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

From: Viresh Kumar
Date: Thu Nov 23 2023 - 02:28:52 EST


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 <cniedermaier@xxxxxxxxxxxxxxxxxx>
> Reviewed-by: Marek Vasut <marex@xxxxxxx>
> Reviewed-by: Fabio Estevam <festevam@xxxxxxx>
> ---
> V2: - Improve the commit message
> - Add Fixes tag
> - Add Reviewed-by tag
> ---
> Cc: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
> Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
> Cc: Sébastien Szymanski <sebastien.szymanski@xxxxxxxxxxxx>
> Cc: Stefan Agner <stefan@xxxxxxxx>
> Cc: Shawn Guo <shawnguo@xxxxxxxxxx>
> Cc: Marek Vasut <marex@xxxxxxx>
> Cc: Fabio Estevam <festevam@xxxxxxx>
> Cc: NXP Linux Team <linux-imx@xxxxxxx>
> Cc: linux-pm@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> To: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> ---
> 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