RE: [PATCH v2] power: regulator: tps65219: Fix LDO selector boundaries

Hello Kumara,

Thanks. I understand now. The values are used for interpolation.

Maybe you can replace 'map' with 'saturate' in your commit log ?
And add 'for interpolation' after:
'Use the correct selector boundary values of 0x38, 0x0c, and 0x36.'

Kind regards,
Maarten Brock

From: Kumara Bhimeswararao <[email protected]>
Sent: Saturday 1 August 2026 8:57
To: Maarten Brock <[email protected]>
Cc: Jaehoon Chung <[email protected]>; Peng Fan <[email protected]>; [email protected]; Tom Rini <[email protected]>; Neil Armstrong <[email protected]>
Subject: Re: [PATCH v2] power: regulator: tps65219: Fix LDO selector boundaries

Hi Maarten,

Thanks for the review.

These macros are used as the saturation boundaries in
tps65219_ldo_val2volt(), which uses:

if (val >= reg_max)
return max;
else if (val <= reg_base)
return base;

Therefore, they represent the first or last selector in the saturated
range rather than the numerically highest or lowest selector value.

According to Table 7-2 of the TPS65219 datasheet:

- LDO1/LDO2: selectors 0x38-0x3f all map to 3.4 V, so reg_max is 0x38.
- LDO3/LDO4: selectors 0x00-0x0c all map to 1.2 V, so reg_base is 0x0c.
- LDO3/LDO4: selectors 0x36-0x3f all map to 3.3 V, so reg_max is 0x36.

Using 0x3f or 0x00 here would not correctly cover the entire saturated
ranges with the current >= and <= comparisons.

Does that clarify the reasoning behind these boundary values?

Kind regards,
Kumara Bhimeswarao Matsa

On Fri, Jul 31, 2026 at 7:51 PM Maarten Brock <[email protected]<mailto:[email protected]>> wrote:
> From: U-Boot <[email protected]<mailto:[email protected]>> On Behalf Of Kumara Bhimeswararao Matsa
>
> According to the TPS65219 datasheet, selectors 0x38 through 0x3f
> map to 3.4 V for LDO1 and LDO2.
>
> For LDO3 and LDO4, selectors 0x00 through 0x0c map to 1.2 V,
> while selectors 0x36 through 0x3f map to 3.3 V.
>
> The driver currently uses 0x56, 0x12, and 0x54 as selector boundary
> values. These values do not match the selector boundaries defined by
> the datasheet.
>
> Use the correct selector boundary values of 0x38, 0x0c, and 0x36.
>
>  #define TPS65219_LDO12_VOLT_MIN               600000
>  #define TPS65219_LDO12_VOLT_MAX              3400000
>  #define TPS65219_LDO12_VOLT_REG_MIN  0
> -#define TPS65219_LDO12_VOLT_REG_MAX  0x56
> +#define TPS65219_LDO12_VOLT_REG_MAX  0x38

If the maximum for 3.4V is 0x3f then why do you use 0x38 here?

>  #define TPS65219_LDO34_VOLT_MIN              1200000
>  #define TPS65219_LDO34_VOLT_MAX              3300000
> -#define TPS65219_LDO34_VOLT_REG_MIN  0x12
> -#define TPS65219_LDO34_VOLT_REG_MAX  0x54
> +#define TPS65219_LDO34_VOLT_REG_MIN  0x0c

If the minimum for 1.2V is 0x00 then why do you use 0x0c here?

> +#define TPS65219_LDO34_VOLT_REG_MAX  0x36

If the maximum for 3.3V is 0x3f then why do you use 0x36 here?

Kind regards,
Maarten Brock