Re: [PATCH 3/3] mfd: cs42l43: Add support for new cs42l44 variant
From: Lee Jones
Date: Thu Jul 16 2026 - 11:15:46 EST
On Wed, 08 Jul 2026, Charles Keepax wrote:
> The cs42l44 is a cost optimised variant of cs42l43b. Add basic support
> for this new device.
>
> Signed-off-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx>
> ---
> drivers/mfd/cs42l43-i2c.c | 2 ++
> drivers/mfd/cs42l43-sdw.c | 1 +
> drivers/mfd/cs42l43.c | 18 ++++++++++++------
> include/linux/mfd/cs42l43-regs.h | 1 +
> 4 files changed, 16 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/mfd/cs42l43-i2c.c b/drivers/mfd/cs42l43-i2c.c
> index bd9752d2cfc34..1af878c7a20b4 100644
> --- a/drivers/mfd/cs42l43-i2c.c
> +++ b/drivers/mfd/cs42l43-i2c.c
> @@ -59,6 +59,7 @@ static int cs42l43_i2c_probe(struct i2c_client *i2c)
> static const struct of_device_id cs42l43_of_match[] = {
> { .compatible = "cirrus,cs42l43", .data = (void *)CS42L43_DEVID_VAL },
> { .compatible = "cirrus,cs42l43b", .data = (void *)CS42L43B_DEVID_VAL },
> + { .compatible = "cirrus,cs42l44", .data = (void *)CS42L43B_DEVID_VAL },
> { }
> };
> MODULE_DEVICE_TABLE(of, cs42l43_of_match);
> @@ -68,6 +69,7 @@ MODULE_DEVICE_TABLE(of, cs42l43_of_match);
> static const struct acpi_device_id cs42l43_acpi_match[] = {
> { .id = "CSC4243", .driver_data = CS42L43_DEVID_VAL },
> { .id = "CSC2A3B", .driver_data = CS42L43B_DEVID_VAL },
> + { .id = "CSC4244", .driver_data = CS42L43B_DEVID_VAL },
> { }
> };
> MODULE_DEVICE_TABLE(acpi, cs42l43_acpi_match);
> diff --git a/drivers/mfd/cs42l43-sdw.c b/drivers/mfd/cs42l43-sdw.c
> index 6ccfdcd3f6698..81dd19df53685 100644
> --- a/drivers/mfd/cs42l43-sdw.c
> +++ b/drivers/mfd/cs42l43-sdw.c
> @@ -184,6 +184,7 @@ static int cs42l43_sdw_probe(struct sdw_slave *sdw, const struct sdw_device_id *
> static const struct sdw_device_id cs42l43_sdw_id[] = {
> SDW_SLAVE_ENTRY(0x01FA, 0x4243, (void *)CS42L43_DEVID_VAL),
> SDW_SLAVE_ENTRY(0x01FA, 0x2A3B, (void *)CS42L43B_DEVID_VAL),
> + SDW_SLAVE_ENTRY(0x01FA, 0x4244, (void *)CS42L43B_DEVID_VAL),
> { }
> };
> MODULE_DEVICE_TABLE(sdw, cs42l43_sdw_id);
> diff --git a/drivers/mfd/cs42l43.c b/drivers/mfd/cs42l43.c
> index 33479ddd539a6..d6027fa4de705 100644
> --- a/drivers/mfd/cs42l43.c
> +++ b/drivers/mfd/cs42l43.c
> @@ -959,6 +959,7 @@ static void cs42l43_boot_work(struct work_struct *work)
> {
> struct cs42l43 *cs42l43 = container_of(work, struct cs42l43, boot_work);
> unsigned int devid, revid, otp;
> + bool valid_id;
> int ret;
>
> ret = cs42l43_wait_for_attach(cs42l43);
> @@ -973,19 +974,24 @@ static void cs42l43_boot_work(struct work_struct *work)
>
> switch (devid) {
> case CS42L43_DEVID_VAL:
> + valid_id = (cs42l43->variant_id == CS42L43_DEVID_VAL);
> + break;
> case CS42L43B_DEVID_VAL:
> - if (devid != cs42l43->variant_id) {
> - dev_err(cs42l43->dev,
> - "Device ID (0x%06x) does not match variant ID (0x%06lx)\n",
> - devid, cs42l43->variant_id);
> - goto err;
> - }
Needs a fall-through statement.
> + case CS42L44_DEVID_VAL:
> + valid_id = (cs42l43->variant_id == CS42L43B_DEVID_VAL);
> break;
> default:
> dev_err(cs42l43->dev, "Unrecognised devid: 0x%06x\n", devid);
> goto err;
> }
>
> + if (!valid_id) {
How is this nor handled in the default branch?
> + dev_err(cs42l43->dev,
> + "Device ID (0x%06x) does not match variant ID (0x%06lx)\n",
> + devid, cs42l43->variant_id);
> + goto err;
> + }
> +
> ret = regmap_read(cs42l43->regmap, CS42L43_REVID, &revid);
> if (ret) {
> dev_err(cs42l43->dev, "Failed to read rev: %d\n", ret);
> diff --git a/include/linux/mfd/cs42l43-regs.h b/include/linux/mfd/cs42l43-regs.h
> index 68831f113589d..4c00ceae8b461 100644
> --- a/include/linux/mfd/cs42l43-regs.h
> +++ b/include/linux/mfd/cs42l43-regs.h
> @@ -1183,6 +1183,7 @@
>
> /* CS42L43B VARIANT REGISTERS */
> #define CS42L43B_DEVID_VAL 0x0042A43B
> +#define CS42L44_DEVID_VAL 0x00042A44
>
> #define CS42L43B_DECIM_VOL_CTRL_CH1_CH2 0x00008280
> #define CS42L43B_DECIM_VOL_CTRL_CH3_CH4 0x00008284
> --
> 2.47.3
>
--
Lee Jones