[PATCH v11 7/8] i2c: fsi: Add bus recovery
From: Eddie James <hidden>
Date: 2018-07-05 18:41:31
Also in:
linux-i2c, lkml
Subsystem:
fsi-attached i2c driver, i2c subsystem, i2c subsystem host drivers, the rest · Maintainers:
Eddie James, Andi Shyti, Linus Torvalds
Bus recovery should reset the bus with the standard i2c recovery procedure. Populate the necessary fields so that the standard procedure can perform the reset. Signed-off-by: Eddie James <redacted> --- drivers/i2c/busses/i2c-fsi.c | 132 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 132 insertions(+)
diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c
index 5520251..42c387d 100644
--- a/drivers/i2c/busses/i2c-fsi.c
+++ b/drivers/i2c/busses/i2c-fsi.c@@ -326,6 +326,115 @@ static int fsi_i2c_read_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg, return 0; } +static int fsi_i2c_get_scl(struct i2c_adapter *adap) +{ + u32 stat = 0; + struct fsi_i2c_port *port = adap->algo_data; + struct fsi_i2c_master *i2c = port->master; + + fsi_i2c_read_reg(i2c->fsi, I2C_FSI_STAT, &stat); + + return !!(stat & I2C_STAT_SCL_IN); +} + +static void fsi_i2c_set_scl(struct i2c_adapter *adap, int val) +{ + u32 dummy = 0; + struct fsi_i2c_port *port = adap->algo_data; + struct fsi_i2c_master *i2c = port->master; + + if (val) + fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SCL, &dummy); + else + fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SCL, &dummy); +} + +static int fsi_i2c_get_sda(struct i2c_adapter *adap) +{ + u32 stat = 0; + struct fsi_i2c_port *port = adap->algo_data; + struct fsi_i2c_master *i2c = port->master; + + fsi_i2c_read_reg(i2c->fsi, I2C_FSI_STAT, &stat); + + return !!(stat & I2C_STAT_SDA_IN); +} + +static void fsi_i2c_set_sda(struct i2c_adapter *adap, int val) +{ + u32 dummy = 0; + struct fsi_i2c_port *port = adap->algo_data; + struct fsi_i2c_master *i2c = port->master; + + if (val) + fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SDA, &dummy); + else + fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SDA, &dummy); +} + +static void fsi_i2c_prepare_recovery(struct i2c_adapter *adap) +{ + int rc; + u32 mode; + struct fsi_i2c_port *port = adap->algo_data; + struct fsi_i2c_master *i2c = port->master; + + rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_MODE, &mode); + if (rc) + return; + + mode |= I2C_MODE_DIAG; + fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); +} + +static void fsi_i2c_unprepare_recovery(struct i2c_adapter *adap) +{ + int rc; + u32 mode; + struct fsi_i2c_port *port = adap->algo_data; + struct fsi_i2c_master *i2c = port->master; + + rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_MODE, &mode); + if (rc) + return; + + mode &= ~I2C_MODE_DIAG; + fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); +} + +static int fsi_i2c_reset_bus(struct fsi_i2c_master *i2c, + struct fsi_i2c_port *port) +{ + int rc; + u32 stat, dummy = 0; + + /* force bus reset, ignore errors */ + i2c_recover_bus(&port->adapter); + + /* reset errors */ + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_ERR, &dummy); + if (rc) + return rc; + + /* wait for command complete */ + usleep_range(I2C_RESET_SLEEP_MIN_US, I2C_RESET_SLEEP_MAX_US); + + rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_STAT, &stat); + if (rc) + return rc; + + if (stat & I2C_STAT_CMD_COMP) + return 0; + + /* failed to get command complete; reset engine again */ + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_I2C, &dummy); + if (rc) + return rc; + + /* re-init engine again */ + return fsi_i2c_dev_init(i2c); +} + static int fsi_i2c_reset_engine(struct fsi_i2c_master *i2c, u16 port) { int rc;
@@ -368,6 +477,7 @@ static int fsi_i2c_abort(struct fsi_i2c_port *port, u32 status) int rc; unsigned long start; u32 cmd = I2C_CMD_WITH_STOP; + u32 stat; struct fsi_i2c_master *i2c = port->master; struct fsi_device *fsi = i2c->fsi;
@@ -375,6 +485,17 @@ static int fsi_i2c_abort(struct fsi_i2c_port *port, u32 status) if (rc) return rc; + rc = fsi_i2c_read_reg(fsi, I2C_FSI_STAT, &stat); + if (rc) + return rc; + + /* if sda is low, peform full bus reset */ + if (!(stat & I2C_STAT_SDA_IN)) { + rc = fsi_i2c_reset_bus(i2c, port); + if (rc) + return rc; + } + /* skip final stop command for these errors */ if (status & (I2C_STAT_PARITY | I2C_STAT_LOST_ARB | I2C_STAT_STOP_ERR)) return 0;
@@ -523,6 +644,16 @@ static u32 fsi_i2c_functionality(struct i2c_adapter *adap) I2C_FUNC_SMBUS_BLOCK_DATA; } +static struct i2c_bus_recovery_info fsi_i2c_bus_recovery_info = { + .recover_bus = i2c_generic_scl_recovery, + .get_scl = fsi_i2c_get_scl, + .set_scl = fsi_i2c_set_scl, + .get_sda = fsi_i2c_get_sda, + .set_sda = fsi_i2c_set_sda, + .prepare_recovery = fsi_i2c_prepare_recovery, + .unprepare_recovery = fsi_i2c_unprepare_recovery, +}; + static const struct i2c_algorithm fsi_i2c_algorithm = { .master_xfer = fsi_i2c_xfer, .functionality = fsi_i2c_functionality,
@@ -565,6 +696,7 @@ static int fsi_i2c_probe(struct device *dev) port->adapter.dev.of_node = np; port->adapter.dev.parent = dev; port->adapter.algo = &fsi_i2c_algorithm; + port->adapter.bus_recovery_info = &fsi_i2c_bus_recovery_info; port->adapter.algo_data = port; snprintf(port->adapter.name, sizeof(port->adapter.name),
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1.8.3.1