +	struct s5k4ecgx *priv;
> +	struct s5k4ecgx_platform_data *pdata = client->dev.platform_data;
> +
> +	if (pdata == NULL) {
> +		dev_err(&client->dev, "platform data is missing!\n");
> +		return -EINVAL;
> +	}
> +	priv = devm_kzalloc(&client->dev, sizeof(struct s5k4ecgx), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	mutex_init(&priv->lock);
> +	priv->streaming = 0;
> +
> +	sd = &priv->sd;
> +	/* Registering subdev */
> +	v4l2_i2c_subdev_init(sd, client, &s5k4ecgx_ops);
> +	strlcpy(sd->name, S5K4ECGX_DRIVER_NAME, sizeof(sd->name));
> +
> +	sd->internal_ops = &s5k4ecgx_subdev_internal_ops;
> +	/* Support v4l2 sub-device user space API */
> +	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
> +
> +	priv->pad.flags = MEDIA_PAD_FL_SOURCE;
> +	sd->entity.type = MEDIA_ENT_T_V4L2_SUBDEV_SENSOR;
> +	ret = media_entity_init(&sd->entity, 1, &priv->pad, 0);
> +	if (ret)
> +		return ret;
> +
> +	ret = s5k4ecgx_config_gpios(priv, pdata);
> +	if (ret) {
> +		dev_err(&client->dev, "Failed to set gpios\n");
> +		goto out_err1;
> +	}
> +	for (i = 0; i < S5K4ECGX_NUM_SUPPLIES; i++)
> +		priv->supplies[i].supply = s5k4ecgx_supply_names[i];
> +
> +	ret = devm_regulator_bulk_get(&client->dev, S5K4ECGX_NUM_SUPPLIES,
> +				 priv->supplies);
> +	if (ret) {
> +		dev_err(&client->dev, "Failed to get regulators\n");
> +		goto out_err2;
> +	}
> +	ret = s5k4ecgx_init_v4l2_ctrls(priv);
> +	if (ret)
> +		goto out_err2;
> +
> +	priv->curr_pixfmt = &s5k4ecgx_formats[0];
> +	priv->curr_frmsize = &s5k4ecgx_prev_sizes[0];
> +
> +	return 0;
> +
> +out_err2:
> +	s5k4ecgx_free_gpios(priv);
> +out_err1:
> +	media_entity_cleanup(&priv->sd.entity);
> +
> +	return ret;
> +}
> +
> +static int s5k4ecgx_remove(struct i2c_client *client)
> +{
> +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> +	struct s5k4ecgx *priv = to_s5k4ecgx(sd);
> +
> +	mutex_destroy(&priv->lock);
> +	v4l2_device_unregister_subdev(sd);
> +	v4l2_ctrl_handler_free(&priv->handler);
> +	media_entity_cleanup(&sd->entity);
> +
> +	return 0;

Maybe s5k4ecgx_free_gpios() should be called?

Regards,
Francesco

Re: [RFC PATCH v6] media: add v4l2 subdev driver for S5K4ECGX sensor

[Sylwester Nawrocki]

Hi,

On 09/09/2012 06:01 PM, Francesco Lavra wrote:
>> +static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
>> +{
>> +	const struct firmware *fw;
>> +	int err, i, regs_num;
>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>> +	u16 val;
>> +	u32 addr, crc, crc_file, addr_inc = 0;
>> +
>> +	err = request_firmware(&fw, S5K4ECGX_FIRMWARE, sd->v4l2_dev->dev);
>> +	if (err) {
>> +		v4l2_err(sd, "Failed to read firmware %s\n", S5K4ECGX_FIRMWARE);
>> +		return err;
>> +	}
>> +	regs_num = *(u32 *)(fw->data);
>> +	v4l2_dbg(3, debug, sd, "FW: %s size %d register sets %d\n",
>> +		 S5K4ECGX_FIRMWARE, fw->size, regs_num);
>> +	regs_num++; /* Add header */
>> +	if (fw->size != regs_num * FW_RECORD_SIZE + FW_CRC_SIZE) {
>> +		err = -EINVAL;
>> +		goto fw_out;
>> +	}
>> +	crc_file = *(u32 *)(fw->data + regs_num * FW_RECORD_SIZE);
> 
> Depending on the value of regs_num, this may result in unaligned access

