linux-kernel - Re: [PATCH 3/4] drm/sun4i: dsi: Add a variant structure

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Date:   Mon, 15 Aug 2022 08:42:48 +0200
From:   Maxime Ripard <maxime@...no.tech>
To:     Samuel Holland <samuel@...lland.org>
Cc:     Chen-Yu Tsai <wens@...e.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>,
        Jagan Teki <jagan@...rulasolutions.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Rob Herring <robh+dt@...nel.org>, devicetree@...r.kernel.org,
        dri-devel@...ts.freedesktop.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-sunxi@...ts.linux.dev
Subject: Re: [PATCH 3/4] drm/sun4i: dsi: Add a variant structure

Hi Samuel,

On Fri, Aug 12, 2022 at 02:42:55AM -0500, Samuel Holland wrote:
> Replace the ad-hoc calls to of_device_is_compatible() with a structure
> describing the differences between variants. This is in preparation for
> adding more variants to the driver.
> 
> Signed-off-by: Samuel Holland <samuel@...lland.org>
> ---
> 
>  drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 50 +++++++++++++++++---------
>  drivers/gpu/drm/sun4i/sun6i_mipi_dsi.h |  7 ++++
>  2 files changed, 40 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> index b4dfa166eccd..6479ade416b9 100644
> --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> @@ -1101,12 +1101,16 @@ static const struct component_ops sun6i_dsi_ops = {
>  
>  static int sun6i_dsi_probe(struct platform_device *pdev)
>  {
> +	const struct sun6i_dsi_variant *variant;
>  	struct device *dev = &pdev->dev;
> -	const char *bus_clk_name = NULL;
>  	struct sun6i_dsi *dsi;
>  	void __iomem *base;
>  	int ret;
>  
> +	variant = device_get_match_data(dev);
> +	if (!variant)
> +		return -EINVAL;
> +
>  	dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
>  	if (!dsi)
>  		return -ENOMEM;
> @@ -1114,10 +1118,7 @@ static int sun6i_dsi_probe(struct platform_device *pdev)
>  	dsi->dev = dev;
>  	dsi->host.ops = &sun6i_dsi_host_ops;
>  	dsi->host.dev = dev;
> -
> -	if (of_device_is_compatible(dev->of_node,
> -				    "allwinner,sun6i-a31-mipi-dsi"))
> -		bus_clk_name = "bus";
> +	dsi->variant = variant;
>  
>  	base = devm_platform_ioremap_resource(pdev, 0);
>  	if (IS_ERR(base)) {
> @@ -1142,7 +1143,7 @@ static int sun6i_dsi_probe(struct platform_device *pdev)
>  		return PTR_ERR(dsi->regs);
>  	}
>  
> -	dsi->bus_clk = devm_clk_get(dev, bus_clk_name);
> +	dsi->bus_clk = devm_clk_get(dev, variant->has_mod_clk ? "bus" : NULL);
>  	if (IS_ERR(dsi->bus_clk))
>  		return dev_err_probe(dev, PTR_ERR(dsi->bus_clk),
>  				     "Couldn't get the DSI bus clock\n");
> @@ -1151,21 +1152,21 @@ static int sun6i_dsi_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> -	if (of_device_is_compatible(dev->of_node,
> -				    "allwinner,sun6i-a31-mipi-dsi")) {
> +	if (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");
>  			ret = PTR_ERR(dsi->mod_clk);
>  			goto err_attach_clk;
>  		}
> -	}
>  
> -	/*
> -	 * In order to operate properly, that clock seems to be always
> -	 * set to 297MHz.
> -	 */
> -	clk_set_rate_exclusive(dsi->mod_clk, 297000000);
> +		/*
> +		 * In order to operate properly, the module clock on the
> +		 * A31 variant always seems to be set to 297MHz.
> +		 */
> +		if (variant->set_mod_clk)
> +			clk_set_rate_exclusive(dsi->mod_clk, 297000000);
> +	}
>
>
>  	dsi->dphy = devm_phy_get(dev, "dphy");
>  	if (IS_ERR(dsi->dphy)) {
> @@ -1205,16 +1206,31 @@ static int sun6i_dsi_remove(struct platform_device *pdev)
>  
>  	component_del(&pdev->dev, &sun6i_dsi_ops);
>  	mipi_dsi_host_unregister(&dsi->host);
> -	clk_rate_exclusive_put(dsi->mod_clk);
> +	if (dsi->variant->has_mod_clk && dsi->variant->set_mod_clk)
> +		clk_rate_exclusive_put(dsi->mod_clk);

There's also a clk_rate_exclusive_put call in the bind error path

Maxime

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