[PATCH v5 1/6] i2c: i801: store and restore the SLVCMD register at load and unload

From: Benjamin Tissoires
Date: Thu Oct 13 2016 - 08:11:30 EST


Also do not override any other configuration in this register.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>

---

no changes in v5

changes in v4:
- add the i801_disable_host_notify function here as this gets the
first in the series

no changes in v3

new in v2
---
drivers/i2c/busses/i2c-i801.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 22a0ed4..3a2fdf5 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -240,6 +240,7 @@ struct i801_priv {
struct i2c_adapter adapter;
unsigned long smba;
unsigned char original_hstcfg;
+ unsigned char original_slvcmd;
struct pci_dev *pci_dev;
unsigned int features;

@@ -952,13 +953,26 @@ static int i801_enable_host_notify(struct i2c_adapter *adapter)
if (!priv->host_notify)
return -ENOMEM;

- outb_p(SMBSLVCMD_HST_NTFY_INTREN, SMBSLVCMD(priv));
+ priv->original_slvcmd = inb_p(SMBSLVCMD(priv));
+
+ if (!(SMBSLVCMD_HST_NTFY_INTREN & priv->original_slvcmd))
+ outb_p(SMBSLVCMD_HST_NTFY_INTREN | priv->original_slvcmd,
+ SMBSLVCMD(priv));
+
/* clear Host Notify bit to allow a new notification */
outb_p(SMBSLVSTS_HST_NTFY_STS, SMBSLVSTS(priv));

return 0;
}

+static void i801_disable_host_notify(struct i801_priv *priv)
+{
+ if (!(priv->features & FEATURE_HOST_NOTIFY))
+ return;
+
+ outb_p(priv->original_slvcmd, SMBSLVCMD(priv));
+}
+
static const struct i2c_algorithm smbus_algorithm = {
.smbus_xfer = i801_access,
.functionality = i801_func,
@@ -1647,6 +1661,7 @@ static void i801_remove(struct pci_dev *dev)
pm_runtime_forbid(&dev->dev);
pm_runtime_get_noresume(&dev->dev);

+ i801_disable_host_notify(priv);
i801_del_mux(priv);
i2c_del_adapter(&priv->adapter);
i801_acpi_remove(priv);
--
2.7.4