i2c: i801: add support of Host Notify

The i801 chip can handle the Host Notify feature since ICH 3 as mentioned
in http://www.intel.com/content/dam/doc/datasheet/82801ca-io-controller-hub-3-datasheet.pdf

Enable the functionality unconditionally and propagate the alert
on each notification.

With a T440s and a Synaptics touchpad that implements Host Notify, the
payload data is always 0x0000, so I am not sure if the device actually
sends the payload or if there is a problem regarding the implementation.

Tested-by: Andrew Duggan <aduggan@synaptics.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index efa3d9b..b4b6cb0 100644 (file)
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -91,6 +91,7 @@ config I2C_I801
        tristate "Intel 82801 (ICH/PCH)"
        depends on PCI
        select CHECK_SIGNATURE if X86 && DMI
+       select I2C_SMBUS
        help
          If you say yes to this option, support will be included for the Intel
          801 family of mainboard I2C interfaces.  Specifically, the following

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index ae5df14..68cec61 100644 (file)
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -72,6 +72,7 @@
  * Block process call transaction      no
  * I2C block read transaction          yes (doesn't use the block buffer)
  * Slave mode                          no
+ * SMBus Host Notify                   yes
  * Interrupt processing                        yes
  *
  * See the file Documentation/i2c/busses/i2c-i801 for details.
@@ -86,6 +87,7 @@
 #include <linux/ioport.h>
 #include <linux/init.h>
 #include <linux/i2c.h>
+#include <linux/i2c-smbus.h>
 #include <linux/acpi.h>
 #include <linux/io.h>
 #include <linux/dmi.h>
@@ -113,6 +115,10 @@
 #define SMBPEC(p)      (8 + (p)->smba)         /* ICH3 and later */
 #define SMBAUXSTS(p)   (12 + (p)->smba)        /* ICH4 and later */
 #define SMBAUXCTL(p)   (13 + (p)->smba)        /* ICH4 and later */
+#define SMBSLVSTS(p)   (16 + (p)->smba)        /* ICH3 and later */
+#define SMBSLVCMD(p)   (17 + (p)->smba)        /* ICH3 and later */
+#define SMBNTFDADD(p)  (20 + (p)->smba)        /* ICH3 and later */
+#define SMBNTFDDAT(p)  (22 + (p)->smba)        /* ICH3 and later */
 
 /* PCI Address Constants */
 #define SMBBAR         4
@@ -181,6 +187,12 @@
 #define SMBHSTSTS_INTR         0x02
 #define SMBHSTSTS_HOST_BUSY    0x01
 
+/* Host Notify Status registers bits */
+#define SMBSLVSTS_HST_NTFY_STS 1
+
+/* Host Notify Command registers bits */
+#define SMBSLVCMD_HST_NTFY_INTREN      0x01
+
 #define STATUS_ERROR_FLAGS     (SMBHSTSTS_FAILED | SMBHSTSTS_BUS_ERR | \
                                 SMBHSTSTS_DEV_ERR)
 
@@ -256,13 +268,17 @@ struct i801_priv {
         */
        bool acpi_reserved;
        struct mutex acpi_lock;
+       struct smbus_host_notify *host_notify;
 };
 
+#define SMBHSTNTFY_SIZE                8
+
 #define FEATURE_SMBUS_PEC      (1 << 0)
 #define FEATURE_BLOCK_BUFFER   (1 << 1)
 #define FEATURE_BLOCK_PROC     (1 << 2)
 #define FEATURE_I2C_BLOCK_READ (1 << 3)
 #define FEATURE_IRQ            (1 << 4)
+#define FEATURE_HOST_NOTIFY    (1 << 5)
 /* Not really a feature, but it's convenient to handle it as such */
 #define FEATURE_IDF            (1 << 15)
 #define FEATURE_TCO            (1 << 16)
@@ -273,6 +289,7 @@ static const char *i801_feature_names[] = {
        "Block process call",
        "I2C block read",
        "Interrupt",
+       "SMBus Host Notify",
 };
 
 static unsigned int disable_features;
@@ -281,7 +298,8 @@ MODULE_PARM_DESC(disable_features, "Disable selected driver features:\n"
        "\t\t  0x01  disable SMBus PEC\n"
        "\t\t  0x02  disable the block buffer\n"
        "\t\t  0x08  disable the I2C block read functionality\n"
-       "\t\t  0x10  don't use interrupts ");
+       "\t\t  0x10  don't use interrupts\n"
+       "\t\t  0x20  disable SMBus Host Notify ");
 
 /* Make sure the SMBus host is ready to start transmitting.
    Return 0 if it is, -EBUSY if it is not. */
@@ -560,8 +578,23 @@ static void i801_isr_byte_done(struct i801_priv *priv)
        outb_p(SMBHSTSTS_BYTE_DONE, SMBHSTSTS(priv));
 }
 
