[PATCH V3] media: i2c: imx334: add new link frequency configuration
From: shravan kumar
Date: Mon Aug 03 2026 - 01:50:59 EST
From: Shravan Chippa <shravan.chippa@xxxxxxxxxxxxx>
Add 222 MHz link frequency support and refactor clock registers into
per-frequency register lists. Introduce imx334_clk_params to map each
link frequency to its register set and supported resolution range.
Make the link frequency control writable so userspace can select the
desired operating point.
Signed-off-by: Shravan Chippa <shravan.chippa@xxxxxxxxxxxxx>
---
Changes from V2 -> V3
- Refactor: Introduce struct imx334_clk_params
- Maps each link frequency to its clock register set and supported
resolution range (width_max, height_max, width_min, height_min).
- Includes a default_mode pointer for fallback when resolution is
out of range for the selected link frequency.
- Enhancement: Make link_freq control writable
- Removed V4L2_CTRL_FLAG_READ_ONLY from link_freq_ctrl so userspace
can select the desired link frequency operating point.
- Enhancement: Add resolution bounds checking in set_pad_format
- imx334_set_pad_format() now validates the selected mode against
the clk_params width/height constraints and falls back to the
default mode if out of range.
- Cleanup: Remove __v4l2_ctrl_s_ctrl for link_freq in update_controls
- Link frequency is no longer tied to mode, so the explicit control
update in imx334_update_controls() was removed.
Changes from V1 -> V2
- Fix: Default mode selection bug
- Problem: Used __ffs(link_freq_bitmap) as index into the compacted
active_modes array. This index corresponds to a bit position in the
bitmap, not an array index in the filtered modes list.
- Fix: Use index 0, which is always the first valid mode in the
filtered array.
- Fix: Rename fields for clarity
- Renamed struct fields:
* new_supported_modes -> active_modes
* new_modes_size -> num_active_modes
- Updated kernel-doc header for struct imx334 to document new fields.
- Fix: INCKSEL2 register write - add error handling and switch-case
- Location: imx334_enable_streams()
- Problem: Original code only handled 222 MHz case with no error
checking (passed NULL to cci_write).
- Fix: Replaced with switch-case covering all three link frequencies:
* 891 MHz -> INCKSEL2 = 0x02
* 445 MHz -> INCKSEL2 = 0x06
* 222 MHz -> INCKSEL2 = 0x0a
- Added proper error handling using &ret accumulator pattern with
dev_err and goto err_rpm_put on failure.
- Fix: Use BIT() macro
- Location: imx334_update_supported_mode_array()
- Replaced (1 << i) with BIT(i) for kernel coding style compliance.
- Fix: Use devm_kmalloc_array() for overflow-safe allocation
- Location: imx334_update_supported_mode_array()
- Replaced: devm_kmalloc(dev, n * sizeof(struct imx334_mode),
GFP_KERNEL)
- With: devm_kmalloc_array(dev, n, sizeof(*temp_ptr), GFP_KERNEL)
- Provides overflow-safe multiplication and uses sizeof(*ptr) idiom.
- Cleanup: Condensed copy loop
- Location: imx334_update_supported_mode_array(), second loop
- Simplified the struct copy with post-increment:
temp_ptr[size++] = supported_modes[j];
- Fix: Updated function kernel-doc comment
- Location: imx334_update_supported_mode_array()
- Reworded: "Search for the supported modes add them in the new list"
- To: "Build filtered modes array based on DTS link frequencies"
- IMX334_LINK_FREQ_222M changed from 222500000 to 222750000
---
drivers/media/i2c/imx334.c | 132 +++++++++++++++++++++++++++++++------
1 file changed, 112 insertions(+), 20 deletions(-)
diff --git a/drivers/media/i2c/imx334.c b/drivers/media/i2c/imx334.c
index 553a16b84f4d..fb036873859c 100644
--- a/drivers/media/i2c/imx334.c
+++ b/drivers/media/i2c/imx334.c
@@ -109,6 +109,7 @@
/* CSI2 HW configuration */
