drm/tilcdc: Clean up LCDC functional clock rate setting code

Clean up LCDC functional clock rate setting code.

The LCDC functional clock is set by two functions: mode_set_nofb() and
cpufreq_transition().

When tilcdc_crtc_mode_set_nofb() is called in atomic commit phase the
drm atomic helpers have taken all the necessary drm locks and turned
off the crtc, while tilcdc_commit() is keeping LCDC powered on. For
mode_set_nofb() just a simple clock setting function without any
locking or power management code is enough. The new tilcdc_crtc_set_clk()
is implemented for that purpose.

cpufreq_transition() on the other hand is called from outside DRM and
it needs to take the necessary locks and turn off the CRTC while
keeping the LCDC powered. The reimplemented tilcdc_crtc_update_clk()
is for that purpose and it uses the new tilcdc_crtc_set_clk() to
actually set the clock.

Signed-off-by: Jyri Sarha <jsarha@ti.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

3 files changed, 47 insertions, 42 deletions

diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
index 208768922030..5579d97b08e6 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
@@ -35,6 +35,8 @@ struct tilcdc_crtc {
         bool frame_done;
         spinlock_t irq_lock;
 
+        unsigned int lcd_fck_rate;
+
         ktime_t last_vblank;
 
         struct drm_framebuffer *curr_fb;
@@ -304,6 +306,37 @@ static bool tilcdc_crtc_mode_fixup(struct drm_crtc *crtc,
         return true;
 }
 
+static void tilcdc_crtc_set_clk(struct drm_crtc *crtc)
+{
+        struct drm_device *dev = crtc->dev;
+        struct tilcdc_drm_private *priv = dev->dev_private;
+        struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc);
+        const unsigned clkdiv = 2; /* using a fixed divider of 2 */
+        int ret;
+
+        /* mode.clock is in KHz, set_rate wants parameter in Hz */
+        ret = clk_set_rate(priv->clk, crtc->mode.clock * 1000 * clkdiv);
+        if (ret < 0) {
+                dev_err(dev->dev, "failed to set display clock rate to: %d\n",
+                        crtc->mode.clock);
+                return;
+        }
+
+        tilcdc_crtc->lcd_fck_rate = clk_get_rate(priv->clk);
+
+        DBG("lcd_clk=%u, mode clock=%d, div=%u",
+            tilcdc_crtc->lcd_fck_rate, crtc->mode.clock, clkdiv);
+
+        /* Configure the LCD clock divisor. */
+        tilcdc_write(dev, LCDC_CTRL_REG, LCDC_CLK_DIVISOR(clkdiv) |
+                     LCDC_RASTER_MODE);
+
+        if (priv->rev == 2)
+                tilcdc_set(dev, LCDC_CLK_ENABLE_REG,
+                                LCDC_V2_DMA_CLK_EN | LCDC_V2_LIDD_CLK_EN |
+                                LCDC_V2_CORE_CLK_EN);
+}
+
 static void tilcdc_crtc_mode_set_nofb(struct drm_crtc *crtc)
 {
         struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc);
@@ -466,7 +499,7 @@ static void tilcdc_crtc_mode_set_nofb(struct drm_crtc *crtc)
 
         set_scanout(crtc, fb);
 
-        tilcdc_crtc_update_clk(crtc);
+        tilcdc_crtc_set_clk(crtc);
 
         crtc->hwmode = crtc->state->adjusted_mode;
 }
@@ -635,41 +668,21 @@ void tilcdc_crtc_update_clk(struct drm_crtc *crtc)
 {
         struct drm_device *dev = crtc->dev;
         struct tilcdc_drm_private *priv = dev->dev_private;
-        unsigned long lcd_clk;
-        const unsigned clkdiv = 2; /* using a fixed divider of 2 */
-        int ret;
+        struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc);
 
