Date: Fri, 21 Jun 2024 14:51:21 +0200
From: Yannick FERTRE <yannick.fertre@...s.st.com>
To: Raphael Gallais-Pou <raphael.gallais-pou@...s.st.com>,
        Philippe Cornu
	<philippe.cornu@...s.st.com>,
        Maarten Lankhorst
	<maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>
CC: <dri-devel@...ts.freedesktop.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RESEND v3 3/3] drm/stm: dsi: expose DSI PHY internal clock

Hi Raphael,

thanks for the patch.

Acked-by: Yannick Fertre <yannick.fertre@...s.st.com>

Tested-by: Yannick Fertre <yannick.fertre@...s.st.com>

BR


Le 29/01/2024 à 11:41, Raphael Gallais-Pou a écrit :
> 	DSISRC __________
> 	               __\_
> 	              |    \
> 	pll4_p_ck   ->|  1  |____dsi_k
> 	ck_dsi_phy  ->|  0  |
> 	              |____/
>
> A DSI clock is missing in the clock framework. Looking at the
> clk_summary, it appears that 'ck_dsi_phy' is not implemented. Since the
> DSI kernel clock is based on the internal DSI pll. The common clock
> driver can not directly expose this 'ck_dsi_phy' clock because it does
> not contain any common registers with the DSI. Thus it needs to be done
> directly within the DSI phy driver.
>
> Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@...s.st.com>
> ---
> Changes in v3:
> 	- Fix smatch warning:
> 	.../dw_mipi_dsi-stm.c:719 dw_mipi_dsi_stm_probe() warn: 'dsi->pclk'
> 	from clk_prepare_enable() not released on lines: 719.
> ---
>   drivers/gpu/drm/stm/dw_mipi_dsi-stm.c | 247 ++++++++++++++++++++++----
>   1 file changed, 216 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c b/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c
> index 82fff9e84345..b20123854c4a 100644
> --- a/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c
> +++ b/drivers/gpu/drm/stm/dw_mipi_dsi-stm.c
> @@ -7,7 +7,9 @@
>    */
>   
>   #include <linux/clk.h>
> +#include <linux/clk-provider.h>
>   #include <linux/iopoll.h>
> +#include <linux/kernel.h>
>   #include <linux/mod_devicetable.h>
>   #include <linux/module.h>
>   #include <linux/platform_device.h>
> @@ -77,9 +79,12 @@ enum dsi_color {
>   
>   struct dw_mipi_dsi_stm {
>   	void __iomem *base;
> +	struct device *dev;
>   	struct clk *pllref_clk;
>   	struct clk *pclk;
> +	struct clk_hw txbyte_clk;
>   	struct dw_mipi_dsi *dsi;
> +	struct dw_mipi_dsi_plat_data pdata;
>   	u32 hw_version;
>   	int lane_min_kbps;
>   	int lane_max_kbps;
> @@ -196,29 +201,198 @@ static int dsi_pll_get_params(struct dw_mipi_dsi_stm *dsi,
>   	return 0;
>   }
>   
> -static int dw_mipi_dsi_phy_init(void *priv_data)
> +#define clk_to_dw_mipi_dsi_stm(clk) \
> +	container_of(clk, struct dw_mipi_dsi_stm, txbyte_clk)
> +
> +static void dw_mipi_dsi_clk_disable(struct clk_hw *clk)
>   {
> -	struct dw_mipi_dsi_stm *dsi = priv_data;
> +	struct dw_mipi_dsi_stm *dsi = clk_to_dw_mipi_dsi_stm(clk);
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	/* Disable the DSI PLL */
> +	dsi_clear(dsi, DSI_WRPCR, WRPCR_PLLEN);
> +
> +	/* Disable the regulator */
> +	dsi_clear(dsi, DSI_WRPCR, WRPCR_REGEN | WRPCR_BGREN);
> +}
> +
> +static int dw_mipi_dsi_clk_enable(struct clk_hw *clk)
> +{
> +	struct dw_mipi_dsi_stm *dsi = clk_to_dw_mipi_dsi_stm(clk);
