| Message ID | 20220826170716.6886-4-andriy.shevchenko@linux.intel.com |
|---|---|
| State | Rejected |
| Headers | show |
| Series | [v2,1/4] pwm: sysfs: Switch to DEFINE_SIMPLE_DEV_PM_OPS() and pm_sleep_ptr() | expand |
On Fri, 2022-08-26 at 20:07 +0300, Andy Shevchenko wrote: > Code is smaller and looks nicer if we combine polarity strings > into an array. It's less robust though as PWM_POLARITY_NORMAL and _INVERSED are now required to be 0 and 1. As the only 2 values in an enum they are, but that's not really guaranteed unless you read the enum definition. > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > --- > v2: added pwm_ prefix to the variable (Uwe), adjusted intendation (Uwe) > drivers/pwm/sysfs.c | 32 ++++++++++++-------------------- > 1 file changed, 12 insertions(+), 20 deletions(-) > > diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c > index 767c4b19afb1..502167e44a3d 100644 > --- a/drivers/pwm/sysfs.c > +++ b/drivers/pwm/sysfs.c > @@ -151,27 +151,23 @@ static ssize_t enable_store(struct device *child, > return ret ? : size; > } > > +static const char * const pwm_polarity_strings[] = { > + [PWM_POLARITY_NORMAL] = "normal", > + [PWM_POLARITY_INVERSED] = "inversed", > +}; > + > static ssize_t polarity_show(struct device *child, > struct device_attribute *attr, > char *buf) > { > const struct pwm_device *pwm = child_to_pwm_device(child); > - const char *polarity = "unknown"; > struct pwm_state state; > > pwm_get_state(pwm, &state); > + if (state.polarity < 0 || state.polarity >= ARRAY_SIZE(pwm_polarity_strings)) > + return sysfs_emit(buf, "unknown\n"); > > - switch (state.polarity) { > - case PWM_POLARITY_NORMAL: > - polarity = "normal"; > - break; > - > - case PWM_POLARITY_INVERSED: > - polarity = "inversed"; > - break; > - } > - > - return sysfs_emit(buf, "%s\n", polarity); > + return sysfs_emit(buf, "%s\n", pwm_polarity_strings[state.polarity]); > } > > static ssize_t polarity_store(struct device *child, > @@ -180,20 +176,16 @@ static ssize_t polarity_store(struct device *child, > { > struct pwm_export *export = child_to_pwm_export(child); > struct pwm_device *pwm = export->pwm; > - enum pwm_polarity polarity; > struct pwm_state state; > int ret; > > - if (sysfs_streq(buf, "normal")) > - polarity = PWM_POLARITY_NORMAL; > - else if (sysfs_streq(buf, "inversed")) > - polarity = PWM_POLARITY_INVERSED; > - else > - return -EINVAL; > + ret = sysfs_match_string(pwm_polarity_strings, buf); > + if (ret < 0) > + return ret; > > mutex_lock(&export->lock); > pwm_get_state(pwm, &state); > - state.polarity = polarity; > + state.polarity = ret; > ret = pwm_apply_state(pwm, &state); > mutex_unlock(&export->lock); >
On Sun, 2022-08-28 at 09:40 +0300, Andy Shevchenko wrote: > On Sunday, August 28, 2022, Joe Perches <joe@perches.com> wrote: > > > On Fri, 2022-08-26 at 20:07 +0300, Andy Shevchenko wrote: > > > Code is smaller and looks nicer if we combine polarity strings > > > into an array. > > First of all, please remove unnecessary context when replying. I am _very_ aware of context. I specifically left the code in. > > It's less robust though as PWM_POLARITY_NORMAL and _INVERSED > > are now required to be 0 and 1. As the only 2 values in > > an enum they are, but that's not really guaranteed unless > > you read the enum definition. > > So, what do you suggest here and in many other similar places (yes, ABI > implied) in the kernel? Leaving the code alone.
On Sun, Aug 28, 2022 at 4:46 PM Joe Perches <joe@perches.com> wrote: > On Sun, 2022-08-28 at 09:40 +0300, Andy Shevchenko wrote: > > On Sunday, August 28, 2022, Joe Perches <joe@perches.com> wrote: > > > On Fri, 2022-08-26 at 20:07 +0300, Andy Shevchenko wrote: > > > > Code is smaller and looks nicer if we combine polarity strings > > > > into an array. > > First of all, please remove unnecessary context when replying. > > I am _very_ aware of context. > I specifically left the code in. > > > > It's less robust though as PWM_POLARITY_NORMAL and _INVERSED > > > are now required to be 0 and 1. As the only 2 values in > > > an enum they are, but that's not really guaranteed unless > > > you read the enum definition. > > > > So, what do you suggest here and in many other similar places (yes, ABI > > implied) in the kernel? > > Leaving the code alone. It's good that PWM maintainers look at this differently.
On Sun, 2022-08-28 at 20:40 +0300, Andy Shevchenko wrote: > On Sun, Aug 28, 2022 at 4:46 PM Joe Perches <joe@perches.com> wrote: > > On Sun, 2022-08-28 at 09:40 +0300, Andy Shevchenko wrote: > > > On Sunday, August 28, 2022, Joe Perches <joe@perches.com> wrote: > > > > On Fri, 2022-08-26 at 20:07 +0300, Andy Shevchenko wrote: > > > > > Code is smaller and looks nicer if we combine polarity strings > > > > > into an array. > > > > First of all, please remove unnecessary context when replying. > > > > I am _very_ aware of context. > > I specifically left the code in. > > > > > > It's less robust though as PWM_POLARITY_NORMAL and _INVERSED > > > > are now required to be 0 and 1. As the only 2 values in > > > > an enum they are, but that's not really guaranteed unless > > > > you read the enum definition. > > > > > > So, what do you suggest here and in many other similar places (yes, ABI > > > implied) in the kernel? > > > > Leaving the code alone. > > It's good that PWM maintainers look at this differently. The enum is not userspace so it's not ABI. The PWM maintainers are free to do what they want but I prefer obviousness over compactness.
