[U-Boot] [PATCH] powerpc/t4240qds: add support of reading Core voltage

[York Sun <yorksun@freescale.com>]

On 08/25/2015 01:30 AM, shh.xie at gmail.com wrote:
> From: Shaohui Xie <Shaohui.Xie@freescale.com>
> 
> A U-boot CMD vdd_read is implemented to read Core voltage.
> 
> Signed-off-by: Shaohui Xie <Shaohui.Xie@freescale.com>
> ---
>  board/freescale/t4qds/t4240qds.c | 30 ++++++++++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
> 
> diff --git a/board/freescale/t4qds/t4240qds.c b/board/freescale/t4qds/t4240qds.c
> index 4f2cccd..56273e4 100644
> --- a/board/freescale/t4qds/t4240qds.c
> +++ b/board/freescale/t4qds/t4240qds.c
> @@ -887,8 +887,38 @@ static int do_vdd_adjust(cmd_tbl_t *cmdtp,
>  	return 0;
>  }
>  
> +static int do_vdd_read(cmd_tbl_t *cmdtp,
> +		       int flag, int argc,
> +		       char * const argv[])
> +{
> +	int vdd, ret;
> +
> +	if (argc < 1)
> +		return CMD_RET_USAGE;
> +
> +	ret = select_i2c_ch_pca9547(I2C_MUX_CH_VOL_MONITOR);
> +	if (ret) {
> +		printf("VID: I2c failed to switch channel\n");
> +		return 0;
> +	}
> +
> +	vdd = read_voltage();
> +	if (vdd < 0)
> +		printf("VID: Could not read voltage\n");
> +	else
> +		printf("VID: Core voltage is at %d mV\n", vdd);
> +
> +	return 0;
> +}
> +
>  U_BOOT_CMD(
>  	vdd_override, 2, 0, do_vdd_adjust,
>  	"Override VDD",
>  	"- override with the voltage specified in mV, eg. 1050"
>  );
> +
> +U_BOOT_CMD(
> +	vdd_read, 1, 0, do_vdd_read,
> +	"read VDD",
> +	" - Read the voltage specified in mV"
> +)
> 

Can you explain why you need this command? You already get the voltage if you
run bdinfo. If you override vdd, you also get a print.

York