Re: [PATCH v3 1/6] OMAP4: Add the new voltage to vsel calculation formula

[Tony Lindgren <tony@atomide.com>]

* Thara Gopinath <thara@ti.com> [101027 09:07]:
> TWL6030 the power IC used along with OMAP4 in OMAP4 SDPs,
> blaze boards and panda boards has a different formula
> from that of TWL4030 for voltage to vsel and
> vsel to voltage calculation. This patch implements the new
> formula depending on the PMIC type.
> 
> Signed-off-by: Thara Gopinath <thara@ti.com>
> ---
>  arch/arm/plat-omap/opp_twl_tps.c |   71 ++++++++++++++++++++++++++++++++++++++
>  1 files changed, 71 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/plat-omap/opp_twl_tps.c b/arch/arm/plat-omap/opp_twl_tps.c
> index 4448fc5..358b67b 100644
> --- a/arch/arm/plat-omap/opp_twl_tps.c
> +++ b/arch/arm/plat-omap/opp_twl_tps.c
> @@ -15,9 +15,16 @@
>  
>  #include <linux/module.h>
>  
> +#include <linux/i2c/twl.h>
> +
>  #include <plat/opp_twl_tps.h>
>  #include <plat/voltage.h>
>  
> +static bool is_offset_valid;
> +static u8 smps_offset;
> +
> +#define REG_SMPS_OFFSET         0xE0
> +
>  /**
>   * omap_twl_vsel_to_vdc - convert TWL/TPS VSEL value to microvolts DC
>   * @vsel: TWL/TPS VSEL value to convert
> @@ -27,6 +34,38 @@
>   */
>  unsigned long omap_twl_vsel_to_uv(const u8 vsel)
>  {
> +	if (twl_class_is_6030()) {
> +		/*
> +		 * In TWL6030 depending on the value of SMPS_OFFSET
> +		 * efuse register the voltage range supported in
> +		 * standard mode can be either between 0.6V - 1.3V or
> +		 * 0.7V - 1.4V. In TWL6030 ES1.0 SMPS_OFFSET efuse
> +		 * is programmed to all 0's where as starting from
> +		 * TWL6030 ES1.1 the efuse is programmed to 1
> +		 */
> +		if (!is_offset_valid) {
> +			twl_i2c_read_u8(TWL6030_MODULE_ID0, &smps_offset, 0xE0);
> +			is_offset_valid = true;
> +		}
> +
> +		if (smps_offset & 0x8) {
> +			return ((((vsel - 1) * 125) + 7000)) * 100;
> +		} else {
> +			/*
> +			 * In case of the supported voltage range being
> +			 * between 0.6V - 1.3V, there is not specific
> +			 * formula for voltage to vsel conversion above
> +			 * 1.3V. There are special hardcoded values for
> +			 * voltages above 1.3V. Currently we are hardcodig
> +			 * only for 1.35 V which is used for 1GH OPP for
> +			 * OMAP4430.
> +			 */
> +			if (vsel == 0x3A)
> +				return 1350000;
> +			return ((((vsel - 1) * 125) + 6000)) * 100;
> +		}
> +	}
> +
>  	return (((vsel * 125) + 6000)) * 100;
>  }

Here too you will want to restructure things a bit so you can avoid
adding the "if twl_class_is_whatever else if" tests. Usually the best
way is to set separate functions for different chips during the init.

Regards,

Tony