diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-davinci.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-davinci.c | 194 |
1 files changed, 143 insertions, 51 deletions
diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c index 6dc7ff5d3d9a..4788a32afb86 100644 --- a/drivers/i2c/busses/i2c-davinci.c +++ b/drivers/i2c/busses/i2c-davinci.c @@ -60,6 +60,12 @@ #define DAVINCI_I2C_IVR_REG 0x28 #define DAVINCI_I2C_EMDR_REG 0x2c #define DAVINCI_I2C_PSC_REG 0x30 +#define DAVINCI_I2C_FUNC_REG 0x48 +#define DAVINCI_I2C_DIR_REG 0x4c +#define DAVINCI_I2C_DIN_REG 0x50 +#define DAVINCI_I2C_DOUT_REG 0x54 +#define DAVINCI_I2C_DSET_REG 0x58 +#define DAVINCI_I2C_DCLR_REG 0x5c #define DAVINCI_I2C_IVR_AAS 0x07 #define DAVINCI_I2C_IVR_SCD 0x06 @@ -93,6 +99,29 @@ #define DAVINCI_I2C_IMR_NACK BIT(1) #define DAVINCI_I2C_IMR_AL BIT(0) +/* set SDA and SCL as GPIO */ +#define DAVINCI_I2C_FUNC_PFUNC0 BIT(0) + +/* set SCL as output when used as GPIO*/ +#define DAVINCI_I2C_DIR_PDIR0 BIT(0) +/* set SDA as output when used as GPIO*/ +#define DAVINCI_I2C_DIR_PDIR1 BIT(1) + +/* read SCL GPIO level */ +#define DAVINCI_I2C_DIN_PDIN0 BIT(0) +/* read SDA GPIO level */ +#define DAVINCI_I2C_DIN_PDIN1 BIT(1) + +/*set the SCL GPIO high */ +#define DAVINCI_I2C_DSET_PDSET0 BIT(0) +/*set the SDA GPIO high */ +#define DAVINCI_I2C_DSET_PDSET1 BIT(1) + +/* set the SCL GPIO low */ +#define DAVINCI_I2C_DCLR_PDCLR0 BIT(0) +/* set the SDA GPIO low */ +#define DAVINCI_I2C_DCLR_PDCLR1 BIT(1) + struct davinci_i2c_dev { struct device *dev; void __iomem *base; @@ -129,43 +158,6 @@ static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg) return readw_relaxed(i2c_dev->base + reg); } -/* 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 = 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 = 0; - struct davinci_i2c_platform_data *pdata = dev->pdata; - - dev_err(dev->dev, "initiating i2c bus recovery\n"); - /* Send NACK to the slave */ - flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); - flag |= 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 = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); - flag |= 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 +255,99 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev) } /* + * This routine does i2c bus recovery by using i2c_generic_gpio_recovery + * which is provided by I2C Bus recovery infrastructure. + */ +static void davinci_i2c_prepare_recovery(struct i2c_adapter *adap) +{ + struct davinci_i2c_dev *dev = 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 = i2c_get_adapdata(adap); + + i2c_davinci_init(dev); +} + +static struct i2c_bus_recovery_info davinci_i2c_gpio_recovery_info = { + .recover_bus = i2c_generic_gpio_recovery, + .prepare_recovery = davinci_i2c_prepare_recovery, + .unprepare_recovery = davinci_i2c_unprepare_recovery, +}; + +static void davinci_i2c_set_scl(struct i2c_adapter *adap, int val) +{ + struct davinci_i2c_dev *dev = i2c_get_adapdata(adap); + + if (val) + davinci_i2c_write_reg(dev, DAVINCI_I2C_DSET_REG, + DAVINCI_I2C_DSET_PDSET0); + else + davinci_i2c_write_reg(dev, DAVINCI_I2C_DCLR_REG, + DAVINCI_I2C_DCLR_PDCLR0); +} + +static int davinci_i2c_get_scl(struct i2c_adapter *adap) +{ + struct davinci_i2c_dev *dev = i2c_get_adapdata(adap); + int val; + + /* read the state of SCL */ + val = davinci_i2c_read_reg(dev, DAVINCI_I2C_DIN_REG); + return val & DAVINCI_I2C_DIN_PDIN0; +} + +static int davinci_i2c_get_sda(struct i2c_adapter *adap) +{ + struct davinci_i2c_dev *dev = i2c_get_adapdata(adap); + int