Currently we get a nasty error message if the cpu clock can't be
changed:
DDRC is clocked by PLL1, can't switch CPU clockinitcall 
vf610_switch_cpu_clock+0x1/0x198 failed: Invalid argument

So let's do the following:
- factor out the check from vf610_switch_cpu_clock_to_500mhz() and
  vf610_switch_cpu_clock_to_400mhz
- if clock can't be changed, don't treat it as an error
- don't call clock notifier chain if clock can't be changed
- add trailing newline to the warning message

Signed-off-by: Heiner Kallweit <[email protected]>
---
 drivers/clk/imx/clk-vf610.c | 33 ++++++++++++++++++---------------
 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/drivers/clk/imx/clk-vf610.c b/drivers/clk/imx/clk-vf610.c
index 1b1b881..d70f441 100644
--- a/drivers/clk/imx/clk-vf610.c
+++ b/drivers/clk/imx/clk-vf610.c
@@ -459,26 +459,30 @@ enum {
        DDRMC_CR117_AXI0_FITYPEREG_SYNC = 0b01 << 16,
 };
 
-static int vf610_switch_cpu_clock_to_500mhz(void)
+static bool vf610_cpu_clk_changeable(void)
 {
-       int ret;
-
        /*
         * When switching A5 CPU to 500Mhz we expect DDRC to be
         * clocked by PLL2_PFD2 and the system to be configured in
         * asynchronous mode.
-        *
-        * We also can't just use default PFD1 output of PLL1 due to
-        * Errata e6235, so we have to re-clock the PLL itself and use
-        * its output to clock the CPU directly.
         */
-
        if (clk_get_parent(clk[VF610_CLK_DDR_SEL]) != clk[VF610_CLK_PLL2_PFD2]) 
{
-               pr_warn("DDRC is clocked by PLL1, can't switch CPU clock");
-               return -EINVAL;
+               pr_warn("DDRC is clocked by PLL1, can't switch CPU clock\n");
+               return false;
        }
 
+       return true;
+}
+
+static int vf610_switch_cpu_clock_to_500mhz(void)
+{
+       int ret;
+
        /*
+        * We can't just use default PFD1 output of PLL1 due to
+        * Errata e6235, so we have to re-clock the PLL itself and use
+        * its output to clock the CPU directly.
+        *
         * Code below alters the frequency of PLL1, and doing so would
         * require us to wait for PLL1 lock before proceeding to
         * select it as a clock source again.
@@ -533,11 +537,6 @@ static int vf610_switch_cpu_clock_to_400mhz(void)
        uint32_t cr117;
        void * __iomem ddrmc = IOMEM(VF610_DDR_BASE_ADDR);
 
-       if (clk_get_parent(clk[VF610_CLK_DDR_SEL]) != clk[VF610_CLK_PLL2_PFD2]) 
{
-               pr_warn("DDRC is clocked by PLL1, can't switch CPU clock");
-               return -EINVAL;
-       }
-
        ret = clk_set_parent(clk[VF610_CLK_PLL2_PFD_SEL], 
clk[VF610_CLK_PLL2_PFD2]);
        if (ret < 0) {
                pr_crit("Unable to re-parent '%s'\n",
@@ -595,10 +594,14 @@ static int vf610_switch_cpu_clock(void)
                return 0;
 
        case VF610_SPEED_500:
+               if (!vf610_cpu_clk_changeable())
+                       return 0;
                ret = vf610_switch_cpu_clock_to_500mhz();
                break;
 
        case VF610_SPEED_400:
+               if (!vf610_cpu_clk_changeable())
+                       return 0;
                ret = vf610_switch_cpu_clock_to_400mhz();
                break;
        }
-- 
2.21.0


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