| Subject | Re: [PATCH v8 03/22] counter: 104-quad-8: Return error when invalid mode during ceiling_write | From | David Lechner <> | Date | Sat, 20 Feb 2021 10:30:03 -0600 |
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On 2/12/21 6:13 AM, William Breathitt Gray wrote: > The 104-QUAD-8 only has two count modes where a ceiling value makes > sense: Range Limit and Modulo-N. Outside of these two modes, setting a > ceiling value is an invalid operation -- so let's report it as such by > returning -EINVAL. > > Fixes: fc069262261c ("counter: 104-quad-8: Add lock guards - generic interface") > Cc: Syed Nayyar Waris <syednwaris@gmail.com> > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> > --- > drivers/counter/104-quad-8.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c > index 9691f8612be8..f0608b21196a 100644 > --- a/drivers/counter/104-quad-8.c > +++ b/drivers/counter/104-quad-8.c > @@ -714,13 +714,14 @@ static ssize_t quad8_count_ceiling_write(struct counter_device *counter, > switch (priv->count_mode[count->id]) { > case 1: > case 3: > + mutex_unlock(&priv->lock); > quad8_preset_register_set(priv, count->id, ceiling); > - break; > + return len; > } > > mutex_unlock(&priv->lock); > > - return len; > + return -EINVAL; > } > > static ssize_t quad8_count_preset_enable_read(struct counter_device *counter, >
What happens if the register is written to when in the wrong mode?
If it doesn't hurt anything, I would suggest always writing the register instead so that users don't have to know worry about the fact that the mode has to be set first.
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