>   	u32 val;
>   	int ret;
>   
> +	DRM_DEBUG_DRIVER("\n");
> +
>   	/* Enable the regulator */
>   	dsi_set(dsi, DSI_WRPCR, WRPCR_REGEN | WRPCR_BGREN);
> -	ret = readl_poll_timeout(dsi->base + DSI_WISR, val, val & WISR_RRS,
> -				 SLEEP_US, TIMEOUT_US);
> +	ret = readl_poll_timeout_atomic(dsi->base + DSI_WISR, val, val & WISR_RRS,
> +					SLEEP_US, TIMEOUT_US);
>   	if (ret)
>   		DRM_DEBUG_DRIVER("!TIMEOUT! waiting REGU, let's continue\n");
>   
>   	/* Enable the DSI PLL & wait for its lock */
>   	dsi_set(dsi, DSI_WRPCR, WRPCR_PLLEN);
> -	ret = readl_poll_timeout(dsi->base + DSI_WISR, val, val & WISR_PLLLS,
> -				 SLEEP_US, TIMEOUT_US);
> +	ret = readl_poll_timeout_atomic(dsi->base + DSI_WISR, val, val & WISR_PLLLS,
> +					SLEEP_US, TIMEOUT_US);
>   	if (ret)
>   		DRM_DEBUG_DRIVER("!TIMEOUT! waiting PLL, let's continue\n");
>   
>   	return 0;
>   }
>   
> +static int dw_mipi_dsi_clk_is_enabled(struct clk_hw *hw)
> +{
> +	struct dw_mipi_dsi_stm *dsi = clk_to_dw_mipi_dsi_stm(hw);
> +
> +	return dsi_read(dsi, DSI_WRPCR) & WRPCR_PLLEN;
> +}
> +
> +static unsigned long dw_mipi_dsi_clk_recalc_rate(struct clk_hw *hw,
> +						 unsigned long parent_rate)
> +{
> +	struct dw_mipi_dsi_stm *dsi = clk_to_dw_mipi_dsi_stm(hw);
> +	unsigned int idf, ndiv, odf, pll_in_khz, pll_out_khz;
> +	u32 val;
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	pll_in_khz = (unsigned int)(parent_rate / 1000);
> +
> +	val = dsi_read(dsi, DSI_WRPCR);
> +
> +	idf = (val & WRPCR_IDF) >> 11;
> +	if (!idf)
> +		idf = 1;
> +	ndiv = (val & WRPCR_NDIV) >> 2;
> +	odf = int_pow(2, (val & WRPCR_ODF) >> 16);
> +
> +	/* Get the adjusted pll out value */
> +	pll_out_khz = dsi_pll_get_clkout_khz(pll_in_khz, idf, ndiv, odf);
> +
> +	return (unsigned long)pll_out_khz * 1000;
> +}
> +
> +static long dw_mipi_dsi_clk_round_rate(struct clk_hw *hw, unsigned long rate,
> +				       unsigned long *parent_rate)
> +{
> +	struct dw_mipi_dsi_stm *dsi = clk_to_dw_mipi_dsi_stm(hw);
> +	unsigned int idf, ndiv, odf, pll_in_khz, pll_out_khz;
> +	int ret;
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	pll_in_khz = (unsigned int)(*parent_rate / 1000);
> +
> +	/* Compute best pll parameters */
> +	idf = 0;
> +	ndiv = 0;
> +	odf = 0;
> +
> +	ret = dsi_pll_get_params(dsi, pll_in_khz, rate / 1000,
> +				 &idf, &ndiv, &odf);
> +	if (ret)
> +		DRM_WARN("Warning dsi_pll_get_params(): bad params\n");
> +
> +	/* Get the adjusted pll out value */
> +	pll_out_khz = dsi_pll_get_clkout_khz(pll_in_khz, idf, ndiv, odf);
> +
> +	return pll_out_khz * 1000;
> +}
> +
> +static int dw_mipi_dsi_clk_set_rate(struct clk_hw *hw, unsigned long rate,
> +				    unsigned long parent_rate)
> +{
> +	struct dw_mipi_dsi_stm *dsi = clk_to_dw_mipi_dsi_stm(hw);
> +	unsigned int idf, ndiv, odf, pll_in_khz, pll_out_khz;
> +	int ret;
> +	u32 val;
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	pll_in_khz = (unsigned int)(parent_rate / 1000);
> +
> +	/* Compute best pll parameters */
> +	idf = 0;
> +	ndiv = 0;
> +	odf = 0;
> +
> +	ret = dsi_pll_get_params(dsi, pll_in_khz, rate / 1000, &idf, &ndiv, &odf);
> +	if (ret)
> +		DRM_WARN("Warning dsi_pll_get_params(): bad params\n");
