From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH v2 6/6] i2c: i2c-stm32f7: Implement I2C recovery mechanism Date: Sat, 24 Mar 2018 23:56:30 +0100 Message-ID: <20180324225630.6jen6mvboxbhyp7n@ninjato> References: <1521650940-11651-1-git-send-email-pierre-yves.mordret@st.com> <1521650940-11651-7-git-send-email-pierre-yves.mordret@st.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="5dzygghgbjypbybi" Return-path: Content-Disposition: inline In-Reply-To: <1521650940-11651-7-git-send-email-pierre-yves.mordret@st.com> Sender: linux-kernel-owner@vger.kernel.org To: Pierre-Yves MORDRET Cc: Maxime Coquelin , Alexandre Torgue , linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org List-Id: linux-i2c@vger.kernel.org --5dzygghgbjypbybi Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Mar 21, 2018 at 05:49:00PM +0100, Pierre-Yves MORDRET wrote: > Feature prevents I2C lock-ups. Mechanism resets I2C state machine > and releases SCL/SDA signals but preserves I2C registers. >=20 > Signed-off-by: Pierre-Yves MORDRET > --- > Version history: > v1: > * Initial > v2: > * Don't use i2c engine recovery mechanism since driver > procedure only recover master and not the slave. s/recovery/release/ throughout the patch, please. Recovery is really something else. Also, I think the dev_info's are too noisy in the log files. I'd think the whole driver could be lifted from quite some logging... > --- > --- > drivers/i2c/busses/i2c-stm32f7.c | 27 ++++++++++++++++++++++++--- > 1 file changed, 24 insertions(+), 3 deletions(-) >=20 > diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-st= m32f7.c > index 91f73e0..9a9c469 100644 > --- a/drivers/i2c/busses/i2c-stm32f7.c > +++ b/drivers/i2c/busses/i2c-stm32f7.c > @@ -718,6 +718,20 @@ static void stm32f7_i2c_smbus_reload(struct stm32f7_= i2c_dev *i2c_dev) > writel_relaxed(cr2, i2c_dev->base + STM32F7_I2C_CR2); > } > =20 > +static int stm32f7_i2c_recover_bus(struct i2c_adapter *i2c_adap) > +{ > + struct stm32f7_i2c_dev *i2c_dev =3D i2c_get_adapdata(i2c_adap); > + > + dev_info(i2c_dev->dev, "Trying to recover bus\n"); > + > + stm32f7_i2c_clr_bits(i2c_dev->base + STM32F7_I2C_CR1, > + STM32F7_I2C_CR1_PE); > + > + stm32f7_i2c_hw_config(i2c_dev); > + > + return 0; > +} > + > static int stm32f7_i2c_wait_free_bus(struct stm32f7_i2c_dev *i2c_dev) > { > u32 status; > @@ -727,12 +741,18 @@ static int stm32f7_i2c_wait_free_bus(struct stm32f7= _i2c_dev *i2c_dev) > status, > !(status & STM32F7_I2C_ISR_BUSY), > 10, 1000); > + if (!ret) > + return 0; > + > + dev_info(i2c_dev->dev, "bus busy\n"); > + > + ret =3D stm32f7_i2c_recover_bus(&i2c_dev->adap); > if (ret) { > - dev_dbg(i2c_dev->dev, "bus busy\n"); > - ret =3D -EBUSY; > + dev_err(i2c_dev->dev, "Failed to recover the bus (%d)\n", ret); > + return ret; > } > =20 > - return ret; > + return -EBUSY; > } > =20 > static void stm32f7_i2c_xfer_msg(struct stm32f7_i2c_dev *i2c_dev, > @@ -1474,6 +1494,7 @@ static irqreturn_t stm32f7_i2c_isr_error(int irq, v= oid *data) > if (status & STM32F7_I2C_ISR_BERR) { > dev_err(dev, "<%s>: Bus error\n", __func__); > writel_relaxed(STM32F7_I2C_ICR_BERRCF, base + STM32F7_I2C_ICR); > + stm32f7_i2c_recover_bus(&i2c_dev->adap); > f7_msg->result =3D -EIO; > } > =20 > --=20 > 2.7.4 >=20 --5dzygghgbjypbybi Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAlq2154ACgkQFA3kzBSg KbbawxAAoUJEkzVgRc9G3hSNXNQr+fGgbL2zXJySwNx3ps8EsW22qCM2ROrABtqS uAy6YJyWoF/bcjlVTK9uHc1Jxv8P2DXQuj8GgCUSpKK+Uh/VoNV/2Pshj5iRIPMo ZwCWqFUpER11RKW3UDY9wqPiy6+TglI/5KHzaXvfyj4//7haLs9kc8QKg2Juq9uZ VXCIHrhkekIbHIPDOhh5iASKQ+DsTfb40Jb0K34VFT2hgF8/WGqZnqIJ9zfVFi+6 6NnlbQqGoPmjBe6CUWgXrL510GueMG0/dyeZITlQ5SHI1+LI1NIYleCaAnDSWI1v /ijL5cfQBPQvkzcSvR3AWLp7pv6/2OqHqLQTxvXOdweb/GovpecRcsKdYFC8rW/Z o+rgF1iqmg8NkqgLn4FtIcrH/HawIfTHAmU/NFihQZKLqwlET9voizrM0fGUexRN VrddMntfaFyTkOokeyiylR00egDyRMWhR5ZiYK+OgPxG8QT5l6CbCUSD9He3oVls d6YZrM2A11o0ScPTloTqMaBPSDedpUojhIkLz0EtjxqdEI4zxAA3INwcko13zByV +UCMYo3jZ3eI2RrA6uFUAVYlRV+8ftgB8MYxyLF8MaUSrB/l2UX6AfIc7m2F63Z/ S7JJdeYxRspkWdvqeO3yFZt/QW+w4BGniG/ugui+N4oZu+XmHGA= =sZuR -----END PGP SIGNATURE----- --5dzygghgbjypbybi--