Commit c36940e6 authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Paul Mundt
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fbdev: sh_mobile_hdmi: add support for more precise HDMI clock configuration 



The HDMI clock has to be reconfigured for different video modes. However, the
precision of the supplying SoC clock on SH-Mobile systems is often
insufficient. This patch allows to additionally reconfigure the parent clock
to achieve the optimal HDMI clock frequency, in case this is supported by the
platform.

Signed-off-by: default avatarGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent 5fd284e6

drivers/video/sh_mobile_hdmi.c

+68 −44
Original line number Diff line number Diff line
@@ -685,11 +685,21 @@ static void sh_hdmi_configure(struct sh_hdmi *hdmi) 
}



static unsigned long sh_hdmi_rate_error(struct sh_hdmi *hdmi,

					const struct fb_videomode *mode)

		const struct fb_videomode *mode,

		unsigned long *hdmi_rate, unsigned long *parent_rate)

{

	long target = PICOS2KHZ(mode->pixclock) * 1000,

		rate = clk_round_rate(hdmi->hdmi_clk, target);

	unsigned long rate_error = rate > 0 ? abs(rate - target) : ULONG_MAX;

	unsigned long target = PICOS2KHZ(mode->pixclock) * 1000, rate_error;

	struct sh_mobile_hdmi_info *pdata = hdmi->dev->platform_data;



	*hdmi_rate = clk_round_rate(hdmi->hdmi_clk, target);

	if ((long)*hdmi_rate < 0)

		*hdmi_rate = clk_get_rate(hdmi->hdmi_clk);



	rate_error = (long)*hdmi_rate > 0 ? abs(*hdmi_rate - target) : ULONG_MAX;

	if (rate_error && pdata->clk_optimize_parent)

		rate_error = pdata->clk_optimize_parent(target, hdmi_rate, parent_rate);

	else if (clk_get_parent(hdmi->hdmi_clk))

		*parent_rate = clk_get_rate(clk_get_parent(hdmi->hdmi_clk));



	dev_dbg(hdmi->dev, "%u-%u-%u-%u x %u-%u-%u-%u\n",

		mode->left_margin, mode->xres,
@@ -697,14 +707,15 @@ static unsigned long sh_hdmi_rate_error(struct sh_hdmi *hdmi, 
		mode->upper_margin, mode->yres,

		mode->lower_margin, mode->vsync_len);



	dev_dbg(hdmi->dev, "\t@%lu(+/-%lu)Hz, e=%lu / 1000, r=%uHz\n", target,

	dev_dbg(hdmi->dev, "\t@%lu(+/-%lu)Hz, e=%lu / 1000, r=%uHz, p=%luHz\n", target,

		rate_error, rate_error ? 10000 / (10 * target / rate_error) : 0,

		 mode->refresh);

		mode->refresh, *parent_rate);



	return rate_error;

}



static int sh_hdmi_read_edid(struct sh_hdmi *hdmi)

static int sh_hdmi_read_edid(struct sh_hdmi *hdmi, unsigned long *hdmi_rate,

			     unsigned long *parent_rate)

{

	struct fb_var_screeninfo tmpvar;

	struct fb_var_screeninfo *var = &tmpvar;
@@ -754,11 +765,14 @@ static int sh_hdmi_read_edid(struct sh_hdmi *hdmi) 
	for (i = 0, mode = hdmi->monspec.modedb;

	     f_width && f_height && i < hdmi->monspec.modedb_len && !exact_match;

	     i++, mode++) {

		unsigned long rate_error = sh_hdmi_rate_error(hdmi, mode);

		unsigned long rate_error;



		/* No interest in unmatching modes */

		if (f_width != mode->xres || f_height != mode->yres)

			continue;



		rate_error = sh_hdmi_rate_error(hdmi, mode, hdmi_rate, parent_rate);



		if (f_refresh == mode->refresh || (!f_refresh && !rate_error))

