| Message ID | 1423241948-31981-8-git-send-email-l.majewski@samsung.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Delegated to: | Eduardo Valentin |
| Headers | show |
On Fri, Feb 06, 2015 at 05:59:07PM +0100, Lukasz Majewski wrote: > This patch provides code for reading PWM FAN configuration data via > device tree. The pwm-fan can work with full speed when configuration > is not provided. However, errors are propagated when wrong DT bindings > are found. > Additionally the struct pwm_fan_ctx has been extended. > > Signed-off-by: Lukasz Majewski <l.majewski@samsung.com> > --- > Changes for v2: > - Rename pwm_fan_max_states to pwm_fan_cooling_levels > - Moving pwm_fan_of_get_cooling_data() call after setting end enabling PWM FAN > - pwm_fan_of_get_cooling_data() now can fail - preserving old behaviour > - Remove unnecessary dev_err() call > Changes for v3: > - Patch's headline has been reedited > - pwm_fan_of_get_cooling_data() return code is now being checked. > - of_property_count_elems_of_size() is now used instead of_find_property() > - More verbose patch description added > --- > drivers/hwmon/pwm-fan.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 53 insertions(+), 1 deletion(-) > > diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c > index 870e100..f3f5843 100644 > --- a/drivers/hwmon/pwm-fan.c > +++ b/drivers/hwmon/pwm-fan.c > @@ -30,7 +30,10 @@ > struct pwm_fan_ctx { > struct mutex lock; > struct pwm_device *pwm; > - unsigned char pwm_value; > + unsigned int pwm_value; > + unsigned int pwm_fan_state; > + unsigned int pwm_fan_max_state; > + unsigned int *pwm_fan_cooling_levels; > }; > > static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) > @@ -100,6 +103,50 @@ static struct attribute *pwm_fan_attrs[] = { > > ATTRIBUTE_GROUPS(pwm_fan); > > +int pwm_fan_of_get_cooling_data(struct device *dev, struct pwm_fan_ctx *ctx) > +{ > + struct device_node *np = dev->of_node; > + int num, i, ret; > + > + ret = of_property_count_elems_of_size(np, "cooling-levels", > + sizeof(u32)); > + > + if (ret == -EINVAL) { > + dev_err(dev, "Property 'cooling-levels' not found\n"); > + return 0; Returning 0 is obviously not an error, otherwise you would not return 0 here. So dev_err is wrong. Also, the message itself is wrong; the property may well be there but have a wrong size. > + } > + > + if (ret <= 0) { > + dev_err(dev, "Wrong data!\n"); > + return ret; > + } This will result in the driver failing to load if devicetree is not configured (of_property_count_elems_of_size will return -ENOSYS). This is not acceptable. Also, if the call returns 0 you don't return an error but display a "Wrong data!" error message. Either it is an error or it is not, but not both. Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, 6 Feb 2015 10:36:57 -0800 Guenter Roeck <linux@roeck-us.net> wrote: > On Fri, Feb 06, 2015 at 05:59:07PM +0100, Lukasz Majewski wrote: > > This patch provides code for reading PWM FAN configuration data via > > device tree. The pwm-fan can work with full speed when configuration > > is not provided. However, errors are propagated when wrong DT > > bindings are found. > > Additionally the struct pwm_fan_ctx has been extended. > > > > Signed-off-by: Lukasz Majewski <l.majewski@samsung.com> > > --- > > Changes for v2: > > - Rename pwm_fan_max_states to pwm_fan_cooling_levels > > - Moving pwm_fan_of_get_cooling_data() call after setting end > > enabling PWM FAN > > - pwm_fan_of_get_cooling_data() now can fail - preserving old > > behaviour > > - Remove unnecessary dev_err() call > > Changes for v3: > > - Patch's headline has been reedited > > - pwm_fan_of_get_cooling_data() return code is now being checked. > > - of_property_count_elems_of_size() is now used instead > > of_find_property() > > - More verbose patch description added > > --- > > drivers/hwmon/pwm-fan.c | 54 > > ++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, > > 53 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c > > index 870e100..f3f5843 100644 > > --- a/drivers/hwmon/pwm-fan.c > > +++ b/drivers/hwmon/pwm-fan.c > > @@ -30,7 +30,10 @@ > > struct pwm_fan_ctx { > > struct mutex lock; > > struct pwm_device *pwm; > > - unsigned char pwm_value; > > + unsigned