linux-kernel - Re: [PATCH v6 5/9] drm/meson: gate px

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Message-ID: <c487ed03-0ab2-74fb-91bc-4a773bfdfc5b@sberdevices.ru>
Date:   Fri, 30 Jun 2023 21:10:55 +0300
From:   George Stark <gnstark@...rdevices.ru>
To:     Neil Armstrong <neil.armstrong@...aro.org>,
        Jerome Brunet <jbrunet@...libre.com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Kevin Hilman <khilman@...libre.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Jagan Teki <jagan@...rulasolutions.com>,
        Nicolas Belin <nbelin@...libre.com>
CC:     <linux-clk@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-amlogic@...ts.infradead.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <dri-devel@...ts.freedesktop.org>
Subject: Re: [PATCH v6 5/9] drm/meson: gate px_clk when setting rate

Hello Neil

On 6/30/23 19:29, Neil Armstrong wrote:
> Disable the px_clk when setting the rate to recover a fully
> configured and correctly reset VCLK clock tree after the rate
> is set.
>
> Fixes: 77d9e1e6b846 ("drm/meson: add support for MIPI-DSI transceiver")
> Signed-off-by: Neil Armstrong <neil.armstrong@...aro.org>
> ---
>   drivers/gpu/drm/meson/meson_dw_mipi_dsi.c | 7 +++++++
>   1 file changed, 7 insertions(+)
>
> diff --git a/drivers/gpu/drm/meson/meson_dw_mipi_dsi.c b/drivers/gpu/drm/meson/meson_dw_mipi_dsi.c
> index 57447abf1a29..dc63d2d813a9 100644
> --- a/drivers/gpu/drm/meson/meson_dw_mipi_dsi.c
> +++ b/drivers/gpu/drm/meson/meson_dw_mipi_dsi.c
> @@ -94,6 +94,7 @@ static int dw_mipi_dsi_phy_init(void *priv_data)
>   		return ret;
>   	}
>   
> +	clk_disable_unprepare(mipi_dsi->px_clk);
>   	ret = clk_set_rate(mipi_dsi->px_clk, mipi_dsi->mode->clock * 1000);
>   
>   	if (ret) {
> @@ -102,6 +103,12 @@ static int dw_mipi_dsi_phy_init(void *priv_data)
>   		return ret;
>   	}
>   
> +	clk_prepare_enable(mipi_dsi->px_clk);
probably should be:
ret = clk_prepare_enable(mipi_dsi->px_clk);
> +	if (ret) {
> +		dev_err(mipi_dsi->dev, "Failed to enable DSI Pixel clock (ret %d)\n", ret);
> +		return ret;
> +	}
> +
>   	switch (mipi_dsi->dsi_device->format) {
>   	case MIPI_DSI_FMT_RGB888:
>   		dpi_data_format = DPI_COLOR_24BIT;
>
-- 
Best regards
George