[PATCH 2/4] i2c: i801: Replace acpi_lock with I2C bus lock

Heiner Kallweit
2023-03-04T21:38:00Z

I2C core ensures in i2c_smbus_xfer() that the I2C bus lock is held when
calling the smbus_xfer callback. That's i801_access() in our case.
I think it's safe in general to assume that the I2C bus lock is held
when the smbus_xfer callback is called.
Therefore I see no need to define an own mutex.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
drivers/i2c/busses/i2c-i801.c | 14 ++++----------
1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index d6a0c3b53..7641bd0ac 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -289,10 +289,9 @@ struct i801_priv {

/*
* If set to true the host controller registers are reserved for
- * ACPI AML use. Protected by acpi_lock.
+ * ACPI AML use.
*/
bool acpi_reserved;
- struct mutex acpi_lock;
};

#define FEATURE_SMBUS_PEC BIT(0)
@@ -871,11 +870,8 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,
int hwpec, ret;
struct i801_priv *priv = i2c_get_adapdata(adap);

- mutex_lock(&priv->acpi_lock);
- if (priv->acpi_reserved) {
- mutex_unlock(&priv->acpi_lock);
+ if (priv->acpi_reserved)
return -EBUSY;
- }

pm_runtime_get_sync(&priv->pci_dev->dev);

@@ -916,7 +912,6 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,

pm_runtime_mark_last_busy(&priv->pci_dev->dev);
pm_runtime_put_autosuspend(&priv->pci_dev->dev);
- mutex_unlock(&priv->acpi_lock);
return ret;
}

@@ -1566,7 +1561,7 @@ i801_acpi_io_handler(u32 function, acpi_physical_address address, u32 bits,
* further access from the driver itself. This device is now owned
* by the system firmware.
*/
- mutex_lock(&priv->acpi_lock);
+ i2c_lock_bus(&priv->adapter, I2C_LOCK_SEGMENT);

if (!priv->acpi_reserved && i801_acpi_is_smbus_ioport(priv, address)) {
priv->acpi_reserved = true;
@@ -1586,7 +1581,7 @@ i801_acpi_io_handler(u32 function, acpi_physical_address address, u32 bits,
else
status = acpi_os_write_port(address, (u32)*value, bits);

- mutex_unlock(&priv->acpi_lock);
+ i2c_unlock_bus(&priv->adapter, I2C_LOCK_SEGMENT);

return status;
}
@@ -1640,7 +1635,6 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
priv->adapter.dev.parent = &dev->dev;
ACPI_COMPANION_SET(&priv->adapter.dev, ACPI_COMPANION(&dev->dev));
priv->adapter.retries = 3;
- mutex_init(&priv->acpi_lock);

priv->pci_dev = dev;
priv->features = id->driver_data;
--
2.39.2