int pwm_value; > > + unsigned int pwm_fan_state; > > + unsigned int pwm_fan_max_state; > > + unsigned int *pwm_fan_cooling_levels; > > }; > > > > static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) > > @@ -100,6 +103,50 @@ static struct attribute *pwm_fan_attrs[] = { > > > > ATTRIBUTE_GROUPS(pwm_fan); > > > > +int pwm_fan_of_get_cooling_data(struct device *dev, struct > > pwm_fan_ctx *ctx) +{ > > + struct device_node *np = dev->of_node; > > + int num, i, ret; > > + > > + ret = of_property_count_elems_of_size(np, "cooling-levels", > > + sizeof(u32)); > > + > > + if (ret == -EINVAL) { > > + dev_err(dev, "Property 'cooling-levels' not > > found\n"); > > + return 0; > > Returning 0 is obviously not an error, otherwise you would not return > 0 here. So dev_err is wrong. pr_info would be more appropriate here. > Also, the message itself is wrong; the > property may well be there but have a wrong size. As fair as I remember the -EINVAL is set only when the property is not defined. Such situation is correct and our pwm-fan driver should work with or without it. > > > + } > > + > > + if (ret <= 0) { > > + dev_err(dev, "Wrong data!\n"); > > + return ret; > > + } > > This will result in the driver failing to load if devicetree is not > configured (of_property_count_elems_of_size will return -ENOSYS). As you pointed out in the comment to v2: It is OK if the "cooling-levels" is not defined in DT. However, if it has broken definition, then we should return error. This is what we do here. > This is not acceptable. Also, if the call returns 0 you don't return > an error but display a "Wrong data!" error message. Either it is an > error or it is not, but not both. This is an error. "cooling-levels" with zero elements is regarded as a broken property. > > Guenter Best regards, Lukasz Majewski
On 02/08/2015 01:36 PM, Lukasz Majewski wrote: > On Fri, 6 Feb 2015 10:36:57 -0800 > Guenter Roeck <linux@roeck-us.net> wrote: > >> On Fri, Feb 06, 2015 at 05:59:07PM +0100, Lukasz Majewski wrote: >>> This patch provides code for reading PWM FAN configuration data via >>> device tree. The pwm-fan can work with full speed when configuration >>> is not provided. However, errors are propagated when wrong DT >>> bindings are found. >>> Additionally the struct pwm_fan_ctx has been extended. >>> >>> Signed-off-by: Lukasz Majewski <l.majewski@samsung.com> >>> --- >>> Changes for v2: >>> - Rename pwm_fan_max_states to pwm_fan_cooling_levels >>> - Moving pwm_fan_of_get_cooling_data() call after setting end >>> enabling PWM FAN >>> - pwm_fan_of_get_cooling_data() now can fail - preserving old >>> behaviour >>> - Remove unnecessary dev_err() call >>> Changes for v3: >>> - Patch's headline has been reedited >>> - pwm_fan_of_get_cooling_data() return code is now being checked. >>> - of_property_count_elems_of_size() is now used instead >>> of_find_property() >>> - More verbose patch description added >>> --- >>> drivers/hwmon/pwm-fan.c | 54 >>> ++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, >>> 53 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c >>> index 870e100..f3f5843 100644 >>> --- a/drivers/hwmon/pwm-fan.c >>> +++ b/drivers/hwmon/pwm-fan.c >>> @@ -30,7 +30,10 @@ >>> struct pwm_fan_ctx { >>> struct mutex lock; >>> struct pwm_device *pwm; >>> - unsigned char pwm_value; >>> + unsigned int pwm_value; >>> + unsigned int pwm_fan_state; >>> + unsigned int pwm_fan_max_state; >>> + unsigned int *pwm_fan_cooling_levels; >>> }; >>> >>> static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) >>> @@ -100,6 +103,50 @@ static struct attribute *pwm_fan_attrs[] = { >>> >>> ATTRIBUTE_GROUPS(pwm_fan); >>> >>> +int pwm_fan_of_get_cooling_data(struct device *dev, struct >>> pwm_fan_ctx *ctx) +{ >>> + struct device_node *np = dev->of_node; >>> + int num, i, ret; >>> + >>> + ret = of_property_count_elems_of_size(np, "cooling-levels", >>> + sizeof(u32)); >>> + >>> + if (ret == -EINVAL) { >>> + dev_err(dev, "Property 'cooling-levels' not >>> found\n"); >>> + return 0; >> >> Returning 0 is obviously not an error, otherwise you would not return >> 0 here. So dev_err is wrong. > > pr_info would be more appropriate here. > >> Also, the message itself is wrong; the >> property may well be there but have a wrong size. > > As fair as I remember the -EINVAL is set only when the property is not > defined. Such situation is correct and our pwm-fan driver should work > with or without it. > of_property_count_elems_of_size returns -EINVAL if np is NULL or if there is no peoperty or prop->length % elem_size != 0, and -ENODATA if there is no value associated with the property. If -EINVAL is not an error, please no message. Noisy drivers are just that, noisy. >> >>> + } >>> + >>> + if (ret <= 0) { >>> + dev_err(dev, "Wrong data!