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Commit 35ab6cfb authored by Yannick Fertré's avatar Yannick Fertré Committed by Benjamin Gaignard
Browse files

drm/stm: support runtime power management 



This patch enables runtime power management (runtime PM) support for
the display controller. pm_runtime_enable() and pm_runtime_disable()
are added during ltdc load and unload respectively.
pm_runtime_get_sync() and pm_runtime_put_sync() are added for ltdc
register access.

Signed-off-by: default avatarYannick Fertré <yannick.fertre@st.com>
Acked-by: default avatarPhilippe Cornu <philippe.cornu@st.com>
Signed-off-by: default avatarBenjamin Gaignard <benjamin.gaignard@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1559550722-14091-1-git-send-email-yannick.fertre@st.com
parent 630bec0c

drivers/gpu/drm/stm/drv.c

+35 −8
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <linux/dma-mapping.h>

#include <linux/module.h>

#include <linux/of_platform.h>

#include <linux/pm_runtime.h>



#include <drm/drm_atomic.h>

#include <drm/drm_atomic_helper.h>
@@ -135,14 +136,15 @@ static __maybe_unused int drv_suspend(struct device *dev) 
	struct ltdc_device *ldev = ddev->dev_private;

	struct drm_atomic_state *state;



	drm_kms_helper_poll_disable(ddev);

	if (WARN_ON(!ldev->suspend_state))

		return -ENOENT;



	state = drm_atomic_helper_suspend(ddev);

	if (IS_ERR(state)) {

		drm_kms_helper_poll_enable(ddev);

	if (IS_ERR(state))

		return PTR_ERR(state);

	}



	ldev->suspend_state = state;

	ltdc_suspend(ddev);

	pm_runtime_force_suspend(dev);



	return 0;

}
@@ -151,16 +153,41 @@ static __maybe_unused int drv_resume(struct device *dev) 
{

	struct drm_device *ddev = dev_get_drvdata(dev);

	struct ltdc_device *ldev = ddev->dev_private;

	int ret;



	pm_runtime_force_resume(dev);

	ret = drm_atomic_helper_resume(ddev, ldev->suspend_state);

	if (ret) {

		pm_runtime_force_suspend(dev);

		ldev->suspend_state = NULL;

		return ret;

	}



	return 0;

}



	ltdc_resume(ddev);

	drm_atomic_helper_resume(ddev, ldev->suspend_state);

	drm_kms_helper_poll_enable(ddev);

static __maybe_unused int drv_runtime_suspend(struct device *dev)

{

	struct drm_device *ddev = dev_get_drvdata(dev);



	DRM_DEBUG_DRIVER("\n");

	ltdc_suspend(ddev);



	return 0;

}



static __maybe_unused int drv_runtime_resume(struct device *dev)

{

	struct drm_device *ddev = dev_get_drvdata(dev);



	DRM_DEBUG_DRIVER("\n");

	return ltdc_resume(ddev);

}



static const struct dev_pm_ops drv_pm_ops = {

	SET_SYSTEM_SLEEP_PM_OPS(drv_suspend, drv_resume)

	SET_RUNTIME_PM_OPS(drv_runtime_suspend,

			   drv_runtime_resume, NULL)

};



static int stm_drm_platform_probe(struct platform_device *pdev)

drivers/gpu/drm/stm/ltdc.c

+51 −16
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <linux/of_address.h>

#include <linux/of_graph.h>

#include <linux/platform_device.h>

#include <linux/pm_runtime.h>

#include <linux/reset.h>



#include <drm/drm_atomic.h>
@@ -444,6 +445,7 @@ static void ltdc_crtc_atomic_disable(struct drm_crtc *crtc, 
				     struct drm_crtc_state *old_state)

{

	struct ltdc_device *ldev = crtc_to_ltdc(crtc);

	struct drm_device *ddev = crtc->dev;



	DRM_DEBUG_DRIVER("\n");
@@ -457,6 +459,8 @@ static void ltdc_crtc_atomic_disable(struct drm_crtc *crtc, 


	/* immediately commit disable of layers before switching off LTDC */

	reg_set(ldev->regs, LTDC_SRCR, SRCR_IMR);



	pm_runtime_put_sync(ddev->dev);

}



#define CLK_TOLERANCE_HZ 50
@@ -505,17 +509,31 @@ static bool ltdc_crtc_mode_fixup(struct drm_crtc *crtc, 
				 struct drm_display_mode *adjusted_mode)

{

	struct ltdc_device *ldev = crtc_to_ltdc(crtc);

	struct drm_device *ddev = crtc->dev;

	int rate = mode->clock * 1000;

	bool runtime_active;

	int ret;



	runtime_active = pm_runtime_active(ddev->dev);



	if (runtime_active)

		pm_runtime_put_sync(ddev->dev);



	clk_disable(ldev->pixel_clk);

	if (clk_set_rate(ldev->pixel_clk, rate) < 0) {

		DRM_ERROR("Cannot set rate (%dHz) for pixel clk\n", rate);

		return false;

