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[79.139.237.54]) by smtp.googlemail.com with ESMTPSA id n1sm4994529ljg.131.2020.06.10.06.14.50 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 10 Jun 2020 06:14:51 -0700 (PDT) Subject: Re: [RFC PATCH v1 05/18] i2c: tegra: Fix runtime resume to re-init VI I2C To: Sowjanya Komatineni , thierry.reding@gmail.com, jonathanh@nvidia.com, frankc@nvidia.com, hverkuil@xs4all.nl, sakari.ailus@iki.fi, robh+dt@kernel.org, helen.koike@collabora.com Cc: sboyd@kernel.org, gregkh@linuxfoundation.org, linux-media@vger.kernel.org, devicetree@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org References: <1591768960-31648-1-git-send-email-skomatineni@nvidia.com> <1591768960-31648-6-git-send-email-skomatineni@nvidia.com> From: Dmitry Osipenko Message-ID: Date: Wed, 10 Jun 2020 16:14:49 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <1591768960-31648-6-git-send-email-skomatineni@nvidia.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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?