From b4c715d04006ccc17d9ae0cf673b2f65267c042b Mon Sep 17 00:00:00 2001 From: Jan Glauber Date: Mon, 25 Apr 2016 16:33:30 +0200 Subject: [PATCH] i2c: octeon: Improve error status checking 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 Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-octeon.c | 129 ++++++++++++++++++++++++++------ 1 file changed, 106 insertions(+), 23 deletions(-) diff --git a/drivers/i2c/busses/i2c-octeon.c b/drivers/i2c/busses/i2c-octeon.c index 4275007c2907..471d06eb8434 100644 --- a/drivers/i2c/busses/i2c-octeon.c +++ b/drivers/i2c/busses/i2c-octeon.c @@ -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; + /* address OK ? */ + result = octeon_i2c_check_status(i2c, false); + 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; - } + /* for the last byte TWSI_CTL_AAK must not be set */ + if (i + 1 == length) + final_read = true; - if (i + 1 < length) - octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_AAK); - else + /* 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; -- 2.39.5