Thanks for the catch. I think it is not the only place where unaligned
issues are possible. Since the data records are 4-byte address + 2-byte
value there is also an issue with reading the address entries. Assuming
fw->data is aligned to at least 2-bytes (not quite sure if we can assume
that) there should be no problem with reading 2-byte register values.

We could change the data types of the register values from u16 to u32,
wasting some memory (there is approximately 3 000 records), so there is
no other data types in the file structure than u32. Or use a patch as
below. Not sure what's better.

8<---------------------------------------------------------------------
>From a970480b99bdb74e2bf48e1a321724231e6516a0 Mon Sep 17 00:00:00 2001
From: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
Date: Sun, 9 Sep 2012 19:56:31 +0200
Subject: [PATCH] s5k4ecgx: Fix unaligned access issues

Signed-off-by: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
---
 drivers/media/i2c/s5k4ecgx.c |   16 ++++++++++++----
 1 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/media/i2c/s5k4ecgx.c b/drivers/media/i2c/s5k4ecgx.c
index 0ef0b7d..4c6439a 100644
--- a/drivers/media/i2c/s5k4ecgx.c
+++ b/drivers/media/i2c/s5k4ecgx.c
@@ -24,6 +24,7 @@
 #include <linux/module.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
+#include <asm/unaligned.h>

 #include <media/media-entity.h>
 #include <media/s5k4ecgx.h>
@@ -331,6 +332,7 @@ static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
 	const struct firmware *fw;
 	int err, i, regs_num;
 	u32 addr, crc, crc_file, addr_inc = 0;
+	const u8 *ptr;
 	u16 val;

 	err = request_firmware(&fw, S5K4ECGX_FIRMWARE, sd->v4l2_dev->dev);
@@ -338,7 +340,7 @@ static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
 		v4l2_err(sd, "Failed to read firmware %s\n", S5K4ECGX_FIRMWARE);
 		return err;
 	}
-	regs_num = le32_to_cpu(*(u32 *)fw->data);
+	regs_num = le32_to_cpu(get_unaligned((__le32 *)fw->data));

 	v4l2_dbg(3, debug, sd, "FW: %s size %d register sets %d\n",
 		 S5K4ECGX_FIRMWARE, fw->size, regs_num);
@@ -349,7 +351,8 @@ static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
 		goto fw_out;
 	}

-	crc_file = *(u32 *)(fw->data + regs_num * FW_RECORD_SIZE);
+	memcpy(&crc_file, fw->data + regs_num * FW_RECORD_SIZE, sizeof(u32));
+
 	crc = crc32_le(~0, fw->data, regs_num * FW_RECORD_SIZE);
 	if (crc != crc_file) {
 		v4l2_err(sd, "FW: invalid crc (%#x:%#x)\n", crc, crc_file);
@@ -357,9 +360,14 @@ static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
 		goto fw_out;
 	}

+	ptr = fw->data + FW_RECORD_SIZE;
+
 	for (i = 1; i < regs_num; i++) {
-		addr = le32_to_cpu(*(u32 *)(fw->data + i * FW_RECORD_SIZE));
-		val = le16_to_cpu(*(u16 *)(fw->data + i * FW_RECORD_SIZE + 4));
+		addr = le32_to_cpu(get_unaligned((__le32 *)ptr));
+		ptr += 4;
+		val = le16_to_cpu(*(__le16 *)ptr);
+		ptr += FW_RECORD_SIZE;
+
 		if (addr - addr_inc != 2)
 			err = s5k4ecgx_write(client, addr, val);
 		else
-- 
1.7.2.5

