On Thu, 2012-03-01 at 14:07 -0800, Kevin Hilman wrote:
> +Tero
>
> Kevin Hilman <khilman@xxxxxx> writes:
>
> > Afzal Mohammed <afzal@xxxxxx> writes:
> >
> >> Specify voltage in ranges for regulator. Range
> >> used is tolerance specified for OPP.
> >>
> >> This helps to achieve DVFS with a wider range of
> >> regulators.
> >>
> >> Cc: Kevin Hilman <khilman@xxxxxx>
> >> Cc: Sekhar Nori <nsekhar@xxxxxx>
> >> Signed-off-by: Afzal Mohammed <afzal@xxxxxx>
> >
> > Thanks, will queue this with the CPUfreq changes for MPU DVFS.
>
> Actually, not quite yet...
>
> After some testing with the SMPS regulators, this won't quite work with
> the current SMPS regulators. Does this actually work with the
> regulators you're using?
>
> For OMAPs using VC/VP for voltage scaling, the TWL regulator passes on
> the voltage requested directly to the voltage layer. When using voltage
> - tolerance, this results in voltages that the voltage layer doesn't
> know about because they do not match any of the voltages from the known
> OPPs.
>
> The problem that we have is that while the regulators can support a
> broad range of voltages (from min to max with a some step), the on-chip
> voltage domains cannot, which is why we have defined the OPPs which are
> known to work.
>
> Tero, for the SMPS regulators, would it be possible to configure the
> regulators so that only a discrete set voltages are availble to pick
> from? These should be initialied from the OPP layer.
I guess this would be possible. Looking at this patch, I guess what we
want to do is that we just use the current API we have at the SMPS
regulator layer to pass the min_uV as target_uV for the regulator, and
just get the next opp voltage that is >= than the target_uV.
Here is an inline patch that does this (also attached), this applies on
top of my SMPS regulator changes:
diff --git a/arch/arm/mach-omap2/twl-common.c
b/arch/arm/mach-omap2/twl-common.c
index f19793e..7dc891f 100644
--- a/arch/arm/mach-omap2/twl-common.c
+++ b/arch/arm/mach-omap2/twl-common.c
@@ -41,7 +41,16 @@ static struct i2c_board_info __initdata
pmic_i2c_board_info = {
static int twl_set_voltage(void *data, int target_uV)
{
struct voltagedomain *voltdm = (struct voltagedomain *)data;
- return voltdm_scale(voltdm, target_uV);
+ struct omap_volt_data *volt_data = voltdm->volt_data;
+
+ while (1) {
+ if (!volt_data->volt_nominal)
+ return -EINVAL;
+ if (volt_data->volt_nominal >= target_uV)
+ break;
+ volt_data++;
+ }
+ return voltdm_scale(voltdm, volt_data->volt_nominal);
}
static int twl_get_voltage(void *data)
Do you want a new version of the whole set or just this as a separate
one?
-Tero
>
> Somehow we need to support something like $SUBJECT patch in order to
> support a broad range of regulators. The OMAP voltagedomain
> limitations need to configured in platform specific way such that the
> CPUfreq driver can remain generic.
>
> Kevin
>
>From 8b4c16fdfee63a414ebee52e674b6d9fbc16e7c9 Mon Sep 17 00:00:00 2001
From: Tero Kristo <t-kristo@xxxxxx>
Date: Fri, 2 Mar 2012 12:14:57 +0200
Subject: [PATCH] ARM: OMAP3+: smps regulator: match target_uV against OPP definitions
Scans through the nominal voltage for OPPs until a voltage is found
that is greater than equal to the one requested. This allows the
target_uV to have some error margin in it, and we will always scale
to the next closest OPP voltage.
Signed-off-by: Tero Kristo <t-kristo@xxxxxx>
---
arch/arm/mach-omap2/twl-common.c | 11 ++++++++++-
1 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/arch/arm/mach-omap2/twl-common.c b/arch/arm/mach-omap2/twl-common.c
index f19793e..7dc891f 100644
--- a/arch/arm/mach-omap2/twl-common.c
+++ b/arch/arm/mach-omap2/twl-common.c
@@ -41,7 +41,16 @@ static struct i2c_board_info __initdata pmic_i2c_board_info = {
static int twl_set_voltage(void *data, int target_uV)
{
struct voltagedomain *voltdm = (struct voltagedomain *)data;
- return voltdm_scale(voltdm, target_uV);
+ struct omap_volt_data *volt_data = voltdm->volt_data;
+
+ while (1) {
+ if (!volt_data->volt_nominal)
+ return -EINVAL;
+ if (volt_data->volt_nominal >= target_uV)
+ break;
+ volt_data++;
+ }
+ return voltdm_scale(voltdm, volt_data->volt_nominal);
}
static int twl_get_voltage(void *data)
--
1.7.4.1
