[PATCH] ARM: mx28: Clear CLKGATE bit prior to changing DIV field

[Fabio Estevam]

2012/1/19 Shawn Guo <shawn.guo at linaro.org>:

> My proposal is we need to clk_prepare_enable before clk_set_rate a clock
> if the clock is gated, and then clk_disable_unprepare the clock after
> clk_set_rate is done.  This applies whatever codes that want to
> clk_set_rate a mxs clock.

So something like:

--- a/arch/arm/mach-mxs/clock-mx28.c
+++ b/arch/arm/mach-mxs/clock-mx28.c
@@ -809,6 +809,8 @@ int __init mx28_clocks_init(void)
        clk_prepare_enable(&xbus_clk);
        clk_prepare_enable(&emi_clk);
        clk_prepare_enable(&uart_clk);
+       clk_prepare_enable(&saif0_clk);
+       clk_prepare_enable(&saif1_clk);

        clk_set_parent(&lcdif_clk, &ref_pix_clk);
        clk_set_parent(&saif0_clk, &pll0_clk);
@@ -822,6 +824,8 @@ int __init mx28_clocks_init(void)
         */
        clk_set_rate(&saif0_clk, 24000000);
        clk_set_rate(&saif1_clk, 24000000);
+       clk_disable_unprepare(&saif0_clk);
+       clk_disable_unprepare(&saif1_clk);

        clkdev_add_table(lookups, ARRAY_SIZE(lookups));
---

didn't work on my tests (probe of mxs-saif fails with the same timeout message).

However if I use the clk_disable versions:

+       clk_disable(&saif0_clk);
+       clk_disable(&saif1_clk);

Then it works fine.

Regards,

Fabio Estevam