> +
> +	/* Get the adjusted pll out value */
> +	pll_out_khz = dsi_pll_get_clkout_khz(pll_in_khz, idf, ndiv, odf);
> +
> +	/* Set the PLL division factors */
> +	dsi_update_bits(dsi, DSI_WRPCR,	WRPCR_NDIV | WRPCR_IDF | WRPCR_ODF,
> +			(ndiv << 2) | (idf << 11) | ((ffs(odf) - 1) << 16));
> +
> +	/* Compute uix4 & set the bit period in high-speed mode */
> +	val = 4000000 / pll_out_khz;
> +	dsi_update_bits(dsi, DSI_WPCR0, WPCR0_UIX4, val);
> +
> +	return 0;
> +}
> +
> +static void dw_mipi_dsi_clk_unregister(void *data)
> +{
> +	struct dw_mipi_dsi_stm *dsi = data;
> +
> +	DRM_DEBUG_DRIVER("\n");
> +
> +	of_clk_del_provider(dsi->dev->of_node);
> +	clk_hw_unregister(&dsi->txbyte_clk);
> +}
> +
> +static const struct clk_ops dw_mipi_dsi_stm_clk_ops = {
> +	.enable = dw_mipi_dsi_clk_enable,
> +	.disable = dw_mipi_dsi_clk_disable,
> +	.is_enabled = dw_mipi_dsi_clk_is_enabled,
> +	.recalc_rate = dw_mipi_dsi_clk_recalc_rate,
> +	.round_rate = dw_mipi_dsi_clk_round_rate,
> +	.set_rate = dw_mipi_dsi_clk_set_rate,
> +};
> +
> +static struct clk_init_data cdata_init = {
> +	.name = "ck_dsi_phy",
> +	.ops = &dw_mipi_dsi_stm_clk_ops,
> +	.parent_names = (const char * []) {"ck_hse"},
> +	.num_parents = 1,
> +};
> +
> +static int dw_mipi_dsi_clk_register(struct dw_mipi_dsi_stm *dsi,
> +				    struct device *dev)
> +{
> +	struct device_node *node = dev->of_node;
> +	int ret;
> +
> +	DRM_DEBUG_DRIVER("Registering clk\n");
> +
> +	dsi->txbyte_clk.init = &cdata_init;
> +
> +	ret = clk_hw_register(dev, &dsi->txbyte_clk);
> +	if (ret)
> +		return ret;
> +
> +	ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get,
> +				     &dsi->txbyte_clk);
> +	if (ret)
> +		clk_hw_unregister(&dsi->txbyte_clk);
> +
> +	return ret;
> +}
> +
> +static int dw_mipi_dsi_phy_init(void *priv_data)
> +{
> +	struct dw_mipi_dsi_stm *dsi = priv_data;
> +	int ret;
> +
> +	ret = clk_prepare_enable(dsi->txbyte_clk.clk);
> +	return ret;
> +}
> +
>   static void dw_mipi_dsi_phy_power_on(void *priv_data)
>   {
>   	struct dw_mipi_dsi_stm *dsi = priv_data;
> @@ -235,6 +409,8 @@ static void dw_mipi_dsi_phy_power_off(void *priv_data)
>   
>   	DRM_DEBUG_DRIVER("\n");
>   
> +	clk_disable_unprepare(dsi->txbyte_clk.clk);
> +
>   	/* Disable the DSI wrapper */
>   	dsi_clear(dsi, DSI_WCR, WCR_DSIEN);
>   }
> @@ -245,9 +421,8 @@ dw_mipi_dsi_get_lane_mbps(void *priv_data, const struct drm_display_mode *mode,
>   			  unsigned int *lane_mbps)
>   {
>   	struct dw_mipi_dsi_stm *dsi = priv_data;
> -	unsigned int idf, ndiv, odf, pll_in_khz, pll_out_khz;
> +	unsigned int pll_in_khz, pll_out_khz;
>   	int ret, bpp;
> -	u32 val;
>   
>   	pll_in_khz = (unsigned int)(clk_get_rate(dsi->pllref_clk) / 1000);
>   
> @@ -268,25 +443,10 @@ dw_mipi_dsi_get_lane_mbps(void *priv_data, const struct drm_display_mode *mode,
>   		DRM_WARN("Warning min phy mbps is used\n");
>   	}
>   
> -	/* Compute best pll parameters */
> -	idf = 0;
> -	ndiv = 0;
> -	odf = 0;
> -	ret = dsi_pll_get_params(dsi, pll_in_khz, pll_out_khz,
> -				 &idf, &ndiv, &odf);
> +	ret = clk_set_rate((dsi->txbyte_clk.clk), pll_out_khz * 1000);
>   	if (ret)
> -		DRM_WARN("Warning dsi_pll_get_params(): bad params\n");
> -
