diff options
Diffstat (limited to 'drivers/i2c/mvtwsi.c')
| -rw-r--r-- | drivers/i2c/mvtwsi.c | 113 |
1 files changed, 75 insertions, 38 deletions
diff --git a/drivers/i2c/mvtwsi.c b/drivers/i2c/mvtwsi.c index e9e7c47461..93bb88b06f 100644 --- a/drivers/i2c/mvtwsi.c +++ b/drivers/i2c/mvtwsi.c @@ -62,15 +62,23 @@ struct mvtwsi_registers { #endif /* - * Control register fields + * enum mvtwsi_ctrl_register_fields - Bit masks for flags in the control + * register */ - -#define MVTWSI_CONTROL_ACK 0x00000004 -#define MVTWSI_CONTROL_IFLG 0x00000008 -#define MVTWSI_CONTROL_STOP 0x00000010 -#define MVTWSI_CONTROL_START 0x00000020 -#define MVTWSI_CONTROL_TWSIEN 0x00000040 -#define MVTWSI_CONTROL_INTEN 0x00000080 +enum mvtwsi_ctrl_register_fields { + /* Acknowledge bit */ + MVTWSI_CONTROL_ACK = 0x00000004, + /* Interrupt flag */ + MVTWSI_CONTROL_IFLG = 0x00000008, + /* Stop bit */ + MVTWSI_CONTROL_STOP = 0x00000010, + /* Start bit */ + MVTWSI_CONTROL_START = 0x00000020, + /* I2C enable */ + MVTWSI_CONTROL_TWSIEN = 0x00000040, + /* Interrupt enable */ + MVTWSI_CONTROL_INTEN = 0x00000080, +}; /* * On sun6i and newer IFLG is a write-clear bit which is cleared by writing 1, @@ -84,22 +92,36 @@ struct mvtwsi_registers { #endif /* - * Status register values -- only those expected in normal master - * operation on non-10-bit-address devices; whatever status we don't - * expect in nominal conditions (bus errors, arbitration losses, - * missing ACKs...) we just pass back to the caller as an error + * enum mvstwsi_status_values - Possible values of I2C controller's status + * register + * + * Only those statuses expected in normal master operation on + * non-10-bit-address devices are specified. + * + * Every status that's unexpected during normal operation (bus errors, + * arbitration losses, missing ACKs...) is passed back to the caller as an error * code. */ - -#define MVTWSI_STATUS_START 0x08 -#define MVTWSI_STATUS_REPEATED_START 0x10 -#define MVTWSI_STATUS_ADDR_W_ACK 0x18 -#define MVTWSI_STATUS_DATA_W_ACK 0x28 -#define MVTWSI_STATUS_ADDR_R_ACK 0x40 -#define MVTWSI_STATUS_ADDR_R_NAK 0x48 -#define MVTWSI_STATUS_DATA_R_ACK 0x50 -#define MVTWSI_STATUS_DATA_R_NAK 0x58 -#define MVTWSI_STATUS_IDLE 0xF8 +enum mvstwsi_status_values { + /* START condition transmitted */ + MVTWSI_STATUS_START = 0x08, + /* Repeated START condition transmitted */ + MVTWSI_STATUS_REPEATED_START = 0x10, + /* Address + write bit transmitted, ACK received */ + MVTWSI_STATUS_ADDR_W_ACK = 0x18, + /* Data transmitted, ACK received */ + MVTWSI_STATUS_DATA_W_ACK = 0x28, + /* Address + read bit transmitted, ACK received */ + MVTWSI_STATUS_ADDR_R_ACK = 0x40, + /* Address + read bit transmitted, ACK not received */ + MVTWSI_STATUS_ADDR_R_NAK = 0x48, + /* Data received, ACK transmitted */ + MVTWSI_STATUS_DATA_R_ACK = 0x50, + /* Data received, ACK not transmitted */ + MVTWSI_STATUS_DATA_R_NAK = 0x58, + /* No relevant status */ + MVTWSI_STATUS_IDLE = 0xF8, +}; /* * MVTWSI controller base @@ -141,20 +163,35 @@ static struct mvtwsi_registers *twsi_get_base(struct i2c_adapter *adap) } /* - * Returned statuses are 0 for success and nonzero otherwise. - * Currently, cmd_i2c and cmd_eeprom do not interpret an error status. - * Thus to ease debugging, the return status contains some debug info: - * - bits 31..24 are error class: 1 is timeout, 2 is 'status mismatch'. - * - bits 23..16 are the last value of the control register. - * - bits 15..8 are the last value of the status register. - * - bits 7..0 are the expected value of the status register. + * enum mvtwsi_error_class - types of I2C errors */ +enum mvtwsi_error_class { + /* The controller returned a different status than expected */ + MVTWSI_ERROR_WRONG_STATUS = 0x01, + /* The controller timed out */ + MVTWSI_ERROR_TIMEOUT = 0x02, +}; -#define MVTWSI_ERROR_WRONG_STATUS 0x01 -#define MVTWSI_ERROR_TIMEOUT 0x02 - -#define MVTWSI_ERROR(ec, lc, ls, es) (((ec << 24) & 0xFF000000) | \ - ((lc << 16) & 0x00FF0000) | ((ls<<8) & 0x0000FF00) | (es & 0xFF)) +/* + * mvtwsi_error() - Build I2C return code from error information + * + * For debugging purposes, this function packs some information of an occurred + * error into a return code. These error codes are returned from I2C API + * functions (i2c_{read,write}, dm_i2c_{read,write}, etc.). + * + * @ec: The error class of the error (enum mvtwsi_error_class). + * @lc: The last value of the control register. + * @ls: The last value of the status register. + * @es: The expected value of the status register. + * @return The generated error code. + */ +inline uint mvtwsi_error(uint ec, uint lc, uint ls, uint es) +{ + return ((ec << 24) & 0xFF000000) + | ((lc << 16) & 0x00FF0000) + | ((ls << 8) & 0x0000FF00) + | (es & 0xFF); +} /* * Wait for IFLG to raise, or return 'timeout'; then if status is as expected, @@ -173,15 +210,15 @@ static int twsi_wait(struct i2c_adapter *adap, int expected_status) if (status == expected_status) return 0; else - return MVTWSI_ERROR( + return mvtwsi_error( MVTWSI_ERROR_WRONG_STATUS, control, status, expected_status); } udelay(10); /* one clock cycle at 100 kHz */ } while (timeout--); status = readl(&twsi->status); - return MVTWSI_ERROR( - MVTWSI_ERROR_TIMEOUT, control, status, expected_status); + return mvtwsi_error(MVTWSI_ERROR_TIMEOUT, control, status, + expected_status); } /* @@ -265,7 +302,7 @@ static int twsi_stop(struct i2c_adapter *adap, int status) control = readl(&twsi->control); if (stop_status != MVTWSI_STATUS_IDLE) if (status == 0) - status = MVTWSI_ERROR( + status = mvtwsi_error( MVTWSI_ERROR_TIMEOUT, control, status, MVTWSI_STATUS_IDLE); return status; |