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clk: at91: clk-main: update key before writing AT91_CKGR_MOR

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[ Upstream commit 85d071e7f19a6a9abf30476b90b3819642568756 ]

SAMA5D2 datasheet specifies on chapter 33.22.8 (PMC Clock Generator
Main Oscillator Register) that writing any value other than
0x37 on KEY field aborts the write operation. Use the key when
selecting main clock parent.

Fixes: 27cb1c2083373 ("clk: at91: rework main clk implementation")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/1598338751-20607-3-git-send-email-claudiu.beznea@microchip.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Claudiu Beznea 2020-08-25 09:59:10 +03:00 committed by Greg Kroah-Hartman
parent c6f85c6d00
commit 66a761e473
1 changed files with 8 additions and 3 deletions
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11
drivers/clk/at91/clk-main.c
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@ -517,12 +517,17 @@ static int clk_sam9x5_main_set_parent(struct clk_hw *hw, u8 index)
return -EINVAL;
regmap_read(regmap, AT91_CKGR_MOR, &tmp);
tmp &= ~MOR_KEY_MASK;
if (index && !(tmp & AT91_PMC_MOSCSEL))
regmap_write(regmap, AT91_CKGR_MOR, tmp | AT91_PMC_MOSCSEL);
tmp = AT91_PMC_MOSCSEL;
else if (!index && (tmp & AT91_PMC_MOSCSEL))
regmap_write(regmap, AT91_CKGR_MOR, tmp & ~AT91_PMC_MOSCSEL);
tmp = 0;
else
return 0;
regmap_update_bits(regmap, AT91_CKGR_MOR,
AT91_PMC_MOSCSEL | MOR_KEY_MASK,
tmp | AT91_PMC_KEY);
while (!clk_sam9x5_main_ready(regmap))
cpu_relax();