[PATCH v6 3/4] i2c: i801: add support of Host Notify
From: Benjamin Tissoires
Date: Wed Mar 16 2016 - 12:39:32 EST
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.
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
---
changes in v2:
- removed the description of the Slave functionality support in the chip table
(the table shows what is supported, not what the hardware is capable of)
- use i2c-smbus to forward the notification
- remove the fifo, and directly retrieve the address and payload in the worker
- do not check for Host Notification is the feature is not enabled
- use inw_p() to read the payload instead of 2 inb_p() calls
- add /* fall-through */ comment
- unconditionally enable Host Notify if the hardware supports it (can be
disabled by the user)
no changes in v3
changes in v4:
- make use of the new API -> no more worker spawning here
- solved a race between the access of the Host Notify registers and the actual
I2C transfers.
changes in v5:
- added SKL Host Notify support
changes in v6:
- select I2C_SMBUS in Kconfig to prevent an undefined reference when I2C_I801
is set to 'Y' while I2C_SMBUS is set to 'M'
drivers/i2c/busses/Kconfig | 1 +
drivers/i2c/busses/i2c-i801.c | 85 +++++++++++++++++++++++++++++++++++++++++--
2 files changed, 83 insertions(+), 3 deletions(-)
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index faa8e68..8c8fa12 100644
--- 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 585a3b7..b244aa40 100644
--- 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>
@@ -112,6 +114,10 @@
#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
@@ -176,6 +182,12 @@
#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)
@@ -244,13 +256,18 @@ struct i801_priv {
struct platform_device *mux_pdev;
#endif
struct platform_device *tco_pdev;
+
+ 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)
@@ -261,6 +278,7 @@ static const char *i801_feature_names[] = {
"Block process call",
"I2C block read",
"Interrupt",
+ "SMBus Host Notify",
};
static unsigned int disable_features;
@@ -269,7 +287,8 @@ 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. */
@@ -503,8 +522,23 @@ 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
@@ -516,6 +550,8 @@ 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)
{
@@ -528,6 +564,12 @@ 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);
@@ -825,7 +867,29 @@ 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 = {
@@ -1279,6 +1343,7 @@ 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:
@@ -1298,6 +1363,8 @@ 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:
@@ -1407,6 +1474,15 @@ 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);
@@ -1445,8 +1521,11 @@ static int i801_suspend(struct pci_dev *dev, pm_message_t mesg)
static int i801_resume(struct pci_dev *dev)
{
+ struct i801_priv *priv = pci_get_drvdata(dev);
+
pci_set_power_state(dev, PCI_D0);
pci_restore_state(dev);
+ i801_enable_host_notify(&priv->adapter);
return 0;
}
#else
--
2.5.0