clk: at91: sam9x60: fix programmable clock prescaler

Commit Message

Eugen Hristev Dec. 10, 2019, 11:25 a.m. UTC

From: Eugen Hristev <[e-mail]>

The prescaler works as parent rate divided by (PRES + 1) (is_pres_direct == 1)
It does not work in the way of parent rate shifted to the right by (PRES + 1),
which means division by 2^(PRES + 1) (is_pres_direct == 0)
Thus is_pres_direct must be enabled for this SoC, to make the right computation.
This field was added in
commit 45b06682113b ("clk: at91: fix programmable clock for sama5d2")
SAM9X60 has the same field as SAMA5D2 in the PCK

Fixes: 01e2113de9a5 ("clk: at91: add sam9x60 pmc driver")
Signed-off-by: Eugen Hristev <[e-mail]>
---
 drivers/clk/at91/sam9x60.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Stephen Boyd Jan. 6, 2020, 3:07 a.m. UTC | #1

Quoting [e-mail] (2019-12-10 03:25:19)
> From: Eugen Hristev <[e-mail]>
> 
> The prescaler works as parent rate divided by (PRES + 1) (is_pres_direct == 1)
> It does not work in the way of parent rate shifted to the right by (PRES + 1),
> which means division by 2^(PRES + 1) (is_pres_direct == 0)
> Thus is_pres_direct must be enabled for this SoC, to make the right computation.
> This field was added in
> commit 45b06682113b ("clk: at91: fix programmable clock for sama5d2")
> SAM9X60 has the same field as SAMA5D2 in the PCK
> 
> Fixes: 01e2113de9a5 ("clk: at91: add sam9x60 pmc driver")
> Signed-off-by: Eugen Hristev <[e-mail]>
> ---

Applied to clk-next

Patch

diff --git a/drivers/clk/at91/sam9x60.c b/drivers/clk/at91/sam9x60.c
index 86238d5..77398ae 100644
--- a/drivers/clk/at91/sam9x60.c
+++ b/drivers/clk/at91/sam9x60.c
@@ -47,6 +47,7 @@  static const struct clk_programmable_layout sam9x60_programmable_layout = {
 	.pres_shift = 8,
 	.css_mask = 0x1f,
 	.have_slck_mck = 0,
+	.is_pres_direct = 1,
 };
 
 static const struct clk_pcr_layout sam9x60_pcr_layout = {