[PATCH] ARM: OMAP2+: voltage: ensure voltage used is exact voltage from OPP table
Tero Kristo
t-kristo at ti.com
Mon Mar 5 04:41:27 EST 2012
On Fri, 2012-03-02 at 14:42 -0800, Kevin Hilman wrote:
> When using the SMPS regulators to scale voltages, the regulator
> framework may pass a minimum voltage that is not an exact OPP voltage.
> For the VC/VP controlled voltage domains, we must ensure that the
> voltage requested is the exact voltage from the OPP table. This is
> especially critical when using SR.
>
> To fix, voltdm_scale() uses the target voltage passed to walk through
> the OPP voltages until it finds a voltage that is >= one of the OPP
> voltages.
I have just one question to this, how about smartreflex class1p5? Do we
have any plans for that one? The old implementation at least was using
voltdm_scale, so if we modify this function, smartreflex class1p5
doesn't work anymore.
Otherwise this patch looks good to me.
-Tero
>
> Cc: Tero Kristo <t-kristo at ti.com>
> Cc: Nishanth Menon <nm at ti.com>
> Signed-off-by: Kevin Hilman <khilman at ti.com>
> ---
> Unless there are any objections, this will be queued along with the
> rest of the SMPS regulator series from Tero. Currently availble in
> my for_3.4/pm/smps-regulator branch at
> git://git.kernel.org/pub/scm/linux/kernel/git/khilman/linux-omap-pm.git
>
> arch/arm/mach-omap2/voltage.c | 21 ++++++++++++++++++---
> 1 file changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/voltage.c b/arch/arm/mach-omap2/voltage.c
> index 8a36342..4dc60e8 100644
> --- a/arch/arm/mach-omap2/voltage.c
> +++ b/arch/arm/mach-omap2/voltage.c
> @@ -73,7 +73,8 @@ unsigned long voltdm_get_voltage(struct voltagedomain *voltdm)
> int voltdm_scale(struct voltagedomain *voltdm,
> unsigned long target_volt)
> {
> - int ret;
> + int ret, i;
> + unsigned long volt = 0;
>
> if (!voltdm || IS_ERR(voltdm)) {
> pr_warning("%s: VDD specified does not exist!\n", __func__);
> @@ -86,9 +87,23 @@ int voltdm_scale(struct voltagedomain *voltdm,
> return -ENODATA;
> }
>
> - ret = voltdm->scale(voltdm, target_volt);
> + /* Adjust voltage to the exact voltage from the OPP table */
> + for (i = 0; voltdm->volt_data[i].volt_nominal != 0; i++) {
> + if (voltdm->volt_data[i].volt_nominal >= target_volt) {
> + volt = voltdm->volt_data[i].volt_nominal;
> + break;
> + }
> + }
> +
> + if (!volt) {
> + pr_warning("%s: not scaling. OPP voltage for %lu, not found.\n",
> + __func__, target_volt);
> + return -EINVAL;
> + }
> +
> + ret = voltdm->scale(voltdm, volt);
> if (!ret)
> - voltdm->nominal_volt = target_volt;
> + voltdm->nominal_volt = volt;
>
> return ret;
> }
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