8<----------------------------------------------------------------------------

--

Regards,
Sylwester

Re: [RFC PATCH v6] media: add v4l2 subdev driver for S5K4ECGX sensor

[Francesco Lavra]

Hi,

On 09/10/2012 05:04 PM, Sylwester Nawrocki wrote:
> Hi,
> 
> On 09/09/2012 06:01 PM, Francesco Lavra wrote:
>>> +static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
>>> +{
>>> +	const struct firmware *fw;
>>> +	int err, i, regs_num;
>>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>>> +	u16 val;
>>> +	u32 addr, crc, crc_file, addr_inc = 0;
>>> +
>>> +	err = request_firmware(&fw, S5K4ECGX_FIRMWARE, sd->v4l2_dev->dev);
>>> +	if (err) {
>>> +		v4l2_err(sd, "Failed to read firmware %s\n", S5K4ECGX_FIRMWARE);
>>> +		return err;
>>> +	}
>>> +	regs_num = *(u32 *)(fw->data);
>>> +	v4l2_dbg(3, debug, sd, "FW: %s size %d register sets %d\n",
>>> +		 S5K4ECGX_FIRMWARE, fw->size, regs_num);
>>> +	regs_num++; /* Add header */
>>> +	if (fw->size != regs_num * FW_RECORD_SIZE + FW_CRC_SIZE) {
>>> +		err = -EINVAL;
>>> +		goto fw_out;
>>> +	}
>>> +	crc_file = *(u32 *)(fw->data + regs_num * FW_RECORD_SIZE);
>>
>> Depending on the value of regs_num, this may result in unaligned access
> 
> Thanks for the catch. I think it is not the only place where unaligned
> issues are possible. Since the data records are 4-byte address + 2-byte
> value there is also an issue with reading the address entries. Assuming
> fw->data is aligned to at least 2-bytes (not quite sure if we can assume
> that) there should be no problem with reading 2-byte register values.

I'm not sure 2-byte alignment can be safely assumed, either.

> We could change the data types of the register values from u16 to u32,
> wasting some memory (there is approximately 3 000 records), so there is
> no other data types in the file structure than u32. Or use a patch as
> below. Not sure what's better.

I prefer the approach of your patch below, but I would use get_unaligned
to get the 2-byte values, too. Also there are another couple of
glitches, see below.

> 
> 8<---------------------------------------------------------------------
> From a970480b99bdb74e2bf48e1a321724231e6516a0 Mon Sep 17 00:00:00 2001
> From: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
> Date: Sun, 9 Sep 2012 19:56:31 +0200
> Subject: [PATCH] s5k4ecgx: Fix unaligned access issues
> 
> Signed-off-by: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
> ---
>  drivers/media/i2c/s5k4ecgx.c |   16 ++++++++++++----
>  1 files changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/i2c/s5k4ecgx.c b/drivers/media/i2c/s5k4ecgx.c
> index 0ef0b7d..4c6439a 100644
> --- a/drivers/media/i2c/s5k4ecgx.c
> +++ b/drivers/media/i2c/s5k4ecgx.c
> @@ -24,6 +24,7 @@
>  #include <linux/module.h>
>  #include <linux/regulator/consumer.h>
>  #include <linux/slab.h>
> +#include <asm/unaligned.h>
> 
>  #include <media/media-entity.h>
>  #include <media/s5k4ecgx.h>
> @@ -331,6 +332,7 @@ static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
>  	const struct firmware *fw;
>  	int err, i, regs_num;
>  	u32 addr, crc, crc_file, addr_inc = 0;
> +	const u8 *ptr;
>  	u16 val;
> 
>  	err = request_firmware(&fw, S5K4ECGX_FIRMWARE, sd->v4l2_dev->dev);
> @@ -338,7 +340,7 @@ static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
>  		v4l2_err(sd, "Failed to read firmware %s\n", S5K4ECGX_FIRMWARE);
>  		return err;
>  	}
> -	regs_num = le32_to_cpu(*(u32 *)fw->data);
> +	regs_num = le32_to_cpu(get_unaligned((__le32 *)fw->data));
> 
>  	v4l2_dbg(3, debug, sd, "FW: %s size %d register sets %d\n",
>  		 S5K4ECGX_FIRMWARE, fw->size, regs_num);
> @@ -349,7 +351,8 @@ static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
>  		goto fw_out;
>  	}
> 
> -	crc_file = *(u32 *)(fw->data + regs_num * FW_RECORD_SIZE);
> +	memcpy(&crc_file, fw->data + regs_num * FW_RECORD_SIZE, sizeof(u32));

