diff options
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-i801.c | 99 |
1 files changed, 95 insertions, 4 deletions
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index a1ce4e68b49a..bcce18dfcc39 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -60,10 +60,12 @@ Block process call transaction no I2C block read transaction yes (doesn't use the block buffer) Slave mode no + Interrupt processing yes See the file Documentation/i2c/busses/i2c-i801 for details. */ +#include <linux/interrupt.h> #include <linux/module.h> #include <linux/pci.h> #include <linux/kernel.h> @@ -76,6 +78,7 @@ #include <linux/io.h> #include <linux/dmi.h> #include <linux/slab.h> +#include <linux/wait.h> /* I801 SMBus address offsets */ #define SMBHSTSTS(p) (0 + (p)->smba) @@ -91,8 +94,12 @@ /* PCI Address Constants */ #define SMBBAR 4 +#define SMBPCISTS 0x006 #define SMBHSTCFG 0x040 +/* Host status bits for SMBPCISTS */ +#define SMBPCISTS_INTS 0x08 + /* Host configuration bits for SMBHSTCFG */ #define SMBHSTCFG_HST_EN 1 #define SMBHSTCFG_SMB_SMI_EN 2 @@ -155,6 +162,10 @@ struct i801_priv { unsigned char original_hstcfg; struct pci_dev *pci_dev; unsigned int features; + + /* isr processing */ + wait_queue_head_t waitq; + u8 status; }; static struct pci_driver i801_driver; @@ -163,6 +174,7 @@ static struct pci_driver i801_driver; #define FEATURE_BLOCK_BUFFER (1 << 1) #define FEATURE_BLOCK_PROC (1 << 2) #define FEATURE_I2C_BLOCK_READ (1 << 3) +#define FEATURE_IRQ (1 << 4) /* Not really a feature, but it's convenient to handle it as such */ #define FEATURE_IDF (1 << 15) @@ -171,6 +183,7 @@ static const char *i801_feature_names[] = { "Block buffer", "Block process call", "I2C block read", + "Interrupt", }; static unsigned int disable_features; @@ -215,7 +228,12 @@ static int i801_check_post(struct i801_priv *priv, int status) { int result = 0; - /* If the SMBus is still busy, we give up */ + /* + * If the SMBus is still busy, we give up + * Note: This timeout condition only happens when using polling + * transactions. For interrupt operation, NAK/timeout is indicated by + * DEV_ERR. + */ if (unlikely(status < 0)) { dev_err(&priv->pci_dev->dev, "Transaction timeout\n"); /* try to stop the current command */ @@ -305,6 +323,14 @@ static int i801_transaction(struct i801_priv *priv, int xact) if (result < 0) return result; + if (priv->features & FEATURE_IRQ) { + outb_p(xact | SMBHSTCNT_INTREN | SMBHSTCNT_START, + SMBHSTCNT(priv)); + wait_event(priv->waitq, (status = priv->status)); + priv->status = 0; + return i801_check_post(priv, status); + } + /* the current contents of SMBHSTCNT can be overwritten, since PEC, * SMBSCMD are passed in xact */ outb_p(xact | SMBHSTCNT_START, SMBHSTCNT(priv)); @@ -348,6 +374,44 @@ static int i801_block_transaction_by_block(struct i801_priv *priv, } /* + * i801 signals transaction completion with one of these interrupts: + * INTR - Success + * DEV_ERR - Invalid command, NAK or communication timeout + * BUS_ERR - SMI# transaction collision + * FAILED - transaction was canceled due to a KILL request + * When any of these occur, update ->status and wake up the waitq. + * ->status must be cleared before kicking off the next transaction. + */ +static irqreturn_t i801_isr(int irq, void *dev_id) +{ + struct i801_priv *priv = dev_id; + u16 pcists; + u8 status; + + /* Confirm this is our interrupt */ + pci_read_config_word(priv->pci_dev, SMBPCISTS, &pcists); + if (!(pcists & SMBPCISTS_INTS)) + return IRQ_NONE; + + status = inb_p(SMBHSTSTS(priv)); + if (status != 0x42) + dev_dbg(&priv->pci_dev->dev, "irq: status = %02x\n", status); + + /* + * Clear irq sources and report transaction result. + * ->status must be cleared before the next transaction is started. + */ + status &= SMBHSTSTS_INTR | STATUS_ERROR_FLAGS; + if (status) { + outb_p(status, SMBHSTSTS(priv)); + priv->status |= status; + wake_up(&priv->waitq); + } + + return IRQ_HANDLED; +} + +/* * For "byte-by-byte" block transactions: * I2C write uses cmd=I801_BLOCK_DATA, I2C_EN=1 * I2C read uses cmd=I801_I2C_BLOCK_DATA @@ -799,6 +863,10 @@ static int __devinit i801_probe(struct pci_dev *dev, break; } + /* IRQ processing only tested on CougarPoint PCH */ + if (dev->device == PCI_DEVICE_ID_INTEL_COUGARPOINT_SMBUS) + priv->features |= FEATURE_IRQ; + /* Disable features on user request */ for (i = 0; i < ARRAY_SIZE(i801_feature_names); i++) { if (priv->features & disable_features & (1 << i)) @@ -846,16 +914,31 @@ static int __devinit i801_probe(struct pci_dev *dev, } pci_write_config_byte(priv->pci_dev, SMBHSTCFG, temp); - if (temp & SMBHSTCFG_SMB_SMI_EN) + if (temp & SMBHSTCFG_SMB_SMI_EN) { dev_dbg(&dev->dev, "SMBus using interrupt SMI#\n"); - else + /* Disable SMBus interrupt feature if SMBus using SMI# */ + priv->features &= ~FEATURE_IRQ; + } else { dev_dbg(&dev->dev, "SMBus using PCI Interrupt\n"); + } /* Clear special mode bits */ if (priv->features & (FEATURE_SMBUS_PEC | FEATURE_BLOCK_BUFFER)) outb_p(inb_p(SMBAUXCTL(priv)) & ~(SMBAUXCTL_CRC | SMBAUXCTL_E32B), SMBAUXCTL(priv)); + if (priv->features & FEATURE_IRQ) { + init_waitqueue_head(&priv->waitq); + + err = request_irq(dev->irq, i801_isr, IRQF_SHARED, + i801_driver.name, priv); + if (err) { + dev_err(&dev->dev, "Failed to allocate irq %d: %d\n", + dev->irq, err); + goto exit_release; + } + } + /* set up the sysfs linkage to our parent device */ priv->adapter.dev.parent = &dev->dev; @@ -867,14 +950,18 @@ static int __devinit i801_probe(struct pci_dev *dev, err = i2c_add_adapter(&priv->adapter); if (err) { dev_err(&dev->dev, "Failed to add SMBus adapter\n"); - goto exit_release; + goto exit_free_irq; } i801_probe_optional_slaves(priv); pci_set_drvdata(dev, priv); + return 0; +exit_free_irq: + if (priv->features & FEATURE_IRQ) + free_irq(dev->irq, priv); exit_release: pci_release_region(dev, SMBBAR); exit: @@ -888,7 +975,11 @@ static void __devexit i801_remove(struct pci_dev *dev) i2c_del_adapter(&priv->adapter); pci_write_config_byte(dev, SMBHSTCFG, priv->original_hstcfg); + + if (priv->features & FEATURE_IRQ) + free_irq(dev->irq, priv); pci_release_region(dev, SMBBAR); + pci_set_drvdata(dev, NULL); kfree(priv); /* |