From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Date: Tue, 13 Oct 2015 07:08:46 +0000 Subject: Re: [PATCH RFC 1/2] dt-bindings: simplefb: Support a list of regulator supply properties Message-Id: <561CADFE.2010609@redhat.com> List-Id: References: <1444669458-5588-1-git-send-email-wens@csie.org> <1444669458-5588-2-git-send-email-wens@csie.org> <20151012171018.GB3659@leverpostej> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-arm-kernel@lists.infradead.org Hi, On 13-10-15 04:22, Chen-Yu Tsai wrote: > On Tue, Oct 13, 2015 at 1:10 AM, Mark Rutland wrote: >> On Tue, Oct 13, 2015 at 01:04:17AM +0800, Chen-Yu Tsai wrote: >>> The physical display tied to the framebuffer may have regulators >>> providing power to it, such as power for LCDs or interface conversion >>> chips. >>> >>> The number of regulators in use may vary, but the regulator supply >>> binding can not be a list. Work around this by adding a "num-supplies" >>> property to communicate the number of supplies, and a list of 0 ~ N >>> "vinN-supply" properties for the actual regulator supply. >> >> This is getting more complicated by the minute... > > Yeah... > > I considered "backlight" and "panel" properties, but that seems to need > more effort to parse. Regulators seemed easier. > >> >>> Signed-off-by: Chen-Yu Tsai >>> --- >>> .../devicetree/bindings/video/simple-framebuffer.txt | 14 ++++++++++---- >>> 1 file changed, 10 insertions(+), 4 deletions(-) >>> >>> diff --git a/Documentation/devicetree/bindings/video/simple-framebuffer.txt b/Documentation/devicetree/bindings/video/simple-framebuffer.txt >>> index 4474ef6e0b95..0cc43e1be8b5 100644 >>> --- a/Documentation/devicetree/bindings/video/simple-framebuffer.txt >>> +++ b/Documentation/devicetree/bindings/video/simple-framebuffer.txt >>> @@ -47,10 +47,14 @@ Required properties: >>> - a8b8g8r8 (32-bit pixels, d[31:24]=a, d[23:16]=b, d[15:8]=g, d[7:0]=r). >>> >>> Optional properties: >>> -- clocks : List of clocks used by the framebuffer. Clocks listed here >>> - are expected to already be configured correctly. The OS must >>> - ensure these clocks are not modified or disabled while the >>> - simple framebuffer remains active. >>> +- clocks : List of clocks used by the framebuffer. >>> +- num-supplies : The number of regulators used by the framebuffer. >>> +- vinN-supply : The N-th (from 0) regulator used by the framebuffer. >> >> I don't see why you need num-supplies. Why not just try probing >> vin${N}-supply until such a property isn't present in the DT? +1 for this. > That's doable. Though I'd add a hard limit on it. Does 16 seem reasonable? I would not add a hard limit to the binding, you can use a fixed array in the code to make the code simpler. I would say 8 should be sufficient, since the limit will only be in the code we can always bump it when we need to. Regards, Hans