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 <eajames@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c
index 27d74a9..1e2be22 100644 (file)
--- 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),