\n"); >>> + return ret; >>> + } >> >> This will result in the driver failing to load if devicetree is not >> configured (of_property_count_elems_of_size will return -ENOSYS). > > As you pointed out in the comment to v2: > > It is OK if the "cooling-levels" is not defined in DT. However, if it > has broken definition, then we should return error. This is what we do > here. > You don't return an error, you return 0, at least in some circumstances. >> This is not acceptable. Also, if the call returns 0 you don't return >> an error but display a "Wrong data!" error message. Either it is an >> error or it is not, but not both. > > This is an error. "cooling-levels" with zero elements is regarded as a > broken property. > It returns -ENOSYS if DT is not configured, which is still unacceptable. And, again, if ret == 0 is an error, you should return an error code, not display an error message and return 0. Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c index 870e100..f3f5843 100644 --- a/drivers/hwmon/pwm-fan.c +++ b/drivers/hwmon/pwm-fan.c @@ -30,7 +30,10 @@ struct pwm_fan_ctx { struct mutex lock; struct pwm_device *pwm; - unsigned char pwm_value; + unsigned int pwm_value; + unsigned int pwm_fan_state; + unsigned int pwm_fan_max_state; + unsigned int *pwm_fan_cooling_levels; }; static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) @@ -100,6 +103,50 @@ static struct attribute *pwm_fan_attrs[] = { ATTRIBUTE_GROUPS(pwm_fan); +int pwm_fan_of_get_cooling_data(struct device *dev, struct pwm_fan_ctx *ctx) +{ + struct device_node *np = dev->of_node; + int num, i, ret; + + ret = of_property_count_elems_of_size(np, "cooling-levels", + sizeof(u32)); + + if (ret == -EINVAL) { + dev_err(dev, "Property 'cooling-levels' not found\n"); + return 0; + } + + if (ret <= 0) { + dev_err(dev, "Wrong data!\n"); + return ret; + } + + num = ret; + ctx->pwm_fan_cooling_levels = devm_kzalloc(dev, num * sizeof(u32), + GFP_KERNEL); + if (!ctx->pwm_fan_cooling_levels) + return -ENOMEM; + + ret = of_property_read_u32_array(np, "cooling-levels", + ctx->pwm_fan_cooling_levels, num); + if (ret) { + dev_err(dev, "Property 'cooling-levels' cannot be read!\n"); + return ret; + } + + for (i = 0; i < num; i++) { + if (ctx->pwm_fan_cooling_levels[i] > MAX_PWM) { + dev_err(dev, "PWM fan state[%d]:%d > %d\n", i, + ctx->pwm_fan_cooling_levels[i], MAX_PWM); + return -EINVAL; + } + } + + ctx->pwm_fan_max_state = num - 1; + + return 0; +} + static int pwm_fan_probe(struct platform_device *pdev) { struct device *hwmon; @@ -145,6 +192,11 @@ static int pwm_fan_probe(struct platform_device *pdev) pwm_disable(ctx->pwm); return PTR_ERR(hwmon); } + + ret = pwm_fan_of_get_cooling_data(&pdev->dev, ctx); + if (ret) + return ret; + return 0; }
This patch provides code for reading PWM FAN configuration data via device tree. The pwm-fan can work with full speed when configuration is not provided. However, errors are propagated when wrong DT bindings are found. Additionally the struct pwm_fan_ctx has been extended. Signed-off-by: Lukasz Majewski <l.majewski@samsung.com> --- Changes for v2: - Rename pwm_fan_max_states to pwm_fan_cooling_levels - Moving pwm_fan_of_get_cooling_data() call after setting end enabling PWM FAN - pwm_fan_of_get_cooling_data() now can fail - preserving old behaviour - Remove unnecessary dev_err() call Changes for v3: - Patch's headline has been reedited - pwm_fan_of_get_cooling_data() return code is now being checked. - of_property_count_elems_of_size() is now used instead of_find_property() - More verbose patch description added --- drivers/hwmon/pwm-fan.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 53 insertions(+), 1 deletion(-)