From: Darren Etheridge detheridge@ti.com
Updating the tilcdc DRM driver code to calculate the LCD controller pixel clock more accurately. Based on a suggested implementation by Tomi Valkeinen.
The current code does not work correctly and produces wrong results with many requested clock rates. It also oddly uses two different clocks, a display pll clock and a divider clock (child of display pll), instead of just using the clock coming to the lcdc.
This patch removes the use of the display pll clock, and rewrites the code to calculate the clock rates. The idea is simply to request a clock rate of pixelclock*2, as the LCD controller has an internal divider which we set to 2.
Signed-off-by: Darren Etheridge detheridge@ti.com [Rewrapped description] Signed-off-by: Jyri Sarha jsarha@ti.com --- drivers/gpu/drm/tilcdc/tilcdc_crtc.c | 16 ++++++++-------- drivers/gpu/drm/tilcdc/tilcdc_drv.c | 11 +---------- drivers/gpu/drm/tilcdc/tilcdc_drv.h | 1 - 3 files changed, 9 insertions(+), 19 deletions(-)
diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c index 7d07733..7b687ae 100644 --- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c +++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c @@ -573,7 +573,8 @@ void tilcdc_crtc_update_clk(struct drm_crtc *crtc) struct drm_device *dev = crtc->dev; struct tilcdc_drm_private *priv = dev->dev_private; int dpms = tilcdc_crtc->dpms; - unsigned int lcd_clk, div; + unsigned long lcd_clk; + const unsigned clkdiv = 2; /* using a fixed divider of 2 */ int ret;
pm_runtime_get_sync(dev->dev); @@ -581,22 +582,21 @@ void tilcdc_crtc_update_clk(struct drm_crtc *crtc) if (dpms == DRM_MODE_DPMS_ON) tilcdc_crtc_dpms(crtc, DRM_MODE_DPMS_OFF);
- /* in raster mode, minimum divisor is 2: */ - ret = clk_set_rate(priv->disp_clk, crtc->mode.clock * 1000 * 2); - if (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); goto out; }
lcd_clk = clk_get_rate(priv->clk); - div = lcd_clk / (crtc->mode.clock * 1000);
- DBG("lcd_clk=%u, mode clock=%d, div=%u", lcd_clk, crtc->mode.clock, div); - DBG("fck=%lu, dpll_disp_ck=%lu", clk_get_rate(priv->clk), clk_get_rate(priv->disp_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(div) | + tilcdc_write(dev, LCDC_CTRL_REG, LCDC_CLK_DIVISOR(clkdiv) | LCDC_RASTER_MODE);
if (priv->rev == 2) diff --git a/drivers/gpu/drm/tilcdc/tilcdc_drv.c b/drivers/gpu/drm/tilcdc/tilcdc_drv.c index d7f5b89..4d75ee3 100644 --- a/drivers/gpu/drm/tilcdc/tilcdc_drv.c +++ b/drivers/gpu/drm/tilcdc/tilcdc_drv.c @@ -192,13 +192,6 @@ static int tilcdc_load(struct drm_device *dev, unsigned long flags) goto fail_iounmap; }
- priv->disp_clk = clk_get(dev->dev, "dpll_disp_ck"); - if (IS_ERR(priv->clk)) { - dev_err(dev->dev, "failed to get display clock\n"); - ret = -ENODEV; - goto fail_put_clk; - } - #ifdef CONFIG_CPU_FREQ priv->lcd_fck_rate = clk_get_rate(priv->clk); priv->freq_transition.notifier_call = cpufreq_transition; @@ -206,7 +199,7 @@ static int tilcdc_load(struct drm_device *dev, unsigned long flags) CPUFREQ_TRANSITION_NOTIFIER); if (ret) { dev_err(dev->dev, "failed to register cpufreq notifier\n"); - goto fail_put_disp_clk; + goto fail_put_clk; } #endif
@@ -330,8 +323,6 @@ fail_cpufreq_unregister: #ifdef CONFIG_CPU_FREQ cpufreq_unregister_notifier(&priv->freq_transition, CPUFREQ_TRANSITION_NOTIFIER); -fail_put_disp_clk: - clk_put(priv->disp_clk); #endif
fail_put_clk: diff --git a/drivers/gpu/drm/tilcdc/tilcdc_drv.h b/drivers/gpu/drm/tilcdc/tilcdc_drv.h index e863ad0..c00f518 100644 --- a/drivers/gpu/drm/tilcdc/tilcdc_drv.h +++ b/drivers/gpu/drm/tilcdc/tilcdc_drv.h @@ -49,7 +49,6 @@ struct tilcdc_drm_private { void __iomem *mmio;
- struct clk *disp_clk; /* display dpll */ struct clk *clk; /* functional clock */ int rev; /* IP revision */