On Tue, 21 Jun 2022 02:48:46 +0200
Jakob Hauser <jahau@xxxxxxxxxxxxxx> wrote:
> Hi Jonathan,
>
> On 18.06.22 16:53, Jonathan Cameron wrote:
> >
> > On Sat, 18 Jun 2022 02:13:12 +0200
> > Jakob Hauser <jahau@xxxxxxxxxxxxxx> wrote:
> ...
> >> /* These variant IDs are known from code dumps */
> >> #define YAS537_DEVICE_ID 0x07 /* YAS537 (MS-3T) */
> >> @@ -314,7 +315,7 @@ static s32 yas5xx_linearize(struct yas5xx *yas5xx, u16 val, int axis)
> >
> > Hmm. I'm not a great fun of big hydra functions to handle differences
> > between devices. This could easily all be one code flow with some
> > lookups into chip specific constant data (as btw could a lot of
> > the other switch statements in the existing driver).
>
> I'll try to implement the chip_info approach. This should become a
> separate patch.
>
> Concerning the patchset, I would prefer to introduce the chip_info
> approach rather late. That would mean to leave this patch unchanged and
> introduce your suggestions later within the patchset. I think it's
> easier to follow the changes along the patchset.
>
> However, you probably would prefer to place the chip_info patch rather
> early in the patchset?
Whilst I'd prefer it earlier, if it's a real pain, just put a note on
that in the cover letter and I'll cope :)
>
> >> static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo, s32 *zo)
> >> {
> >> struct yas5xx_calibration *c = &yas5xx->calibration;
> >> - u16 t, x, y1, y2;
> >> + u16 t_ref, t, x, y1, y2;
> >> /* These are "signed x, signed y1 etc */
> >> s32 sx, sy1, sy2, sy, sz;
> >> int ret;
> >> @@ -329,16 +330,46 @@ static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo,
> >> sy1 = yas5xx_linearize(yas5xx, y1, 1);
> >> sy2 = yas5xx_linearize(yas5xx, y2, 2);
> >>
> >> - /*
> >> - * Temperature compensation for x, y1, y2 respectively:
> >> - *
> >> - * Cx * t
> >> - * x' = x - ------
> >> - * 100
> >> - */
> >> - sx = sx - (c->Cx * t) / 100;
> >> - sy1 = sy1 - (c->Cy1 * t) / 100;
> >> - sy2 = sy2 - (c->Cy2 * t) / 100;
> >> + /* Set the temperature reference value (unit: counts) */
> >> + switch (yas5xx->devid) {
> >> + case YAS530_DEVICE_ID:
> >> + t_ref = YAS530_20DEGREES;
> >
> > One thought to simplify the divergent flow below.
> >
> > t_ref2 = 0;
> >> + break;
> >> + case YAS532_DEVICE_ID:
> >> + t_ref = YAS532_20DEGREES;
> > if (yas5xx->version == YAS532_VERSION_AC)
> > t_ref2 = YAS432_20DEGREES;
> > else
> > t_ref2 = 0;
>
> The t_ref2 approach looks confusing to me. Because for the most version
> it's "t_ref2 = 0", only one version out of four needs this.
>
> Another approach: I would rather introduce t_comp (for compensation). In
> the chip_info, for the most version it would be...
>
> .t_comp = t,
>
> ... and for the one variant it would be:
>
> .t_comp = t - t_ref,
That looks sensible to me.
>
> A problem: I would include the YAS variants like YAS530, YAS532 etc. in
> the chip_info. The versions like "AB" and "AC", on the other hand, I
> wouldn't include into the chip_info, instead I would handle these in the
> functions. In that case the, "t_comp" thing would need to be done in the
> function using an if statement, similar to what you suggested up here.
I'd assume there won't be too many different versions that need separate
support and have a chipinfo for each of those versions. So you
select the chipinfo based on both the device part number and version.
>
Thanks,
J
