2023-11-22 13:43:18

by Christoph Niedermaier

[permalink] [raw]
Subject: [PATCH V2] cpufreq: imx6q: Only disabling 792MHz OPP for i.MX6ULL types below 792MHz

For a 900MHz i.MX6ULL CPU the 792MHz OPP is disabled. There is no
convincing reason to disable this OPP. If a CPU can run at 900MHz,
it should also be able to cope with 792MHz. Looking at the voltage
level of 792MHz in [1] (page 24, table 10. "Operating Ranges") the
current defined OPP is above the minimum. So the voltage level
shouldn't be a problem. However in [2] (page 24, table 10.
"Operating Ranges"), it is not mentioned that 792MHz OPP isn't
allowed. Change it to only disable 792MHz OPP for i.MX6ULL types
below 792 MHz.

[1] https://www.nxp.com/docs/en/data-sheet/IMX6ULLIEC.pdf
[2] https://www.nxp.com/docs/en/data-sheet/IMX6ULLCEC.pdf

Fixes: 0aa9abd4c212 ("cpufreq: imx6q: check speed grades for i.MX6ULL")
Signed-off-by: Christoph Niedermaier <[email protected]>
Reviewed-by: Marek Vasut <[email protected]>
Reviewed-by: Fabio Estevam <[email protected]>
---
V2: - Improve the commit message
- Add Fixes tag
- Add Reviewed-by tag
---
Cc: Viresh Kumar <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Sébastien Szymanski <[email protected]>
Cc: Stefan Agner <[email protected]>
Cc: Shawn Guo <[email protected]>
Cc: Marek Vasut <[email protected]>
Cc: Fabio Estevam <[email protected]>
Cc: NXP Linux Team <[email protected]>
Cc: [email protected]
Cc: [email protected]
To: [email protected]
---
drivers/cpufreq/imx6q-cpufreq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
index 494d044b9e72..33728c242f66 100644
--- a/drivers/cpufreq/imx6q-cpufreq.c
+++ b/drivers/cpufreq/imx6q-cpufreq.c
@@ -327,7 +327,7 @@ static int imx6ul_opp_check_speed_grading(struct device *dev)
imx6x_disable_freq_in_opp(dev, 696000000);

if (of_machine_is_compatible("fsl,imx6ull")) {
- if (val != OCOTP_CFG3_6ULL_SPEED_792MHZ)
+ if (val < OCOTP_CFG3_6ULL_SPEED_792MHZ)
imx6x_disable_freq_in_opp(dev, 792000000);

if (val != OCOTP_CFG3_6ULL_SPEED_900MHZ)
--
2.11.0


2023-11-23 07:29:00

by Viresh Kumar

[permalink] [raw]
Subject: Re: [PATCH V2] cpufreq: imx6q: Only disabling 792MHz OPP for i.MX6ULL types below 792MHz

On 22-11-23, 14:41, Christoph Niedermaier wrote:
> For a 900MHz i.MX6ULL CPU the 792MHz OPP is disabled. There is no
> convincing reason to disable this OPP. If a CPU can run at 900MHz,
> it should also be able to cope with 792MHz. Looking at the voltage
> level of 792MHz in [1] (page 24, table 10. "Operating Ranges") the
> current defined OPP is above the minimum. So the voltage level
> shouldn't be a problem. However in [2] (page 24, table 10.
> "Operating Ranges"), it is not mentioned that 792MHz OPP isn't
> allowed. Change it to only disable 792MHz OPP for i.MX6ULL types
> below 792 MHz.
>
> [1] https://www.nxp.com/docs/en/data-sheet/IMX6ULLIEC.pdf
> [2] https://www.nxp.com/docs/en/data-sheet/IMX6ULLCEC.pdf
>
> Fixes: 0aa9abd4c212 ("cpufreq: imx6q: check speed grades for i.MX6ULL")
> Signed-off-by: Christoph Niedermaier <[email protected]>
> Reviewed-by: Marek Vasut <[email protected]>
> Reviewed-by: Fabio Estevam <[email protected]>
> ---
> V2: - Improve the commit message
> - Add Fixes tag
> - Add Reviewed-by tag
> ---
> Cc: Viresh Kumar <[email protected]>
> Cc: "Rafael J. Wysocki" <[email protected]>
> Cc: S?bastien Szymanski <[email protected]>
> Cc: Stefan Agner <[email protected]>
> Cc: Shawn Guo <[email protected]>
> Cc: Marek Vasut <[email protected]>
> Cc: Fabio Estevam <[email protected]>
> Cc: NXP Linux Team <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> To: [email protected]
> ---
> drivers/cpufreq/imx6q-cpufreq.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
> index 494d044b9e72..33728c242f66 100644
> --- a/drivers/cpufreq/imx6q-cpufreq.c
> +++ b/drivers/cpufreq/imx6q-cpufreq.c
> @@ -327,7 +327,7 @@ static int imx6ul_opp_check_speed_grading(struct device *dev)
> imx6x_disable_freq_in_opp(dev, 696000000);
>
> if (of_machine_is_compatible("fsl,imx6ull")) {
> - if (val != OCOTP_CFG3_6ULL_SPEED_792MHZ)
> + if (val < OCOTP_CFG3_6ULL_SPEED_792MHZ)
> imx6x_disable_freq_in_opp(dev, 792000000);
>
> if (val != OCOTP_CFG3_6ULL_SPEED_900MHZ)

