From: Heiko Stuebner <heiko@sntech.de>
To: Mark yao <mark.yao@rock-chips.com>
Cc: Mark Rutland <mark.rutland@arm.com>, devicetree@vger.kernel.org,
        David Airlie <airlied@linux.ie>, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org, linux-rockchip@lists.infradead.org,
        Rob Herring <robh+dt@kernel.org>, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3.1 1/3] drm/rockchip: dw_hdmi: add RK3399 HDMI support
Date: Thu, 22 Jun 2017 10:25:49 +0200
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Am Donnerstag, 22. Juni 2017, 16:02:44 CEST schrieb Mark yao:
> On 2017年06月22日 15:31, Heiko Stuebner wrote:
> >> +
> >> >+/**
> >> >+ * struct rockchip_hdmi_chip_data - splite the grf setting of kind of chips
> >> >+ * @lcdsel_grf_reg: grf register offset of lcdc select
> >> >+ * @lcdsel_big: reg value of selecting vop big for HDMI
> >> >+ * @lcdsel_lit: reg value of selecting vop little for HDMI
> >> >+ */
> >> >+struct rockchip_hdmi_chip_data {
> >> >+	u32	lcdsel_grf_reg;
> > How do you plan on handling the rk3368 (with only one VOP and thus
> > no selection happening)? I'd just make the above an int, so we could
> > set it to -1 for that case. (value 0 is after all a valid reg).
> 
> It's a problem handling on rk3368, using -1 to judge means that we need
> initial the lcdsel_grf_reg to -1 on rk3368 platform, we need always add a platform
> data to handle it, seems not good enough.
> 
> Since the hdmi chip data only use for vop selection, maybe we can judge with
> checking hdmi->chip_data == NULL for the case.

yeah, that could work as well ... as long as the grf-vop-select is the only chip-data