On Sun, Aug 28, 2022 at 9:19 PM Joe Perches <joe@perches.com> wrote: > On Sun, 2022-08-28 at 20:40 +0300, Andy Shevchenko wrote: > > On Sun, Aug 28, 2022 at 4:46 PM Joe Perches <joe@perches.com> wrote: > > > On Sun, 2022-08-28 at 09:40 +0300, Andy Shevchenko wrote: > > > > On Sunday, August 28, 2022, Joe Perches <joe@perches.com> wrote: > > > > > On Fri, 2022-08-26 at 20:07 +0300, Andy Shevchenko wrote: > > > > > > Code is smaller and looks nicer if we combine polarity strings > > > > > > into an array. > > > > > > First of all, please remove unnecessary context when replying. > > > > > > I am _very_ aware of context. > > > I specifically left the code in. > > > > > > > > It's less robust though as PWM_POLARITY_NORMAL and _INVERSED > > > > > are now required to be 0 and 1. As the only 2 values in > > > > > an enum they are, but that's not really guaranteed unless > > > > > you read the enum definition. > > > > > > > > So, what do you suggest here and in many other similar places (yes, ABI > > > > implied) in the kernel? > > > > > > Leaving the code alone. > > > > It's good that PWM maintainers look at this differently. > > The enum is not userspace so it's not ABI. > > The PWM maintainers are free to do what they want but I > prefer obviousness over compactness. Why do you not start "fixing" other similar places in the kernel?
On Sun, Aug 28, 2022 at 02:19:22PM -0400, Joe Perches wrote: > On Sun, 2022-08-28 at 20:40 +0300, Andy Shevchenko wrote: > > On Sun, Aug 28, 2022 at 4:46 PM Joe Perches <joe@perches.com> wrote: > > > On Sun, 2022-08-28 at 09:40 +0300, Andy Shevchenko wrote: > > > > On Sunday, August 28, 2022, Joe Perches <joe@perches.com> wrote: > > > > > On Fri, 2022-08-26 at 20:07 +0300, Andy Shevchenko wrote: > > > > > > Code is smaller and looks nicer if we combine polarity strings > > > > > > into an array. > > > > > > First of all, please remove unnecessary context when replying. > > > > > > I am _very_ aware of context. > > > I specifically left the code in. > > > > > > > > It's less robust though as PWM_POLARITY_NORMAL and _INVERSED > > > > > are now required to be 0 and 1. As the only 2 values in > > > > > an enum they are, but that's not really guaranteed unless > > > > > you read the enum definition. > > > > > > > > So, what do you suggest here and in many other similar places (yes, ABI > > > > implied) in the kernel? > > > > > > Leaving the code alone. > > > > It's good that PWM maintainers look at this differently. > > The enum is not userspace so it's not ABI. > > The PWM maintainers are free to do what they want but I > prefer obviousness over compactness. I do agree with Joe, I don't see any benefit in this. Thierry
diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c index 767c4b19afb1..502167e44a3d 100644 --- a/drivers/pwm/sysfs.c +++ b/drivers/pwm/sysfs.c @@ -151,27 +151,23 @@ static ssize_t enable_store(struct device *child, return ret ? : size; } +static const char * const pwm_polarity_strings[] = { + [PWM_POLARITY_NORMAL] = "normal", + [PWM_POLARITY_INVERSED] = "inversed", +}; + static ssize_t polarity_show(struct device *child, struct device_attribute *attr, char *buf) { const struct pwm_device *pwm = child_to_pwm_device(child); - const char *polarity = "unknown"; struct pwm_state state; pwm_get_state(pwm, &state); + if (state.polarity < 0 || state.polarity >= ARRAY_SIZE(pwm_polarity_strings)) + return sysfs_emit(buf, "unknown\n"); - switch (state.polarity) { - case PWM_POLARITY_NORMAL: - polarity = "normal"; - break; - - case PWM_POLARITY_INVERSED: - polarity = "inversed"; - break; - } - - return sysfs_emit(buf, "%s\n", polarity); + return sysfs_emit(buf, "%s\n", pwm_polarity_strings[state.polarity]); } static ssize_t polarity_store(struct device *child, @@ -180,20 +176,16 @@ static ssize_t polarity_store(struct device *child, { struct pwm_export *export = child_to_pwm_export(child); struct pwm_device *pwm = export->pwm; - enum pwm_polarity polarity; struct pwm_state state; int ret; - if (sysfs_streq(buf, "normal")) - polarity = PWM_POLARITY_NORMAL; - else if (sysfs_streq(buf, "inversed")) - polarity = PWM_POLARITY_INVERSED; - else - return -EINVAL; + ret = sysfs_match_string(pwm_polarity_strings, buf); + if (ret < 0) + return ret; mutex_lock(&export->lock); pwm_get_state(pwm, &state); - state.polarity = polarity; + state.polarity = ret; ret = pwm_apply_state(pwm, &state); mutex_unlock(&export->lock);
Code is smaller and looks nicer if we combine polarity strings into an array. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> --- v2: added pwm_ prefix to the variable (Uwe), adjusted intendation (Uwe) drivers/pwm/sysfs.c | 32 ++++++++++++-------------------- 1 file changed, 12 insertions(+), 20 deletions(-)