| Message ID | 1490355070-21818-1-git-send-email-al.kochet@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/drivers/clk/rockchip/clk-rk3188.c b/drivers/clk/rockchip/clk-rk3188.c index d0e722a..e883f48 100644 --- a/drivers/clk/rockchip/clk-rk3188.c +++ b/drivers/clk/rockchip/clk-rk3188.c @@ -849,6 +849,15 @@ static void __init rk3188a_clk_init(struct device_node *np) __func__); } + /* limit i2s0_pre max rate */ + clk1 = __clk_lookup("aclk_cpu_pre"); + clk2 = __clk_lookup("i2s0_pre"); + if (clk1 && clk2) { + rate = clk_get_rate(clk1); + clk_set_max_rate(clk2, rate); + clk_set_rate(clk2, rate); + } + rockchip_clk_protect_critical(rk3188_critical_clocks, ARRAY_SIZE(rk3188_critical_clocks)); rockchip_clk_of_add_provider(np, ctx);
Change i2s0_pre from 768MHz to 192MHz and limit it's rate to 192MHz in order to fix issues described below. If right after the boot change i2s0_clk to 16.384MHz, real rate on i2s0_clk pin may differ from 16.384MHz. The issue is random. Sometimes rate on i2s0_clk pin equal to 16.384MHz, sometimes not. There is another 100% reproducable issue. First we have to boot and see the correct frequency on i2s0_clk pin (16.384MHz). Then we change its rate to 8.192MHz (and it changes), then we change its rate again to 16.384MHz. Rate leaves unchanged and equal to 8.192MHz. 'clk_summary' shows following clock connection in all the cases, where rate was set to 16.384MHz (even then real rate differs). clock rate ----- ---- xin24m 24000000 pll_gpll 768000000 gpll 768000000 i2s_src 768000000 i2s0_pre 768000000 i2s0_frac 16384000 sclk_i2s0 16384000 Also I found, that if I change i2s0_pre to 192MHz all the issues described above gone. I supposed that the issues is due to high i2s0_pre rate. Probably rk3188 has some sort of frequency restrictions imposed. Haven't found anything in the RK3188 TRM, so this is my assumption. Anyway, with the patch, all the issues gone. Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com> --- drivers/clk/rockchip/clk-rk3188.c | 9 +++++++++ 1 file changed, 9 insertions(+)