Commit 85d071e7 authored Aug 25, 2020 by Claudiu Beznea Committed by Stephen Boyd Oct 13, 2020

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



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: 27cb1c20 ("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>

parent eddfb2e1

drivers/clk/at91/clk-main.c

+8 −3

Original line number	Diff line number	Diff line
		@@ -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();

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