diff options
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-i801.c | 108 |
1 files changed, 53 insertions, 55 deletions
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index 569a282e3347..a1ce4e68b49a 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -206,13 +206,17 @@ static int i801_check_pre(struct i801_priv *priv) return 0; } -/* Convert the status register to an error code, and clear it. */ -static int i801_check_post(struct i801_priv *priv, int status, int timeout) +/* + * Convert the status register to an error code, and clear it. + * Note that status only contains the bits we want to clear, not the + * actual register value. + */ +static int i801_check_post(struct i801_priv *priv, int status) { int result = 0; /* If the SMBus is still busy, we give up */ - if (timeout) { + if (unlikely(status < 0)) { dev_err(&priv->pci_dev->dev, "Transaction timeout\n"); /* try to stop the current command */ dev_dbg(&priv->pci_dev->dev, "Terminating the current operation\n"); @@ -245,64 +249,68 @@ static int i801_check_post(struct i801_priv *priv, int status, int timeout) dev_dbg(&priv->pci_dev->dev, "Lost arbitration\n"); } - if (result) { - /* Clear error flags */ - outb_p(status & STATUS_FLAGS, SMBHSTSTS(priv)); - status = inb_p(SMBHSTSTS(priv)) & STATUS_FLAGS; - if (status) { - dev_warn(&priv->pci_dev->dev, "Failed clearing status " - "flags at end of transaction (%02x)\n", - status); - } - } + /* Clear status flags except BYTE_DONE, to be cleared by caller */ + outb_p(status, SMBHSTSTS(priv)); return result; } -static int i801_transaction(struct i801_priv *priv, int xact) +/* Wait for BUSY being cleared and either INTR or an error flag being set */ +static int i801_wait_intr(struct i801_priv *priv) { - int status; - int result; int timeout = 0; - - result = i801_check_pre(priv); - if (result < 0) - return result; - - /* the current contents of SMBHSTCNT can be overwritten, since PEC, - * SMBSCMD are passed in xact */ - outb_p(xact | SMBHSTCNT_START, SMBHSTCNT(priv)); + int status; /* We will always wait for a fraction of a second! */ do { usleep_range(250, 500); status = inb_p(SMBHSTSTS(priv)); - } while ((status & SMBHSTSTS_HOST_BUSY) && (timeout++ < MAX_RETRIES)); + } while (((status & SMBHSTSTS_HOST_BUSY) || + !(status & (STATUS_ERROR_FLAGS | SMBHSTSTS_INTR))) && + (timeout++ < MAX_RETRIES)); - result = i801_check_post(priv, status, timeout > MAX_RETRIES); - if (result < 0) - return result; - - outb_p(SMBHSTSTS_INTR, SMBHSTSTS(priv)); - return 0; + if (timeout > MAX_RETRIES) { + dev_dbg(&priv->pci_dev->dev, "INTR Timeout!\n"); + return -ETIMEDOUT; + } + return status & (STATUS_ERROR_FLAGS | SMBHSTSTS_INTR); } -/* wait for INTR bit as advised by Intel */ -static void i801_wait_hwpec(struct i801_priv *priv) +/* Wait for either BYTE_DONE or an error flag being set */ +static int i801_wait_byte_done(struct i801_priv *priv) { int timeout = 0; int status; + /* We will always wait for a fraction of a second! */ do { usleep_range(250, 500); status = inb_p(SMBHSTSTS(priv)); - } while ((!(status & SMBHSTSTS_INTR)) - && (timeout++ < MAX_RETRIES)); + } while (!(status & (STATUS_ERROR_FLAGS | SMBHSTSTS_BYTE_DONE)) && + (timeout++ < MAX_RETRIES)); + + if (timeout > MAX_RETRIES) { + dev_dbg(&priv->pci_dev->dev, "BYTE_DONE Timeout!\n"); + return -ETIMEDOUT; + } + return status & STATUS_ERROR_FLAGS; +} + +static int i801_transaction(struct i801_priv *priv, int xact) +{ + int status; + int result; - if (timeout > MAX_RETRIES) - dev_dbg(&priv->pci_dev->dev, "PEC Timeout!\n"); + result = i801_check_pre(priv); + if (result < 0) + return result; - outb_p(status & STATUS_FLAGS, SMBHSTSTS(priv)); + /* the current contents of SMBHSTCNT can be overwritten, since PEC, + * SMBSCMD are passed in xact */ + outb_p(xact | SMBHSTCNT_START, SMBHSTCNT(priv)); + + status = i801_wait_intr(priv); + return i801_check_post(priv, status); } static int i801_block_transaction_by_block(struct i801_priv *priv, @@ -353,7 +361,6 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, int smbcmd; int status; int result; - int timeout; result = i801_check_pre(priv); if (result < 0) @@ -381,17 +388,9 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, outb_p(inb(SMBHSTCNT(priv)) | SMBHSTCNT_START, SMBHSTCNT(priv)); - /* We will always wait for a fraction of a second! */ - timeout = 0; - do { - usleep_range(250, 500); - status = inb_p(SMBHSTSTS(priv)); - } while (!(status & (SMBHSTSTS_BYTE_DONE | STATUS_ERROR_FLAGS)) - && (timeout++ < MAX_RETRIES)); - - result = i801_check_post(priv, status, timeout > MAX_RETRIES); - if (result < 0) - return result; + status = i801_wait_byte_done(priv); + if (status) + goto exit; if (i == 1 && read_write == I2C_SMBUS_READ && command != I2C_SMBUS_I2C_BLOCK_DATA) { @@ -418,10 +417,12 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, outb_p(data->block[i+1], SMBBLKDAT(priv)); /* signals SMBBLKDAT ready */ - outb_p(SMBHSTSTS_BYTE_DONE | SMBHSTSTS_INTR, SMBHSTSTS(priv)); + outb_p(SMBHSTSTS_BYTE_DONE, SMBHSTSTS(priv)); } - return 0; + status = i801_wait_intr(priv); +exit: + return i801_check_post(priv, status); } static int i801_set_block_buffer_mode(struct i801_priv *priv) @@ -476,9 +477,6 @@ static int i801_block_transaction(struct i801_priv *priv, read_write, command, hwpec); - if (result == 0 && hwpec) - i801_wait_hwpec(priv); - if (command == I2C_SMBUS_I2C_BLOCK_DATA && read_write == I2C_SMBUS_WRITE) { /* restore saved configuration register value */ |