From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <532031FC.6010401@metafoo.de> Date: Wed, 12 Mar 2014 11:07:56 +0100 From: Lars-Peter Clausen MIME-Version: 1.0 To: Srinivas Pandruvada CC: jic23@kernel.org, linux-iio@vger.kernel.org Subject: Re: [PATCH 1/3] iio: ak8975 : Add AK8963 compatibility mode support References: <1394572557-8102-1-git-send-email-srinivas.pandruvada@linux.intel.com> In-Reply-To: <1394572557-8102-1-git-send-email-srinivas.pandruvada@linux.intel.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed List-ID: On 03/11/2014 10:15 PM, Srinivas Pandruvada wrote: > 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 Hi, a few small comments. > --- > drivers/iio/magnetometer/Kconfig | 3 ++- > drivers/iio/magnetometer/ak8975.c | 40 +++++++++++++++++++++++++++++++++++---- > 2 files changed, 38 insertions(+), 5 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..a55c94f 100644 > --- a/drivers/iio/magnetometer/ak8975.c > +++ b/drivers/iio/magnetometer/ak8975.c > @@ -85,7 +85,15 @@ > #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, > + AK_INVALID, Not sure if you need AK_INVALID, it is never used. > +}; > > /* > * Per-instance context data for the device. > @@ -101,6 +109,7 @@ struct ak8975_data { > int eoc_irq; > wait_queue_head_t data_ready_queue; > unsigned long flags; > + int chipset; enum asahi_compass_chipset ... > }; > > static const int ak8975_index_to_reg[] = { > @@ -272,9 +281,21 @@ 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 +520,16 @@ static int ak8975_probe(struct i2c_client *client, > data->eoc_gpio = eoc_gpio; > data->eoc_irq = 0; > > + if (id) { id will never be NULL. > + data->chipset = (int)(id->driver_data); > + if (data->chipset == AK8963) > + dev_dbg(&client->dev, > + "AK8975 driver is running in AK8963 mode\n"); > + else > + dev_dbg(&client->dev, > + "AK8975 driver is running in normal mode\n"); How about printing just id->name, this way you do not have to add a new else branch when a new part is supported. > + } > + > /* Perform some basic start-of-day setup of the device. */ > err = ak8975_setup(client); > if (err < 0) { > @@ -552,6 +583,7 @@ static int ak8975_remove(struct i2c_client *client) > > static const struct i2c_device_id ak8975_id[] = { > {"ak8975", 0}, Should change the 0 to AK8975 > + {"ak8963", AK8963}, > {} > }; > >