Re: [PATCH v4 7/8] hwmon: pwm-fan: Read PWM FAN configuration from device tree
Hi Guenter,
> On Mon, Feb 23, 2015 at 05:13:36PM +0100, Lukasz Majewski wrote:
> > Hi Guenter,
> >
> [ ... ]
>
> > >
> > > If devicetree is not configured, of_property_count_elems_of_size
> > > returns -ENOSYS, which is returned, causing the driver to fail
> > > loading.
> >
> > Has of_property_count_elems_of_size() returns -ENOSYS?
> >
> > Maybe something has changed, but in my linux-vanila (3.19-rc4)
> > at ./drivers/of/base.c it returns -EINVAL, -ENODATA or number of
> > elements.
> >
> > Have I missed something?
> >
> Hi Lukasz,
>
> Yes, you have. Check include/linux/of.h, line 484, in latest mainline.
Ok. Now I got it.
The above situation shouldn't happen if I put of_find_property() check
on the very beginning of this function (it returns NULL when DT support
is not compiled).
The function would look as follows:
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;
if (!of_find_property(np, "cooling-levels", NULL))
return 0;
ret = of_property_count_u32_elems(np, "cooling-levels");
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;
}
>
> Guenter
--
Best regards,
Lukasz Majewski
Samsung R&D Institute Poland (SRPOL) | Linux Platform Group
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Re: [PATCH v4 7/8] hwmon: pwm-fan: Read PWM FAN configuration from device tree
On Mon, Feb 23, 2015 at 05:51:22PM +0100, Lukasz Majewski wrote:
> Hi Guenter,
>
> > On Mon, Feb 23, 2015 at 05:13:36PM +0100, Lukasz Majewski wrote:
> > > Hi Guenter,
> > >
> > [ ... ]
> >
> > > >
> > > > If devicetree is not configured, of_property_count_elems_of_size
> > > > returns -ENOSYS, which is returned, causing the driver to fail
> > > > loading.
> > >
> > > Has of_property_count_elems_of_size() returns -ENOSYS?
> > >
> > > Maybe something has changed, but in my linux-vanila (3.19-rc4)
> > > at ./drivers/of/base.c it returns -EINVAL, -ENODATA or number of
> > > elements.
> > >
> > > Have I missed something?
> > >
> > Hi Lukasz,
> >
> > Yes, you have. Check include/linux/of.h, line 484, in latest mainline.
>
> Ok. Now I got it.
>
> The above situation shouldn't happen if I put of_find_property() check
> on the very beginning of this function (it returns NULL when DT support
> is not compiled).
>
Correct.
> The function would look as follows:
>
> 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;
>
> if (!of_find_property(np, "cooling-levels", NULL))
> return 0;
>
> ret = of_property_count_u32_elems(np, "cooling-levels");
> if (ret <= 0) {
> dev_err(dev, "Wrong data!\n");
> return ret;
This should probably be something like
return ret ? : -EINVAL;
or ret == 0 is not an error, and you should not display an error message
in that case.
Thanks,
Guenter
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Re: [PATCH v4 7/8] hwmon: pwm-fan: Read PWM FAN configuration from device tree
On Mon, Feb 23, 2015 at 05:13:36PM +0100, Lukasz Majewski wrote: > Hi Guenter, > [ ... ] > > > > If devicetree is not configured, of_property_count_elems_of_size > > returns -ENOSYS, which is returned, causing the driver to fail > > loading. > > Has of_property_count_elems_of_size() returns -ENOSYS? > > Maybe something has changed, but in my linux-vanila (3.19-rc4) > at ./drivers/of/base.c it returns -EINVAL, -ENODATA or number of > elements. > > Have I missed something? > Hi Lukasz, Yes, you have. Check include/linux/of.h, line 484, in latest mainline. Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v4 7/8] hwmon: pwm-fan: Read PWM FAN configuration from device tree
Hi Guenter,
> On 02/18/2015 02:07 AM, 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
> > ---
> > 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
> > Changes for v4:
> > - dev_err() has been removed from pwm_fan_of_get_cooling_data()
> > - Returning -EINVAL when "cooling-levels" are defined in DT, but
> > doesn't have the value
> > ---
> > drivers/hwmon/pwm-fan.c | 52
> > - 1 file changed,
> > 51 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
> > index bd42d39..82cd06a 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 +103,48 @@ 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)
> > + return 0;
>
> The function returns -EINVAL if there is no such property,
> but also if prop->length % elem_size != 0. The latter _would_
> be an error.
