linux-kernel - Re: [PATCH 2/3] nvmem: qfprom: sc7280: Handle the additional power-domains vote

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Date:   Fri, 23 Jul 2021 09:43:47 -0700
From:   Doug Anderson <dianders@...omium.org>
To:     Rajendra Nayak <rnayak@...eaurora.org>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>,
        "Ravi Kumar Bokka (Temp)" <rbokka@...eaurora.org>
Subject: Re: [PATCH 2/3] nvmem: qfprom: sc7280: Handle the additional
 power-domains vote

Hi,

On Wed, Jul 21, 2021 at 10:29 PM Rajendra Nayak <rnayak@...eaurora.org> wrote:
>
> On sc7280, to reliably blow fuses, we need an additional vote
> on max performance state of 'MX' power-domain.
> Add support for power-domain performance state voting in the
> driver.
>
> Signed-off-by: Rajendra Nayak <rnayak@...eaurora.org>
> ---
>  drivers/nvmem/qfprom.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
>
> diff --git a/drivers/nvmem/qfprom.c b/drivers/nvmem/qfprom.c
> index 81fbad5..4d0a576 100644
> --- a/drivers/nvmem/qfprom.c
> +++ b/drivers/nvmem/qfprom.c
> @@ -12,6 +12,8 @@
>  #include <linux/mod_devicetable.h>
>  #include <linux/nvmem-provider.h>
>  #include <linux/platform_device.h>
> +#include <linux/pm_domain.h>
> +#include <linux/pm_runtime.h>
>  #include <linux/property.h>
>  #include <linux/regulator/consumer.h>
>
> @@ -149,6 +151,11 @@ static void qfprom_disable_fuse_blowing(const struct qfprom_priv *priv,
>         if (ret)
>                 dev_warn(priv->dev, "Failed to set 0 voltage (ignoring)\n");
>
> +       if (priv->dev->pm_domain) {
> +               dev_pm_genpd_set_performance_state(priv->dev, 0);
> +               pm_runtime_put(priv->dev);
> +       }
> +
>         ret = regulator_disable(priv->vcc);
>         if (ret)
>                 dev_warn(priv->dev, "Failed to disable regulator (ignoring)\n");
> @@ -212,6 +219,16 @@ static int qfprom_enable_fuse_blowing(const struct qfprom_priv *priv,
>                 goto err_clk_rate_set;
>         }
>
> +       if (priv->dev->pm_domain) {
> +               ret = pm_runtime_get_sync(priv->dev);
> +               if (ret < 0) {
> +                       pm_runtime_put_noidle(priv->dev);
> +                       dev_err(priv->dev, "Failed to enable power-domain\n");
> +                       goto err_reg_enable;
> +               }
> +               dev_pm_genpd_set_performance_state(priv->dev, INT_MAX);
> +       }
> +
>         old->timer_val = readl(priv->qfpconf + QFPROM_BLOW_TIMER_OFFSET);
>         old->accel_val = readl(priv->qfpconf + QFPROM_ACCEL_OFFSET);
>         writel(priv->soc_data->qfprom_blow_timer_value,
> @@ -221,6 +238,8 @@ static int qfprom_enable_fuse_blowing(const struct qfprom_priv *priv,
>
>         return 0;
>
> +err_reg_enable:
> +       regulator_disable(priv->vcc);
>  err_clk_rate_set:
>         clk_set_rate(priv->secclk, old->clk_rate);
>  err_clk_prepared:
> @@ -420,6 +439,9 @@ static int qfprom_probe(struct platform_device *pdev)
>                         econfig.reg_write = qfprom_reg_write;
>         }
>
> +       if (dev->pm_domain)
> +               pm_runtime_enable(dev);
> +

Where is the matching pm_runtime_disable()? Should be one in
.remove(), or use devm_add_action_or_reset() to wrap a call to it.

Also: do you really need to test for dev->pm_domain in your patch?
Seems like it should always be fine to call pm_runtime_enable() and
then always fine to call the get/put. ...and presumably always fine to
even set the performance state?

-Doug