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i2c: octeon: Improve error status checking

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Introduce a function that checks for valid status codes depending
on the phase of a transmit or receive. Also add all existing status
codes and improve error handling for various states.

The Octeon TWSI has an "assert acknowledge" bit (TWSI_CTL_AAK) that
is required to be set in master receive mode until the last byte is
requested. The state check needs to consider if this bit was set.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Jan Glauber 2016-04-25 16:33:30 +02:00 committed by Wolfram Sang
parent f6903783eb
commit b4c715d040
1 changed files with 107 additions and 24 deletions
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131
drivers/i2c/busses/i2c-octeon.c
View file

@ -55,13 +55,35 @@
#define TWSI_CTL_IFLG 0x08 /* HW event, SW writes 0 to ACK */
#define TWSI_CTL_AAK 0x04 /* Assert ACK */
/* Some status values */
/* Status values */
#define STAT_ERROR 0x00
#define STAT_START 0x08
#define STAT_RSTART 0x10
#define STAT_REP_START 0x10
#define STAT_TXADDR_ACK 0x18
#define STAT_TXADDR_NAK 0x20
#define STAT_TXDATA_ACK 0x28
#define STAT_TXDATA_NAK 0x30
#define STAT_LOST_ARB_38 0x38
#define STAT_RXADDR_ACK 0x40
#define STAT_RXADDR_NAK 0x48
#define STAT_RXDATA_ACK 0x50
#define STAT_RXDATA_NAK 0x58
#define STAT_SLAVE_60 0x60
#define STAT_LOST_ARB_68 0x68
#define STAT_SLAVE_70 0x70
#define STAT_LOST_ARB_78 0x78
#define STAT_SLAVE_80 0x80
#define STAT_SLAVE_88 0x88
#define STAT_GENDATA_ACK 0x90
#define STAT_GENDATA_NAK 0x98
#define STAT_SLAVE_A0 0xA0
#define STAT_SLAVE_A8 0xA8
#define STAT_LOST_ARB_B0 0xB0
#define STAT_SLAVE_LOST 0xB8
#define STAT_SLAVE_NAK 0xC0
#define STAT_SLAVE_ACK 0xC8
#define STAT_AD2W_ACK 0xD0
#define STAT_AD2W_NAK 0xD8
#define STAT_IDLE 0xF8
/* TWSI_INT values */
@ -225,6 +247,67 @@ static int octeon_i2c_wait(struct octeon_i2c *i2c)
return 0;
}
static int octeon_i2c_check_status(struct octeon_i2c *i2c, int final_read)
{
u8 stat = octeon_i2c_stat_read(i2c);
switch (stat) {
/* Everything is fine */
case STAT_IDLE:
case STAT_AD2W_ACK:
case STAT_RXADDR_ACK:
case STAT_TXADDR_ACK:
case STAT_TXDATA_ACK:
return 0;
/* ACK allowed on pre-terminal bytes only */
case STAT_RXDATA_ACK:
if (!final_read)
return 0;
return -EIO;
/* NAK allowed on terminal byte only */
case STAT_RXDATA_NAK:
if (final_read)
return 0;
return -EIO;
/* Arbitration lost */
case STAT_LOST_ARB_38:
case STAT_LOST_ARB_68:
case STAT_LOST_ARB_78:
case STAT_LOST_ARB_B0:
return -EAGAIN;
/* Being addressed as slave, should back off & listen */
case STAT_SLAVE_60:
case STAT_SLAVE_70:
case STAT_GENDATA_ACK:
case STAT_GENDATA_NAK:
return -EOPNOTSUPP;
/* Core busy as slave */
case STAT_SLAVE_80:
case STAT_SLAVE_88:
case STAT_SLAVE_A0:
case STAT_SLAVE_A8:
case STAT_SLAVE_LOST:
case STAT_SLAVE_NAK:
case STAT_SLAVE_ACK:
return -EOPNOTSUPP;
case STAT_TXDATA_NAK:
return -EIO;
case STAT_TXADDR_NAK:
case STAT_RXADDR_NAK:
case STAT_AD2W_NAK:
return -ENXIO;
default:
dev_err(i2c->dev, "unhandled state: %d\n", stat);
return -EIO;
}
}
/* calculate and set clock divisors */
static void octeon_i2c_set_clock(struct octeon_i2c *i2c)
{
@ -318,7 +401,7 @@ static int octeon_i2c_start(struct octeon_i2c *i2c)
}
data = octeon_i2c_stat_read(i2c);
if ((data != STAT_START) && (data != STAT_RSTART)) {
if ((data != STAT_START) && (data != STAT_REP_START)) {
dev_err(i2c->dev, "%s: bad status (0x%x)\n", __func__, data);
return -EIO;
}
@ -347,7 +430,6 @@ static int octeon_i2c_write(struct octeon_i2c *i2c, int target,
const u8 *data, int length)
{
int i, result;
u8 tmp;
result = octeon_i2c_start(i2c);
if (result)
@ -361,14 +443,9 @@ static int octeon_i2c_write(struct octeon_i2c *i2c, int target,
return result;
for (i = 0; i < length; i++) {
tmp = octeon_i2c_stat_read(i2c);
if ((tmp != STAT_TXADDR_ACK) && (tmp != STAT_TXDATA_ACK)) {
dev_err(i2c->dev,
"%s: bad status before write (0x%x)\n",
__func__, tmp);
return -EIO;
}
result = octeon_i2c_check_status(i2c, false);
if (result)
return result;
octeon_i2c_data_write(i2c, data[i]);
octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
@ -397,7 +474,7 @@ static int octeon_i2c_read(struct octeon_i2c *i2c, int target,
u8 *data, u16 *rlength, bool recv_len)
{
int i, result, length = *rlength;
u8 tmp;
bool final_read = false;
if (length < 1)
return -EINVAL;
@ -413,19 +490,21 @@ static int octeon_i2c_read(struct octeon_i2c *i2c, int target,
if (result)
return result;
for (i = 0; i < length; i++) {
tmp = octeon_i2c_stat_read(i2c);
if ((tmp != STAT_RXDATA_ACK) && (tmp != STAT_RXADDR_ACK)) {
dev_err(i2c->dev,
"%s: bad status before read (0x%x)\n",
__func__, tmp);
return -EIO;
}
/* address OK ? */
result = octeon_i2c_check_status(i2c, false);
if (result)
return result;
if (i + 1 < length)
octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_AAK);
else
for (i = 0; i < length; i++) {
/* for the last byte TWSI_CTL_AAK must not be set */
if (i + 1 == length)
final_read = true;
/* clear iflg to allow next event */
if (final_read)
octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
else
octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_AAK);
result = octeon_i2c_wait(i2c);
if (result)
@ -441,6 +520,10 @@ static int octeon_i2c_read(struct octeon_i2c *i2c, int target,
}
length += data[i];
}
result = octeon_i2c_check_status(i2c, final_read);
if (result)
return result;
}
*rlength = length;
return 0;