RE: [PATCH] iio: adc: imx8qxp: Fix address for command buffer registers

[Bough Chen]

> -----Original Message-----
> From: Philipp Rossak <embed3d@xxxxxxxxx>
> Sent: 2023年9月5日 6:02
> To: Cai Huoqing <cai.huoqing@xxxxxxxxx>; Bough Chen <haibo.chen@xxxxxxx>;
> Jonathan Cameron <jic23@xxxxxxxxxx>; Lars-Peter Clausen <lars@xxxxxxxxxx>;
> Shawn Guo <shawnguo@xxxxxxxxxx>; Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>;
> Pengutronix Kernel Team <kernel@xxxxxxxxxxxxxx>; Fabio Estevam
> <festevam@xxxxxxxxx>; dl-linux-imx <linux-imx@xxxxxxx>
> Cc: linux-iio@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; Philipp Rossak <embed3d@xxxxxxxxx>
> Subject: [PATCH] iio: adc: imx8qxp: Fix address for command buffer registers
> 
> The ADC Command Buffer Register high and low are currently pointing to the
> wrong address and makes it impossible to perform correct ADC measurements
> over all channels.
> 
> According to the datasheet of the imx8qxp the ADC_CMDL register starts at
> address 0x100 and the ADC_CMDH register starts at address 0x104.
> 
> This bug seems to be in the kernel since the introduction of this driver.
> 
> This can be observed by checking all raw voltages of the adc and they are all
> nearly identical:
> 
> cat /sys/bus/iio/devices/iio\:device0/in_voltage*_raw
> 3498
> 3494
> 3491
> 3491
> 3489
> 3490
> 3490
> 3490

Oh, really thanks for this catch.

Acked-by: Haibo Chen <haibo.chen@xxxxxxx>

Best Regards
Haibo Chen
> 
> Fixes: 1e23dcaa1a9fa ("iio: imx8qxp-adc: Add driver support for NXP IMX8QXP
> ADC")
> 
> Signed-off-by: Philipp Rossak <embed3d@xxxxxxxxx>
> ---
>  drivers/iio/adc/imx8qxp-adc.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/adc/imx8qxp-adc.c b/drivers/iio/adc/imx8qxp-adc.c index
> f5a0fc9e64c5..fff6e5a2d956 100644
> --- a/drivers/iio/adc/imx8qxp-adc.c
> +++ b/drivers/iio/adc/imx8qxp-adc.c
> @@ -38,8 +38,8 @@
>  #define IMX8QXP_ADR_ADC_FCTRL		0x30
>  #define IMX8QXP_ADR_ADC_SWTRIG		0x34
>  #define IMX8QXP_ADR_ADC_TCTRL(tid)	(0xc0 + (tid) * 4)
> -#define IMX8QXP_ADR_ADC_CMDH(cid)	(0x100 + (cid) * 8)
> -#define IMX8QXP_ADR_ADC_CMDL(cid)	(0x104 + (cid) * 8)
> +#define IMX8QXP_ADR_ADC_CMDL(cid)	(0x100 + (cid) * 8)
> +#define IMX8QXP_ADR_ADC_CMDH(cid)	(0x104 + (cid) * 8)
>  #define IMX8QXP_ADR_ADC_RESFIFO		0x300
>  #define IMX8QXP_ADR_ADC_TST		0xffc
> 
> --
> 2.39.2