From: Jonathan Cameron <jic23@kernel.org> To: Dan Carpenter <dan.carpenter@oracle.com> Cc: devel@driverdev.osuosl.org, lars@metafoo.de, Michael.Hennerich@analog.com, linux-iio@vger.kernel.org, gregkh@linuxfoundation.org, 21cnbao@gmail.com, linux-kernel@vger.kernel.org, Himanshu Jha <himanshujha199640@gmail.com>, pmeerw@pmeerw.net, knaack.h@gmx.de Subject: Re: [PATCH 3/4] staging: iio: accel: Use sign_extend32 and adjust a switch statement Date: Sat, 17 Feb 2018 12:23:53 +0000 [thread overview] Message-ID: <20180217122353.7ee9bf96@archlinux> (raw) In-Reply-To: <20180212131000.h4tbinr4s6m4ckh4@mwanda> On Mon, 12 Feb 2018 16:10:01 +0300 Dan Carpenter <dan.carpenter@oracle.com> wrote: > On Mon, Feb 12, 2018 at 05:24:58PM +0530, Himanshu Jha wrote: > > Use sign_extend32 function instead of manually coding it. Also, adjust a > ^^^^^ > > switch block to explicitly match channels and return -EINVAL as default > > case which improves code readability. > > Greg likes to say something along the lines of "when you start your > sentence with "Also, " that could be a clue that it should be a separate > patch.". > > > > > Signed-off-by: Himanshu Jha <himanshujha199640@gmail.com> > > --- > > drivers/staging/iio/accel/adis16201.c | 13 ++++++++----- > > 1 file changed, 8 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/staging/iio/accel/adis16201.c b/drivers/staging/iio/accel/adis16201.c > > index 011d2c5..6800347 100644 > > --- a/drivers/staging/iio/accel/adis16201.c > > +++ b/drivers/staging/iio/accel/adis16201.c > > @@ -112,12 +112,17 @@ static int adis16201_read_raw(struct iio_dev *indio_dev, > > case IIO_CHAN_INFO_SCALE: > > switch (chan->type) { > > case IIO_VOLTAGE: > > - if (chan->channel == 0) { > > + switch (chan->channel) { > > + case 0: > > *val = 1; > > *val2 = 220000; > > - } else { > > + break; > > + case 1: > > *val = 0; > > *val2 = 610000; > > + break; > > + default: > > + return -EINVAL; > > } > > I don't think this improves readability. The -EINVAL is to handle a > driver bug which we haven't introduced yet. Probably we would be better > off printing a warning or something? But it feels weird to introduce so > much code to handle a bug which would actually be pretty difficult to > write. The original code is fine. Hmm. My thought here was that it is not obvious from the code that we only have channel 0 and channel 1. The if statement kind of implies that channel 0 is special compared to 'all the other' elements where as what we are actually doing is picking from a set of options. So semantically it's a switch statement being implemented as an if else pair ;) Perhaps we can compromise on the addition of a comment on the else case to say it only applies to channel 1? Dan, what do you think? It isn't particularly important either way though so feel free to just drop this one. > > > return IIO_VAL_INT_PLUS_MICRO; > > case IIO_TEMP: > > @@ -155,9 +160,7 @@ static int adis16201_read_raw(struct iio_dev *indio_dev, > > if (ret) > > return ret; > > > > - val16 &= (1 << bits) - 1; > > - val16 = (s16)(val16 << (16 - bits)) >> (16 - bits); > > - *val = val16; > > + *val = sign_extend32(val16, bits - 1); > > Yeah. This is a nice clean up. > > regards, > dan carpenter > _______________________________________________ devel mailing list devel@linuxdriverproject.org http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
WARNING: multiple messages have this Message-ID (diff)
From: Jonathan Cameron <jic23@kernel.org> To: Dan Carpenter <dan.carpenter@oracle.com> Cc: Himanshu Jha <himanshujha199640@gmail.com>, 21cnbao@gmail.com, devel@driverdev.osuosl.org, lars@metafoo.de, Michael.Hennerich@analog.com, linux-iio@vger.kernel.org, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, pmeerw@pmeerw.net, knaack.h@gmx.de Subject: Re: [PATCH 3/4] staging: iio: accel: Use sign_extend32 and adjust a switch statement Date: Sat, 17 Feb 2018 12:23:53 +0000 [thread overview] Message-ID: <20180217122353.7ee9bf96@archlinux> (raw) In-Reply-To: <20180212131000.h4tbinr4s6m4ckh4@mwanda> On Mon, 12 Feb 2018 16:10:01 +0300 Dan Carpenter <dan.carpenter@oracle.com> wrote: > On Mon, Feb 12, 2018 at 05:24:58PM +0530, Himanshu Jha wrote: > > Use sign_extend32 function instead of manually coding it. Also, adjust a > ^^^^^ > > switch block to explicitly match channels and return -EINVAL as default > > case which improves code readability. > > Greg likes to say something along the lines of "when you start your > sentence with "Also, " that could be a clue that