Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753425AbcKPIRO (ORCPT ); Wed, 16 Nov 2016 03:17:14 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:40122 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751955AbcKPIRL (ORCPT ); Wed, 16 Nov 2016 03:17:11 -0500 DMARC-Filter: OpenDMARC Filter v1.3.1 smtp.codeaurora.org B1162614F8 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=pass smtp.mailfrom=architt@codeaurora.org Subject: Re: [linux-sunxi] Re: [PATCH v3 1/2] drm/bridge: dumb-vga-dac: Support a VDD regulator supply To: Chen-Yu Tsai References: <20161029110611.28951-1-wens@csie.org> <20161029110611.28951-2-wens@csie.org> <20161031062836.mnzdprqfezrfkx4g@rob-hp-laptop> Cc: David Airlie , Rob Herring , Maxime Ripard , Mark Rutland , dri-devel , linux-arm-kernel , linux-kernel , devicetree , linux-sunxi From: Archit Taneja Message-ID: <8cda4dc8-8804-c34c-3a64-53c0ee01f2e8@codeaurora.org> Date: Wed, 16 Nov 2016 13:47:03 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5253 Lines: 172 Hi, On 11/15/2016 08:29 AM, Chen-Yu Tsai wrote: > Hi, > > On Wed, Nov 2, 2016 at 9:33 AM, Chen-Yu Tsai wrote: >> On Mon, Oct 31, 2016 at 2:28 PM, Rob Herring wrote: >>> On Sat, Oct 29, 2016 at 07:06:10PM +0800, Chen-Yu Tsai wrote: >>>> Some dumb VGA DACs are active components which require external power. >>>> Add support for specifying a regulator as its power supply. >>>> >>>> Signed-off-by: Chen-Yu Tsai >>>> --- >>>> .../bindings/display/bridge/dumb-vga-dac.txt | 2 ++ >>> >>> For the binding, >>> >>> Acked-by: Rob Herring > > Any comments on this patch from the DRM people? A comment below. > > ChenYu > >>> >>> One code comment below... >>> >>>> drivers/gpu/drm/bridge/dumb-vga-dac.c | 35 ++++++++++++++++++++++ >>>> 2 files changed, 37 insertions(+) >>>> >>>> diff --git a/Documentation/devicetree/bindings/display/bridge/dumb-vga-dac.txt b/Documentation/devicetree/bindings/display/bridge/dumb-vga-dac.txt >>>> index 003bc246a270..164cbb15f04c 100644 >>>> --- a/Documentation/devicetree/bindings/display/bridge/dumb-vga-dac.txt >>>> +++ b/Documentation/devicetree/bindings/display/bridge/dumb-vga-dac.txt >>>> @@ -16,6 +16,8 @@ graph bindings specified in Documentation/devicetree/bindings/graph.txt. >>>> - Video port 0 for RGB input >>>> - Video port 1 for VGA output >>>> >>>> +Optional properties: >>>> +- vdd-supply: Power supply for DAC >>>> >>>> Example >>>> ------- >>>> diff --git a/drivers/gpu/drm/bridge/dumb-vga-dac.c b/drivers/gpu/drm/bridge/dumb-vga-dac.c >>>> index afec232185a7..59781e031220 100644 >>>> --- a/drivers/gpu/drm/bridge/dumb-vga-dac.c >>>> +++ b/drivers/gpu/drm/bridge/dumb-vga-dac.c >>>> @@ -12,6 +12,7 @@ >>>> >>>> #include >>>> #include >>>> +#include >>>> >>>> #include >>>> #include >>>> @@ -23,6 +24,7 @@ struct dumb_vga { >>>> struct drm_connector connector; >>>> >>>> struct i2c_adapter *ddc; >>>> + struct regulator *vdd; >>>> }; >>>> >>>> static inline struct dumb_vga * >>>> @@ -124,8 +126,33 @@ static int dumb_vga_attach(struct drm_bridge *bridge) >>>> return 0; >>>> } >>>> >>>> +static void dumb_vga_enable(struct drm_bridge *bridge) >>>> +{ >>>> + struct dumb_vga *vga = drm_bridge_to_dumb_vga(bridge); >>>> + int ret; >>>> + >>>> + if (!IS_ERR(vga->vdd)) { >>> >>> if (IS_ERR()) >>> return; >>> >>> ...will save some intentation. >> >> I thought about that, though if someone were to add more stuff to >> this, such as an enable GPIO, they might have to rework it. A standalone >> block of code would be easier to work with. I'm OK either way though. >> >> ChenYu >> >>> >>>> + ret = regulator_enable(vga->vdd); >>>> + >>>> + if (ret) { >>>> + DRM_ERROR("Failed to enable vdd regulator: %d\n", ret); >>>> + return; >>>> + } >>>> + } >>>> +} >>>> + >>>> +static void dumb_vga_disable(struct drm_bridge *bridge) >>>> +{ >>>> + struct dumb_vga *vga = drm_bridge_to_dumb_vga(bridge); >>>> + >>>> + if (!IS_ERR(vga->vdd)) >>>> + regulator_disable(vga->vdd); >>>> +} >>>> + >>>> static const struct drm_bridge_funcs dumb_vga_bridge_funcs = { >>>> .attach = dumb_vga_attach, >>>> + .enable = dumb_vga_enable, >>>> + .disable = dumb_vga_disable, >>>> }; >>>> >>>> static struct i2c_adapter *dumb_vga_retrieve_ddc(struct device *dev) >>>> @@ -169,6 +196,14 @@ static int dumb_vga_probe(struct platform_device *pdev) >>>> return -ENOMEM; >>>> platform_set_drvdata(pdev, vga); >>>> >>>> + vga->vdd = devm_regulator_get_optional(&pdev->dev, "vdd"); >>>> + if (IS_ERR(vga->vdd)) { >>>> + ret = PTR_ERR(vga->vdd); >>>> + if (ret == -EPROBE_DEFER) >>>> + return -EPROBE_DEFER; >>>> + dev_dbg(&pdev->dev, "No vdd regulator found: %d\n", ret); A cleaner way would be to set vga->vdd to NULL here, and do: int ret = 0; if (vga->vdd) ret = regulator_enable(vga->vdd); if (ret) { ... return; } /* if a gpio is added later */ if (vga->gpio) ret = gpiod_set_value_cansleep(vga->gpio, 1); if (ret) { ... return; } ... We don't really care what error code is contained in vga->vdd once we have identified whether we got a regulator or not. The same thing can be done for ddc too, but that can done left for later. If you're okay with the suggestion, can you re-spin a patch? Thanks, Archit >>>> + } >>>> + >>>> vga->ddc = dumb_vga_retrieve_ddc(&pdev->dev); >>>> if (IS_ERR(vga->ddc)) { >>>> if (PTR_ERR(vga->ddc) == -ENODEV) { >>>> -- >>>> 2.9.3 >>>> >>> >>> -- >>> You received this message because you are subscribed to the Google Groups "linux-sunxi" group. >>> To unsubscribe from this group and stop receiving emails from it, send an email to linux-sunxi+unsubscribe@googlegroups.com. >>> For more options, visit https://groups.google.com/d/optout. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project