Re: [PATCH v9 10/17] phy: Add driver for rockchip Display Port PHY

From: Yakir Yang <ykk@rock-chips.com>
To: Brian Norris <computersforpeace@gmail.com>
Cc: Inki Dae <inki.dae@samsung.com>,
	Andrzej Hajda <a.hajda@samsung.com>,
	Joonyoung Shim <jy0922.shim@samsung.com>,
	Seung-Woo Kim <sw0312.kim@samsung.com>,
	Kyungmin Park <kyungmin.park@samsung.com>,
	Jingoo Han <jingoohan1@gmail.com>,
	Thierry Reding <treding@nvidia.com>,
	Krzysztof Kozlowski <k.kozlowski@samsung.com>,
	Rob Herring <robh+dt@kernel.org>,
	Heiko Stuebner <heiko@sntech.de>,
	Mark Yao <mark.yao@rock-chips.com>,
	djkurtz@chromium.org, dianders@chromium.org,
	Gustavo Padovan <gustavo.padovan@collabora.co.uk>,
	linux-samsung-soc@vger.kernel.org,
	Russell King <linux@arm.linux.org.uk>,
	linux-rockchip@lists.infradead.org,
	Kishon Vijay Abraham I <kishon@ti.com>,
	javier@osg.samsung.com, Kukjin Kim <kgene@kernel.org>,
	robherring2@gmail.com, devicetree@vger.kernel.org,
	Pawel Moll <pawel.moll@arm.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Sean Paul <seanpaul@chromium.org>,
	dri-devel@lists.freedesktop.org,
	linux-arm-kernel@lists.infradead.org, emil.l.velikov@gmail.com,
	linux-kernel@vger.kernel.org, Kumar Gala <galak@codeaurora.org>,
	ajaynumb@gmail.com, Andy Yan <andy.yan@rock-chips.com>
Subject: Re: [PATCH v9 10/17] phy: Add driver for rockchip Display Port PHY
Date: Wed, 4 Nov 2015 08:48:38 +0800	[thread overview]
Message-ID: <563955E6.7000905@rock-chips.com> (raw)
In-Reply-To: <20151103043827.GA17261@localhost>

Hi Brain,

On 11/03/2015 12:38 PM, Brian Norris wrote:
> Hi Yakir,
>
> On Thu, Oct 29, 2015 at 09:58:38AM +0800, Yakir Yang wrote:
>> Add phy driver for the Rockchip DisplayPort PHY module. This
>> is required to get DisplayPort working in Rockchip SoCs.
>>
>> Reviewed-by: Heiko Stuebner<heiko@sntech.de>
>> Signed-off-by: Yakir Yang<ykk@rock-chips.com>
>> ---
> ...
>> diff --git a/drivers/phy/phy-rockchip-dp.c b/drivers/phy/phy-rockchip-dp.c
>> new file mode 100644
>> index 0000000..f3e0058
>> --- /dev/null
>> +++ b/drivers/phy/phy-rockchip-dp.c
>> @@ -0,0 +1,151 @@
>> +/*
>> + * Rockchip DP PHY driver
>> + *
>> + * Copyright (C) 2015 FuZhou Rockchip Co., Ltd.
>> + * Author: Yakir Yang<ykk@@rock-chips.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License.
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/clk.h>
>> +#include <linux/phy/phy.h>
>> +#include <linux/regmap.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/platform_device.h>
>> +
>> +#define GRF_SOC_CON12                           0x0274
>> +
>> +#define GRF_EDP_REF_CLK_SEL_INTER_HIWORD_MASK   BIT(4)
>> +#define GRF_EDP_REF_CLK_SEL_INTER               BIT(4)
> Why are the above two macros the same? Judging by the RK3288 manual and
> other downstream drivers, it seems like you want the _MASK one to be
> shifted left by 16 (i.e., BIT(20)).

Oops, yes, you're right, it should be BIT(20), thanks for the catch.

>> +
>> +#define GRF_EDP_PHY_SIDDQ_HIWORD_MASK           BIT(21)
>> +#define GRF_EDP_PHY_SIDDQ_ON                    0
>> +#define GRF_EDP_PHY_SIDDQ_OFF                   BIT(5)
>> +
> ...
>
>> +	ret = regmap_write(dp->grf, GRF_SOC_CON12, GRF_EDP_REF_CLK_SEL_INTER |
>> +			   GRF_EDP_REF_CLK_SEL_INTER_HIWORD_MASK);
> IOW, the above is writing:
>
> 	BIT(4) | BIT(4)
>
> whereas I think you want:
>
> 	BIT(4) | BIT(20)
>
>> +	if (ret != 0) {
>> +		dev_err(dp->dev, "Could not config GRF edp ref clk: %d\n", ret);
>> +		return ret;
>> +	}
>> +
> ...
>
> (FYI, I came across this by inspection when comparing Heiko's
> 'somewhat-stable' branch [1] with this series. The former brings up eDP
> fine on veyron-jaq, whereas this one doesn't yet, even with the above
> change. Still debugging the issue.)

Hmm... I'm not sure whether your eDP screen have the hotplug signal, so I
think you can try to add "analogix,force-hpd" flag into 
rk3288-veyron-jaq.dts

&edp {
     analogix,need-force-hpd;
}


If that changes couldn't fix the problem, guess you may need max the panel
power up delay time which pointed by Heiko. Like:

Thanks,
- Yakir

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c 
b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 4fa5f69..546a506 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -82,6 +82,13 @@ static int analogix_dp_detect_hpd(struct 
analogix_dp_device *dp)
          */
         dev_dbg(dp->dev, "failed to get hpd plug status, try to force 
hpd\n");

+       /*
+        * Hotplug signal would indicate the right time to operate
+        * panel after poweron, but if the hotplug is missing, then
+        * panel would need wait hundreds of milliseconds at here.
+        */
+       mdelay(100);
+
         analogix_dp_force_hpd(dp);

         if (analogix_dp_get_plug_in_status(dp) != 0) {


> Brian
>
> [1]https://github.com/mmind/linux-rockchip/tree/devel/somewhat-stable
>
>
>


