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From:   Priit Laes <plaes@plaes.org>
To:     Maxime Ripard <maxime.ripard@bootlin.com>,
        Chen-Yu Tsai <wens@csie.org>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Jernej Skrabec <jernej.skrabec@siol.net>
Cc:     Priit Laes <plaes@plaes.org>
Subject: [RFC PATCH] clk: sunxi-ng: sun4i: Use CLK_SET_RATE_PARENT for mmc2 clock
Date:   Sat,  2 Feb 2019 17:52:09 +0200
Message-Id: <20190202155209.31617-1-plaes@plaes.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Recent patch of improving MP clock rate calculations by taking
into account whether adjusting parent rate is allowed, have
unfortunately broken eMMC support on A20 Olinuxino-Lime2-eMMC
boards which fail with following error:

[snip]
EXT4-fs (mmcblk1p4): INFO: recovery required on readonly filesystem
EXT4-fs (mmcblk1p4): write access will be enabled during recovery
sunxi-mmc 1c11000.mmc: data error, sending stop command
sunxi-mmc 1c11000.mmc: send stop command failed
[/snip]

Previously, mmc2 clock was requesting 520MHz and settling at 512MHz
clock rate with following parents:
[snip]
pll-ddr-base        2  2        0   768000000 0     0  50000
   pll-ddr-other    1  1        0   768000000 0     0  50000
      mmc2          0  0        0    51200000 0     0  50000
[/snip]

Now, after the improvements, requested and settled rate are both
520MHz, but as mmc2 clock cannot adjust parent rate, the situation
ends up like this:
[snip]
pll-periph-base     3  3        0  1200000000 0     0  50000
   pll-periph       6  6        0   600000000 0     0  50000
      mmc2          3  3        0    50000000 0     0  50000
[/snip]

With this patch (allowing mmc2 to set parent rate), we end up with
working tree with both mmc0 (sd-card) and mmc2 (eMMC) working:
[snip]
pll-periph-base     3  3        0   312000000 0     0  50000
   mbus             1  1        0    78000000 0     0  50000
   pll-periph-sata  1  1        0    26000000 0     0  50000
      sata          1  1        0    26000000 0     0  50000
   pll-periph       5  5        0   156000000 0     0  50000
      mmc2          0  0        0    52000000 0     0  50000
      mmc0          0  0        0    39000000 0     0  50000
[/snip]

Fixes: 3f790433c3cb ("clk: sunxi-ng: Adjust MP clock parent rate when allowed")
Signed-off-by: Priit Laes <plaes@plaes.org>
---
 drivers/clk/sunxi-ng/ccu-sun4i-a10.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/sunxi-ng/ccu-sun4i-a10.c b/drivers/clk/sunxi-ng/ccu-sun4i-a10.c
index 129ebd2588fd..605e13b4ef90 100644
--- a/drivers/clk/sunxi-ng/ccu-sun4i-a10.c
+++ b/drivers/clk/sunxi-ng/ccu-sun4i-a10.c
@@ -498,7 +498,7 @@ static SUNXI_CCU_MP_WITH_MUX_GATE(mmc2_clk, "mmc2", mod0_default_parents, 0x090,
 				  16, 2,	/* P */
 				  24, 2,	/* mux */
 				  BIT(31),	/* gate */
-				  0);
+				  CLK_SET_RATE_PARENT);
 
 /* MMC output and sample clocks are not present on A10 */
 static SUNXI_CCU_PHASE(mmc2_output_clk, "mmc2_output", "mmc2",
-- 
2.11.0