crc_file should be converted from little endian to native endian.

> +
>  	crc = crc32_le(~0, fw->data, regs_num * FW_RECORD_SIZE);
>  	if (crc != crc_file) {
>  		v4l2_err(sd, "FW: invalid crc (%#x:%#x)\n", crc, crc_file);
> @@ -357,9 +360,14 @@ static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
>  		goto fw_out;
>  	}
> 
> +	ptr = fw->data + FW_RECORD_SIZE;
> +
>  	for (i = 1; i < regs_num; i++) {
> -		addr = le32_to_cpu(*(u32 *)(fw->data + i * FW_RECORD_SIZE));
> -		val = le16_to_cpu(*(u16 *)(fw->data + i * FW_RECORD_SIZE + 4));
> +		addr = le32_to_cpu(get_unaligned((__le32 *)ptr));
> +		ptr += 4;
> +		val = le16_to_cpu(*(__le16 *)ptr);
> +		ptr += FW_RECORD_SIZE;

ptr is being incremented by (4 + FW_RECORD_SIZE) bytes at each iteration.

> +
>  		if (addr - addr_inc != 2)
>  			err = s5k4ecgx_write(client, addr, val);
>  		else

--
Francesco

Re: [RFC PATCH v6] media: add v4l2 subdev driver for S5K4ECGX sensor

[Sylwester Nawrocki]

On 09/10/2012 08:52 PM, Francesco Lavra wrote:
> On 09/10/2012 05:04 PM, Sylwester Nawrocki wrote:
>> On 09/09/2012 06:01 PM, Francesco Lavra wrote:
>>>> +static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
>>>> +{
>>>> +	const struct firmware *fw;
>>>> +	int err, i, regs_num;
>>>> +	struct i2c_client *client = v4l2_get_subdevdata(sd);
>>>> +	u16 val;
>>>> +	u32 addr, crc, crc_file, addr_inc = 0;
>>>> +
>>>> +	err = request_firmware(&fw, S5K4ECGX_FIRMWARE, sd->v4l2_dev->dev);
>>>> +	if (err) {
>>>> +		v4l2_err(sd, "Failed to read firmware %s\n", S5K4ECGX_FIRMWARE);
>>>> +		return err;
>>>> +	}
>>>> +	regs_num = *(u32 *)(fw->data);
>>>> +	v4l2_dbg(3, debug, sd, "FW: %s size %d register sets %d\n",
>>>> +		 S5K4ECGX_FIRMWARE, fw->size, regs_num);
>>>> +	regs_num++; /* Add header */
>>>> +	if (fw->size != regs_num * FW_RECORD_SIZE + FW_CRC_SIZE) {
>>>> +		err = -EINVAL;
>>>> +		goto fw_out;
>>>> +	}
>>>> +	crc_file = *(u32 *)(fw->data + regs_num * FW_RECORD_SIZE);
>>>
>>> Depending on the value of regs_num, this may result in unaligned access
>>
>> Thanks for the catch. I think it is not the only place where unaligned
>> issues are possible. Since the data records are 4-byte address + 2-byte
>> value there is also an issue with reading the address entries. Assuming
>> fw->data is aligned to at least 2-bytes (not quite sure if we can assume
>> that) there should be no problem with reading 2-byte register values.
> 
> I'm not sure 2-byte alignment can be safely assumed, either.
> 
>> We could change the data types of the register values from u16 to u32,
>> wasting some memory (there is approximately 3 000 records), so there is
>> no other data types in the file structure than u32. Or use a patch as
>> below. Not sure what's better.
> 
> I prefer the approach of your patch below, but I would use get_unaligned
> to get the 2-byte values, too. Also there are another couple of
> glitches, see below.

