Ping... > -----Original Message----- > From: Gao Pan [mailto:b54642@xxxxxxxxxxxxx] > Sent: Friday, July 17, 2015 10:37 AM > To: wsa@xxxxxxxxxxxxx > Cc: linux-i2c@xxxxxxxxxxxxxxx; Li Frank-B20596; Duan Fugang-B38611; Gao > Pan-B54642; u.kleine-koenig@xxxxxxxxxxxxxx > Subject: [Patch v2] i2c: imx: implement bus recovery > > Implement bus recovery methods for i2c-imx so we can recover from > situations where SCL/SDA are stuck low. > > Once i2c bus SCL/SDA are stuck low during transfer, config the i2c > pinctrl to gpio mode by calling pinctrl sleep set function, and then use > GPIO to emulate the i2c protocol to send nine dummy clock to recover i2c > device. After recovery, set i2c pinctrl to default group setting. > > V2: > As Uwe Kleine-König's suggestion, the version do below changes: > -replace of_get_named_gpio() with devm_gpiod_get_optional() -move > gpio_direction_input() and gpio_direction_output() call to the > prepare callback > -use 0 and 1 as return value for the get_scl and get_sda callbacks > > Signed-off-by: Fugang Duan <B38611@xxxxxxxxxxxxx> > Signed-off-by: Gao Pan <b54642@xxxxxxxxxxxxx> > --- > Documentation/devicetree/bindings/i2c/i2c-imx.txt | 4 + > drivers/i2c/busses/i2c-imx.c | 104 > ++++++++++++++++++++-- > 2 files changed, 100 insertions(+), 8 deletions(-) > > diff --git a/Documentation/devicetree/bindings/i2c/i2c-imx.txt > b/Documentation/devicetree/bindings/i2c/i2c-imx.txt > index ce4311d..a9fe525 100644 > --- a/Documentation/devicetree/bindings/i2c/i2c-imx.txt > +++ b/Documentation/devicetree/bindings/i2c/i2c-imx.txt > @@ -14,6 +14,8 @@ Optional properties: > The absence of the propoerty indicates the default frequency 100 kHz. > - dmas: A list of two dma specifiers, one for each entry in dma-names. > - dma-names: should contain "tx" and "rx". > +- scl-gpio: specify the gpio related to SCL pin > +- sda-gpio: specify the gpio related to SDA pin > > Examples: > > @@ -37,4 +39,6 @@ i2c0: i2c@40066000 { /* i2c0 on vf610 */ > dmas = <&edma0 0 50>, > <&edma0 0 51>; > dma-names = "rx","tx"; > + scl-gpio = <&gpio5 26 0>; > + sda-gpio = <&gpio5 27 0>; > }; > diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c > index 785aa67..4f75370 100644 > --- a/drivers/i2c/busses/i2c-imx.c > +++ b/drivers/i2c/busses/i2c-imx.c > @@ -40,6 +40,7 @@ > #include <linux/dmapool.h> > #include <linux/err.h> > #include <linux/errno.h> > +#include <linux/gpio.h> > #include <linux/i2c.h> > #include <linux/init.h> > #include <linux/interrupt.h> > @@ -48,6 +49,7 @@ > #include <linux/module.h> > #include <linux/of.h> > #include <linux/of_device.h> > +#include <linux/of_gpio.h> > #include <linux/of_dma.h> > #include <linux/platform_data/i2c-imx.h> #include > <linux/platform_device.h> @@ -175,6 +177,11 @@ enum imx_i2c_type { > VF610_I2C, > }; > > +struct imx_i2c_pinctrl { > + struct gpio_desc *sda; > + struct gpio_desc *scl; > +}; > + > struct imx_i2c_hwdata { > enum imx_i2c_type devtype; > unsigned regshift; > @@ -206,6 +213,7 @@ struct imx_i2c_struct { > unsigned int ifdr; /* IMX_I2C_IFDR */ > unsigned int cur_clk; > unsigned int bitrate; > + struct imx_i2c_pinctrl pins; > const struct imx_i2c_hwdata *hwdata; > > struct imx_i2c_dma *dma; > @@ -436,7 +444,7 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct > *i2c_imx, int for_busy) > if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) > { > dev_dbg(&i2c_imx->adapter.dev, > "<%s> I2C bus is busy\n", __func__); > - return -ETIMEDOUT; > + return i2c_recover_bus(&i2c_imx->adapter); > } > schedule(); > } > @@ -450,7 +458,7 @@ static int i2c_imx_trx_complete(struct imx_i2c_struct > *i2c_imx) > > if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) { > dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__); > - return -ETIMEDOUT; > + return i2c_recover_bus(&i2c_imx->adapter); > } > dev_dbg(&i2c_imx->adapter.dev, "<%s> TRX