From mboxrd@z Thu Jan 1 00:00:00 1970 From: Subject: [PATCH v4 2/3] i2c: davinci: use bus recovery infrastructure Date: Mon, 6 Apr 2015 15:38:40 +0300 Message-ID: <1428323921-25832-3-git-send-email-grygorii.strashko@linaro.org> References: <1428323921-25832-1-git-send-email-grygorii.strashko@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1428323921-25832-1-git-send-email-grygorii.strashko-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Wolfram Sang , Sekhar Nori , =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Cc: grygorii.strashko-l0cyMroinI0@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Kevin Hilman , Santosh Shilimkar , Murali Karicheri , Alexander Sverdlin List-Id: linux-i2c@vger.kernel.org =46rom: Grygorii Strashko This patch converts Davinci I2C driver to use I2C bus recovery infrastructure, introduced by commit 5f9296ba21b3 ("i2c: Add bus recovery infrastructure"). The i2c_bus_recovery_info is configured for Davinci I2C adapter only in case scl_pin is provided in platform data. As the controller must be held in reset while doing so, the recovery routine must re-init the controller. Since this was already being done after each call to i2c_recover_bus, move those calls into the recovery_prepare/unprepare routines and as well. CC: Sekhar Nori CC: Kevin Hilman CC: Santosh Shilimkar CC: Murali Karicheri CC: Alexander Sverdlin Acked-by: Uwe Kleine-K=C3=B6nig Signed-off-by: Grygorii Strashko --- drivers/i2c/busses/i2c-davinci.c | 77 +++++++++++++++++++-------------= -------- 1 file changed, 36 insertions(+), 41 deletions(-) diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-= davinci.c index 120a4ef..54819fb 100644 --- a/drivers/i2c/busses/i2c-davinci.c +++ b/drivers/i2c/busses/i2c-davinci.c @@ -129,43 +129,6 @@ static inline u16 davinci_i2c_read_reg(struct davi= nci_i2c_dev *i2c_dev, int reg) return readw_relaxed(i2c_dev->base + reg); } =20 -/* Generate a pulse on the i2c clock pin. */ -static void davinci_i2c_clock_pulse(unsigned int scl_pin) -{ - u16 i; - - if (scl_pin) { - /* Send high and low on the SCL line */ - for (i =3D 0; i < 9; i++) { - gpio_set_value(scl_pin, 0); - udelay(20); - gpio_set_value(scl_pin, 1); - udelay(20); - } - } -} - -/* This routine does i2c bus recovery as specified in the - * i2c protocol Rev. 03 section 3.16 titled "Bus clear" - */ -static void davinci_i2c_recover_bus(struct davinci_i2c_dev *dev) -{ - u32 flag =3D 0; - struct davinci_i2c_platform_data *pdata =3D dev->pdata; - - dev_err(dev->dev, "initiating i2c bus recovery\n"); - /* Send NACK to the slave */ - flag =3D davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); - flag |=3D DAVINCI_I2C_MDR_NACK; - /* write the data into mode register */ - davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag); - davinci_i2c_clock_pulse(pdata->scl_pin); - /* Send STOP */ - flag =3D davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); - flag |=3D DAVINCI_I2C_MDR_STP; - davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag); -} - static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_= dev, int val) { @@ -263,6 +226,34 @@ static int i2c_davinci_init(struct davinci_i2c_dev= *dev) } =20 /* + * This routine does i2c bus recovery by using i2c_generic_gpio_recove= ry + * which is provided by I2C Bus recovery infrastructure. + */ +static void davinci_i2c_prepare_recovery(struct i2c_adapter *adap) +{ + struct davinci_i2c_dev *dev =3D i2c_get_adapdata(adap); + + /* Disable interrupts */ + davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, 0); + + /* put I2C into reset */ + davinci_i2c_reset_ctrl(dev, 0); +} + +static void davinci_i2c_unprepare_recovery(struct i2c_adapter *adap) +{ + struct davinci_i2c_dev *dev =3D i2c_get_adapdata(adap); + + i2c_davinci_init(dev); +} + +static struct i2c_bus_recovery_info davinci_i2c_gpio_recovery_info =3D= { + .recover_bus =3D i2c_generic_gpio_recovery, + .prepare_recovery =3D davinci_i2c_prepare_recovery, + .unprepare_recovery =3D davinci_i2c_unprepare_recovery, +}; + +/* * Waiting for bus not busy */ static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev, @@ -282,8 +273,7 @@ static int i2c_davinci_wait_bus_not_busy(struct dav= inci_i2c_dev *dev, return -ETIMEDOUT; } else { to_cnt =3D 0; - davinci_i2c_recover_bus(dev); - i2c_davinci_init(dev); + i2c_recover_bus(&dev->adapter); } } if (allow_sleep) @@ -372,8 +362,7 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, stru= ct i2c_msg *msg, int stop) dev->adapter.timeout); if (!time_left) { dev_err(dev->dev, "controller timed out\n"); - davinci_i2c_recover_bus(dev); - i2c_davinci_init(dev); + i2c_recover_bus(adap); dev->buf_len =3D 0; return -ETIMEDOUT; } @@ -712,6 +701,12 @@ static int davinci_i2c_probe(struct platform_devic= e *pdev) adap->timeout =3D DAVINCI_I2C_TIMEOUT; adap->dev.of_node =3D pdev->dev.of_node; =20 + if (dev->pdata->scl_pin) { + adap->bus_recovery_info =3D &davinci_i2c_gpio_recovery_info; + adap->bus_recovery_info->scl_gpio =3D dev->pdata->scl_pin; + adap->bus_recovery_info->sda_gpio =3D dev->pdata->sda_pin; + } + adap->nr =3D pdev->id; r =3D i2c_add_numbered_adapter(adap); if (r) { --=20 1.9.1