#define IMX334_LINK_FREQ_891M 891000000
#define IMX334_LINK_FREQ_445M 445500000
+#define IMX334_LINK_FREQ_222M 222750000
#define IMX334_NUM_DATA_LANES 4
#define IMX334_REG_MIN 0x00
@@ -154,7 +155,6 @@ struct imx334_reg_list {
* @vblank_min: Minimal vertical blanking in lines
* @vblank_max: Maximum vertical blanking in lines
* @pclk: Sensor pixel clock
- * @link_freq_idx: Link frequency index
* @reg_list: Register list for sensor mode
*/
struct imx334_mode {
@@ -165,7 +165,28 @@ struct imx334_mode {
u32 vblank_min;
u32 vblank_max;
u64 pclk;
- u32 link_freq_idx;
+ struct imx334_reg_list reg_list;
+};
+
+/**
+ * struct imx334_clk_params - imx334 sensor clock parameters
+ * @data_rate_per_lane: Data rate per lane in bits per second
+ * @link_freq: Link frequency in Hz
+ * @width_max: Maximum image width in pixels
+ * @height_max: Maximum image height in pixels
+ * @width_min: Minimum image width in pixels
+ * @height_min: Minimum image height in pixels
+ * @default_mode: Pointer to the default sensor mode
+ * @reg_list: Register list for clock configuration
+ */
+struct imx334_clk_params {
+ u32 data_rate_per_lane;
+ u32 link_freq;
+ u32 width_max;
+ u32 height_max;
+ u32 width_min;
+ u32 height_min;
+ const struct imx334_mode *default_mode;
struct imx334_reg_list reg_list;
};
@@ -216,6 +237,7 @@ struct imx334 {
static const s64 link_freq[] = {
IMX334_LINK_FREQ_891M,
IMX334_LINK_FREQ_445M,
+ IMX334_LINK_FREQ_222M,
};
/* Sensor common mode registers values */
@@ -233,13 +255,6 @@ static const struct cci_reg_sequence common_mode_regs[] = {
{ IMX334_REG_UNREAD_PARAM6, 0x0008 },
{ IMX334_REG_XVS_XHS_OUTSEL, 0x20 },
{ IMX334_REG_XVS_XHS_DRV, 0x0f },
- { IMX334_REG_BCWAIT_TIME, 0x3b },
- { IMX334_REG_CPWAIT_TIME, 0x2a },
- { IMX334_REG_INCKSEL1, 0x0129 },
- { IMX334_REG_INCKSEL2, 0x06 },
- { IMX334_REG_INCKSEL3, 0xa0 },
- { IMX334_REG_INCKSEL4, 0x7e },
- { IMX334_REG_SYS_MODE, 0x02 },
{ IMX334_REG_HADD_VADD, 0x00 },
{ IMX334_REG_VALID_EXPAND, 0x03 },
{ IMX334_REG_TCYCLE, 0x00 },
@@ -397,6 +412,39 @@ static const struct cci_reg_sequence mode_3840x2160_regs[] = {
{ IMX334_REG_TPLX, 0x005f },
};
+/* Data rate 1782Mbps per lane and 891Mhz link frequency */
+static const struct cci_reg_sequence link_freq_891m_regs[] = {
+ { IMX334_REG_BCWAIT_TIME, 0x3b },
+ { IMX334_REG_CPWAIT_TIME, 0x2a },
+ { IMX334_REG_INCKSEL1, 0x0129 },
+ { IMX334_REG_INCKSEL2, 0x02 },
+ { IMX334_REG_INCKSEL3, 0xa0 },
+ { IMX334_REG_INCKSEL4, 0x7e },
+ { IMX334_REG_SYS_MODE, 0x00 },
+};
+
+/* Data rate 891Mbps per lane and 445Mhz link frequency */
+static const struct cci_reg_sequence link_freq_445m_regs[] = {
+ { IMX334_REG_BCWAIT_TIME, 0x3b },
+ { IMX334_REG_CPWAIT_TIME, 0x2a },
+ { IMX334_REG_INCKSEL1, 0x0129 },
+ { IMX334_REG_INCKSEL2, 0x06 },
+ { IMX334_REG_INCKSEL3, 0xa0 },
+ { IMX334_REG_INCKSEL4, 0x7e },
+ { IMX334_REG_SYS_MODE, 0x02 },
+};
+
+/* Data rate 445Mbps per lane and 222Mhz link frequency */
+static const struct cci_reg_sequence link_freq_222m_regs[] = {
+ { IMX334_REG_BCWAIT_TIME, 0x3b },
+ { IMX334_REG_CPWAIT_TIME, 0x2a },
+ { IMX334_REG_INCKSEL1, 0x0129 },
+ { IMX334_REG_INCKSEL2, 0x0a },
+ { IMX334_REG_INCKSEL3, 0xa0 },
+ { IMX334_REG_INCKSEL4, 0x7e },
+ { IMX334_REG_SYS_MODE, 0x02 },
+};
+
static const char * const imx334_test_pattern_menu[] = {
"Disabled",
"Vertical Color Bars",
@@ -442,7 +490,6 @@ static const struct imx334_mode supported_modes[] = {
.vblank_min = 90,
.vblank_max = 132840,
.pclk = 594000000,
- .link_freq_idx = 0,
.reg_list = {
.num_of_regs = ARRAY_SIZE(mode_3840x2160_regs),
.regs = mode_3840x2160_regs,
@@ -455,7 +502,6 @@ static const struct imx334_mode supported_modes[] = {
.vblank_min = 45,
.vblank_max = 132840,
.pclk = 297000000,
- .link_freq_idx = 1,