val; + + /* read the state of SDA */ + val = davinci_i2c_read_reg(dev, DAVINCI_I2C_DIN_REG); + return val & DAVINCI_I2C_DIN_PDIN1; +} + +static void davinci_i2c_scl_prepare_recovery(struct i2c_adapter *adap) +{ + struct davinci_i2c_dev *dev = i2c_get_adapdata(adap); + + davinci_i2c_prepare_recovery(adap); + + /* SCL output, SDA input */ + davinci_i2c_write_reg(dev, DAVINCI_I2C_DIR_REG, DAVINCI_I2C_DIR_PDIR0); + + /* change to GPIO mode */ + davinci_i2c_write_reg(dev, DAVINCI_I2C_FUNC_REG, + DAVINCI_I2C_FUNC_PFUNC0); +} + +static void davinci_i2c_scl_unprepare_recovery(struct i2c_adapter *adap) +{ + struct davinci_i2c_dev *dev = i2c_get_adapdata(adap); + + /* change back to I2C mode */ + davinci_i2c_write_reg(dev, DAVINCI_I2C_FUNC_REG, 0); + + davinci_i2c_unprepare_recovery(adap); +} + +static struct i2c_bus_recovery_info davinci_i2c_scl_recovery_info = { + .recover_bus = i2c_generic_scl_recovery, + .set_scl = davinci_i2c_set_scl, + .get_scl = davinci_i2c_get_scl, + .get_sda = davinci_i2c_get_sda, + .prepare_recovery = davinci_i2c_scl_prepare_recovery, + .unprepare_recovery = davinci_i2c_scl_unprepare_recovery, +}; + +/* * Waiting for bus not busy */ static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev, @@ -282,8 +367,7 @@ static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev, return -ETIMEDOUT; } else { to_cnt = 0; - davinci_i2c_recover_bus(dev); - i2c_davinci_init(dev); + i2c_recover_bus(&dev->adapter); } } if (allow_sleep) @@ -304,7 +388,7 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop) struct davinci_i2c_platform_data *pdata = dev->pdata; u32 flag; u16 w; - int r; + unsigned long time_left; /* Introduce a delay, required for some boards (e.g Davinci EVM) */ if (pdata->bus_delay) @@ -368,11 +452,11 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop) flag |= DAVINCI_I2C_MDR_STP; davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag); - r = wait_for_completion_timeout(&dev->cmd_complete, dev->adapter.timeout); - if (r == 0) { + time_left = wait_for_completion_timeout(&dev->cmd_complete, + 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 = 0; return -ETIMEDOUT; } @@ -380,17 +464,13 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop) /* This should be 0 if all bytes were transferred * or dev->cmd_err denotes an error. */ - if (r >= 0) { - dev_err(dev->dev, "abnormal termination buf_len=%i\n", - dev->buf_len); - r = -EREMOTEIO; - } + dev_err(dev->dev, "abnormal termination buf_len=%i\n", + dev->buf_len); dev->terminate = 1; wmb(); dev->buf_len = 0; + return -EREMOTEIO; } - if (r < 0) - return r; /* no error */ if (likely(!dev->cmd_err)) @@ -674,6 +754,10 @@ static int davinci_i2c_probe(struct platform_device *pdev) if (!of_property_read_u32(pdev->dev.of_node, "clock-frequency", &prop)) dev->pdata->bus_freq = prop / 1000; + + dev->pdata->has_pfunc = + of_property_read_bool(pdev->dev.of_node, + "ti,has-pfunc"); } else if (!dev->pdata) { dev->pdata = &davinci_i2c_platform_data_default; } @@ -715,6 +799,14 @@ static int davinci_i2c_probe(struct platform_device *pdev) adap->timeout = DAVINCI_I2C_TIMEOUT; adap->dev.of_node = pdev->dev.of_node; + if (dev->pdata->has_pfunc) + adap->bus_recovery_info = &davinci_i2c_scl_recovery_info; + else if (dev->pdata->scl_pin) { + adap->bus_recovery_info = &davinci_i2c_gpio_recovery_info; + adap->bus_recovery_info->scl_gpio = dev->pdata->scl_pin; + adap->bus_recovery_info->sda_gpio = dev->pdata->sda_pin; + } + adap->nr = pdev->id; r = i2c_add_numbered_adapter(adap); if (r) { |