OK, thanks for the feedback. It was also my preference. The performance
impact seems insignificant, given a write of each record takes time of
1 ms order.

>> 8<---------------------------------------------------------------------
>>  From a970480b99bdb74e2bf48e1a321724231e6516a0 Mon Sep 17 00:00:00 2001
>> From: Sylwester Nawrocki<sylvester.nawrocki@gmail.com>
>> Date: Sun, 9 Sep 2012 19:56:31 +0200
>> Subject: [PATCH] s5k4ecgx: Fix unaligned access issues
>>
>> Signed-off-by: Sylwester Nawrocki<sylvester.nawrocki@gmail.com>
>> ---
>>   drivers/media/i2c/s5k4ecgx.c |   16 ++++++++++++----
>>   1 files changed, 12 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/media/i2c/s5k4ecgx.c b/drivers/media/i2c/s5k4ecgx.c
>> index 0ef0b7d..4c6439a 100644
>> --- a/drivers/media/i2c/s5k4ecgx.c
>> +++ b/drivers/media/i2c/s5k4ecgx.c
>> @@ -24,6 +24,7 @@
>>   #include<linux/module.h>
>>   #include<linux/regulator/consumer.h>
>>   #include<linux/slab.h>
>> +#include<asm/unaligned.h>
>>
>>   #include<media/media-entity.h>
>>   #include<media/s5k4ecgx.h>
>> @@ -331,6 +332,7 @@ static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
>>   	const struct firmware *fw;
>>   	int err, i, regs_num;
>>   	u32 addr, crc, crc_file, addr_inc = 0;
>> +	const u8 *ptr;
>>   	u16 val;
>>
>>   	err = request_firmware(&fw, S5K4ECGX_FIRMWARE, sd->v4l2_dev->dev);
>> @@ -338,7 +340,7 @@ static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
>>   		v4l2_err(sd, "Failed to read firmware %s\n", S5K4ECGX_FIRMWARE);
>>   		return err;
>>   	}
>> -	regs_num = le32_to_cpu(*(u32 *)fw->data);
>> +	regs_num = le32_to_cpu(get_unaligned((__le32 *)fw->data));
>>
>>   	v4l2_dbg(3, debug, sd, "FW: %s size %d register sets %d\n",
>>   		 S5K4ECGX_FIRMWARE, fw->size, regs_num);
>> @@ -349,7 +351,8 @@ static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
>>   		goto fw_out;
>>   	}
>>
>> -	crc_file = *(u32 *)(fw->data + regs_num * FW_RECORD_SIZE);
>> +	memcpy(&crc_file, fw->data + regs_num * FW_RECORD_SIZE, sizeof(u32));
> 
> crc_file should be converted from little endian to native endian.

Right, I should have verified that crc32_le() return value is in native
endianness.

>> +
>>   	crc = crc32_le(~0, fw->data, regs_num * FW_RECORD_SIZE);
>>   	if (crc != crc_file) {
>>   		v4l2_err(sd, "FW: invalid crc (%#x:%#x)\n", crc, crc_file);
>> @@ -357,9 +360,14 @@ static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
>>   		goto fw_out;
>>   	}
>>
>> +	ptr = fw->data + FW_RECORD_SIZE;
>> +
>>   	for (i = 1; i<  regs_num; i++) {
>> -		addr = le32_to_cpu(*(u32 *)(fw->data + i * FW_RECORD_SIZE));
>> -		val = le16_to_cpu(*(u16 *)(fw->data + i * FW_RECORD_SIZE + 4));
>> +		addr = le32_to_cpu(get_unaligned((__le32 *)ptr));
>> +		ptr += 4;
>> +		val = le16_to_cpu(*(__le16 *)ptr);
>> +		ptr += FW_RECORD_SIZE;
> 
> ptr is being incremented by (4 + FW_RECORD_SIZE) bytes at each iteration.

