[PATCH] ARM: imx: propagate DI clock changes up the clock tree to PLL5

[p.zabel@pengutronix.de (Philipp Zabel)]

Hi Russell,

Am Mittwoch, den 09.04.2014, 16:39 +0100 schrieb Russell King:
> Allows clk_set_rate() on the DI clocks to propagate up to PLL5.
> 
> This allows imx-drm to produce the exact clock rate required with no
> modulation due to the fractional divider.  Modulation of the clock rate
> can and does prevent TVs from locking to the HDMI signal - they will
> report no signal rather than trying to lock to such a signal.
> 
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
> ---
> I still have this patch which is required so that imx-drm is capable of
> producing HDMI clocks which are close enough to the HDMI defined
> frequencies such that TVs and similar can recognise the signal.  Without
> this, I don't get any kind of output on my TV desite imx-drm being set
> to the correct mode.  I have proven that this is because the HDMI clock
> is *very* wrong without this patch.
> 
>  arch/arm/mach-imx/clk-imx6q.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm/mach-imx/clk-imx6q.c b/arch/arm/mach-imx/clk-imx6q.c
> index 4d677f442539..3cf03a132534 100644
> --- a/arch/arm/mach-imx/clk-imx6q.c
> +++ b/arch/arm/mach-imx/clk-imx6q.c
> @@ -262,10 +262,10 @@ static void __init imx6q_clocks_init(struct device_node *ccm_node)
>  	clk[ipu1_di1_pre_sel] = imx_clk_mux("ipu1_di1_pre_sel", base + 0x34, 15, 3, ipu_di_pre_sels,   ARRAY_SIZE(ipu_di_pre_sels));
>  	clk[ipu2_di0_pre_sel] = imx_clk_mux("ipu2_di0_pre_sel", base + 0x38, 6,  3, ipu_di_pre_sels,   ARRAY_SIZE(ipu_di_pre_sels));
>  	clk[ipu2_di1_pre_sel] = imx_clk_mux("ipu2_di1_pre_sel", base + 0x38, 15, 3, ipu_di_pre_sels,   ARRAY_SIZE(ipu_di_pre_sels));
> -	clk[ipu1_di0_sel]     = imx_clk_mux("ipu1_di0_sel",     base + 0x34, 0,  3, ipu1_di0_sels,     ARRAY_SIZE(ipu1_di0_sels));
> -	clk[ipu1_di1_sel]     = imx_clk_mux("ipu1_di1_sel",     base + 0x34, 9,  3, ipu1_di1_sels,     ARRAY_SIZE(ipu1_di1_sels));
> -	clk[ipu2_di0_sel]     = imx_clk_mux("ipu2_di0_sel",     base + 0x38, 0,  3, ipu2_di0_sels,     ARRAY_SIZE(ipu2_di0_sels));
> -	clk[ipu2_di1_sel]     = imx_clk_mux("ipu2_di1_sel",     base + 0x38, 9,  3, ipu2_di1_sels,     ARRAY_SIZE(ipu2_di1_sels));
> +	clk[ipu1_di0_sel]     = imx_clk_mux_flags("ipu1_di0_sel",     base + 0x34, 0,  3, ipu1_di0_sels,     ARRAY_SIZE(ipu1_di0_sels), CLK_SET_RATE_PARENT);
> +	clk[ipu1_di1_sel]     = imx_clk_mux_flags("ipu1_di1_sel",     base + 0x34, 9,  3, ipu1_di1_sels,     ARRAY_SIZE(ipu1_di1_sels), CLK_SET_RATE_PARENT);
> +	clk[ipu2_di0_sel]     = imx_clk_mux_flags("ipu2_di0_sel",     base + 0x38, 0,  3, ipu2_di0_sels,     ARRAY_SIZE(ipu2_di0_sels), CLK_SET_RATE_PARENT);
> +	clk[ipu2_di1_sel]     = imx_clk_mux_flags("ipu2_di1_sel",     base + 0x38, 9,  3, ipu2_di1_sels,     ARRAY_SIZE(ipu2_di1_sels), CLK_SET_RATE_PARENT);

Yes, those muxes should be able to propagate rate changes.

