[PATCH 4.9 078/139] clk: at91: clk-main: update key before writing AT91_CKGR_MOR

From: Claudiu Beznea claudiu.beznea@microchip.com

[ 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@m... Signed-off-by: Stephen Boyd sboyd@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/clk/at91/clk-main.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/at91/clk-main.c b/drivers/clk/at91/clk-main.c index 90988e7a5b47f..2e7da9b379d48 100644 --- a/drivers/clk/at91/clk-main.c +++ b/drivers/clk/at91/clk-main.c @@ -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();