Re: [RFC v2 02/11] OPP: Make dev_pm_opp_set_rate() with freq=0 as valid

From: Viresh Kumar <viresh.kumar@linaro.org>
To: Rajendra Nayak <rnayak@codeaurora.org>
Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-pm@vger.kernel.org, linux-serial@vger.kernel.org,
	linux-spi@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-scsi@vger.kernel.org, swboyd@chromium.org,
	ulf.hansson@linaro.org, dianders@chromium.org, rafael@kernel.org
Subject: Re: [RFC v2 02/11] OPP: Make dev_pm_opp_set_rate() with freq=0 as valid
Date: Fri, 14 Jun 2019 12:02:10 +0530	[thread overview]
Message-ID: <20190614063210.lfsquoycronah3fe@vireshk-i7> (raw)
In-Reply-To: <20190320094918.20234-3-rnayak@codeaurora.org>

On 20-03-19, 15:19, Rajendra Nayak wrote:
> For devices with performance state, we use dev_pm_opp_set_rate()
> to set the appropriate clk rate and the performance state.
> We do need a way to *remove* the performance state vote when
> we idle the device and turn the clocks off. Use dev_pm_opp_set_rate()
> with freq=0 to achieve this.
> 
> Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
> Signed-off-by: Stephen Boyd <swboyd@chromium.org>
> ---
>  drivers/opp/core.c | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)

What about this instead ?

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 2fe96c2363a3..9accf8bb6afc 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -711,7 +711,7 @@ static int _set_required_opps(struct device *dev,
 
        /* Single genpd case */
        if (!genpd_virt_devs) {
-               pstate = opp->required_opps[0]->pstate;
+               pstate = likely(opp) ? opp->required_opps[0]->pstate : 0;
                ret = dev_pm_genpd_set_performance_state(dev, pstate);
                if (ret) {
                        dev_err(dev, "Failed to set performance state of %s: %d (%d)\n",
@@ -729,7 +729,7 @@ static int _set_required_opps(struct device *dev,
        mutex_lock(&opp_table->genpd_virt_dev_lock);
 
        for (i = 0; i < opp_table->required_opp_count; i++) {
-               pstate = opp->required_opps[i]->pstate;
+               pstate = likely(opp) ? opp->required_opps[i]->pstate : 0;
 
                if (!genpd_virt_devs[i])
                        continue;
@@ -770,14 +770,13 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 
        if (unlikely(!target_freq)) {
                if (opp_table->required_opp_tables) {
-                       /* drop the performance state vote */
-                       dev_pm_genpd_set_performance_state(dev, 0);
-                       return 0;
+                       ret = _set_required_opps(dev, opp_table, NULL);
                } else {
-                       dev_err(dev, "%s: Invalid target frequency %lu\n", __func__,
-                               target_freq);
-                       return -EINVAL;
+                       dev_err(dev, "target frequency can't be 0\n");
+                       ret = -EINVAL;
                }
+
+               goto put_opp_table;
        }
 
        clk = opp_table->clk;
