Subject: Re: [PATCH] ARM: davinci: register the usb20_phy clock on the DT file
To: ahaslam@baylibre.com, nsekhar@ti.com, khilman@kernel.org
References: <20161026194916.14546-1-ahaslam@baylibre.com>
Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
From: David Lechner <david@lechnology.com>
Message-ID: <f2aeafb1-38f4-9b1e-c3fd-a2984333d00f@lechnology.com>
Date: Wed, 26 Oct 2016 15:01:35 -0500
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On 10/26/2016 02:49 PM, ahaslam@baylibre.com wrote:
> From: Axel Haslam <ahaslam@baylibre.com>
>
> The usb20_phy clock needs to be registered for the driver to be able
> to get and enable a clock. Currently the usb phy clocks are registered
> form board files, which will not be called during a device tree based
> boot.
>
> To be able to probe correctly usb form a device tree boot, register
> the usb phy clocks form the DT specific init.
>
> Unfourtunatly, davinci does not have proper clock support on device tree
> yet, so by registering the clock form de DT specific file we are
> forced to hardcode the parent clock, and cannot select refclkin as
> parent for any of the phy clocks of the da850 family.
>
> As none of the current da850 based boards currently in mainline use
> refclkin as source. I guess we can live with this limitation until clocks
> are correctly represented through CCF/device tree.
>
> Signed-off-by: Axel Haslam <ahaslam@baylibre.com>
> ---
>
> This patch depends on David's series for usb clocks:
>
> currently:
> [PATCH v6 0/5] da8xx USB PHY platform devices and clocks
> https://lkml.org/lkml/2016/10/25/867
>
>  arch/arm/mach-davinci/da8xx-dt.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/arch/arm/mach-davinci/da8xx-dt.c b/arch/arm/mach-davinci/da8xx-dt.c
> index c9f7e92..7947267 100644
> --- a/arch/arm/mach-davinci/da8xx-dt.c
> +++ b/arch/arm/mach-davinci/da8xx-dt.c
> @@ -45,6 +45,8 @@
>
>  static void __init da850_init_machine(void)
>  {
> +	da8xx_register_usb20_phy_clk(false);
> +	da8xx_register_usb11_phy_clk(false);
>  	of_platform_default_populate(NULL, da850_auxdata_lookup, NULL);
>  }
>
>


You should check for error on return and print a warning if there is an 
error. Like this: https://patchwork.kernel.org/patch/9395635/

(I actually just had to make this change a few minutes ago to 
troubleshoot a problem that I am working on. 
da8xx_register_usb11_phy_clk() is failing for some reason that I have 
not figured out yet.)