V3s_Allwinner
/
uboot
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases 2 Wiki Activity

i2c: mvtwsi: Streamline code and add documentation 

Convert groups of logically connected preprocessor defines into proper
enums, one macro into an inline function, and add documentation
to/extend existing documentation of these items.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
Reviewed-by: Stefan Roese <sr@denx.de>
This commit is contained in:
mario.six@gdsys.cc 2016-07-21 11:57:02 +02:00 committed by Heiko Schocher
parent 9ec43b0c3f
commit dfc3958cd3
1 changed files with 75 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

113
drivers/i2c/mvtwsi.c
View File

@ -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;