>  	clk[hsi_tx_sel]       = imx_clk_mux("hsi_tx_sel",       base + 0x30, 28, 1, hsi_tx_sels,       ARRAY_SIZE(hsi_tx_sels));
>  	clk[pcie_axi_sel]     = imx_clk_mux("pcie_axi_sel",     base + 0x18, 10, 1, pcie_axi_sels,     ARRAY_SIZE(pcie_axi_sels));
>  	clk[ssi1_sel]         = imx_clk_fixup_mux("ssi1_sel",   base + 0x1c, 10, 2, ssi_sels,          ARRAY_SIZE(ssi_sels),          imx_cscmr1_fixup);
> @@ -307,9 +307,9 @@ static void __init imx6q_clocks_init(struct device_node *ccm_node)
>  	clk[ipu1_podf]        = imx_clk_divider("ipu1_podf",        "ipu1_sel",          base + 0x3c, 11, 3);
>  	clk[ipu2_podf]        = imx_clk_divider("ipu2_podf",        "ipu2_sel",          base + 0x3c, 16, 3);
>  	clk[ldb_di0_div_3_5]  = imx_clk_fixed_factor("ldb_di0_div_3_5", "ldb_di0_sel", 2, 7);
> -	clk[ldb_di0_podf]     = imx_clk_divider_flags("ldb_di0_podf", "ldb_di0_div_3_5", base + 0x20, 10, 1, 0);
> +	clk[ldb_di0_podf]     = imx_clk_divider("ldb_di0_podf", "ldb_di0_div_3_5", base + 0x20, 10, 1);
>  	clk[ldb_di1_div_3_5]  = imx_clk_fixed_factor("ldb_di1_div_3_5", "ldb_di1_sel", 2, 7);
> -	clk[ldb_di1_podf]     = imx_clk_divider_flags("ldb_di1_podf", "ldb_di1_div_3_5", base + 0x20, 11, 1, 0);
> +	clk[ldb_di1_podf]     = imx_clk_divider("ldb_di1_podf", "ldb_di1_div_3_5", base + 0x20, 11, 1);

I fear this will break LVDS, which depends on being able to set this
divisor manually (depending on whether it is in single or dual channel
mode).
I'd rather route the di clock inputs to the video pll via the
ipu_di_pre_sel muxes:

