Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161297AbaKNNqL (ORCPT ); Fri, 14 Nov 2014 08:46:11 -0500 Received: from va-smtp01.263.net ([54.88.144.211]:49103 "EHLO va-smtp01.263.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161250AbaKNNqI (ORCPT ); Fri, 14 Nov 2014 08:46:08 -0500 X-RL-SENDER: andy.yan@rock-chips.com X-FST-TO: airlied@linux.ie X-SENDER-IP: 127.0.0.1 X-LOGIN-NAME: andy.yan@rock-chips.com X-UNIQUE-TAG: <8deb6cbad009c32c7331768253f9aa82> X-ATTACHMENT-NUM: 0 X-DNS-TYPE: 1 From: Andy Yan To: airlied@linux.ie, heiko@sntech.de, fabio.estevam@freescale.com, rmk+kernel@arm.linux.org.uk Cc: Greg Kroah-Hartman , Grant Likely , Rob Herring , Philipp Zabel , Shawn Guo , Andy yan , Josh Boyer , Sean Paul , Inki Dae , Dave Airlie , Arnd Bergmann , Lucas Stach , Zubair.Kakakhel@imgtec.com, djkurtz@google.com, ykk@rock-chips.com, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, devel@driverdev.osuosl.org, devicetree@vger.kernel.org, linux-rockchip@lists.infradead.org, jay.xu@rock-chips.com, Pawel Moll , mark.yao@rock-chips.com, Mark Rutland , Ian Campbell , Kumar Gala Subject: [PATCH v11 09/12] drm: bridge/dw_hdmi: clear i2cmphy_stat0 reg in hdmi_phy_wait_i2c_done Date: Fri, 14 Nov 2014 21:45:41 +0800 Message-Id: <1415972741-8718-1-git-send-email-andy.yan@rock-chips.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1415972231-8283-1-git-send-email-andy.yan@rock-chips.com> References: <1415972231-8283-1-git-send-email-andy.yan@rock-chips.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org HDMI_IH_I2CMPHY_STAT0 is a clear on write register, which indicates i2cm operation status(i2c transfer done or error), every hdmi phy register configuration must check this register to make sure the configuration has complete. But the indication bit should be cleared after check, otherwise the corresponding bit will hold on forever, this may give a wrong signal for next check. Signed-off-by: Andy Yan --- Changes in v11: - split form patch Changes in v10: None Changes in v9: None Changes in v8: None Changes in v7: None Changes in v6: None Changes in v5: None Changes in v4: None Changes in v3: None Changes in v2: None drivers/gpu/drm/bridge/dw_hdmi.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c b/drivers/gpu/drm/bridge/dw_hdmi.c index e94f6bb..d5d5207 100644 --- a/drivers/gpu/drm/bridge/dw_hdmi.c +++ b/drivers/gpu/drm/bridge/dw_hdmi.c @@ -668,11 +668,15 @@ static inline void hdmi_phy_test_dout(struct dw_hdmi *hdmi, static bool hdmi_phy_wait_i2c_done(struct dw_hdmi *hdmi, int msec) { - while ((hdmi_readb(hdmi, HDMI_IH_I2CMPHY_STAT0) & 0x3) == 0) { + u32 val; + + while ((val = hdmi_readb(hdmi, HDMI_IH_I2CMPHY_STAT0) & 0x3) == 0) { if (msec-- == 0) return false; udelay(1000); } + hdmi_writeb(hdmi, val, HDMI_IH_I2CMPHY_STAT0); + return true; } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/