diff options
| author | Hans de Goede <hdegoede@redhat.com> | 2020-04-28 20:29:18 +0300 |
|---|---|---|
| committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2020-05-10 12:43:03 +0300 |
| commit | c1e62062ff5477f3cd40e956fb1c18808cc894a4 (patch) | |
| tree | ea0ab22769340936627146fe8877c2f92edd533f /drivers | |
| parent | b885d0fa6790b8b2c8502dc93fed27ce85e68922 (diff) | |
| download | linux-c1e62062ff5477f3cd40e956fb1c18808cc894a4.tar.xz | |
iio: light: cm32181: Handle CM3218 ACPI devices with 2 I2C resources
Some ACPI systems list 2 I2C resources for the CM3218 sensor. On these
systems the first I2cSerialBus ACPI-resource points to the SMBus Alert
Response Address (ARA, 0x0c) and the second I2cSerialBus ACPI-resource
points to the actual CM3218 sensor address:
Method (_CRS, 0, NotSerialized) // _CRS: Current Resource Settings
{
Name (SBUF, ResourceTemplate ()
{
I2cSerialBusV2 (0x000C, ControllerInitiated, 0x00061A80,
AddressingMode7Bit, "\\_SB.I2C3",
0x00, ResourceConsumer, , Exclusive,
)
I2cSerialBusV2 (0x0048, ControllerInitiated, 0x00061A80,
AddressingMode7Bit, "\\_SB.I2C3",
0x00, ResourceConsumer, , Exclusive,
)
Interrupt (ResourceConsumer, Level, ActiveHigh, Exclusive, ,, )
{
0x00000033,
}
})
Return (SBUF) /* \_SB_.I2C3.ALSD._CRS.SBUF */
}
Detect this and take the following step to deal with it:
1. When a SMBus Alert capable sensor has an Alert asserted, it will
not respond on its actual I2C address. Read a byte from the ARA
to clear any pending Alerts.
2. Create a "dummy" client for the actual I2C address and
use that client to communicate with the sensor.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/iio/light/cm32181.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/iio/light/cm32181.c b/drivers/iio/light/cm32181.c index a02ec59f2a94..84a5e3927558 100644 --- a/drivers/iio/light/cm32181.c +++ b/drivers/iio/light/cm32181.c @@ -52,6 +52,8 @@ #define CM32181_CALIBSCALE_RESOLUTION 1000 #define MLUX_PER_LUX 1000 +#define SMBUS_ALERT_RESPONSE_ADDRESS 0x0c + static const u8 cm32181_reg[CM32181_CONF_REG_NUM] = { CM32181_REG_ADDR_CMD, }; @@ -336,6 +338,26 @@ static int cm32181_probe(struct i2c_client *client) if (!indio_dev) return -ENOMEM; + /* + * Some ACPI systems list 2 I2C resources for the CM3218 sensor, the + * SMBus Alert Response Address (ARA, 0x0c) and the actual I2C address. + * Detect this and take the following step to deal with it: + * 1. When a SMBus Alert capable sensor has an Alert asserted, it will + * not respond on its actual I2C address. Read a byte from the ARA + * to clear any pending Alerts. + * 2. Create a "dummy" client for the actual I2C address and + * use that client to communicate with the sensor. + */ + if (ACPI_HANDLE(dev) && client->addr == SMBUS_ALERT_RESPONSE_ADDRESS) { + struct i2c_board_info board_info = { .type = "dummy" }; + + i2c_smbus_read_byte(client); + + client = i2c_acpi_new_device(dev, 1, &board_info); + if (IS_ERR(client)) + return PTR_ERR(client); + } + cm32181 = iio_priv(indio_dev); cm32181->client = client; |