--- a/arch/arm/mach-imx/clk-imx6q.c
+++ b/arch/arm/mach-imx/clk-imx6q.c
@@ -258,14 +258,14 @@ static void __init imx6q_clocks_init(struct device_node *ccm_node)
        clk[ipu2_sel]         = imx_clk_mux("ipu2_sel",         base + 0x3c, 14, 2, ipu_sels,          ARRAY_SIZE(ipu_sels));
        clk[ldb_di0_sel]      = imx_clk_mux_flags("ldb_di0_sel", base + 0x2c, 9,  3, ldb_di_sels,      ARRAY_SIZE(ldb_di_sels), CLK_SET_RATE_P
        clk[ldb_di1_sel]      = imx_clk_mux_flags("ldb_di1_sel", base + 0x2c, 12, 3, ldb_di_sels,      ARRAY_SIZE(ldb_di_sels), CLK_SET_RATE_P
-       clk[ipu1_di0_pre_sel] = imx_clk_mux("ipu1_di0_pre_sel", base + 0x34, 6,  3, ipu_di_pre_sels,   ARRAY_SIZE(ipu_di_pre_sels));
-       clk[ipu1_di1_pre_sel] = imx_clk_mux("ipu1_di1_pre_sel", base + 0x34, 15, 3, ipu_di_pre_sels,   ARRAY_SIZE(ipu_di_pre_sels));
-       clk[ipu2_di0_pre_sel] = imx_clk_mux("ipu2_di0_pre_sel", base + 0x38, 6,  3, ipu_di_pre_sels,   ARRAY_SIZE(ipu_di_pre_sels));
-       clk[ipu2_di1_pre_sel] = imx_clk_mux("ipu2_di1_pre_sel", base + 0x38, 15, 3, ipu_di_pre_sels,   ARRAY_SIZE(ipu_di_pre_sels));
-       clk[ipu1_di0_sel]     = imx_clk_mux("ipu1_di0_sel",     base + 0x34, 0,  3, ipu1_di0_sels,     ARRAY_SIZE(ipu1_di0_sels));
-       clk[ipu1_di1_sel]     = imx_clk_mux("ipu1_di1_sel",     base + 0x34, 9,  3, ipu1_di1_sels,     ARRAY_SIZE(ipu1_di1_sels));
-       clk[ipu2_di0_sel]     = imx_clk_mux("ipu2_di0_sel",     base + 0x38, 0,  3, ipu2_di0_sels,     ARRAY_SIZE(ipu2_di0_sels));
-       clk[ipu2_di1_sel]     = imx_clk_mux("ipu2_di1_sel",     base + 0x38, 9,  3, ipu2_di1_sels,     ARRAY_SIZE(ipu2_di1_sels));
+       clk[ipu1_di0_pre_sel] = imx_clk_mux_flags("ipu1_di0_pre_sel", base + 0x34, 6,  3, ipu_di_pre_sels,   ARRAY_SIZE(ipu_di_pre_sels), CLK_
+       clk[ipu1_di1_pre_sel] = imx_clk_mux_flags("ipu1_di1_pre_sel", base + 0x34, 15, 3, ipu_di_pre_sels,   ARRAY_SIZE(ipu_di_pre_sels), CLK_
+       clk[ipu2_di0_pre_sel] = imx_clk_mux_flags("ipu2_di0_pre_sel", base + 0x38, 6,  3, ipu_di_pre_sels,   ARRAY_SIZE(ipu_di_pre_sels), CLK_
+       clk[ipu2_di1_pre_sel] = imx_clk_mux_flags("ipu2_di1_pre_sel", base + 0x38, 15, 3, ipu_di_pre_sels,   ARRAY_SIZE(ipu_di_pre_sels), CLK_
+       clk[ipu1_di0_sel]     = imx_clk_mux_flags("ipu1_di0_sel",     base + 0x34, 0,  3, ipu1_di0_sels,     ARRAY_SIZE(ipu1_di0_sels), CLK_SE
+       clk[ipu1_di1_sel]     = imx_clk_mux_flags("ipu1_di1_sel",     base + 0x34, 9,  3, ipu1_di1_sels,     ARRAY_SIZE(ipu1_di1_sels), CLK_SE
+       clk[ipu2_di0_sel]     = imx_clk_mux_flags("ipu2_di0_sel",     base + 0x38, 0,  3, ipu2_di0_sels,     ARRAY_SIZE(ipu2_di0_sels), CLK_SE
+       clk[ipu2_di1_sel]     = imx_clk_mux_flags("ipu2_di1_sel",     base + 0x38, 9,  3, ipu2_di1_sels,     ARRAY_SIZE(ipu2_di1_sels), CLK_SE
        clk[hsi_tx_sel]       = imx_clk_mux("hsi_tx_sel",       base + 0x30, 28, 1, hsi_tx_sels,       ARRAY_SIZE(hsi_tx_sels));
        clk[pcie_axi_sel]     = imx_clk_mux("pcie_axi_sel",     base + 0x18, 10, 1, pcie_axi_sels,     ARRAY_SIZE(pcie_axi_sels));
        clk[ssi1_sel]         = imx_clk_fixup_mux("ssi1_sel",   base + 0x1c, 10, 2, ssi_sels,          ARRAY_SIZE(ssi_sels),          imx_cscm
@@ -445,6 +445,15 @@ static void __init imx6q_clocks_init(struct device_node *ccm_node)
                clk_set_parent(clk[ldb_di1_sel], clk[pll5_video_div]);
        }
 
+       clk_set_parent(clk[ipu1_di0_sel], clk[ipu1_di0_pre]);
+       clk_set_parent(clk[ipu1_di1_sel], clk[ipu1_di1_pre]);
+       clk_set_parent(clk[ipu2_di0_sel], clk[ipu2_di0_pre]);
+       clk_set_parent(clk[ipu2_di1_sel], clk[ipu2_di1_pre]);
+       clk_set_parent(clk[ipu1_di0_pre_sel], clk[pll5_video_div]);
+       clk_set_parent(clk[ipu1_di1_pre_sel], clk[pll5_video_div]);
+       clk_set_parent(clk[ipu2_di0_pre_sel], clk[pll5_video_div]);
+       clk_set_parent(clk[ipu2_di1_pre_sel], clk[pll5_video_div]);
+
        /*
         * The gpmi needs 100MHz frequency in the EDO/Sync mode,
         * We can not get the 100MHz from the pll2_pfd0_352m.

regards
Philipp