Re: [PATCH v2 1/4] ARM: davinci: fix cpufreq registration on da850-evm

From: Adam Ford <aford173@gmail.com>
To: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Sekhar Nori <nsekhar@ti.com>, Kevin Hilman <khilman@kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	David Lechner <david@lechnology.com>,
	devicetree <devicetree@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	arm-soc <linux-arm-kernel@lists.infradead.org>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>
Subject: Re: [PATCH v2 1/4] ARM: davinci: fix cpufreq registration on da850-evm
Date: Tue, 26 Mar 2019 09:00:21 -0500	[thread overview]
Message-ID: <CAHCN7xJj_aA8XFR6=ZxO-WrfkJRY5fS6NgjHbeqpdfhUnn1apA@mail.gmail.com> (raw)
In-Reply-To: <20190322133105.5945-2-brgl@bgdev.pl>

On Fri, Mar 22, 2019 at 8:31 AM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>
> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
>
> The system_rev variable is never set on davinci and is always 0, so
> we're using the default max operating point of 300MHz. The cvdd supply
> comes from the tps6507 pmic and the voltage can go all the way to 1.3V
> so the maximum supported rate should be 456MHz.

My understanding is that only certain revisions of the silicon can go
to 456MHz.   The L138's Datasheet lists both a 456 and 375 version.  I
cannot find a way to read a register to determine which version of the
silicon is available. Maybe Sekhar can confirm.

adam
>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> ---
>  arch/arm/mach-davinci/board-da850-evm.c | 12 +-----------
>  1 file changed, 1 insertion(+), 11 deletions(-)
>
> diff --git a/arch/arm/mach-davinci/board-da850-evm.c b/arch/arm/mach-davinci/board-da850-evm.c
> index 1fdc9283a8c5..58b2a485b527 100644
> --- a/arch/arm/mach-davinci/board-da850-evm.c
> +++ b/arch/arm/mach-davinci/board-da850-evm.c
> @@ -1155,17 +1155,7 @@ static struct edma_rsv_info *da850_edma_rsv[2] = {
>  #ifdef CONFIG_CPU_FREQ
>  static __init int da850_evm_init_cpufreq(void)
>  {
> -       switch (system_rev & 0xF) {
> -       case 3:
> -               da850_max_speed = 456000;
> -               break;
> -       case 2:
> -               da850_max_speed = 408000;
> -               break;
> -       case 1:
> -               da850_max_speed = 372000;
> -               break;
> -       }
> +       da850_max_speed = 456000;
>
>         return da850_register_cpufreq("pll0_sysclk3");
>  }
> --
> 2.20.1
>
>
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