Re: [PATCH 3/3] iio: magnetometer: ak8974: add Alps hscdtd008a

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 6 Apr 2020 16:31:13 +0200
Stephan Gerhold <stephan@gerhold.net> wrote:

> On Mon, Apr 06, 2020 at 04:13:53PM +0200, Nick Reitemeyer wrote:
> > The hscdtd008a is similar to the AK8974:
> > Only the whoami value and some registers are different.
> > 
> > Signed-off-by: Nick Reitemeyer <nick.reitemeyer@web.de>  
> 
> Thanks a lot for sending this patch upstream!
> 
> I checked this with the datasheet available here:
> https://tech.alpsalpine.com/prod/c/pdf/sensor/geomagnetic/hscd/hscdtd008a_data.pdf
> 
> Reviewed-by: Stephan Gerhold <stephan@gerhold.net>
> 
> ... and it seems to produce reasonable values on samsung-golden:
> 
> Tested-by: Stephan Gerhold <stephan@gerhold.net>
> 
> Linus Walleij might want to test this on his samsung-skomer :)

Looks good to me, but I'll need a review on the binding (particularly
the vendor prefix as it's in a generic file). 

Thanks,

Jonathan

> 
> Thanks,
> Stephan
> 
> > ---
> >  drivers/iio/magnetometer/ak8974.c | 38 ++++++++++++++++++++++++-------
> >  1 file changed, 30 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/iio/magnetometer/ak8974.c b/drivers/iio/magnetometer/ak8974.c
> > index d32996702110..ade4ed8f67d2 100644
> > --- a/drivers/iio/magnetometer/ak8974.c
> > +++ b/drivers/iio/magnetometer/ak8974.c
> > @@ -49,6 +49,7 @@
> >  #define AK8974_WHOAMI_VALUE_AMI306 0x46
> >  #define AK8974_WHOAMI_VALUE_AMI305 0x47
> >  #define AK8974_WHOAMI_VALUE_AK8974 0x48
> > +#define AK8974_WHOAMI_VALUE_HSCDTD008A 0x49
> > 
> >  #define AK8974_DATA_X		0x10
> >  #define AK8974_DATA_Y		0x12
> > @@ -140,6 +141,12 @@
> >  #define AK8974_INT_CTRL_PULSE	BIT(1) /* 0 = latched; 1 = pulse (50 usec) */
> >  #define AK8974_INT_CTRL_RESDEF	(AK8974_INT_CTRL_XYZEN | AK8974_INT_CTRL_POL)
> > 
> > +/* HSCDTD008A-specific control register */
> > +#define HSCDTD008A_CTRL4	0x1E
> > +#define HSCDTD008A_CTRL4_MMD	BIT(7)	/* must be set to 1 */
> > +#define HSCDTD008A_CTRL4_RANGE	BIT(4)	/* 0 = 14-bit output; 1 = 15-bit output */
> > +#define HSCDTD008A_CTRL4_RESDEF	(HSCDTD008A_CTRL4_MMD | HSCDTD008A_CTRL4_RANGE)
> > +
> >  /* The AMI305 has elaborate FW version and serial number registers */
> >  #define AMI305_VER		0xE8
> >  #define AMI305_SN		0xEA
> > @@ -241,10 +248,17 @@ static int ak8974_reset(struct ak8974 *ak8974)
> >  	ret = regmap_write(ak8974->map, AK8974_CTRL3, AK8974_CTRL3_RESDEF);
> >  	if (ret)
> >  		return ret;
> > -	ret = regmap_write(ak8974->map, AK8974_INT_CTRL,
> > -			   AK8974_INT_CTRL_RESDEF);
> > -	if (ret)
> > -		return ret;
> > +	if (ak8974->variant != AK8974_WHOAMI_VALUE_HSCDTD008A) {
> > +		ret = regmap_write(ak8974->map, AK8974_INT_CTRL,
> > +				   AK8974_INT_CTRL_RESDEF);
> > +		if (ret)
> > +			return ret;
> > +	} else {
> > +		ret = regmap_write(ak8974->map, HSCDTD008A_CTRL4,
> > +				   HSCDTD008A_CTRL4_RESDEF);
> > +		if (ret)
> > +			return ret;
> > +	}
> > 
> >  	/* After reset, power off is default state */
> >  	return ak8974_set_power(ak8974, AK8974_PWR_OFF);
> > @@ -267,6 +281,8 @@ static int ak8974_configure(struct ak8974 *ak8974)
> >  		if (ret)
> >  			return ret;
> >  	}
> > +	if (ak8974->variant == AK8974_WHOAMI_VALUE_HSCDTD008A)
> > +		return 0;
> >  	ret = regmap_write(ak8974->map, AK8974_INT_CTRL, AK8974_INT_CTRL_POL);
> >  	if (ret)
> >  		return ret;
> > @@ -495,6 +511,10 @@ static int ak8974_detect(struct ak8974 *ak8974)
> >  		name = "ak8974";
> >  		dev_info(&ak8974->i2c->dev, "detected AK8974\n");
> >  		break;
> > +	case AK8974_WHOAMI_VALUE_HSCDTD008A:
> > +		name = "hscdtd008a";
> > +		dev_info(&ak8974->i2c->dev, "detected hscdtd008a\n");
> > +		break;
> >  	default:
> >  		dev_err(&ak8974->i2c->dev, "unsupported device (%02x) ",
> >  			whoami);
> > @@ -674,18 +694,18 @@ static bool ak8974_writeable_reg(struct device *dev, unsigned int reg)
> >  	case AK8974_INT_CTRL:
> >  	case AK8974_INT_THRES:
> >  	case AK8974_INT_THRES + 1:
> > +		return true;
> >  	case AK8974_PRESET:
> >  	case AK8974_PRESET + 1:
> > -		return true;
> > +		return ak8974->variant != AK8974_WHOAMI_VALUE_HSCDTD008A;
> >  	case AK8974_OFFSET_X:
> >  	case AK8974_OFFSET_X + 1:
> >  	case AK8974_OFFSET_Y:
> >  	case AK8974_OFFSET_Y + 1:
> >  	case AK8974_OFFSET_Z:
> >  	case AK8974_OFFSET_Z + 1:
> > -		if (ak8974->variant == AK8974_WHOAMI_VALUE_AK8974)
> > -			return true;
> > -		return false;
> > +		return ak8974->variant == AK8974_WHOAMI_VALUE_AK8974 ||
> > +		       ak8974->variant == AK8974_WHOAMI_VALUE_HSCDTD008A;
> >  	case AMI305_OFFSET_X:
> >  	case AMI305_OFFSET_X + 1:
> >  	case AMI305_OFFSET_Y:
> > @@ -926,12 +946,14 @@ static const struct i2c_device_id ak8974_id[] = {
> >  	{"ami305", 0 },
> >  	{"ami306", 0 },
> >  	{"ak8974", 0 },
> > +	{"hscdtd008a", 0 },
> >  	{}
> >  };
> >  MODULE_DEVICE_TABLE(i2c, ak8974_id);
> > 
> >  static const struct of_device_id ak8974_of_match[] = {
> >  	{ .compatible = "asahi-kasei,ak8974", },
> > +	{ .compatible = "alps,hscdtd008a", },
> >  	{}
> >  };
> >  MODULE_DEVICE_TABLE(of, ak8974_of_match);
> > --
> > 2.26.0
> >