From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Subject: Re: [RFC PATCH v1 05/18] i2c: tegra: Fix runtime resume to re-init VI I2C Date: Wed, 10 Jun 2020 16:14:49 +0300 Message-ID: References: <1591768960-31648-1-git-send-email-skomatineni@nvidia.com> <1591768960-31648-6-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: <1591768960-31648-6-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 10.06.2020 09:02, Sowjanya Komatineni пишет: > VI I2C is on host1x bus and is part of VE power domain. > > During suspend/resume VE power domain goes through power off/on. > > So, controller reset followed by i2c re-initialization is required > after the domain power up. > > This patch fixes it. > > Signed-off-by: Sowjanya Komatineni > --- > drivers/i2c/busses/i2c-tegra.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c > index dba38a5..650240d 100644 > --- a/drivers/i2c/busses/i2c-tegra.c > +++ b/drivers/i2c/busses/i2c-tegra.c > @@ -293,6 +293,8 @@ struct tegra_i2c_dev { > bool is_curr_atomic_xfer; > }; > > +static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev, bool clk_reinit); > + > static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val, > unsigned long reg) > { > @@ -679,8 +681,22 @@ static int __maybe_unused tegra_i2c_runtime_resume(struct device *dev) > goto disable_slow_clk; > } > > + /* > + * VI I2C device is attached to VE power domain which goes through > + * power ON/OFF during PM runtime resume/suspend. So, controller > + * should go through reset and need to re-initialize after power > + * domain ON. > + */ > + if (i2c_dev->is_vi) { > + ret = tegra_i2c_init(i2c_dev, true); > + if (ret) > + goto disable_div_clk; > + } > + > return 0; > > +disable_div_clk: > + clk_disable(i2c_dev->div_clk); > disable_slow_clk: > if (i2c_dev->slow_clk) > clk_disable(i2c_dev->slow_clk); > The clk_disable() can cope with a NULL argument. Won't it be cleaner to remove the conditions?