Oops, I was to quick in sending that patch out. Indeed, that's wrong.
Sangwook, FWIW, I just pushed the corrected patch to my tree
(http://git.linuxtv.org/snawrocki/media.git/commitdiff/4a0ecad6f08ccbba3)

--

Thanks,
Sylwester

Re: [RFC PATCH v6] media: add v4l2 subdev driver for S5K4ECGX sensor

[Sangwook Lee]

Hi  Francesco

Thanks for your advice.

@ Sylwester
Thanks for your nice patch, and I will squash  and then send it again.


Thanks
Sangwook


On 10 September 2012 21:29, Sylwester Nawrocki
<sylvester.nawrocki@gmail.com> wrote:
> On 09/10/2012 08:52 PM, Francesco Lavra wrote:
>> On 09/10/2012 05:04 PM, Sylwester Nawrocki wrote:
>>> On 09/09/2012 06:01 PM, Francesco Lavra wrote:
>>>>> +static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
>>>>> +{
>>>>> +  const struct firmware *fw;
>>>>> +  int err, i, regs_num;
>>>>> +  struct i2c_client *client = v4l2_get_subdevdata(sd);
>>>>> +  u16 val;
>>>>> +  u32 addr, crc, crc_file, addr_inc = 0;
>>>>> +
>>>>> +  err = request_firmware(&fw, S5K4ECGX_FIRMWARE, sd->v4l2_dev->dev);
>>>>> +  if (err) {
>>>>> +          v4l2_err(sd, "Failed to read firmware %s\n", S5K4ECGX_FIRMWARE);
>>>>> +          return err;
>>>>> +  }
>>>>> +  regs_num = *(u32 *)(fw->data);
>>>>> +  v4l2_dbg(3, debug, sd, "FW: %s size %d register sets %d\n",
>>>>> +           S5K4ECGX_FIRMWARE, fw->size, regs_num);
>>>>> +  regs_num++; /* Add header */
>>>>> +  if (fw->size != regs_num * FW_RECORD_SIZE + FW_CRC_SIZE) {
>>>>> +          err = -EINVAL;
>>>>> +          goto fw_out;
>>>>> +  }
>>>>> +  crc_file = *(u32 *)(fw->data + regs_num * FW_RECORD_SIZE);
>>>>
>>>> Depending on the value of regs_num, this may result in unaligned access
>>>
>>> Thanks for the catch. I think it is not the only place where unaligned
>>> issues are possible. Since the data records are 4-byte address + 2-byte
>>> value there is also an issue with reading the address entries. Assuming
>>> fw->data is aligned to at least 2-bytes (not quite sure if we can assume
>>> that) there should be no problem with reading 2-byte register values.
>>
>> I'm not sure 2-byte alignment can be safely assumed, either.
>>
>>> We could change the data types of the register values from u16 to u32,
>>> wasting some memory (there is approximately 3 000 records), so there is
>>> no other data types in the file structure than u32. Or use a patch as
>>> below. Not sure what's better.
>>
>> I prefer the approach of your patch below, but I would use get_unaligned
>> to get the 2-byte values, too. Also there are another couple of
>> glitches, see below.
>
> OK, thanks for the feedback. It was also my preference. The performance
> impact seems insignificant, given a write of each record takes time of
> 1 ms order.
>
>>> 8<---------------------------------------------------------------------
>>>  From a970480b99bdb74e2bf48e1a321724231e6516a0 Mon Sep 17 00:00:00 2001
>>> From: Sylwester Nawrocki<sylvester.nawrocki@gmail.com>
>>> Date: Sun, 9 Sep 2012 19:56:31 +0200