> -	/* Get the adjusted pll out value */
> -	pll_out_khz = dsi_pll_get_clkout_khz(pll_in_khz, idf, ndiv, odf);
> -
> -	/* Set the PLL division factors */
> -	dsi_update_bits(dsi, DSI_WRPCR,	WRPCR_NDIV | WRPCR_IDF | WRPCR_ODF,
> -			(ndiv << 2) | (idf << 11) | ((ffs(odf) - 1) << 16));
> -
> -	/* Compute uix4 & set the bit period in high-speed mode */
> -	val = 4000000 / pll_out_khz;
> -	dsi_update_bits(dsi, DSI_WPCR0, WPCR0_UIX4, val);
> +		DRM_DEBUG_DRIVER("ERROR Could not set rate of %d to %s clk->name",
> +				 pll_out_khz, clk_hw_get_name(&dsi->txbyte_clk));
>   
>   	/* Select video mode by resetting DSIM bit */
>   	dsi_clear(dsi, DSI_WCFGR, WCFGR_DSIM);
> @@ -445,6 +605,7 @@ static int dw_mipi_dsi_stm_probe(struct platform_device *pdev)
>   {
>   	struct device *dev = &pdev->dev;
>   	struct dw_mipi_dsi_stm *dsi;
> +	const struct dw_mipi_dsi_plat_data *pdata = of_device_get_match_data(dev);
>   	int ret;
>   
>   	dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
> @@ -514,18 +675,41 @@ static int dw_mipi_dsi_stm_probe(struct platform_device *pdev)
>   		dsi->lane_max_kbps *= 2;
>   	}
>   
> -	dw_mipi_dsi_stm_plat_data.base = dsi->base;
> -	dw_mipi_dsi_stm_plat_data.priv_data = dsi;
> +	dsi->pdata = *pdata;
> +	dsi->pdata.base = dsi->base;
> +	dsi->pdata.priv_data = dsi;
> +
> +	dsi->pdata.max_data_lanes = 2;
> +	dsi->pdata.phy_ops = &dw_mipi_dsi_stm_phy_ops;
>   
>   	platform_set_drvdata(pdev, dsi);
>   
> -	dsi->dsi = dw_mipi_dsi_probe(pdev, &dw_mipi_dsi_stm_plat_data);
> +	dsi->dsi = dw_mipi_dsi_probe(pdev, &dsi->pdata);
>   	if (IS_ERR(dsi->dsi)) {
>   		ret = PTR_ERR(dsi->dsi);
>   		dev_err_probe(dev, ret, "Failed to initialize mipi dsi host\n");
>   		goto err_dsi_probe;
>   	}
>   
> +	/*
> +	 * We need to wait for the generic bridge to probe before enabling and
> +	 * register the internal pixel clock.
> +	 */
> +	ret = clk_prepare_enable(dsi->pclk);
> +	if (ret) {
> +		DRM_ERROR("%s: Failed to enable peripheral clk\n", __func__);
> +		goto err_dsi_probe;
> +	}
> +
> +	ret = dw_mipi_dsi_clk_register(dsi, dev);
> +	if (ret) {
> +		DRM_ERROR("Failed to register DSI pixel clock: %d\n", ret);
> +		clk_disable_unprepare(dsi->pclk);
> +		goto err_dsi_probe;
> +	}
> +
> +	clk_disable_unprepare(dsi->pclk);
> +
>   	return 0;
>   
>   err_dsi_probe:
> @@ -542,12 +726,13 @@ static void dw_mipi_dsi_stm_remove(struct platform_device *pdev)
>   
>   	dw_mipi_dsi_remove(dsi->dsi);
>   	clk_disable_unprepare(dsi->pllref_clk);
> +	dw_mipi_dsi_clk_unregister(dsi);
>   	regulator_disable(dsi->vdd_supply);
>   }
>   
>   static int dw_mipi_dsi_stm_suspend(struct device *dev)
>   {
> -	struct dw_mipi_dsi_stm *dsi = dw_mipi_dsi_stm_plat_data.priv_data;
> +	struct dw_mipi_dsi_stm *dsi = dev_get_drvdata(dev);
>   
>   	DRM_DEBUG_DRIVER("\n");
>   
> @@ -560,7 +745,7 @@ static int dw_mipi_dsi_stm_suspend(struct device *dev)
>   
>   static int dw_mipi_dsi_stm_resume(struct device *dev)
>   {
> -	struct dw_mipi_dsi_stm *dsi = dw_mipi_dsi_stm_plat_data.priv_data;
> +	struct dw_mipi_dsi_stm *dsi = dev_get_drvdata(dev);
>   	int ret;
>   
>   	DRM_DEBUG_DRIVER("\n");

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