From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sowjanya Komatineni Subject: Re: [RFC PATCH v1 05/18] i2c: tegra: Fix runtime resume to re-init VI I2C Date: Wed, 10 Jun 2020 09:58:28 -0700 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"; format=flowed Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: Content-Language: en-US Sender: linux-i2c-owner@vger.kernel.org To: Dmitry Osipenko , 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 List-Id: linux-tegra@vger.kernel.org On 6/10/20 6:14 AM, Dmitry Osipenko wrote: > 10.06.2020 09:02, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >> 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-teg= ra.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; >> }; >> =20 >> +static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev, bool clk_reini= t); >> + >> 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; >> } >> =20 >> + /* >> + * 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 =3D tegra_i2c_init(i2c_dev, true); >> + if (ret) >> + goto disable_div_clk; >> + } >> + >> return 0; >> =20 >> +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? will remove in v2