From 720d5ce9309d5503b2c29b621f5490e961f5953c Mon Sep 17 00:00:00 2001 From: Eddie James Date: Tue, 17 Jul 2018 10:31:05 -0500 Subject: [PATCH] i2c: fsi: Add bus recovery 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 Tested-by: Joel Stanley Signed-off-by: Wolfram Sang --- 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 27d74a944c72..1e2be2219a60 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; @@ -522,6 +643,16 @@ static u32 fsi_i2c_functionality(struct i2c_adapter *adap) I2C_FUNC_SMBUS_EMUL | 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, @@ -564,6 +695,7 @@ 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), -- 2.30.2