Hi Neil,
On Mon, 9 Nov 2020 at 19:56, Neil Armstrong narmstrong@baylibre.com wrote:
On 09/11/2020 15:10, Mark Kettenis wrote:
From: Neil Armstrong narmstrong@baylibre.com Date: Mon, 9 Nov 2020 14:37:09 +0100
Hi,
On 09/11/2020 04:12, Jaehoon Chung wrote:
Core clock phase value is changed from 180' to 270'. It's more stable than before.
- Odroidn-N2/C4 : Working fine with 52MHz
- VIM3 : Working fine with 52MHz
Before this patch, Odroid-C4 doesn't work fine with 52MHz.
Signed-off-by: Jaehoon Chung jh80.chung@samsung.com
drivers/mmc/meson_gx_mmc.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/drivers/mmc/meson_gx_mmc.c b/drivers/mmc/meson_gx_mmc.c index 719dd1e5e570..7c60e0566560 100644 --- a/drivers/mmc/meson_gx_mmc.c +++ b/drivers/mmc/meson_gx_mmc.c @@ -52,10 +52,16 @@ static void meson_mmc_config_clock(struct mmc *mmc) } clk_div = DIV_ROUND_UP(clk, mmc->clock);
- /* 180 phase core clock */
- meson_mmc_clk |= CLK_CO_PHASE_180;
- /* 180 phase tx clock */
/*
- Clock Phase needs to set a proper value.
- It can be changed to other value.
- Because CORE : 270' Phase and TX : 0' Phase are stable,
- set to them by default.
*/
/* Core Clock Phase */
meson_mmc_clk |= CLK_CO_PHASE_270;
/* TX Clock Phase */ meson_mmc_clk |= CLK_TX_PHASE_000;
/* clock settings */
The previous values were aligned on the Linux driver, which is functional.
Actually the Linux driver isn't really functional; the 52 MHz high-speed mode doesn't work. But since HS200 does work in Linux, probably nobody noticed this.
That said, I'm not confident a single clock phase setting will work across all Amlogic SoCs and across different boards. Maybe we need something in the device tree such that we can control the values on a per-board level.
So this is specific to SM1 SoCs then, because others families doesn't have such issues at 52MHz.
So the Linux must be fixes, including the bindings to introduce a new compatible, then ported to U-Boot.
So in the meantime, it's right to limit to 26MHz on SM1 in U-boot until we have all this clarified.
Neil
Earlier I had a similar approach for this FIX but somehow it did not get merged.
Please add my Tested-by: Anand Moon linux.amoon@gmail.com
Best Regards -Anand