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SubjectRe: [PATCH v2 1/1] phy: fsl-imx8-mipi-dphy: Hook into runtime pm
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Hi Guido,

On Wed, 2020-12-16 at 12:27 +0100, Guido Günther wrote:
> This allows us to shut down the mipi power domain on the imx8. The
> alternative would be to drop the dphy from the mipi power domain in the
> SOCs device tree and only have the DSI host controller visible there but
> since the PD is mostly about the PHY that would defeat it's purpose.
>
> This allows to shut off the power domain hen blanking the LCD panel:
>
> pm_genpd_summary before:
>
> domain status slaves
> /device runtime status
> ----------------------------------------------------------------------
> mipi on
> /devices/platform/soc@0/soc@0:bus@30800000/30a00300.dphy unsupported
> /devices/platform/soc@0/soc@0:bus@30800000/30a00000.mipi_dsi suspended
>
> after:
>
> mipi off-0
> /devices/platform/soc@0/soc@0:bus@30800000/30a00300.dphy suspended
> /devices/platform/soc@0/soc@0:bus@30800000/30a00000.mipi_dsi suspended
>
> Signed-off-by: Guido Günther <agx@sigxcpu.org>
> ---
> .../phy/freescale/phy-fsl-imx8-mipi-dphy.c | 22 ++++++++++++++++++-
> 1 file changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c b/drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c
> index a95572b397ca..34e2d801e520 100644
> --- a/drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c
> +++ b/drivers/phy/freescale/phy-fsl-imx8-mipi-dphy.c
> @@ -14,6 +14,7 @@
> #include <linux/of_platform.h>
> #include <linux/phy/phy.h>
> #include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> #include <linux/regmap.h>
>
> /* DPHY registers */
> @@ -93,6 +94,7 @@ struct mixel_dphy_cfg {
> };
>
> struct mixel_dphy_priv {
> + struct device *dev;
> struct mixel_dphy_cfg cfg;
> struct regmap *regmap;
> struct clk *phy_ref_clk;
> @@ -382,6 +384,7 @@ static int mixel_dphy_power_on(struct phy *phy)
> ret = clk_prepare_enable(priv->phy_ref_clk);
> if (ret < 0)
> return ret;
> + pm_runtime_get_sync(priv->dev);
>
> phy_write(phy, PWR_ON, DPHY_PD_PLL);
> ret = regmap_read_poll_timeout(priv->regmap, DPHY_LOCK, locked,
> @@ -395,6 +398,7 @@ static int mixel_dphy_power_on(struct phy *phy)
>
> return 0;
> clock_disable:
> + pm_runtime_put(priv->dev);
> clk_disable_unprepare(priv->phy_ref_clk);
> return ret;
> }
> @@ -406,6 +410,7 @@ static int mixel_dphy_power_off(struct phy *phy)
> phy_write(phy, PWR_OFF, DPHY_PD_PLL);
> phy_write(phy, PWR_OFF, DPHY_PD_DPHY);
>
> + pm_runtime_put(priv->dev);
> clk_disable_unprepare(priv->phy_ref_clk);
>
> return 0;
> @@ -467,6 +472,7 @@ static int mixel_dphy_probe(struct platform_device *pdev)
> dev_dbg(dev, "phy_ref clock rate: %lu\n",
> clk_get_rate(priv->phy_ref_clk));
>
> + priv->dev = dev;
> dev_set_drvdata(dev, priv);
>
> phy = devm_phy_create(dev, np, &mixel_dphy_phy_ops);
> @@ -477,12 +483,26 @@ static int mixel_dphy_probe(struct platform_device *pdev)
> phy_set_drvdata(phy, priv);
>
> phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
> + if (IS_ERR(phy_provider))
> + return PTR_ERR(phy_provider);
>
> - return PTR_ERR_OR_ZERO(phy_provider);
> + pm_runtime_enable(dev);

If this enablement is done prior to devm_phy_create(), then the
phy-core will manage runtime PM for this device. This way, this driver
doesn't have to manage it by itself.

Regards,
Liu Ying

> +
> + return 0;
> +}
> +
> +static int mixel_dphy_remove(struct platform_device *pdev)
> +{
> + struct mixel_dphy_priv *priv = platform_get_drvdata(pdev);
> +
> + pm_runtime_disable(priv->dev);
> +
> + return 0;
> }
>
> static struct platform_driver mixel_dphy_driver = {
> .probe = mixel_dphy_probe,
> + .remove = mixel_dphy_remove,
> .driver = {
> .name = "mixel-mipi-dphy",
> .of_match_table = mixel_dphy_of_match,

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