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

[ Upstream commit 85d071e7f1 ]

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: 27cb1c2083 ("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>
5.4-rM2-2.2.x-imx-squashed
Claudiu Beznea 2020-08-25 09:59:10 +03:00 committed by Greg Kroah-Hartman
parent 1ed7508e68
commit c10e3c919a
1 changed files with 8 additions and 3 deletions
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11
drivers/clk/at91/clk-main.c
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@ -437,12 +437,17 @@ 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();