			/*

			 * Exact match if either the refresh rate matches or it
@@ -802,7 +816,7 @@ static int sh_hdmi_read_edid(struct sh_hdmi *hdmi) 


		if (modelist) {

			found = &modelist->mode;

			found_rate_error = sh_hdmi_rate_error(hdmi, found);

			found_rate_error = sh_hdmi_rate_error(hdmi, found, hdmi_rate, parent_rate);

		}

	}
@@ -810,10 +824,6 @@ static int sh_hdmi_read_edid(struct sh_hdmi *hdmi) 
	if (!found)

		return -ENXIO;



	dev_info(hdmi->dev, "Using %s mode %ux%u@%uHz (%luHz), clock error %luHz\n",

		 modelist ? "default" : "EDID", found->xres, found->yres,

		 found->refresh, PICOS2KHZ(found->pixclock) * 1000, found_rate_error);



	if ((found->xres == 720 && found->yres == 480) ||

	    (found->xres == 1280 && found->yres == 720) ||

	    (found->xres == 1920 && found->yres == 1080))
@@ -821,6 +831,11 @@ static int sh_hdmi_read_edid(struct sh_hdmi *hdmi) 
	else

		hdmi->preprogrammed_mode = false;



	dev_dbg(hdmi->dev, "Using %s %s mode %ux%u@%uHz (%luHz), clock error %luHz\n",

		modelist ? "default" : "EDID", hdmi->preprogrammed_mode ? "VIC" : "external",

		found->xres, found->yres, found->refresh,

		PICOS2KHZ(found->pixclock) * 1000, found_rate_error);



	fb_videomode_to_var(&hdmi->var, found);

	sh_hdmi_external_video_param(hdmi);
@@ -973,38 +988,37 @@ static bool sh_hdmi_must_reconfigure(struct sh_hdmi *hdmi) 
/**

 * sh_hdmi_clk_configure() - set HDMI clock frequency and enable the clock

 * @hdmi:		driver context

 * @pixclock:	pixel clock period in picoseconds

 * @hdmi_rate:		HDMI clock frequency in Hz

 * @parent_rate:	if != 0 - set parent clock rate for optimal precision

 * return:		configured positive rate if successful

 *		0 if couldn't set the rate, but managed to enable the clock

 *		negative error, if couldn't enable the clock

 *			0 if couldn't set the rate, but managed to enable the

 *			clock, negative error, if couldn't enable the clock

 */

static long sh_hdmi_clk_configure(struct sh_hdmi *hdmi, unsigned long pixclock)

static long sh_hdmi_clk_configure(struct sh_hdmi *hdmi, unsigned long hdmi_rate,

				  unsigned long parent_rate)

{

	long rate;

	struct sh_mobile_hdmi_info *pdata = hdmi->dev->platform_data;

	int ret;



	rate = PICOS2KHZ(pixclock) * 1000;

	rate = clk_round_rate(hdmi->hdmi_clk, rate);

	if (rate > 0) {

		ret = clk_set_rate(hdmi->hdmi_clk, rate);

	if (parent_rate && clk_get_parent(hdmi->hdmi_clk)) {

		ret = clk_set_rate(clk_get_parent(hdmi->hdmi_clk), parent_rate);

		if (ret < 0) {

			dev_warn(hdmi->dev, "Cannot set rate %ld: %d\n", rate, ret);

			rate = 0;

			dev_warn(hdmi->dev, "Cannot set parent rate %ld: %d\n", parent_rate, ret);

			hdmi_rate = clk_round_rate(hdmi->hdmi_clk, hdmi_rate);

		} else {

			dev_dbg(hdmi->dev, "HDMI set frequency %lu\n", rate);

			dev_dbg(hdmi->dev, "HDMI set parent frequency %lu\n", parent_rate);

		}

	} else {

		rate = 0;

		dev_warn(hdmi->dev, "Cannot get suitable rate: %ld\n", rate);

	}



	ret = clk_enable(hdmi->hdmi_clk);

	ret = clk_set_rate(hdmi->hdmi_clk, hdmi_rate);

	if (ret < 0) {

		dev_err(hdmi->dev, "Cannot enable clock: %d\n", ret);

		return ret;

		dev_warn(hdmi->dev, "Cannot set rate %ld: %d\n", hdmi_rate, ret);

		hdmi_rate = 0;

