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SubjectRe: [RFC v3 04/10] OPP: Add and export helper to update voltage
On 2020-01-29 03:03, Matthias Kaehlcke wrote:
> Hi Sibi,
>
> On Tue, Jan 28, 2020 at 01:33:44AM +0530, Sibi Sankar wrote:
>> Add and export 'dev_pm_opp_update_voltage' to find and update voltage
>> of an opp for a given frequency. This will be useful to update the
>> opps
>> with voltages read back from firmware.
>>
>> Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
>> ---
>> drivers/opp/core.c | 55
>> ++++++++++++++++++++++++++++++++++++++++++
>> include/linux/pm_opp.h | 10 ++++++++
>> 2 files changed, 65 insertions(+)
>>
>> diff --git a/drivers/opp/core.c b/drivers/opp/core.c
>> index 9aa2a44a5d638..f241e83ec926a 100644
>> --- a/drivers/opp/core.c
>> +++ b/drivers/opp/core.c
>> @@ -2503,6 +2503,61 @@ int dev_pm_opp_disable(struct device *dev,
>> unsigned long freq)
>> }
>> EXPORT_SYMBOL_GPL(dev_pm_opp_disable);
>>
>> +/**
>> + * dev_pm_opp_update_voltage() - Find and update voltage
>
> The comment should mention that this is done for an OPP.
>
> Maybe omit the 'find' part here and just say 'Update the voltage of
> an OPP'?

sure makes sense

>
>> + * @dev: device for which we do this operation
>> + * @freq: OPP frequency to update voltage
>> + * @u_volt: voltage requested for this opp
>> + *
>> + * Find and update voltage of a disabled opp corresponding to the
>> given
>> + * frequency. This is useful only for devices with single power
>> supply.
>> + *
>> + * Return: 0 if modification was successful or a negative error
>> value.
>> + */
>> +int dev_pm_opp_update_voltage(struct device *dev, unsigned long freq,
>> + unsigned long u_volt)
>> +{
>> + struct dev_pm_opp *opp = ERR_PTR(-ENODEV);
>
> initialization is not needed
>
>> + struct opp_table *opp_table;
>> + unsigned long tol;
>> + int ret = 0;
>> +
>> + /* Find the opp_table */
>
> Drop the comment, it's obvious from the code.
>
>> + opp_table = _find_opp_table(dev);
>> + if (IS_ERR(opp_table)) {
>> + ret = PTR_ERR(opp_table);
>> + dev_err(dev, "%s: OPP table not found (%d)\n", __func__, ret);
>> + return PTR_ERR(opp_table);
>
> return ret;

missed that :(

>
>> + }
>> +
>> + opp = dev_pm_opp_find_freq_exact(dev, freq, false);
>> + if (IS_ERR(opp)) {
>> + ret = PTR_ERR(opp);
>> + goto put_table;
>> + }
>> +
>> + mutex_lock(&opp_table->lock);
>> +
>> + /* update only if the opp is disabled */
>> + if (opp->available) {
>> + ret = -EBUSY;
>> + goto unlock;
>> + }
>> +
>> + tol = u_volt * opp_table->voltage_tolerance_v1 / 100;
>> + opp->supplies[0].u_volt_min = u_volt - tol;
>> + opp->supplies[0].u_volt = u_volt;
>> + opp->supplies[0].u_volt_min = u_volt + tol;
>
> .u_volt_max =
>
> I suppose the assignments need to be done for all possible supplies,
> i.e. 0 to (opp_table->regulator_count - 1).

a single value for all possible
supplies seems wrong. Anyway
will wait to see what Viresh
thinks about it.

--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project.

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