Set the LVDS PLL rate to 7x the pixel clock.
set ATMEL_XLCDC_CLKBYP for the LVDS path, leaving clock
lifecycle management to the atomic callbacks and fallback to
sys_clk for non-LVDS displays with proper error handling.

Signed-off-by: Manikandan Muralidharan <[email protected]>
---
 .../gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c    | 45 +++++++++++++++++--
 1 file changed, 42 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c 
b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
index f837684654ea..73a8650bc9b7 100644
--- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
+++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
@@ -26,6 +26,8 @@
 
 #include "atmel_hlcdc_dc.h"
 
+#define ATMEL_LVDS_PLL_MULT    7
+
 /**
  * struct atmel_hlcdc_crtc_state - Atmel HLCDC CRTC state structure
  *
@@ -66,6 +68,14 @@ drm_crtc_to_atmel_hlcdc_crtc(struct drm_crtc *crtc)
        return container_of(crtc, struct atmel_hlcdc_crtc, base);
 }
 
+static void atmel_hlcdc_crtc_disable_clock(struct atmel_hlcdc_crtc *crtc)
+{
+       if (crtc->dc->hlcdc->lvds_pll_clk)
+               clk_disable_unprepare(crtc->dc->hlcdc->lvds_pll_clk);
+       else
+               clk_disable_unprepare(crtc->dc->hlcdc->sys_clk);
+}
+
 static int atmel_hlcdc_crtc_setup_clock(struct atmel_hlcdc_crtc *crtc,
                                        unsigned long mode_rate,
                                        unsigned int *cfg,
@@ -74,6 +84,12 @@ static int atmel_hlcdc_crtc_setup_clock(struct 
atmel_hlcdc_crtc *crtc,
        unsigned long prate;
        int div, ret;
 
+       if (crtc->dc->hlcdc->lvds_pll_clk) {
+               *cfg |= ATMEL_XLCDC_CLKBYP;
+               *mask |= ATMEL_XLCDC_CLKBYP;
+               return clk_prepare_enable(crtc->dc->hlcdc->lvds_pll_clk);
+       }
+
        ret = clk_prepare_enable(crtc->dc->hlcdc->sys_clk);
        if (ret)
                return ret;
@@ -198,7 +214,7 @@ static void atmel_hlcdc_crtc_mode_set_nofb(struct drm_crtc 
*c)
                           ATMEL_XLCDC_DPI : ATMEL_HLCDC_MODE_MASK),
                           cfg);
 
-       clk_disable_unprepare(crtc->dc->hlcdc->sys_clk);
+       atmel_hlcdc_crtc_disable_clock(crtc);
 }
 
 static enum drm_mode_status
@@ -254,7 +270,8 @@ static void atmel_hlcdc_crtc_atomic_disable(struct drm_crtc 
*c,
                                    10, 1000))
                drm_warn(dev, "Atmel LCDC status register CLKSTS timeout\n");
 
-       clk_disable_unprepare(crtc->dc->hlcdc->sys_clk);
+       atmel_hlcdc_crtc_disable_clock(crtc);
+
        pinctrl_pm_select_sleep_state(dev->dev);
 
        pm_runtime_allow(dev->dev);
@@ -267,15 +284,33 @@ static void atmel_hlcdc_crtc_atomic_enable(struct 
drm_crtc *c,
 {
        struct drm_device *dev = c->dev;
        struct atmel_hlcdc_crtc *crtc = drm_crtc_to_atmel_hlcdc_crtc(c);
+       struct drm_display_mode *adj = &c->state->adjusted_mode;
        struct regmap *regmap = crtc->dc->hlcdc->regmap;
        unsigned int status;
+       int ret;
 
        pm_runtime_get_sync(dev->dev);
 
        pm_runtime_forbid(dev->dev);
 
        pinctrl_pm_select_default_state(dev->dev);
-       clk_prepare_enable(crtc->dc->hlcdc->sys_clk);
+
+       /*
+        * Set LVDS PLL clock rate (7x pixel clock) if available
+        */
+       if (crtc->dc->hlcdc->lvds_pll_clk) {
+               ret = clk_set_rate(crtc->dc->hlcdc->lvds_pll_clk,
+                                  adj->clock * 1000 * ATMEL_LVDS_PLL_MULT);
+               if (ret) {
+                       drm_err(dev, "Failed to set LVDS PLL clk rate: %d\n", 
ret);
+                       goto err_clk;
+               }
+               ret = clk_prepare_enable(crtc->dc->hlcdc->lvds_pll_clk);
+       } else {
+               ret = clk_prepare_enable(crtc->dc->hlcdc->sys_clk);
+       }
+       if (ret)
+               goto err_clk;
 
        regmap_write(regmap, ATMEL_HLCDC_EN, ATMEL_HLCDC_PIXEL_CLK);
        if (regmap_read_poll_timeout(regmap, ATMEL_HLCDC_SR, status,
@@ -310,7 +345,11 @@ static void atmel_hlcdc_crtc_atomic_enable(struct drm_crtc 
*c,
        }
 
        pm_runtime_put_sync(dev->dev);
+       return;
 
+err_clk:
+       pm_runtime_allow(dev->dev);
+       pm_runtime_put_sync(dev->dev);
 }
 
 #define ATMEL_HLCDC_RGB444_OUTPUT              BIT(0)
-- 
2.25.1

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