Added I2C to Cc.
On 12/15/2014 10:19 PM, Srinivas Pandruvada wrote:
Using i2c auto detect feature and auto device creation feature,
enumerate ak8975 device, by checking their presence.
This is needed because when this device sits behind an i2c mux, there
is no way to define i2c mux in ACPI. This will enable ak8975 on
windows based tablets/laptops running Linux when connected via a mux.
Since DT model already can define an i2c mux and devices connected to
it, this feature is only enabled for ACPI.
This is quite a bit of a hack. Did they decide to not include the device in
the ACPI description at all or is there a special id for INV6050+AK8975?
How does Windows decide whether there is a device or not?
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
---
drivers/iio/magnetometer/ak8975.c | 35 +++++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)
diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c
index 0d10a4b..c3455bd 100644
--- a/drivers/iio/magnetometer/ak8975.c
+++ b/drivers/iio/magnetometer/ak8975.c
@@ -820,6 +820,36 @@ static const struct i2c_device_id ak8975_id[] = {
MODULE_DEVICE_TABLE(i2c, ak8975_id);
+#if defined(CONFIG_ACPI)
+static int ak8975_detect(struct i2c_client *temp_client,
+ struct i2c_board_info *info)
+{
+ struct i2c_adapter *adapter;
+ int i, j;
+ int ret;
+
+ /* autodetect only when we are behind a mux */
+ adapter = i2c_parent_is_i2c_adapter(temp_client->adapter);
+ if (!adapter)
+ return -ENODEV;
+
+ for (i = 0; i < AK_MAX_TYPE; ++i) {
+ ret = ak8975_who_i_am(temp_client, i);
+ if (ret >= 0) {
+ for (j = 0; j < ARRAY_SIZE(ak8975_id) - 1; ++j) {
+ if (i == (int)ak8975_id[j].driver_data) {
+ strlcpy(info->type, ak8975_id[j].name,
+ I2C_NAME_SIZE);
+ return 0;
+ }
+ }
+ }
+ }
+
+ return -ENODEV;
+}
+#endif
+
static const struct of_device_id ak8975_of_match[] = {
{ .compatible = "asahi-kasei,ak8975", },
{ .compatible = "ak8975", },
@@ -841,6 +871,11 @@ static struct i2c_driver ak8975_driver = {
},
.probe = ak8975_probe,
.id_table = ak8975_id,
+#if defined(CONFIG_ACPI)
+ .class = I2C_CLASS_HWMON,
+ .address_list = I2C_ADDRS(0x0C, 0x0D, 0x0E, 0x0F),
+ .detect = ak8975_detect,
In contrast to the commit message this is always enabled if the kernel
contains ACPI support, not if the device is a ACPI device.
+#endif
};
module_i2c_driver(ak8975_driver);
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