Re: [PATCH v12 3/7] drm/sun4i: dsi: Add has_mod_clk quirk

Jagan Teki
2019-12-03T16:41:00Z

On Tue, Dec 3, 2019 at 8:09 PM Chen-Yu Tsai <wens@csie.org> wrote:
>
> On Tue, Dec 3, 2019 at 9:48 PM Jagan Teki <jagan@amarulasolutions.com> wrote:
> >
> > As per the user manual, look like mod clock is not mandatory
> > for all Allwinner MIPI DSI controllers, it is connected to
> > CLK_DSI_SCLK for A31 and not available in A64.
> >
> > So add has_mod_clk quirk and process the mod clk accordingly.
> >
> > Tested-by: Merlijn Wajer <merlijn@wizzup.org>
> > Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> > ---
> > Changes for v12:
> > - none
> >
> > drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 38 ++++++++++++++++++--------
> > drivers/gpu/drm/sun4i/sun6i_mipi_dsi.h | 5 ++++
> > 2 files changed, 32 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> > index c958ca9bae63..8c4c541224dd 100644
> > --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> > +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> > @@ -11,6 +11,7 @@
> > #include <linux/crc-ccitt.h>
> > #include <linux/module.h>
> > #include <linux/of_address.h>
> > +#include <linux/of_device.h>
> > #include <linux/phy/phy-mipi-dphy.h>
> > #include <linux/phy/phy.h>
> > #include <linux/platform_device.h>
> > @@ -1093,6 +1094,7 @@ static int sun6i_dsi_probe(struct platform_device *pdev)
> > dsi->dev = dev;
> > dsi->host.ops = &sun6i_dsi_host_ops;
> > dsi->host.dev = dev;
> > + dsi->variant = of_device_get_match_data(dev);
> >
> > res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > base = devm_ioremap_resource(dev, res);
> > @@ -1120,17 +1122,20 @@ static int sun6i_dsi_probe(struct platform_device *pdev)
> > return PTR_ERR(dsi->reset);
> > }
> >
> > - dsi->mod_clk = devm_clk_get(dev, "mod");
> > - if (IS_ERR(dsi->mod_clk)) {
> > - dev_err(dev, "Couldn't get the DSI mod clock\n");
> > - return PTR_ERR(dsi->mod_clk);
> > + if (dsi->variant->has_mod_clk) {
> > + dsi->mod_clk = devm_clk_get(dev, "mod");
> > + if (IS_ERR(dsi->mod_clk)) {
> > + dev_err(dev, "Couldn't get the DSI mod clock\n");
> > + return PTR_ERR(dsi->mod_clk);
> > + }
> > }
> >
> > /*
> > * In order to operate properly, that clock seems to be always
> > * set to 297MHz.
> > */
> > - clk_set_rate_exclusive(dsi->mod_clk, 297000000);
> > + if (dsi->variant->has_mod_clk)
> > + clk_set_rate_exclusive(dsi->mod_clk, 297000000);
>
> The clk API can handle NULL pointers, so you don't need to add the if here...

Ohh. I'm not aware of this. does it added recently?

>
> >
> > dsi->dphy = devm_phy_get(dev, "dphy");
> > if (IS_ERR(dsi->dphy)) {
> > @@ -1160,7 +1165,8 @@ static int sun6i_dsi_probe(struct platform_device *pdev)
> > err_pm_disable:
> > pm_runtime_disable(dev);
> > err_unprotect_clk:
> > - clk_rate_exclusive_put(dsi->mod_clk);
> > + if (dsi->variant->has_mod_clk)
> > + clk_rate_exclusive_put(dsi->mod_clk);
>
> and here...
>
> > return ret;
> > }
> >
> > @@ -1172,7 +1178,8 @@ static int sun6i_dsi_remove(struct platform_device *pdev)
> > component_del(&pdev->dev, &sun6i_dsi_ops);
> > mipi_dsi_host_unregister(&dsi->host);
> > pm_runtime_disable(dev);
> > - clk_rate_exclusive_put(dsi->mod_clk);
> > + if (dsi->variant->has_mod_clk)
> > + clk_rate_exclusive_put(dsi->mod_clk);
>
> and here ...
>
> >
> > return 0;
> > }
> > @@ -1189,7 +1196,8 @@ static int __maybe_unused sun6i_dsi_runtime_resume(struct device *dev)
> > }
> >
> > reset_control_deassert(dsi->reset);
> > - clk_prepare_enable(dsi->mod_clk);
> > + if (dsi->variant->has_mod_clk)
> > + clk_prepare_enable(dsi->mod_clk);
>
> and here...
>
> >
> > /*
> > * Enable the DSI block.
> > @@ -1217,7 +1225,8 @@ static int __maybe_unused sun6i_dsi_runtime_suspend(struct device *dev)
> > {
> > struct sun6i_dsi *dsi = dev_get_drvdata(dev);
> >
> > - clk_disable_unprepare(dsi->mod_clk);
> > + if (dsi->variant->has_mod_clk)
> > + clk_disable_unprepare(dsi->mod_clk);
>
> and here.
>
> > reset_control_assert(dsi->reset);
> > regulator_disable(dsi->regulator);
> >
> > @@ -1230,9 +1239,16 @@ static const struct dev_pm_ops sun6i_dsi_pm_ops = {
> > NULL)
> > };
> >
> > +static const struct sun6i_dsi_variant sun6i_a31_mipi_dsi = {
> > + .has_mod_clk = true,
> > +};
> > +
> > static const struct of_device_id sun6i_dsi_of_table[] = {
> > - { .compatible = "allwinner,sun6i-a31-mipi-dsi" },
> > - { }
> > + {
> > + .compatible = "allwinner,sun6i-a31-mipi-dsi",
> > + .data = &sun6i_a31_mipi_dsi,
> > + },
> > + { /* sentinel */ }
> > };
> > MODULE_DEVICE_TABLE(of, sun6i_dsi_of_table);
> >
> > diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.h b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.h
> > index 3f4846f581ef..d791c9f6fccf 100644
> > --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.h
> > +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.h
> > @@ -15,6 +15,10 @@
> >
> > #define SUN6I_DSI_TCON_DIV 4
> >
> > +struct sun6i_dsi_variant {
> > + bool has_mod_clk;
> > +};
> > +
>
> You could choose to put this above the probe function, since this isn't used
> anywhere else, and a pointer field doesn't need the full definition.

Okay. Will it be okay to check the compatibility directly on probe
using of_device_is_compatible?

Jagan.