From c579bc45752b8b6b447baecf7d50b064c9edc8d2 Mon Sep 17 00:00:00 2001 From: Claudiu Beznea Date: Tue, 25 Aug 2020 09:59:10 +0300 Subject: [PATCH] clk: at91: clk-main: update key before writing AT91_CKGR_MOR [ 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 Reviewed-by: Alexandre Belloni Link: https://lore.kernel.org/r/1598338751-20607-3-git-send-email-claudiu.beznea@microchip.com Signed-off-by: Stephen Boyd Signed-off-by: Sasha Levin --- 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(); -- 2.51.0