diff mbox

[v3,1/2] clk: exynos5433: do not use CLK_IGNORE_UNUSED for SPI clocks

Message ID 1467270911-10971-2-git-send-email-andi.shyti@samsung.com (mailing list archive)
State Not Applicable
Headers show

Commit Message

Andi Shyti June 30, 2016, 7:15 a.m. UTC
The CLK_IGNORE_UNUSED flag has to be avoided whenever possible.
Use the CLK_IS_CRITICAL flag instead for critical SPI1 clocks,
which enables the clock line during boot time.

Suggested-by: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Andi Shyti <andi.shyti@samsung.com>
---
 drivers/clk/samsung/clk-exynos5433.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

On 06/30/2016 09:15 AM, Andi Shyti wrote:
> The CLK_IGNORE_UNUSED flag has to be avoided whenever possible.

In general I would rather disagree.

> Use the CLK_IS_CRITICAL flag instead for critical SPI1 clocks,
> which enables the clock line during boot time.
> 
> Suggested-by: Tomasz Figa <tomasz.figa@gmail.com>
> Signed-off-by: Andi Shyti <andi.shyti@samsung.com>
> ---
>  drivers/clk/samsung/clk-exynos5433.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/clk/samsung/clk-exynos5433.c b/drivers/clk/samsung/clk-exynos5433.c
> index c3a5318..1f7c4951 100644
> --- a/drivers/clk/samsung/clk-exynos5433.c
> +++ b/drivers/clk/samsung/clk-exynos5433.c
> @@ -1662,7 +1662,7 @@ static struct samsung_gate_clock peric_gate_clks[] __initdata = {

> @@ -1677,7 +1677,7 @@ static struct samsung_gate_clock peric_gate_clks[] __initdata = {
>  	GATE(CLK_SCLK_SPI2, "sclk_spi2", "sclk_spi2_peric", ENABLE_SCLK_PERIC,
>  			5, CLK_SET_RATE_PARENT, 0),
>  	GATE(CLK_SCLK_SPI1, "sclk_spi1", "sclk_spi1_peric", ENABLE_SCLK_PERIC,
> -			4, CLK_IGNORE_UNUSED | CLK_SET_RATE_PARENT, 0),
> +			4, CLK_IS_CRITICAL | CLK_SET_RATE_PARENT, 0),

As Tomasz pointed out, this should be addressed in the driver/dts,
we shouldn't be patching board configurations into a per-SoC driver.
Other boards may want to keep this clock disabled.

What is an exact problem here, are you perhaps testing suspend to RAM?
I tested my sound support patches on top of v4.7-rc1 and everything
seemed to work well, I didn't notice any issues with the audio codec
which was the only slave on the SPI 1 bus.

Doesn't it help when you specify CLK_SCLK_SPI1 as the second clock
("spi_busclk0") of the spi_1 bus controller instead of
CLK_SCLK_SPI0_PERIC? CLK_SCLK_SPI0_PERIC seem to be parent of
CLK_SCLK_SPI1 so the enable state would be propagated.


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Andi Shyti July 4, 2016, 10:26 a.m. UTC | #2
Hi Sylwester,

> >  	GATE(CLK_SCLK_SPI1, "sclk_spi1", "sclk_spi1_peric", ENABLE_SCLK_PERIC,
> > -			4, CLK_IGNORE_UNUSED | CLK_SET_RATE_PARENT, 0),
> > +			4, CLK_IS_CRITICAL | CLK_SET_RATE_PARENT, 0),
> 
> As Tomasz pointed out, this should be addressed in the driver/dts,
> we shouldn't be patching board configurations into a per-SoC driver.
> Other boards may want to keep this clock disabled.

The single clock lines are not configured in the exynos5433 dts,
but in the drivers/clk/samsung/clk-exynos5433.c file and it's the
only place where we can set the flags.

> What is an exact problem here, are you perhaps testing suspend to RAM?
> I tested my sound support patches on top of v4.7-rc1 and everything
> seemed to work well, I didn't notice any issues with the audio codec
> which was the only slave on the SPI 1 bus.

Yes, because the audio codec is on SPI1 and its bus line
(spi_busclk0) is CLK_SCLK_SPI1_PERIC while the CLK_SCLK_SPI1 is
set as CLK_IGNORE_UNUSED.

> Doesn't it help when you specify CLK_SCLK_SPI1 as the second clock
> ("spi_busclk0") of the spi_1 bus controller instead of
> CLK_SCLK_SPI0_PERIC? CLK_SCLK_SPI0_PERIC seem to be parent of
> CLK_SCLK_SPI1 so the enable state would be propagated.

nope! :(

For some reasons, if you set in the DTS as spi_busclk0 the
CLK_SCLK_SPI1 from cmu_peric you get a synchronus abort in the
s3c64xx_spi_config (the first read performed on the device).

Andi
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diff mbox

Patch

diff --git a/drivers/clk/samsung/clk-exynos5433.c b/drivers/clk/samsung/clk-exynos5433.c
index c3a5318..1f7c4951 100644
--- a/drivers/clk/samsung/clk-exynos5433.c
+++ b/drivers/clk/samsung/clk-exynos5433.c
@@ -1662,7 +1662,7 @@  static struct samsung_gate_clock peric_gate_clks[] __initdata = {
 			ENABLE_SCLK_PERIC, 13, CLK_SET_RATE_PARENT, 0),
 	GATE(CLK_SCLK_IOCLK_SPI1, "sclk_ioclk_spi1", "ioclk_spi1_clk_in",
 			ENABLE_SCLK_PERIC, 12,
-			CLK_IGNORE_UNUSED | CLK_SET_RATE_PARENT, 0),
+			CLK_IS_CRITICAL | CLK_SET_RATE_PARENT, 0),
 	GATE(CLK_SCLK_IOCLK_SPI0, "sclk_ioclk_spi0", "ioclk_spi0_clk_in",
 			ENABLE_SCLK_PERIC, 11, CLK_SET_RATE_PARENT, 0),
 	GATE(CLK_SCLK_IOCLK_I2S1_BCLK, "sclk_ioclk_i2s1_bclk",
@@ -1677,7 +1677,7 @@  static struct samsung_gate_clock peric_gate_clks[] __initdata = {
 	GATE(CLK_SCLK_SPI2, "sclk_spi2", "sclk_spi2_peric", ENABLE_SCLK_PERIC,
 			5, CLK_SET_RATE_PARENT, 0),
 	GATE(CLK_SCLK_SPI1, "sclk_spi1", "sclk_spi1_peric", ENABLE_SCLK_PERIC,
-			4, CLK_IGNORE_UNUSED | CLK_SET_RATE_PARENT, 0),
+			4, CLK_IS_CRITICAL | CLK_SET_RATE_PARENT, 0),
 	GATE(CLK_SCLK_SPI0, "sclk_spi0", "sclk_spi0_peric", ENABLE_SCLK_PERIC,
 			3, CLK_SET_RATE_PARENT, 0),
 	GATE(CLK_SCLK_UART2, "sclk_uart2", "sclk_uart2_peric",