-        pm_runtime_get_sync(dev->dev);
+        drm_modeset_lock_crtc(crtc, NULL);
+        if (tilcdc_crtc->lcd_fck_rate != clk_get_rate(priv->clk)) {
+                if (tilcdc_crtc_is_on(crtc)) {
+                        pm_runtime_get_sync(dev->dev);
+                        tilcdc_crtc_disable(crtc);
 
-        tilcdc_crtc_disable(crtc);
+                        tilcdc_crtc_set_clk(crtc);
 
-        /* mode.clock is in KHz, set_rate wants parameter in Hz */
-        ret = clk_set_rate(priv->clk, crtc->mode.clock * 1000 * clkdiv);
-        if (ret < 0) {
-                dev_err(dev->dev, "failed to set display clock rate to: %d\n",
-                                crtc->mode.clock);
-                goto out;
+                        tilcdc_crtc_enable(crtc);
+                        pm_runtime_put_sync(dev->dev);
+                }
         }
-
-        lcd_clk = clk_get_rate(priv->clk);
-
-        DBG("lcd_clk=%lu, mode clock=%d, div=%u",
-                lcd_clk, crtc->mode.clock, clkdiv);
-
-        /* Configure the LCD clock divisor. */
-        tilcdc_write(dev, LCDC_CTRL_REG, LCDC_CLK_DIVISOR(clkdiv) |
-                        LCDC_RASTER_MODE);
-
-        if (priv->rev == 2)
-                tilcdc_set(dev, LCDC_CLK_ENABLE_REG,
-                                LCDC_V2_DMA_CLK_EN | LCDC_V2_LIDD_CLK_EN |
-                                LCDC_V2_CORE_CLK_EN);
-
-        if (tilcdc_crtc_is_on(crtc))
-                tilcdc_crtc_enable(crtc);
-
-out:
-        pm_runtime_put_sync(dev->dev);
+        drm_modeset_unlock_crtc(crtc);
 }
 
 #define SYNC_LOST_COUNT_LIMIT 50
diff --git a/drivers/gpu/drm/tilcdc/tilcdc_drv.c b/drivers/gpu/drm/tilcdc/tilcdc_drv.c
index b1ac61eac056..52ff3e120bb9 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_drv.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_drv.c
@@ -185,14 +185,8 @@ static int cpufreq_transition(struct notifier_block *nb,
         struct tilcdc_drm_private *priv = container_of(nb,
                         struct tilcdc_drm_private, freq_transition);
 
-        if (val == CPUFREQ_POSTCHANGE) {
-                if (priv->lcd_fck_rate != clk_get_rate(priv->clk)) {
-                        drm_modeset_lock_crtc(priv->crtc, NULL);
-                        priv->lcd_fck_rate = clk_get_rate(priv->clk);
-                        tilcdc_crtc_update_clk(priv->crtc);
-                        drm_modeset_unlock_crtc(priv->crtc);
-                }
-        }
+        if (val == CPUFREQ_POSTCHANGE)
+                tilcdc_crtc_update_clk(priv->crtc);
 
         return 0;
 }
@@ -286,7 +280,6 @@ static int tilcdc_load(struct drm_device *dev, unsigned long flags)
         }
 
 #ifdef CONFIG_CPU_FREQ
-        priv->lcd_fck_rate = clk_get_rate(priv->clk);
         priv->freq_transition.notifier_call = cpufreq_transition;
         ret = cpufreq_register_notifier(&priv->freq_transition,
                         CPUFREQ_TRANSITION_NOTIFIER);
diff --git a/drivers/gpu/drm/tilcdc/tilcdc_drv.h b/drivers/gpu/drm/tilcdc/tilcdc_drv.h
index a6e5e6d4970c..9780c37ec4cd 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_drv.h
+++ b/drivers/gpu/drm/tilcdc/tilcdc_drv.h
@@ -74,7 +74,6 @@ struct tilcdc_drm_private {
 
 #ifdef CONFIG_CPU_FREQ
         struct notifier_block freq_transition;
-        unsigned int lcd_fck_rate;
 #endif
 
         struct workqueue_struct *wq;