.reg_list = {
.num_of_regs = ARRAY_SIZE(mode_1920x1080_regs),
.regs = mode_1920x1080_regs,
@@ -468,7 +514,6 @@ static const struct imx334_mode supported_modes[] = {
.vblank_min = 45,
.vblank_max = 132840,
.pclk = 297000000,
- .link_freq_idx = 1,
.reg_list = {
.num_of_regs = ARRAY_SIZE(mode_1280x720_regs),
.regs = mode_1280x720_regs,
@@ -481,7 +526,6 @@ static const struct imx334_mode supported_modes[] = {
.vblank_min = 45,
.vblank_max = 132840,
.pclk = 297000000,
- .link_freq_idx = 1,
.reg_list = {
.num_of_regs = ARRAY_SIZE(mode_640x480_regs),
.regs = mode_640x480_regs,
@@ -489,6 +533,46 @@ static const struct imx334_mode supported_modes[] = {
},
};
+static const struct imx334_clk_params imx334_clk_params[] = {
+ {
+ .data_rate_per_lane = 1782000000,
+ .link_freq = IMX334_LINK_FREQ_891M,
+ .width_max = 3840,
+ .height_max = 2160,
+ .width_min = 3840,
+ .height_min = 2160,
+ .default_mode = &supported_modes[0], /* 3840x2160 */
+ .reg_list = {
+ .num_of_regs = ARRAY_SIZE(link_freq_891m_regs),
+ .regs = link_freq_891m_regs,
+ },
+ }, {
+ .data_rate_per_lane = 891000000,
+ .link_freq = IMX334_LINK_FREQ_445M,
+ .width_max = 1920,
+ .height_max = 1080,
+ .width_min = 640,
+ .height_min = 480,
+ .default_mode = &supported_modes[1], /* 1920x1080 */
+ .reg_list = {
+ .num_of_regs = ARRAY_SIZE(link_freq_445m_regs),
+ .regs = link_freq_445m_regs,
+ },
+ }, {
+ .data_rate_per_lane = 445500000,
+ .link_freq = IMX334_LINK_FREQ_222M,
+ .width_max = 1920,
+ .height_max = 1080,
+ .width_min = 640,
+ .height_min = 480,
+ .default_mode = &supported_modes[1], /* 1920x1080 */
+ .reg_list = {
+ .num_of_regs = ARRAY_SIZE(link_freq_222m_regs),
+ .regs = link_freq_222m_regs,
+ },
+ }
+};
+
/**
* to_imx334() - imv334 V4L2 sub-device to imx334 device.
* @subdev: pointer to imx334 V4L2 sub-device
@@ -512,10 +596,6 @@ static int imx334_update_controls(struct imx334 *imx334,
{
int ret;
- ret = __v4l2_ctrl_s_ctrl(imx334->link_freq_ctrl, mode->link_freq_idx);
- if (ret)
- return ret;
-
ret = __v4l2_ctrl_modify_range(imx334->pclk_ctrl, mode->pclk,
mode->pclk, 1, mode->pclk);
if (ret)
@@ -746,6 +826,7 @@ static int imx334_set_pad_format(struct v4l2_subdev *sd,
{
struct imx334 *imx334 = to_imx334(sd);
const struct imx334_mode *mode;
+ const struct imx334_clk_params *clk_params;
int ret = 0;
mode = v4l2_find_nearest_size(supported_modes,
@@ -753,6 +834,11 @@ static int imx334_set_pad_format(struct v4l2_subdev *sd,
width, height,
fmt->format.width, fmt->format.height);
+ clk_params = &imx334_clk_params[imx334->link_freq_ctrl->val];
+ if (mode->width > clk_params->width_max || mode->height > clk_params->height_max ||
+ mode->width < clk_params->width_min || mode->height < clk_params->height_min)
+ mode = clk_params->default_mode;
+
imx334_fill_pad_format(imx334, mode, fmt);
fmt->format.code = imx334_get_format_code(imx334, fmt->format.code);
@@ -824,6 +910,15 @@ static int imx334_enable_streams(struct v4l2_subdev *sd,
goto err_rpm_put;
}
+ /* Write sensor link freq registers */
+ reg_list = &imx334_clk_params[imx334->link_freq_ctrl->val].reg_list;
+ ret = cci_multi_reg_write(imx334->cci, reg_list->regs,
+ reg_list->num_of_regs, NULL);
+ if (ret) {
+ dev_err(imx334->dev, "fail to write initial registers\n");
+ goto err_rpm_put;
+ }
+
/* Write sensor mode registers */
reg_list = &imx334->cur_mode->reg_list;
ret = cci_multi_reg_write(imx334->cci, reg_list->regs,
@@ -1096,9 +1191,6 @@ static int imx334_init_controls(struct imx334 *imx334)
__ffs(imx334->link_freq_bitmap),
link_freq);
- if (imx334->link_freq_ctrl)
- imx334->link_freq_ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;
-
imx334->hblank_ctrl = v4l2_ctrl_new_std(ctrl_hdlr,
&imx334_ctrl_ops,
V4L2_CID_HBLANK,
--
2.34.1