complete\n", __func__); > i2c_imx->i2csr = 0; > @@ -956,6 +964,67 @@ fail0: > return (result < 0) ? result : num; > } > > +static int i2c_imx_get_scl(struct i2c_adapter *adap) { > + struct imx_i2c_struct *i2c_imx; > + > + i2c_imx = container_of(adap, struct imx_i2c_struct, adapter); > + if (i2c_imx->pins.scl) > + return gpiod_get_value(i2c_imx->pins.scl); > + > + return 1; > +} > + > +static int i2c_imx_get_sda(struct i2c_adapter *adap) { > + struct imx_i2c_struct *i2c_imx; > + > + i2c_imx = container_of(adap, struct imx_i2c_struct, adapter); > + if (i2c_imx->pins.sda) > + return gpiod_get_value(i2c_imx->pins.sda); > + > + return 1; > +} > + > +static void i2c_imx_set_scl(struct i2c_adapter *adap, int val) { > + struct imx_i2c_struct *i2c_imx; > + > + i2c_imx = container_of(adap, struct imx_i2c_struct, adapter); > + if (i2c_imx->pins.scl) > + gpiod_set_value(i2c_imx->pins.scl, val); } > + > +static void i2c_imx_prepare_recovery(struct i2c_adapter *adap) { > + struct imx_i2c_struct *i2c_imx; > + > + i2c_imx = container_of(adap, struct imx_i2c_struct, adapter); > + if (i2c_imx->pins.sda && i2c_imx->pins.scl) { > + pinctrl_pm_select_sleep_state(&adap->dev); > + gpiod_direction_input(i2c_imx->pins.sda); > + gpiod_direction_output(i2c_imx->pins.scl, 1); > + } > +} > + > +static void i2c_imx_unprepare_recovery(struct i2c_adapter *adap) { > + struct imx_i2c_struct *i2c_imx; > + > + i2c_imx = container_of(adap, struct imx_i2c_struct, adapter); > + if (i2c_imx->pins.sda && i2c_imx->pins.scl) > + pinctrl_pm_select_default_state(&adap->dev); > +} > + > +static struct i2c_bus_recovery_info i2c_imx_bus_recovery_info = { > + .get_scl = i2c_imx_get_scl, > + .get_sda = i2c_imx_get_sda, > + .set_scl = i2c_imx_set_scl, > + .prepare_recovery = i2c_imx_prepare_recovery, > + .unprepare_recovery = i2c_imx_unprepare_recovery, > + .recover_bus = i2c_generic_scl_recovery, }; > + > static u32 i2c_imx_func(struct i2c_adapter *adapter) { > return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL @@ -1004,12 +1073,13 @@ > static int i2c_imx_probe(struct platform_device *pdev) > > /* Setup i2c_imx driver structure */ > strlcpy(i2c_imx->adapter.name, pdev->name, sizeof(i2c_imx- > >adapter.name)); > - i2c_imx->adapter.owner = THIS_MODULE; > - i2c_imx->adapter.algo = &i2c_imx_algo; > - i2c_imx->adapter.dev.parent = &pdev->dev; > - i2c_imx->adapter.nr = pdev->id; > - i2c_imx->adapter.dev.of_node = pdev->dev.of_node; > - i2c_imx->base = base; > + i2c_imx->adapter.owner = THIS_MODULE; > + i2c_imx->adapter.algo = &i2c_imx_algo; > + i2c_imx->adapter.dev.parent = &pdev->dev; > + i2c_imx->adapter.nr = pdev->id; > + i2c_imx->adapter.dev.of_node = pdev->dev.of_node; > + i2c_imx->adapter.bus_recovery_info = &i2c_imx_bus_recovery_info; > + i2c_imx->base = base; > > /* Get I2C clock */ > i2c_imx->clk = devm_clk_get(&pdev->dev, NULL); @@ -1037,6 +1107,24 > @@ static int i2c_imx_probe(struct platform_device *pdev) > /* Set up adapter data */ > i2c_set_adapdata(&i2c_imx->adapter, i2c_imx); > > + /* Init recover pins */ > + i2c_imx->pins.sda = > + devm_gpiod_get_optional(&pdev->dev, "sda-gpio", 0); > + i2c_imx->pins.scl = > + devm_gpiod_get_optional(&pdev->dev, "scl-gpio", 0); > + > + if (IS_ERR(i2c_imx->pins.sda)) { > + ret = PTR_ERR(i2c_imx->pins.sda); > + dev_err(&pdev->dev, "Failed to get sda gpio: %d\n", ret); > + i2c_imx->pins.sda = NULL; > + } > + > + if (IS_ERR(i2c_imx->pins.scl)) { > + ret = PTR_ERR(i2c_imx->pins.scl); > + dev_err(&pdev->dev, "Failed to get scl gpio: %d\n", ret); > + i2c_imx->pins.scl = NULL; > + } > + > /* Set up clock divider */ > i2c_imx->bitrate = IMX_I2C_BIT_RATE; > ret = of_property_read_u32(pdev->dev.of_node, > -- > 1.9.1 ��.n��������+%������w��{.n�����{��-��)�� jg��� �����ݢj����G���� ���j:+v���w�m������w�������h�����٥
