diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/i2c/busses/i2c-octeon.c | 159 |
1 files changed, 96 insertions, 63 deletions
diff --git a/drivers/i2c/busses/i2c-octeon.c b/drivers/i2c/busses/i2c-octeon.c index 471d06eb8434..f83f6b8892b5 100644 --- a/drivers/i2c/busses/i2c-octeon.c +++ b/drivers/i2c/busses/i2c-octeon.c @@ -90,6 +90,8 @@ #define TWSI_INT_CORE_EN BIT_ULL(6) #define TWSI_INT_SDA_OVR BIT_ULL(8) #define TWSI_INT_SCL_OVR BIT_ULL(9) +#define TWSI_INT_SDA BIT_ULL(10) +#define TWSI_INT_SCL BIT_ULL(11) struct octeon_i2c { wait_queue_head_t queue; @@ -153,6 +155,17 @@ static u8 octeon_i2c_reg_read(struct octeon_i2c *i2c, u64 eop_reg) octeon_i2c_reg_read(i2c, SW_TWSI_EOP_TWSI_STAT) /** + * octeon_i2c_read_int - read the TWSI_INT register + * @i2c: The struct octeon_i2c + * + * Returns the value of the register. + */ +static u64 octeon_i2c_read_int(struct octeon_i2c *i2c) +{ + return __raw_readq(i2c->twsi_base + TWSI_INT); +} + +/** * octeon_i2c_write_int - write the TWSI_INT register * @i2c: The struct octeon_i2c * @data: Value to be written @@ -182,33 +195,6 @@ static void octeon_i2c_int_disable(struct octeon_i2c *i2c) octeon_i2c_write_int(i2c, 0); } -/** - * octeon_i2c_unblock - unblock the bus - * @i2c: The struct octeon_i2c - * - * If there was a reset while a device was driving 0 to bus, bus is blocked. - * We toggle it free manually by some clock cycles and send a stop. - */ -static void octeon_i2c_unblock(struct octeon_i2c *i2c) -{ - int i; - - dev_dbg(i2c->dev, "%s\n", __func__); - - for (i = 0; i < 9; i++) { - octeon_i2c_write_int(i2c, 0); - udelay(5); - octeon_i2c_write_int(i2c, TWSI_INT_SCL_OVR); - udelay(5); - } - /* hand-crank a STOP */ - octeon_i2c_write_int(i2c, TWSI_INT_SDA_OVR | TWSI_INT_SCL_OVR); - udelay(5); - octeon_i2c_write_int(i2c, TWSI_INT_SDA_OVR); - udelay(5); - octeon_i2c_write_int(i2c, 0); -} - /* interrupt service routine */ static irqreturn_t octeon_i2c_isr(int irq, void *dev_id) { @@ -371,6 +357,17 @@ static int octeon_i2c_init_lowlevel(struct octeon_i2c *i2c) return -EIO; } +static int octeon_i2c_recovery(struct octeon_i2c *i2c) +{ + int ret; + + ret = i2c_recover_bus(&i2c->adap); + if (ret) + /* recover failed, try hardware re-init */ + ret = octeon_i2c_init_lowlevel(i2c); + return ret; +} + /** * octeon_i2c_start - send START to the bus * @i2c: The struct octeon_i2c @@ -379,34 +376,23 @@ static int octeon_i2c_init_lowlevel(struct octeon_i2c *i2c) */ static int octeon_i2c_start(struct octeon_i2c *i2c) { - int result; - u8 data; + int ret; + u8 stat; octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_STA); + ret = octeon_i2c_wait(i2c); + if (ret) + goto error; - result = octeon_i2c_wait(i2c); - if (result) { - if (octeon_i2c_stat_read(i2c) == STAT_IDLE) { - /* - * Controller refused to send start flag May - * be a client is holding SDA low - let's try - * to free it. - */ - octeon_i2c_unblock(i2c); - octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_STA); - result = octeon_i2c_wait(i2c); - } - if (result) - return result; - } - - data = octeon_i2c_stat_read(i2c); - if ((data != STAT_START) && (data != STAT_REP_START)) { - dev_err(i2c->dev, "%s: bad status (0x%x)\n", __func__, data); - return -EIO; - } + stat = octeon_i2c_stat_read(i2c); + if (stat == STAT_START || stat == STAT_REP_START) + /* START successful, bail out */ + return 0; - return 0; +error: + /* START failed, try to recover */ + ret = octeon_i2c_recovery(i2c); + return (ret) ? ret : -EAGAIN; } /* send STOP to the bus */ @@ -431,10 +417,6 @@ static int octeon_i2c_write(struct octeon_i2c *i2c, int target, { int i, result; - result = octeon_i2c_start(i2c); - if (result) - return result; - octeon_i2c_data_write(i2c, target << 1); octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB); @@ -479,10 +461,6 @@ static int octeon_i2c_read(struct octeon_i2c *i2c, int target, if (length < 1) return -EINVAL; - result = octeon_i2c_start(i2c); - if (result) - return result; - octeon_i2c_data_write(i2c, (target << 1) | 1); octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB); @@ -546,10 +524,10 @@ static int octeon_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, for (i = 0; ret == 0 && i < num; i++) { struct i2c_msg *pmsg = &msgs[i]; - dev_dbg(i2c->dev, - "Doing %s %d byte(s) to/from 0x%02x - %d of %d messages\n", - pmsg->flags & I2C_M_RD ? "read" : "write", - pmsg->len, pmsg->addr, i + 1, num); + ret = octeon_i2c_start(i2c); + if (ret) + return ret; + if (pmsg->flags & I2C_M_RD) ret = octeon_i2c_read(i2c, pmsg->addr, pmsg->buf, &pmsg->len, pmsg->flags & I2C_M_RECV_LEN); @@ -562,6 +540,60 @@ static int octeon_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, return (ret != 0) ? ret : num; } +static int octeon_i2c_get_scl(struct i2c_adapter *adap) +{ + struct octeon_i2c *i2c = i2c_get_adapdata(adap); + u64 state; + + state = octeon_i2c_read_int(i2c); + return state & TWSI_INT_SCL; +} + +static void octeon_i2c_set_scl(struct i2c_adapter *adap, int val) +{ + struct octeon_i2c *i2c = i2c_get_adapdata(adap); + + octeon_i2c_write_int(i2c, TWSI_INT_SCL_OVR); +} + +static int octeon_i2c_get_sda(struct i2c_adapter *adap) +{ + struct octeon_i2c *i2c = i2c_get_adapdata(adap); + u64 state; + + state = octeon_i2c_read_int(i2c); + return state & TWSI_INT_SDA; +} + +static void octeon_i2c_prepare_recovery(struct i2c_adapter *adap) +{ + struct octeon_i2c *i2c = i2c_get_adapdata(adap); + + /* + * The stop resets the state machine, does not _transmit_ STOP unless + * engine was active. + */ + octeon_i2c_stop(i2c); + + octeon_i2c_write_int(i2c, 0); +} + +static void octeon_i2c_unprepare_recovery(struct i2c_adapter *adap) +{ + struct octeon_i2c *i2c = i2c_get_adapdata(adap); + + octeon_i2c_write_int(i2c, 0); +} + +static struct i2c_bus_recovery_info octeon_i2c_recovery_info = { + .recover_bus = i2c_generic_scl_recovery, + .get_scl = octeon_i2c_get_scl, + .set_scl = octeon_i2c_set_scl, + .get_sda = octeon_i2c_get_sda, + .prepare_recovery = octeon_i2c_prepare_recovery, + .unprepare_recovery = octeon_i2c_unprepare_recovery, +}; + static u32 octeon_i2c_functionality(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | @@ -642,6 +674,7 @@ static int octeon_i2c_probe(struct platform_device *pdev) i2c->adap = octeon_i2c_ops; i2c->adap.timeout = msecs_to_jiffies(2); i2c->adap.retries = 5; + i2c->adap.bus_recovery_info = &octeon_i2c_recovery_info; i2c->adap.dev.parent = &pdev->dev; i2c->adap.dev.of_node = node; i2c_set_adapdata(&i2c->adap, i2c); |