	} else {

		dev_dbg(hdmi->dev, "HDMI set frequency %lu\n", hdmi_rate);

	}



	return rate;

	return hdmi_rate;

}



/* Hotplug interrupt occurred, read EDID */
@@ -1024,16 +1038,17 @@ static void sh_hdmi_edid_work_fn(struct work_struct *work) 
	mutex_lock(&hdmi->mutex);



	if (hdmi->hp_state == HDMI_HOTPLUG_EDID_DONE) {

		unsigned long parent_rate = 0, hdmi_rate;



		/* A device has been plugged in */

		pm_runtime_get_sync(hdmi->dev);



		ret = sh_hdmi_read_edid(hdmi);

		ret = sh_hdmi_read_edid(hdmi, &hdmi_rate, &parent_rate);

		if (ret < 0)

			goto out;



		/* Reconfigure the clock */

		clk_disable(hdmi->hdmi_clk);

		ret = sh_hdmi_clk_configure(hdmi, hdmi->var.pixclock);

		ret = sh_hdmi_clk_configure(hdmi, hdmi_rate, parent_rate);

		if (ret < 0)

			goto out;
@@ -1166,13 +1181,22 @@ static int __init sh_hdmi_probe(struct platform_device *pdev) 
		goto egetclk;

	}



	/* Some arbitrary relaxed pixclock just to get things started */

	rate = sh_hdmi_clk_configure(hdmi, 37037);

	/* An arbitrary relaxed pixclock just to get things started: from standard 480p */

	rate = clk_round_rate(hdmi->hdmi_clk, PICOS2KHZ(37037));

	if (rate > 0)

		rate = sh_hdmi_clk_configure(hdmi, rate, 0);



	if (rate < 0) {

		ret = rate;

		goto erate;

	}



	ret = clk_enable(hdmi->hdmi_clk);

	if (ret < 0) {

		dev_err(hdmi->dev, "Cannot enable clock: %d\n", ret);

		goto erate;

	}



	dev_dbg(&pdev->dev, "Enabled HDMI clock at %luHz\n", rate);



	if (!request_mem_region(res->start, resource_size(res), dev_name(&pdev->dev))) {
@@ -1190,10 +1214,6 @@ static int __init sh_hdmi_probe(struct platform_device *pdev) 


	platform_set_drvdata(pdev, hdmi);



	/* Product and revision IDs are 0 in sh-mobile version */

	dev_info(&pdev->dev, "Detected HDMI controller 0x%x:0x%x\n",

		 hdmi_read(hdmi, HDMI_PRODUCT_ID), hdmi_read(hdmi, HDMI_REVISION_ID));



	/* Set up LCDC callbacks */

	board_cfg = &pdata->lcd_chan->board_cfg;

	board_cfg->owner = THIS_MODULE;
@@ -1206,6 +1226,10 @@ static int __init sh_hdmi_probe(struct platform_device *pdev) 
	pm_runtime_enable(&pdev->dev);

	pm_runtime_resume(&pdev->dev);



	/* Product and revision IDs are 0 in sh-mobile version */

	dev_info(&pdev->dev, "Detected HDMI controller 0x%x:0x%x\n",

		 hdmi_read(hdmi, HDMI_PRODUCT_ID), hdmi_read(hdmi, HDMI_REVISION_ID));



	ret = request_irq(irq, sh_hdmi_hotplug, 0,

			  dev_name(&pdev->dev), hdmi);

	if (ret < 0) {

include/video/sh_mobile_hdmi.h

+3 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 


struct sh_mobile_lcdc_chan_cfg;

struct device;

struct clk;



/*

 * flags format
@@ -33,6 +34,8 @@ struct sh_mobile_hdmi_info { 
	struct sh_mobile_lcdc_chan_cfg	*lcd_chan;

	struct device			*lcd_dev;

	unsigned int			 flags;

	long (*clk_optimize_parent)(unsigned long target, unsigned long *best_freq,

				    unsigned long *parent_freq);

};



#endif

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