Re: [PATCH] media: ipu-bridge: Add Himax HM1092 IR sensor

Hi Jake,

On Wed, Jul 29, 2026 at 01:46:41PM -0400, Jake S wrote:
> From: Jake Steinman <[email protected]>
> 
> The HM1092 is a 648x368 mono IR sensor used for face unlock on recent
> Intel IPU6/IPU7 laptops, sitting behind a Synaptics or Intel vision
> bridge. Without an entry here ipu-bridge builds the sensor endpoint with
> no link-frequencies property, the driver's frequency validation rejects
> every mode, and the sensor never binds.
> 
> Two frequencies are listed because the sensor is driven from different
> external clocks depending on the platform, and the PLL registers are
> programmed to match:
> 
>   0x030d (pre-divider), 0x030f (multiplier), link_freq = EXTCLK * m / p
> 
>   Dell, IPU7      EXTCLK 19.2 MHz, p=10, m=94  ->  180,480,000 Hz
>   ASUS, Qualcomm  EXTCLK 24.0 MHz, p=12, m=90  ->  180,000,000 Hz

Please avoid commas in numbers unless there are non-integer parts in them.

> 
> Both are the CSI-2 DDR clock, so the per-lane bit rate is twice the
> value, 360.96 and 360 Mbit/s respectively, over one data lane.
> 
> Worth stating explicitly because published figures for this part have
> been wrong: V4L2_CID_LINK_FREQ is the DDR clock, while the vendor mode
> descriptors publish the per-lane BIT rate. Taking the descriptor value
> verbatim gives 360,960,000, isys then configures the D-PHY for 721 Mbit/s
> against a sensor transmitting 361, the clock lane toggles, and no frame
> is ever framed. Halving it to the DDR clock is what produced the first
> captured frames from this sensor on Linux.
> 
> The two platform values differ by 0.27%, which is within what the
> sensor's PLL tolerates, but they are listed separately rather than
> merged so each platform matches exactly what its firmware programs.

Is Documentation/process/coding-assistants.rst relevant for this?

A lot of this could be on a cover letter (or after '---') but the commit
messages should be more concise than this.

> 
> Depends on the HM1092 sensor driver, currently in review.
> 
> Signed-off-by: Jake Steinman <[email protected]>
> ---
>  drivers/media/pci/intel/ipu-bridge.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/media/pci/intel/ipu-bridge.c b/drivers/media/pci/intel/ipu-bridge.c
> --- a/drivers/media/pci/intel/ipu-bridge.c
> +++ b/drivers/media/pci/intel/ipu-bridge.c
> @@ -50,6 +50,8 @@
>   * Please keep the list sorted by ACPI HID.
>   */
>  static const struct ipu_sensor_config ipu_supported_sensors[] = {
> +	/* Himax HM1092 */
> +	IPU_SENSOR_CONFIG("HIMX1092", 2, 180000000, 180480000),
>  	/* Himax HM11B1 */
>  	IPU_SENSOR_CONFIG("HIMX11B1", 1, 384000000),
>  	/* Himax HM2170 */

-- 
Regards,

Sakari Ailus