[Patch v1 1/2] iio: ak8975 : Add AK8963 compatibility mode support

Srinivas Pandruvada
2014-03-19T16:53:52Z

AK8963 and AK8975 use same register definitions, except the range
of X,Y,Z values. Added support of 8963 based on i2c_device_id.
Unfortunately there is no way to detect the type via registers,
both device registers return 0x48 as id of chipset.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
drivers/iio/magnetometer/Kconfig | 3 ++-
drivers/iio/magnetometer/ak8975.c | 34 +++++++++++++++++++++++++++++-----
2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig
index d86d226..05a364c54 100644
--- a/drivers/iio/magnetometer/Kconfig
+++ b/drivers/iio/magnetometer/Kconfig
@@ -11,7 +11,8 @@ config AK8975
depends on GPIOLIB
help
Say yes here to build support for Asahi Kasei AK8975 3-Axis
- Magnetometer.
+ Magnetometer. This driver can also support AK8963, if i2c
+ device name is identified as ak8963.

To compile this driver as a module, choose M here: the module
will be called ak8975.
diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c
index 0542354..aa7682d 100644
--- a/drivers/iio/magnetometer/ak8975.c
+++ b/drivers/iio/magnetometer/ak8975.c
@@ -85,7 +85,14 @@
#define AK8975_MAX_CONVERSION_TIMEOUT 500
#define AK8975_CONVERSION_DONE_POLL_TIME 10
#define AK8975_DATA_READY_TIMEOUT ((100*HZ)/1000)
-#define RAW_TO_GAUSS(asa) ((((asa) + 128) * 3000) / 256)
+#define RAW_TO_GAUSS_8975(asa) ((((asa) + 128) * 3000) / 256)
+#define RAW_TO_GAUSS_8963(asa) ((((asa) + 128) * 6000) / 256)
+
+/* Compatible Asahi Kasei Compass parts */
+enum asahi_compass_chipset {
+ AK8975,
+ AK8963,
+};

/*
* Per-instance context data for the device.
@@ -101,6 +108,7 @@ struct ak8975_data {
int eoc_irq;
wait_queue_head_t data_ready_queue;
unsigned long flags;
+ enum asahi_compass_chipset chipset;
};

static const int ak8975_index_to_reg[] = {
@@ -272,9 +280,21 @@ static int ak8975_setup(struct i2c_client *client)
* Since ASA doesn't change, we cache the resultant scale factor into the
* device context in ak8975_setup().
*/
- data->raw_to_gauss[0] = RAW_TO_GAUSS(data->asa[0]);
- data->raw_to_gauss[1] = RAW_TO_GAUSS(data->asa[1]);
- data->raw_to_gauss[2] = RAW_TO_GAUSS(data->asa[2]);
+ if (data->chipset == AK8963) {
+ /*
+ * H range is +-8190 and magnetometer range is +-4912.
+ * So HuT using the above explanation for 8975,
+ * 4912/8190 = ~ 6/10.
+ * So the Hadj should use 6/10 instead of 3/10.
+ */
+ data->raw_to_gauss[0] = RAW_TO_GAUSS_8963(data->asa[0]);
+ data->raw_to_gauss[1] = RAW_TO_GAUSS_8963(data->asa[1]);
+ data->raw_to_gauss[2] = RAW_TO_GAUSS_8963(data->asa[2]);
+ } else {
+ data->raw_to_gauss[0] = RAW_TO_GAUSS_8975(data->asa[0]);
+ data->raw_to_gauss[1] = RAW_TO_GAUSS_8975(data->asa[1]);
+ data->raw_to_gauss[2] = RAW_TO_GAUSS_8975(data->asa[2]);
+ }

return 0;
}
@@ -499,6 +519,9 @@ static int ak8975_probe(struct i2c_client *client,
data->eoc_gpio = eoc_gpio;
data->eoc_irq = 0;

+ data->chipset = (enum asahi_compass_chipset)(id->driver_data);
+ dev_dbg(&client->dev, "Asahi compass chip %s\n", id->name);
+
/* Perform some basic start-of-day setup of the device. */
err = ak8975_setup(client);
if (err < 0) {
@@ -551,7 +574,8 @@ static int ak8975_remove(struct i2c_client *client)
}

static const struct i2c_device_id ak8975_id[] = {
- {"ak8975", 0},
+ {"ak8975", AK8975},
+ {"ak8963", AK8963},
{}
};

--
1.7.11.7