+static irqreturn_t i801_host_notify_isr(struct i801_priv *priv)
+{
+       unsigned short addr;
+       unsigned int data;
+
+       addr = inb_p(SMBNTFDADD(priv)) >> 1;
+       data = inw_p(SMBNTFDDAT(priv));
+
+       i2c_handle_smbus_host_notify(priv->host_notify, addr, data);
+
+       /* clear Host Notify bit and return */
+       outb_p(SMBSLVSTS_HST_NTFY_STS, SMBSLVSTS(priv));
+       return IRQ_HANDLED;
+}
+
 /*
- * There are two kinds of interrupts:
+ * There are three kinds of interrupts:
  *
  * 1) i801 signals transaction completion with one of these interrupts:
  *      INTR - Success
@@ -573,6 +606,8 @@ static void i801_isr_byte_done(struct i801_priv *priv)
  *
  * 2) For byte-by-byte (I2C read/write) transactions, one BYTE_DONE interrupt
  *    occurs for each byte of a byte-by-byte to prepare the next byte.
+ *
+ * 3) Host Notify interrupts
  */
 static irqreturn_t i801_isr(int irq, void *dev_id)
 {
@@ -585,6 +620,12 @@ static irqreturn_t i801_isr(int irq, void *dev_id)
        if (!(pcists & SMBPCISTS_INTS))
                return IRQ_NONE;
 
+       if (priv->features & FEATURE_HOST_NOTIFY) {
+               status = inb_p(SMBSLVSTS(priv));
+               if (status & SMBSLVSTS_HST_NTFY_STS)
+                       return i801_host_notify_isr(priv);
+       }
+
        status = inb_p(SMBHSTSTS(priv));
        if (status & SMBHSTSTS_BYTE_DONE)
                i801_isr_byte_done(priv);
@@ -896,7 +937,28 @@ static u32 i801_func(struct i2c_adapter *adapter)
               I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_WRITE_I2C_BLOCK |
               ((priv->features & FEATURE_SMBUS_PEC) ? I2C_FUNC_SMBUS_PEC : 0) |
               ((priv->features & FEATURE_I2C_BLOCK_READ) ?
-               I2C_FUNC_SMBUS_READ_I2C_BLOCK : 0);
+               I2C_FUNC_SMBUS_READ_I2C_BLOCK : 0) |
+              ((priv->features & FEATURE_HOST_NOTIFY) ?
+               I2C_FUNC_SMBUS_HOST_NOTIFY : 0);
+}
+
+static int i801_enable_host_notify(struct i2c_adapter *adapter)
+{
+       struct i801_priv *priv = i2c_get_adapdata(adapter);
+
+       if (!(priv->features & FEATURE_HOST_NOTIFY))
+               return -ENOTSUPP;
+
+       if (!priv->host_notify)
+               priv->host_notify = i2c_setup_smbus_host_notify(adapter);
+       if (!priv->host_notify)
+               return -ENOMEM;
+
+       outb_p(SMBSLVCMD_HST_NTFY_INTREN, SMBSLVCMD(priv));
+       /* clear Host Notify bit to allow a new notification */
+       outb_p(SMBSLVSTS_HST_NTFY_STS, SMBSLVSTS(priv));
+
+       return 0;
 }
 
 static const struct i2c_algorithm smbus_algorithm = {
@@ -1428,6 +1490,7 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
                priv->features |= FEATURE_SMBUS_PEC;
                priv->features |= FEATURE_BLOCK_BUFFER;
                priv->features |= FEATURE_TCO;
+               priv->features |= FEATURE_HOST_NOTIFY;
                break;
 
        case PCI_DEVICE_ID_INTEL_PATSBURG_SMBUS_IDF0:
@@ -1447,6 +1510,8 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
                priv->features |= FEATURE_BLOCK_BUFFER;
                /* fall through */
        case PCI_DEVICE_ID_INTEL_82801CA_3:
+               priv->features |= FEATURE_HOST_NOTIFY;
+               /* fall through */
        case PCI_DEVICE_ID_INTEL_82801BA_2:
        case PCI_DEVICE_ID_INTEL_82801AB_3:
        case PCI_DEVICE_ID_INTEL_82801AA_3:
@@ -1556,6 +1621,15 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
                return err;
        }
 
+       /*
+        * Enable Host Notify for chips that supports it.
+        * It is done after i2c_add_adapter() so that we are sure the work queue
+        * is not used if i2c_add_adapter() fails.
+        */
+       err = i801_enable_host_notify(&priv->adapter);
+       if (err && err != -ENOTSUPP)
+               dev_warn(&dev->dev, "Unable to enable SMBus Host Notify\n");
+
        i801_probe_optional_slaves(priv);
        /* We ignore errors - multiplexing is optional */
        i801_add_mux(priv);
@@ -1602,6 +1676,14 @@ static int i801_suspend(struct device *dev)
 
 static int i801_resume(struct device *dev)
 {
+       struct pci_dev *pci_dev = to_pci_dev(dev);
+       struct i801_priv *priv = pci_get_drvdata(pci_dev);
+       int err;
+
+       err = i801_enable_host_notify(&priv->adapter);
+       if (err && err != -ENOTSUPP)
+               dev_warn(dev, "Unable to enable SMBus Host Notify\n");
+
        return 0;
 }
 #endif