Ping... From: Gao Pan <mailto:b54642@xxxxxxxxxxxxx> Sent: Monday, September 21, 2015 4:39 PM > To: wsa@xxxxxxxxxxxxx; u.kleine-koenig@xxxxxxxxxxxxxx > Cc: linux-i2c@xxxxxxxxxxxxxxx; Li Frank-B20596; Duan Fugang-B38611; Gao > Pan-B54642; kernel@xxxxxxxxxxxxxx; hkallweit1@xxxxxxxxx > Subject: [Patch V6] 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. > > Signed-off-by: Fugang Duan <B38611@xxxxxxxxxxxxx> > Signed-off-by: Gao Pan <b54642@xxxxxxxxxxxxx> > --- > 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 > > V3: > -replace "...-gpio" with "...-gpios" in i2c binding doc -document the > requirement of using sleep state to configure > the pins as gpio in i2c binding doc > -remove i2c_recover_bus() in i2c_imx_trx_complete() -use GPIOD_OUT_HIGH > as the parameter of devm_gpiod_get_optional to > config the gpios as output high > -add error disposal as devm_gpiod_get_optional meets error > > V4: > -remove include <linux/of_gpio.h> > -call i2c_recover_bus under the condition of the existing of > both sda and scl. Drop the sda and scl check in i2c_imx_get_scl, > i2c_imx_get_sda, i2c_imx_set_scl, i2c_imx_prepare_recovery and > i2c_imx_prepare_recovery > -use GPIOD_OUT_IN as the parameter of devm_gpiod_get_optional -remove > documenting the requirement of using sleep state to configure > the pins as gpio in i2c binding doc > > V5: > -introduce a dedicated gpio state for bus recovery. > -assign adapter.bus_recovery_info after the two gpios were aquired > successfully. > > V6: > -assign adapter.bus_recovery_info under the condition that gpios are > acquired successfully -not try the recovery when pinctrl_lookup_state > returns an error > > Documentation/devicetree/bindings/i2c/i2c-imx.txt | 9 ++ > drivers/i2c/busses/i2c-imx.c | 124 > ++++++++++++++++++++-- > 2 files changed, 126 insertions(+), 7 deletions(-) > > diff --git a/Documentation/devicetree/bindings/i2c/i2c-imx.txt > b/Documentation/devicetree/bindings/i2c/i2c-imx.txt > index ce4311d..eab5836 100644 > --- a/Documentation/devicetree/bindings/i2c/i2c-imx.txt > +++ b/Documentation/devicetree/bindings/i2c/i2c-imx.txt > @@ -14,6 +14,10 @@ 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-gpios: specify the gpio related to SCL pin > +- sda-gpios: specify the gpio related to SDA pin > +- pinctrl: add extra pinctrl to configure i2c pins to gpio function for > +i2c > + bus recovery, call it "gpio" state > > Examples: > > @@ -37,4 +41,9 @@ i2c0: i2c@40066000 { /* i2c0 on vf610 */ > dmas = <&edma0 0 50>, > <&edma0 0 51>; > dma-names = "rx","tx"; > + pinctrl-names = "default", "gpio"; > + pinctrl-0 = <&pinctrl_i2c1>; > + pinctrl-1 = <&pinctrl_i2c1_gpio>; > + scl-gpios = <&gpio5 26 GPIO_ACTIVE_HIGH>; > + sda-gpios = <&gpio5 27 GPIO_ACTIVE_HIGH>; > }; > diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c > index 91bdf28..0773ed1 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> > @@ -64,6 +65,8 @@ > /* Default value */ > #define IMX_I2C_BIT_RATE 100000 /* 100kHz */ > > +#define I2C_PINCTRL_STATE_GPIO "gpio" > + > /* > * Enable DMA if transfer byte size is bigger than this threshold. > * As the hardware request, it must bigger than 4 bytes.\ @@ -178,6 > +181,11 @@ 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; > @@ -209,8 +217,13 @@ 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 pinctrl *pinctrl; > + struct pinctrl_state *pinctrl_pins_default; > + struct pinctrl_state *pinctrl_pins_gpio; > + > struct imx_i2c_dma *dma; > }; > > @@ -439,7 +452,10 @@ 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; > + if (i2c_imx->adapter.bus_recovery_info) > + return i2c_recover_bus(&i2c_imx->adapter); > + else > + return -ETIMEDOUT; > } > schedule(); > } > @@ -963,6 +979,62 @@ out: > 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); > + > + return gpiod_get_value(i2c_imx->pins.scl); > +} > + > +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); > + > + return gpiod_get_value(i2c_imx->pins.sda); > +} > + > +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); > + > + 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); > + > + pinctrl_select_state(i2c_imx->pinctrl, i2c_imx->pinctrl_pins_gpio); > + 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); > + > + pinctrl_select_state(i2c_imx->pinctrl, i2c_imx- > >pinctrl_pins_default); > +} > + > +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 @@ -1011,12 +1083,12 @@ > 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->base = base; > > /* Get I2C clock */ > i2c_imx->clk = devm_clk_get(&pdev->dev, NULL); @@ -1031,6 +1103,23 > @@ static int i2c_imx_probe(struct platform_device *pdev) > return ret; > } > > + i2c_imx->pinctrl = devm_pinctrl_get(&pdev->dev); > + if (IS_ERR(i2c_imx->pinctrl)) { > + ret = PTR_ERR(i2c_imx->pinctrl); > + goto clk_disable; > + } > + > + i2c_imx->pinctrl_pins_default = pinctrl_lookup_state(i2c_imx- > >pinctrl, > + PINCTRL_STATE_DEFAULT); > + if (IS_ERR(i2c_imx->pinctrl_pins_default)) > + dev_warn(&pdev->dev, "could not get default state\n"); > + else { > + i2c_imx->pinctrl_pins_gpio = pinctrl_lookup_state(i2c_imx- > >pinctrl, > + I2C_PINCTRL_STATE_GPIO); > + if (IS_ERR(i2c_imx->pinctrl_pins_gpio)) > + dev_warn(&pdev->dev, "could not get gpio state\n"); > + } > + > /* Request IRQ */ > ret = devm_request_irq(&pdev->dev, irq, i2c_imx_isr, 0, > pdev->name, i2c_imx); > @@ -1057,6 +1146,27 @@ static int i2c_imx_probe(struct platform_device > *pdev) > if (ret < 0) > goto rpm_disable; > > + /* Init recover pins */ > + if (!IS_ERR(i2c_imx->pinctrl_pins_default) && !IS_ERR(i2c_imx- > >pinctrl_pins_gpio)) { > + i2c_imx->pins.sda = > + devm_gpiod_get_optional(&pdev->dev, "sda-gpios", > GPIOD_IN); > + i2c_imx->pins.scl = > + devm_gpiod_get_optional(&pdev->dev, "scl-gpios", > GPIOD_IN); > + > + if (IS_ERR(i2c_imx->pins.sda)) { > + ret = PTR_ERR(i2c_imx->pins.sda); > + goto clk_disable; > + } > + > + if (IS_ERR(i2c_imx->pins.scl)) { > + ret = PTR_ERR(i2c_imx->pins.scl); > + goto clk_disable; > + } > + > + if (i2c_imx->pins.scl && i2c_imx->pins.sda) > + i2c_imx->adapter.bus_recovery_info = > &i2c_imx_bus_recovery_info; > + } > + > /* 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