What about another similar check ?

if (val != OCOTP_CFG3_6ULL_SPEED_900MHZ)

--
viresh

2023-11-23 07:33:30

by Viresh Kumar

[permalink] [raw]
Subject: Re: [PATCH V2] cpufreq: imx6q: Only disabling 792MHz OPP for i.MX6ULL types below 792MHz

On 23-11-23, 12:58, Viresh Kumar wrote:
> On 22-11-23, 14:41, Christoph Niedermaier wrote:
> > For a 900MHz i.MX6ULL CPU the 792MHz OPP is disabled. There is no
> > convincing reason to disable this OPP. If a CPU can run at 900MHz,
> > it should also be able to cope with 792MHz. Looking at the voltage
> > level of 792MHz in [1] (page 24, table 10. "Operating Ranges") the
> > current defined OPP is above the minimum. So the voltage level
> > shouldn't be a problem. However in [2] (page 24, table 10.
> > "Operating Ranges"), it is not mentioned that 792MHz OPP isn't
> > allowed. Change it to only disable 792MHz OPP for i.MX6ULL types
> > below 792 MHz.
> >
> > [1] https://www.nxp.com/docs/en/data-sheet/IMX6ULLIEC.pdf
> > [2] https://www.nxp.com/docs/en/data-sheet/IMX6ULLCEC.pdf
> >
> > Fixes: 0aa9abd4c212 ("cpufreq: imx6q: check speed grades for i.MX6ULL")
> > Signed-off-by: Christoph Niedermaier <[email protected]>
> > Reviewed-by: Marek Vasut <[email protected]>
> > Reviewed-by: Fabio Estevam <[email protected]>
> > ---
> > V2: - Improve the commit message
> > - Add Fixes tag
> > - Add Reviewed-by tag
> > ---
> > Cc: Viresh Kumar <[email protected]>
> > Cc: "Rafael J. Wysocki" <[email protected]>
> > Cc: S?bastien Szymanski <[email protected]>
> > Cc: Stefan Agner <[email protected]>
> > Cc: Shawn Guo <[email protected]>
> > Cc: Marek Vasut <[email protected]>
> > Cc: Fabio Estevam <[email protected]>
> > Cc: NXP Linux Team <[email protected]>
> > Cc: [email protected]
> > Cc: [email protected]
> > To: [email protected]
> > ---
> > drivers/cpufreq/imx6q-cpufreq.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
> > index 494d044b9e72..33728c242f66 100644
> > --- a/drivers/cpufreq/imx6q-cpufreq.c
> > +++ b/drivers/cpufreq/imx6q-cpufreq.c
> > @@ -327,7 +327,7 @@ static int imx6ul_opp_check_speed_grading(struct device *dev)
> > imx6x_disable_freq_in_opp(dev, 696000000);
> >
> > if (of_machine_is_compatible("fsl,imx6ull")) {
> > - if (val != OCOTP_CFG3_6ULL_SPEED_792MHZ)
> > + if (val < OCOTP_CFG3_6ULL_SPEED_792MHZ)
> > imx6x_disable_freq_in_opp(dev, 792000000);
> >
> > if (val != OCOTP_CFG3_6ULL_SPEED_900MHZ)
>
> What about another similar check ?
>
> if (val != OCOTP_CFG3_6ULL_SPEED_900MHZ)

Yeah, that isn't required I guess.

Applied. Thanks.

--
viresh