Messages in this thread | | | Date | Fri, 14 May 2021 13:54:56 +0200 | From | Greg KH <> | Subject | Re: [PATCH -next v2] staging: co medi: Remove unused variable ‘min full scale ’ and function 'get_min_full_scales' |
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On Fri, May 14, 2021 at 12:16:11PM +0100, Ian Abbott wrote: > On 14/05/2021 08:52, Greg KH wrote: > > On Fri, May 14, 2021 at 04:52:14PM +0800, Bixuan Cui wrote: > > > The variable ‘min_full_scale’ and function 'get_min_full_scales' are > > > not used, So delete them. > > > > > > Signed-off-by: Bixuan Cui <cuibixuan@huawei.com> > > > --- > > > Changes from v2: > > > * Delete function 'get_min_full_scales' > > > > > > drivers/comedi/drivers/jr3_pci.c | 15 --------------- > > > 1 file changed, 15 deletions(-) > > > > > > diff --git a/drivers/comedi/drivers/jr3_pci.c b/drivers/comedi/drivers/jr3_pci.c > > > index 7a02c4fa3cda..f963080dd61f 100644 > > > --- a/drivers/comedi/drivers/jr3_pci.c > > > +++ b/drivers/comedi/drivers/jr3_pci.c > > > @@ -186,19 +186,6 @@ static void set_full_scales(struct jr3_sensor __iomem *sensor, > > > set_s16(&sensor->command_word0, 0x0a00); > > > } > > > -static struct six_axis_t get_min_full_scales(struct jr3_sensor __iomem *sensor) > > > -{ > > > - struct six_axis_t result; > > > - > > > - result.fx = get_s16(&sensor->min_full_scale.fx); > > > - result.fy = get_s16(&sensor->min_full_scale.fy); > > > - result.fz = get_s16(&sensor->min_full_scale.fz); > > > - result.mx = get_s16(&sensor->min_full_scale.mx); > > > - result.my = get_s16(&sensor->min_full_scale.my); > > > - result.mz = get_s16(&sensor->min_full_scale.mz); > > > - return result; > > > > Are you _SURE_ that this is ok to do? You are reading from the > > hardware, and that is sometimes required depending on the > > internal-to-the-device state machine. > > > > Have you tested to verify that not doing these reads does not break > > something? > > > > This is a constant theme in these "remove variables that are not being > > used" patches, please be aware that how hardware works is very specific > > and when you mess with how it is accessed, that has the chance of > > causing problems. > > I don't think removing this would do any harm. The `get_s16` function is > just a simple wrapper around `readl` that converts the type of the returned > value to `s16`. The registers for minimum full scale and maximum full scale > are just informational, and there is nothing in the manual[1] about reading > registers in a particular order. The driver used to print these values to > the kernel log, but that code was removed in commit a1d16659538a ("staging: > comedi: jr3_pci: remove noisy printk"). > > [1] 5907E - Legacy PCI Receiver Manual > <https://www.jr3.com/component/phocadownload/category/6-product-manuals?download=36:5907e-legacy-pci-receiver-manual> >
Ok, can I get a "reviewed-by:" then?
thanks,
greg k-h
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