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SubjectRe: [PATCH 6/7] drm: atmel-hlcdc: enable sys_clk during initalization.
Hi Claudiu

On Wed, Feb 27, 2019 at 04:24:40PM +0000, Claudiu.Beznea@microchip.com wrote:
> From: Sandeep Sheriker Mallikarjun <sandeepsheriker.mallikarjun@microchip.com>
>
> For SAM9X60 SoC, sys_clk is through lcd_gclk clock source and this
> needs to be enabled before enabling lcd_clk.

We have "ownership" of the clocks in the mfd device.
So it would make more sense to let the mfd device handle
the base clocks.
In other words - what about pushing enable of perigh_clk and sys_clk to
the mfd driver.

This may have the nice side-effect that we avoid
that both the drm driver and the pwm driver enable/disable the periph_clk
as it is today.

Another comment - fixed_clksrc is used to determine if sys_clk is enabled.
But that flag is about the clksource selection, and it is just a coincidence
that the same flag can be used here.
Why we cannot always enable sys_clk? Do we need to do this only
for sam9x60?
IF yes, then add a new falg. If no, then skip the flag.

Sam


>
> Signed-off-by: Sandeep Sheriker Mallikarjun <sandeepsheriker.mallikarjun@microchip.com>
> [claudiu.beznea@microchip.com: add fixed_clksrc checks]
> Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
> ---
> drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c | 19 ++++++++++++++++++-
> 1 file changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c
> index 0be13eceedba..8bf51f853721 100644
> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c
> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c
> @@ -625,10 +625,18 @@ static int atmel_hlcdc_dc_load(struct drm_device *dev)
> dc->hlcdc = dev_get_drvdata(dev->dev->parent);
> dev->dev_private = dc;
>
> + if (dc->desc->fixed_clksrc) {
> + ret = clk_prepare_enable(dc->hlcdc->sys_clk);
> + if (ret) {
> + dev_err(dev->dev, "failed to enable sys_clk\n");
> + goto err_destroy_wq;
> + }
> + }
> +
> ret = clk_prepare_enable(dc->hlcdc->periph_clk);
> if (ret) {
> dev_err(dev->dev, "failed to enable periph_clk\n");
> - goto err_destroy_wq;
> + goto err_sys_clk_disable;
> }
>
> pm_runtime_enable(dev->dev);
> @@ -664,6 +672,9 @@ static int atmel_hlcdc_dc_load(struct drm_device *dev)
> err_periph_clk_disable:
> pm_runtime_disable(dev->dev);
> clk_disable_unprepare(dc->hlcdc->periph_clk);
> +err_sys_clk_disable:
> + if (dc->desc->fixed_clksrc)
> + clk_disable_unprepare(dc->hlcdc->sys_clk);
>
> err_destroy_wq:
> destroy_workqueue(dc->wq);
> @@ -688,6 +699,8 @@ static void atmel_hlcdc_dc_unload(struct drm_device *dev)
>
> pm_runtime_disable(dev->dev);
> clk_disable_unprepare(dc->hlcdc->periph_clk);
> + if (dc->desc->fixed_clksrc)
> + clk_disable_unprepare(dc->hlcdc->sys_clk);
> destroy_workqueue(dc->wq);
> }
>
> @@ -805,6 +818,8 @@ static int atmel_hlcdc_dc_drm_suspend(struct device *dev)
> regmap_read(regmap, ATMEL_HLCDC_IMR, &dc->suspend.imr);
> regmap_write(regmap, ATMEL_HLCDC_IDR, dc->suspend.imr);
> clk_disable_unprepare(dc->hlcdc->periph_clk);
> + if (dc->desc->fixed_clksrc)
> + clk_disable_unprepare(dc->hlcdc->sys_clk);
>
> return 0;
> }
> @@ -814,6 +829,8 @@ static int atmel_hlcdc_dc_drm_resume(struct device *dev)
> struct drm_device *drm_dev = dev_get_drvdata(dev);
> struct atmel_hlcdc_dc *dc = drm_dev->dev_private;
>
> + if (dc->desc->fixed_clksrc)
> + clk_prepare_enable(dc->hlcdc->sys_clk);
> clk_prepare_enable(dc->hlcdc->periph_clk);
> regmap_write(dc->hlcdc->regmap, ATMEL_HLCDC_IER, dc->suspend.imr);
>
> --
> 2.7.4
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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