	}

	clk_enable(ldev->pixel_clk);



	adjusted_mode->clock = clk_get_rate(ldev->pixel_clk) / 1000;



	if (runtime_active) {

		ret = pm_runtime_get_sync(ddev->dev);

		if (ret) {

			DRM_ERROR("Failed to fixup mode, cannot get sync\n");

			return false;

		}

	}



	DRM_DEBUG_DRIVER("requested clock %dkHz, adjusted clock %dkHz\n",

			 mode->clock, adjusted_mode->clock);
@@ -525,11 +543,21 @@ static bool ltdc_crtc_mode_fixup(struct drm_crtc *crtc, 
static void ltdc_crtc_mode_set_nofb(struct drm_crtc *crtc)

{

	struct ltdc_device *ldev = crtc_to_ltdc(crtc);

	struct drm_device *ddev = crtc->dev;

	struct drm_display_mode *mode = &crtc->state->adjusted_mode;

	struct videomode vm;

	u32 hsync, vsync, accum_hbp, accum_vbp, accum_act_w, accum_act_h;

	u32 total_width, total_height;

	u32 val;

	int ret;



	if (!pm_runtime_active(ddev->dev)) {

		ret = pm_runtime_get_sync(ddev->dev);

		if (ret) {

			DRM_ERROR("Failed to set mode, cannot get sync\n");

			return;

		}

	}



	drm_display_mode_to_videomode(mode, &vm);
@@ -590,6 +618,7 @@ static void ltdc_crtc_atomic_flush(struct drm_crtc *crtc, 
				   struct drm_crtc_state *old_crtc_state)

{

	struct ltdc_device *ldev = crtc_to_ltdc(crtc);

	struct drm_device *ddev = crtc->dev;

	struct drm_pending_vblank_event *event = crtc->state->event;



	DRM_DEBUG_ATOMIC("\n");
@@ -602,12 +631,12 @@ static void ltdc_crtc_atomic_flush(struct drm_crtc *crtc, 
	if (event) {

		crtc->state->event = NULL;



		spin_lock_irq(&crtc->dev->event_lock);

		spin_lock_irq(&ddev->event_lock);

		if (drm_crtc_vblank_get(crtc) == 0)

			drm_crtc_arm_vblank_event(crtc, event);

		else

			drm_crtc_send_vblank_event(crtc, event);

		spin_unlock_irq(&crtc->dev->event_lock);

		spin_unlock_irq(&ddev->event_lock);

	}

}
@@ -663,6 +692,7 @@ bool ltdc_crtc_scanoutpos(struct drm_device *ddev, unsigned int pipe, 
	 * Computation for the two first cases are identical so we can

	 * simplify the code and only test if line > vactive_end

	 */

	if (pm_runtime_active(ddev->dev)) {

		line = reg_read(ldev->regs, LTDC_CPSR) & CPSR_CYPOS;

		vactive_start = reg_read(ldev->regs, LTDC_BPCR) & BPCR_AVBP;

		vactive_end = reg_read(ldev->regs, LTDC_AWCR) & AWCR_AAH;
@@ -672,6 +702,9 @@ bool ltdc_crtc_scanoutpos(struct drm_device *ddev, unsigned int pipe, 
			*vpos = line - vtotal - vactive_start;

		else

			*vpos = line - vactive_start;

	} else {

		*vpos = 0;

	}



	*hpos = 0;
@@ -1243,8 +1276,11 @@ int ltdc_load(struct drm_device *ddev) 
	/* Allow usage of vblank without having to call drm_irq_install */

	ddev->irq_enabled = 1;



	return 0;

	clk_disable_unprepare(ldev->pixel_clk);



	pm_runtime_enable(ddev->dev);



	return 0;

err:

	for (i = 0; i < MAX_ENDPOINTS; i++)

		drm_panel_bridge_remove(bridge[i]);
@@ -1256,7 +1292,6 @@ int ltdc_load(struct drm_device *ddev) 


void ltdc_unload(struct drm_device *ddev)

{

	struct ltdc_device *ldev = ddev->dev_private;

	int i;



	DRM_DEBUG_DRIVER("\n");
@@ -1264,7 +1299,7 @@ void ltdc_unload(struct drm_device *ddev) 
	for (i = 0; i < MAX_ENDPOINTS; i++)

		drm_of_panel_bridge_remove(ddev->dev->of_node, 0, i);



	clk_disable_unprepare(ldev->pixel_clk);

	pm_runtime_disable(ddev->dev);

}



MODULE_AUTHOR("Philippe Cornu <philippe.cornu@st.com>");