RE: [PATCH v2] lis3lv02d: Add STMicroelectronics lis331dlh digitalaccelerometer

[AnilKumar, Chimata]

Hi Chinmay,

Thanks for the comments

On Wed, Aug 22, 2012 at 14:14:55, Chinmay V S wrote:
> Hi All,
> 
> A few nitpicks.
> 
> > + * LIS3331DLH spec says 1LSBs corresponds 4G/1024 -> 1LSB is 1000/1024 mG.
> > + * Sensitivity values for +/-2G, outdata in 12 bits for +/-2G scale. so 4
> > + * bits adjustment is required
> Shouldn't it be "1LSB is 4000/1024 mG" ?

Typo mistake this should be 4G/4096

> Also "outdata in 12bits" (typo. in->is?)
> 

If we look at the lis331dlh datasheet 12 bits outdata for +/- 2G resolution
range and 13 bits for +/- 4G range and 14 bits for +/- 8G range. So output
data is only 12 bits.

> On a more technical note, now that LIS3331DLH has 16bit resolution,
> why don't we simply return the entire 16-bit value in
> lis3lv02d_read_16(). The fact that lis3lv02d_read_16() has 16-bit
> resolution can be indicated by

Depending on the range 2 or 4 or 8 we have to pass the outdata that is
handled by using the shift_adj member to shift the outdata to corresponding
bits 12/13/14.

> 
> @@ -954,6 +984,16 @@ int lis3lv02d_init_device(struct lis3lv02d *lis3)
>                 lis3->odr_mask = CTRL1_ODR0|CTRL1_ODR1|CTRL1_ODR2|CTRL1_ODR3;
>                 lis3->scale = LIS3_SENSITIVITY_8B;
>                 break;
> +       case WAI_3DLH:
> +               pr_info("16 bits 3DLH sensor found\n");
> +               lis3->read_data = lis3lv02d_read_16;
> +               lis3->mdps_max_val = 32768; /* 16 bits for +/-2G */

This driver supports only +/-2G range of values so it is limited to 2048.
With this we do not have the runtime change of G range so by default 2G
is added.

Regards
AnilKumar
 
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