From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Subject: Re: [RFC PATCH v3 16/18] gpu: host1x: mipi: Split tegra_mipi_calibrate and tegra_mipi_wait Date: Thu, 16 Jul 2020 23:38:27 +0300 Message-ID: References: <1594786855-26506-1-git-send-email-skomatineni@nvidia.com> <1594786855-26506-17-git-send-email-skomatineni@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <1594786855-26506-17-git-send-email-skomatineni-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> Content-Language: en-US Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Sowjanya Komatineni , thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, frankc-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, hverkuil-qWit8jRvyhVmR6Xm/wNWPw@public.gmane.org, sakari.ailus-X3B1VOXEql0@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, helen.koike-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org Cc: sboyd-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, linux-media-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-tegra@vger.kernel.org 15.07.2020 07:20, Sowjanya Komatineni пишет: > SW can trigger MIPI pads calibration any time after power on > but calibration results will be latched and applied to the pads > by MIPI CAL unit only when the link is in LP-11 state and then > status register will be updated. > > For CSI, trigger of pads calibration happen during CSI stream > enable where CSI receiver is kept ready prior to sensor or CSI > transmitter stream start. > > So, pads may not be in LP-11 at this time and waiting for the > calibration to be done immediate after calibration start will > result in timeout. > > This patch splits tegra_mipi_calibrate() and tegra_mipi_wait() > so triggering for calibration and waiting for it to complete can > happen at different stages. > > Signed-off-by: Sowjanya Komatineni > --- ... > int tegra_mipi_calibrate(struct tegra_mipi_device *device) > { > @@ -370,12 +381,10 @@ int tegra_mipi_calibrate(struct tegra_mipi_device *device) > value |= MIPI_CAL_CTRL_START; > tegra_mipi_writel(device->mipi, value, MIPI_CAL_CTRL); > > - err = tegra_mipi_wait(device->mipi); Doesn't MIPI clock need to be enabled during of the calibration process? > mutex_unlock(&device->mipi->lock); > clk_disable(device->mipi->clk); > > - return err; > + return 0; > } > EXPORT_SYMBOL(tegra_mipi_calibrate);