Hi,

On Wed, Sep 19 2012, Jaehoon Chung wrote:
>> On Wed, Sep 19 2012, Tomasz Figa wrote:
>>> We could just check if the regulator provides the capability to change the 
>>> voltage.
>>>
>>> I don't see any direct way of querying the regulator for provided 
>>> capabilities (correct me if I'm just blind), but calling 
>>> regulator_count_voltages() on the regulator and checking if the returned 
>>> value is 1 should be enough to assume that the regulator is fixed.
>> 
>> Sounds good, I agree.  Are you able to test that the obvious patch below
>> works on your fixed-regulator board?
>> 
>> Jaehoon and Adrian, can you think of any reason why we shouldn't replace
>> MMC_CAP2_BROKEN_VOLTAGE with the regulator_count_voltages() call below?
>> Thanks.
>
> I think this is better than using MMC_CAP2_BROKEN_VOLTAGE.
> I tested with this..and working fine.

Great, here's the patch.  Jaehoon, once this is merged, maybe you could
help remove the uses of MMC_CAP2_BROKEN_VOLTAGE from arch/arm/mach-exynos
and arch/arm/mach-s5pv210 now that they're no longer needed?

Thanks,

- Chris.


Subject: [PATCH] mmc: core: Replace MMC_CAP2_BROKEN_VOLTAGE with test for fixed 
regulator

Before this patch, we were using MMC_CAP2_BROKEN_VOLTAGE as a way to
avoid calling regulator_set_voltage() on a fixed regulator, but that's
just duplicating information that already exists -- we should test
whether the regulator is fixed directly, instead of via a capability.

This patch implements that test.  We can't reclaim the capability bit
just yet, since there are still boards in arch/arm/ that reference it;
those references can be removed now.

Reported-by: Tomasz Figa <[email protected]>
Signed-off-by: Chris Ball <[email protected]>
---
 drivers/mmc/core/core.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 044cd01..6612163 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -1113,7 +1113,8 @@ int mmc_regulator_set_ocr(struct mmc_host *mmc,
                int             tmp;
                int             voltage;
 
-               /* REVISIT mmc_vddrange_to_ocrmask() may have set some
+               /*
+                * REVISIT mmc_vddrange_to_ocrmask() may have set some
                 * bits this regulator doesn't quite support ... don't
                 * be too picky, most cards and regulators are OK with
                 * a 0.1V range goof (it's a small error percentage).
@@ -1127,12 +1128,13 @@ int mmc_regulator_set_ocr(struct mmc_host *mmc,
                        max_uV = min_uV + 100 * 1000;
                }
 
-               /* avoid needless changes to this voltage; the regulator
-                * might not allow this operation
+               /*
+                * If we're using a fixed/static regulator, don't call
+                * regulator_set_voltage; it would fail.
                 */
                voltage = regulator_get_voltage(supply);
 
-               if (mmc->caps2 & MMC_CAP2_BROKEN_VOLTAGE)
+               if (regulator_count_voltages(supply) == 1)
                        min_uV = max_uV = voltage;
 
                if (voltage < 0)
-- 
Chris Ball   <[email protected]>   <http://printf.net/>
One Laptop Per Child
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