>
> Overall I don't entirely understand why you do not call
> of_find_property first. If that returns NULL, you would know for sure
> that the property does not exist, and you would not have to second
> guess the returned error from of_property_count_elems_of_size.
For sake of readability I will at v5 first check of_find_property() and
if it is correct, then I will call of_property_count_u32_elems().
>
> On a side note, there is of_property_count_u32_elems() to count
> properties of size u32.
>
> > +
> > + if (ret <= 0) {
> > + dev_err(dev, "Wrong data!\n");
> > + return ret ? ret : -EINVAL;
> > + }
>
> If devicetree is not configured, of_property_count_elems_of_size
> returns -ENOSYS, which is returned, causing the driver to fail
> loading.
Has of_property_count_elems_of_size() returns -ENOSYS?
Maybe something has changed, but in my linux-vanila (3.19-rc4)
at ./drivers/of/base.c it returns -EINVAL, -ENODATA or number of
elements.
Have I missed something?
>
> > +
> > + 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 +190,11 @@ 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;
I think that here is the confusing part. Please compare this patch with
the following one.
Here we configure ctx struct via DT. If of_property_count_u32_elems()
returns -EINVAL, then we consider that "cooling-levels" wasn't defined
in DT and return with 0. Other error codes a
Re: [PATCH v4 7/8] hwmon: pwm-fan: Read PWM FAN configuration from device tree
On 02/18/2015 02:07 AM, 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
---
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
Changes for v4:
- dev_err() has been removed from pwm_fan_of_get_cooling_data()
- Returning -EINVAL when "cooling-levels" are defined in DT, but doesn't
have the value
---
drivers/hwmon/pwm-fan.c | 52 -
1 file changed, 51 insertions(+), 1 deletion(-)
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index bd42d39..82cd06a 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 +103,48 @@ 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)
+ return 0;
The function returns -EINVAL if there is no such property,
but also if prop->length % elem_size != 0. The latter _would_
be an error.
Overall I don't entirely understand why you do not call
of_find_property first. If that returns NULL, you would know for sure
that the property does not exist, and you would not have to second
guess the returned error from of_property_count_elems_of_size.
On a side note, there is of_property_count_u32_elems() to count
properties of size u32.
+
+ if (ret <= 0) {
+ dev_err(dev, "Wrong data!\n");
+ return ret ? ret : -EINVAL;
+ }
If devicetree is not configured, of_property_count_elems_of_size
returns -ENOSYS, which is returned, causing the driver to fail loading.
+
+ 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 +190,11 @@ 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;
}
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[PATCH v4 7/8] hwmon: pwm-fan: Read PWM FAN configuration from device tree
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
---
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
Changes for v4:
- dev_err() has been removed from pwm_fan_of_get_cooling_data()
- Returning -EINVAL when "cooling-levels" are defined in DT, but doesn't
have the value
---
drivers/hwmon/pwm-fan.c | 52 -
1 file changed, 51 insertions(+), 1 deletion(-)
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index bd42d39..82cd06a 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 +103,48 @@ 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)
+ return 0;
+
+ if (ret <= 0) {
+ dev_err(dev, "Wrong data!\n");
+ return ret ? ret : -EINVAL;
+ }
+
+ 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 +190,11 @@ 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;
}
--
2.0.0.rc2
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