From 7566656c992063a0835688cd908d6924fc7ef112 Mon Sep 17 00:00:00 2001 From: Hermes Wu Date: Wed, 30 Sep 2026 14:41:31 +0800 Subject: [PATCH] media: i2c: it6625: decode detected timings via typed register structs it6625_get_detected_timings() manually assembled each 16-bit field from raw byte-buffer offsets with a shift-and-add sequence. Define two named structs of __be16 fields matching the contiguous REG_H_ACTIVE_1.. REG_V_ACTIVE_0 and REG_H_FP_1..REG_V_BP_0 register layouts at file scope, immediately above the function that uses them -- this driver accesses many such register areas, so keep the layout struct separate from its one caller instead of declaring it locally. Read directly into them, and decode each field with be16_to_cpu(). Guard each struct's size with static_assert() against the expected register range width. Every member is 2 bytes wide and naturally aligned, so the struct is laid out with no padding -- this is safe because the struct is the I2C read target itself, not a cast over a pre-existing raw buffer. Signed-off-by: Hermes Wu Signed-off-by: Hans Verkuil --- drivers/media/i2c/it6625.c | 48 +++++++++++++++++++++++++------------- 1 file changed, 32 insertions(+), 16 deletions(-) diff --git a/drivers/media/i2c/it6625.c b/drivers/media/i2c/it6625.c index 09af11db5aa8..dc0b12a6512f 100644 --- a/drivers/media/i2c/it6625.c +++ b/drivers/media/i2c/it6625.c @@ -768,14 +768,33 @@ static void it6625_hpd_delayed_work(struct work_struct *work) it6625_update_config(it6625); } +/* REG_H_ACTIVE_1..REG_V_ACTIVE_0 */ +struct it6625_active_size_regs { + __be16 h_active; + __be16 v_active; +}; + +static_assert(sizeof(struct it6625_active_size_regs) == 4); + +/* REG_H_FP_1..REG_V_BP_0 */ +struct it6625_porch_regs { + __be16 hfrontporch; + __be16 hsync; + __be16 hbackporch; + __be16 vfrontporch; + __be16 vsync; + __be16 vbackporch; +}; + +static_assert(sizeof(struct it6625_porch_regs) == 12); + static int it6625_get_detected_timings(struct it6625 *it6625, struct v4l2_dv_timings *timings) { struct v4l2_bt_timings *bt = &timings->bt; + struct it6625_active_size_regs active; + struct it6625_porch_regs porch; int val; - unsigned int width, height; - u8 buffer[4]; - u8 buffer2[12]; if (no_signal(it6625)) { dev_err(it6625->dev, "no signal detected"); @@ -795,24 +814,21 @@ static int it6625_get_detected_timings(struct it6625 *it6625, bt->interlaced = val & B_INTERLACE ? V4L2_DV_INTERLACED : V4L2_DV_PROGRESSIVE; - if (it6625_read_bytes(it6625, REG_H_ACTIVE_1, buffer, 4) < 0) + if (it6625_read_bytes(it6625, REG_H_ACTIVE_1, (u8 *)&active, sizeof(active)) < 0) return -EIO; - width = ((buffer[0] & 0xff) << 8) + buffer[1]; - height = ((buffer[2] & 0xff) << 8) + buffer[3]; + bt->width = be16_to_cpu(active.h_active); + bt->height = be16_to_cpu(active.v_active); - bt->width = width; - bt->height = height; - - if (it6625_read_bytes(it6625, REG_H_FP_1, buffer2, 12) < 0) + if (it6625_read_bytes(it6625, REG_H_FP_1, (u8 *)&porch, sizeof(porch)) < 0) return -EIO; - bt->hfrontporch = ((buffer2[0] & 0xff) << 8) + buffer2[1]; - bt->hsync = ((buffer2[2] & 0xff) << 8) + buffer2[3]; - bt->hbackporch = ((buffer2[4] & 0xff) << 8) + buffer2[5]; - bt->vfrontporch = ((buffer2[6] & 0xff) << 8) + buffer2[7]; - bt->vsync = ((buffer2[8] & 0xff) << 8) + buffer2[9]; - bt->vbackporch = ((buffer2[10] & 0xff) << 8) + buffer2[11]; + bt->hfrontporch = be16_to_cpu(porch.hfrontporch); + bt->hsync = be16_to_cpu(porch.hsync); + bt->hbackporch = be16_to_cpu(porch.hbackporch); + bt->vfrontporch = be16_to_cpu(porch.vfrontporch); + bt->vsync = be16_to_cpu(porch.vsync); + bt->vbackporch = be16_to_cpu(porch.vbackporch); bt->pixelclock = it6625_get_pclk(it6625); if (bt->interlaced == V4L2_DV_INTERLACED) {