>>> Subject: [PATCH] s5k4ecgx: Fix unaligned access issues
>>>
>>> Signed-off-by: Sylwester Nawrocki<sylvester.nawrocki@gmail.com>
>>> ---
>>>   drivers/media/i2c/s5k4ecgx.c |   16 ++++++++++++----
>>>   1 files changed, 12 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/media/i2c/s5k4ecgx.c b/drivers/media/i2c/s5k4ecgx.c
>>> index 0ef0b7d..4c6439a 100644
>>> --- a/drivers/media/i2c/s5k4ecgx.c
>>> +++ b/drivers/media/i2c/s5k4ecgx.c
>>> @@ -24,6 +24,7 @@
>>>   #include<linux/module.h>
>>>   #include<linux/regulator/consumer.h>
>>>   #include<linux/slab.h>
>>> +#include<asm/unaligned.h>
>>>
>>>   #include<media/media-entity.h>
>>>   #include<media/s5k4ecgx.h>
>>> @@ -331,6 +332,7 @@ static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
>>>      const struct firmware *fw;
>>>      int err, i, regs_num;
>>>      u32 addr, crc, crc_file, addr_inc = 0;
>>> +    const u8 *ptr;
>>>      u16 val;
>>>
>>>      err = request_firmware(&fw, S5K4ECGX_FIRMWARE, sd->v4l2_dev->dev);
>>> @@ -338,7 +340,7 @@ static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
>>>              v4l2_err(sd, "Failed to read firmware %s\n", S5K4ECGX_FIRMWARE);
>>>              return err;
>>>      }
>>> -    regs_num = le32_to_cpu(*(u32 *)fw->data);
>>> +    regs_num = le32_to_cpu(get_unaligned((__le32 *)fw->data));
>>>
>>>      v4l2_dbg(3, debug, sd, "FW: %s size %d register sets %d\n",
>>>               S5K4ECGX_FIRMWARE, fw->size, regs_num);
>>> @@ -349,7 +351,8 @@ static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
>>>              goto fw_out;
>>>      }
>>>
>>> -    crc_file = *(u32 *)(fw->data + regs_num * FW_RECORD_SIZE);
>>> +    memcpy(&crc_file, fw->data + regs_num * FW_RECORD_SIZE, sizeof(u32));
>>
>> crc_file should be converted from little endian to native endian.
>
> Right, I should have verified that crc32_le() return value is in native
> endianness.
>
>>> +
>>>      crc = crc32_le(~0, fw->data, regs_num * FW_RECORD_SIZE);
>>>      if (crc != crc_file) {
>>>              v4l2_err(sd, "FW: invalid crc (%#x:%#x)\n", crc, crc_file);
>>> @@ -357,9 +360,14 @@ static int s5k4ecgx_load_firmware(struct v4l2_subdev *sd)
>>>              goto fw_out;
>>>      }
>>>
>>> +    ptr = fw->data + FW_RECORD_SIZE;
>>> +
>>>      for (i = 1; i<  regs_num; i++) {
>>> -            addr = le32_to_cpu(*(u32 *)(fw->data + i * FW_RECORD_SIZE));
>>> -            val = le16_to_cpu(*(u16 *)(fw->data + i * FW_RECORD_SIZE + 4));
>>> +            addr = le32_to_cpu(get_unaligned((__le32 *)ptr));
>>> +            ptr += 4;
>>> +            val = le16_to_cpu(*(__le16 *)ptr);
>>> +            ptr += FW_RECORD_SIZE;
>>
>> ptr is being incremented by (4 + FW_RECORD_SIZE) bytes at each iteration.
>
> Oops, I was to quick in sending that patch out. Indeed, that's wrong.
> Sangwook, FWIW, I just pushed the corrected patch to my tree
> (http://git.linuxtv.org/snawrocki/media.git/commitdiff/4a0ecad6f08ccbba3)
>
> --
>
> Thanks,
> Sylwester