it should be a separate > patch.". > > > > > Signed-off-by: Himanshu Jha <himanshujha199640@gmail.com> > > --- > > drivers/staging/iio/accel/adis16201.c | 13 ++++++++----- > > 1 file changed, 8 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/staging/iio/accel/adis16201.c b/drivers/staging/iio/accel/adis16201.c > > index 011d2c5..6800347 100644 > > --- a/drivers/staging/iio/accel/adis16201.c > > +++ b/drivers/staging/iio/accel/adis16201.c > > @@ -112,12 +112,17 @@ static int adis16201_read_raw(struct iio_dev *indio_dev, > > case IIO_CHAN_INFO_SCALE: > > switch (chan->type) { > > case IIO_VOLTAGE: > > - if (chan->channel == 0) { > > + switch (chan->channel) { > > + case 0: > > *val = 1; > > *val2 = 220000; > > - } else { > > + break; > > + case 1: > > *val = 0; > > *val2 = 610000; > > + break; > > + default: > > + return -EINVAL; > > } > > I don't think this improves readability. The -EINVAL is to handle a > driver bug which we haven't introduced yet. Probably we would be better > off printing a warning or something? But it feels weird to introduce so > much code to handle a bug which would actually be pretty difficult to > write. The original code is fine. Hmm. My thought here was that it is not obvious from the code that we only have channel 0 and channel 1. The if statement kind of implies that channel 0 is special compared to 'all the other' elements where as what we are actually doing is picking from a set of options. So semantically it's a switch statement being implemented as an if else pair ;) Perhaps we can compromise on the addition of a comment on the else case to say it only applies to channel 1? Dan, what do you think? It isn't particularly important either way though so feel free to just drop this one. > > > return IIO_VAL_INT_PLUS_MICRO; > > case IIO_TEMP: > > @@ -155,9 +160,7 @@ static int adis16201_read_raw(struct iio_dev *indio_dev, > > if (ret) > > return ret; > > > > - val16 &= (1 << bits) - 1; > > - val16 = (s16)(val16 << (16 - bits)) >> (16 - bits); > > - *val = val16; > > + *val = sign_extend32(val16, bits - 1); > > Yeah. This is a nice clean up. > > regards, > dan carpenter >
next prev parent reply other threads:[~2018-02-17 12:23 UTC|newest] Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-02-12 11:54 [PATCH 0/4] staging: iio: accel: adis16201 driver cleanup Himanshu Jha 2018-02-12 11:54 ` Himanshu Jha 2018-02-12 11:54 ` [PATCH 1/4] staging: iio: accel: adis16201: Use SPDX identifier Himanshu Jha 2018-02-12 11:54 ` Himanshu Jha 2018-02-12 11:54 ` [PATCH 2/4] staging: iio: accel: Remove unnecessary comments and add suitable suffix Himanshu Jha 2018-02-12 11:54 ` Himanshu Jha 2018-02-12 12:53 ` Dan Carpenter 2018-02-12 12:53 ` Dan Carpenter 2018-02-12 14:35 ` Himanshu Jha 2018-02-12 14:35 ` Himanshu Jha 2018-02-12 14:57 ` Dan Carpenter 2018-02-12 14:57 ` Dan Carpenter 2018-02-12 19:46 ` Himanshu Jha 2018-02-12 19:46 ` Himanshu Jha 2018-02-17 12:19 ` Jonathan Cameron 2018-02-17 12:19 ` Jonathan Cameron 2018-02-17 12:16 ` Jonathan Cameron 2018-02-17 12:16 ` Jonathan Cameron 2018-02-12 11:54 ` [PATCH 3/4] staging: iio: accel: Use sign_extend32 and adjust a switch statement Himanshu Jha 2018-02-12 11:54 ` Himanshu Jha 2018-02-12 13:10 ` Dan Carpenter 2018-02-12 13:10 ` Dan Carpenter 2018-02-17 12:23 ` Jonathan Cameron [this message] 2018-02-17 12:23 ` Jonathan Cameron 2018-02-17 17:24 ` Dan Carpenter 2018-02-17 17:24 ` Dan Carpenter 2018-02-12 11:54 ` [PATCH 4/4] staging: iio: accel: Move adis16201 driver out of staging Himanshu Jha 2018-02-12 11:54 ` Himanshu Jha 2018-02-12 13:18 ` Dan Carpenter 2018-02-12 13:18 ` Dan Carpenter 2018-02-12 14:41 ` Himanshu Jha 2018-02-12 14:41 ` Himanshu Jha 2018-02-12 14:45 ` Dan Carpenter 2018-02-12 14:45 ` Dan Carpenter 2018-02-17 12:26 ` Jonathan Cameron 2018-02-17 12:26 ` Jonathan Cameron 2018-02-12 14:10 ` Philippe Ombredanne 2018-02-12 14:10 ` Philippe Ombredanne 2018-02-12 14:37 ` Himanshu Jha 2018-02-12 14:37 ` Himanshu Jha 2018-02-12 22:18 ` Philippe Ombredanne
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20180217122353.7ee9bf96@archlinux \ --to=jic23@kernel.org \ --cc=21cnbao@gmail.com \ --cc=Michael.Hennerich@analog.com \ --cc=dan.carpenter@oracle.com \ --cc=devel@driverdev.osuosl.org \ --cc=gregkh@linuxfoundation.org \ --cc=himanshujha199640@gmail.com \ --cc=knaack.h@gmx.de \ --cc=lars@metafoo.de \ --cc=linux-iio@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=pmeerw@pmeerw.net \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.