imx-drm: ipu-v3: don't use clk_round_rate() before clk_set_rate()

This is nonsense; clk_round_rate() is just clk_set_rate() without the
side effect of changing the hardware.

Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/drivers/staging/imx-drm/ipu-v3/ipu-di.c b/drivers/staging/imx-drm/ipu-v3/ipu-di.c
index 8c7241b..d766e18 100644 (file)
--- a/drivers/staging/imx-drm/ipu-v3/ipu-di.c
+++ b/drivers/staging/imx-drm/ipu-v3/ipu-di.c
@@ -560,9 +560,10 @@ int ipu_di_init_sync_panel(struct ipu_di *di, struct ipu_di_signal_cfg *sig)
         * rate within 1% of the requested frequency, otherwise we use
         * the DI clock.
         */
-       if (sig->clkflags & IPU_DI_CLKMODE_EXT)
+       round = sig->pixelclock;
+       if (sig->clkflags & IPU_DI_CLKMODE_EXT) {
                parent = di->clk_di;
-       else {
+       } else {
                unsigned long rate, clkrate;
                unsigned div, error;
 
@@ -584,6 +585,9 @@ int ipu_di_init_sync_panel(struct ipu_di *di, struct ipu_di_signal_cfg *sig)
                        ret = clk_set_rate(parent, sig->pixelclock);
                        if (ret)
                                dev_err(di->ipu->dev, "Setting of DI clock failed: %d\n", ret);
+
+                       /* Use the integer divisor rate - avoid fractional dividers */
+                       round = rate;
                }
        }
 
@@ -599,11 +603,12 @@ int ipu_di_init_sync_panel(struct ipu_di *di, struct ipu_di_signal_cfg *sig)
         * CLKMODE_SYNC means that we want the DI to be clocked at the
         * same rate as the parent clock.  This is needed (eg) for LDB
         * which needs to be fed with the same pixel clock.
+        *
+        * Note: clk_set_rate(clk, clk_round_rate(clk, rate)) is the
+        * same as clk_set_rate(clk, rate);
         */
        if (sig->clkflags & IPU_DI_CLKMODE_SYNC)
                round = clk_get_rate(parent);
-       else
-               round = clk_round_rate(di->clk_di_pixel, sig->pixelclock);
 
        ret = clk_set_rate(di->clk_di_pixel, round);