The TLC chips actually offer 257 levels:
- 0: led OFF
- 1-255: Led dimmed is using a PWM. The duty cycle range from 0.4% to 99.6%
- 256: led fully ON
Signed-off-by: Jean-Jacques Hiblot <[email protected]>
---
drivers/leds/leds-tlc591xx.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/leds/leds-tlc591xx.c b/drivers/leds/leds-tlc591xx.c
index 8eadb673dc2e..a8911ebd30e5 100644
--- a/drivers/leds/leds-tlc591xx.c
+++ b/drivers/leds/leds-tlc591xx.c
@@ -13,6 +13,7 @@
#include <linux/slab.h>
#define TLC591XX_MAX_LEDS 16
+#define TLC591XX_MAX_BRIGHTNESS 256
#define TLC591XX_REG_MODE1 0x00
#define MODE1_RESPON_ADDR_MASK 0xF0
@@ -112,11 +113,11 @@ tlc591xx_brightness_set(struct led_classdev *led_cdev,
struct tlc591xx_priv *priv = led->priv;
int err;
- switch (brightness) {
+ switch ((int)brightness) {
case 0:
err = tlc591xx_set_ledout(priv, led, LEDOUT_OFF);
break;
- case LED_FULL:
+ case TLC591XX_MAX_BRIGHTNESS:
err = tlc591xx_set_ledout(priv, led, LEDOUT_ON);
break;
default:
@@ -209,7 +210,7 @@ tlc591xx_probe(struct i2c_client *client,
led->priv = priv;
led->led_no = reg;
led->ldev.brightness_set_blocking = tlc591xx_brightness_set;
- led->ldev.max_brightness = LED_FULL;
+ led->ldev.max_brightness = TLC591XX_MAX_BRIGHTNESS;
err = devm_led_classdev_register_ext(dev, &led->ldev,
&init_data);
if (err < 0) {
--
2.17.1
Hi Jean,
Thank you for the patch.
On 9/23/19 12:02 PM, Jean-Jacques Hiblot wrote:
> The TLC chips actually offer 257 levels:
> - 0: led OFF
> - 1-255: Led dimmed is using a PWM. The duty cycle range from 0.4% to 99.6%
> - 256: led fully ON
>
> Signed-off-by: Jean-Jacques Hiblot <[email protected]>
> ---
> drivers/leds/leds-tlc591xx.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/leds/leds-tlc591xx.c b/drivers/leds/leds-tlc591xx.c
> index 8eadb673dc2e..a8911ebd30e5 100644
> --- a/drivers/leds/leds-tlc591xx.c
> +++ b/drivers/leds/leds-tlc591xx.c
> @@ -13,6 +13,7 @@
> #include <linux/slab.h>
>
> #define TLC591XX_MAX_LEDS 16
> +#define TLC591XX_MAX_BRIGHTNESS 256
>
> #define TLC591XX_REG_MODE1 0x00
> #define MODE1_RESPON_ADDR_MASK 0xF0
> @@ -112,11 +113,11 @@ tlc591xx_brightness_set(struct led_classdev *led_cdev,
> struct tlc591xx_priv *priv = led->priv;
> int err;
>
> - switch (brightness) {
> + switch ((int)brightness) {
> case 0:
> err = tlc591xx_set_ledout(priv, led, LEDOUT_OFF);
> break;
> - case LED_FULL:
> + case TLC591XX_MAX_BRIGHTNESS:
> err = tlc591xx_set_ledout(priv, led, LEDOUT_ON);
> break;
> default:
> @@ -209,7 +210,7 @@ tlc591xx_probe(struct i2c_client *client,
> led->priv = priv;
> led->led_no = reg;
> led->ldev.brightness_set_blocking = tlc591xx_brightness_set;
> - led->ldev.max_brightness = LED_FULL;
> + led->ldev.max_brightness = TLC591XX_MAX_BRIGHTNESS;
> err = devm_led_classdev_register_ext(dev, &led->ldev,
> &init_data);
> if (err < 0) {
>
Added tag:
Fixes: e370d010a5fe ("leds: tlc591xx: Driver for the TI 8/16 Channel i2c
LED driver")
and applied to the for-5.5 branch.
It is also a good habit to cc the author of the driver.
Cc Andrew.
--
Best regards,
Jacek Anaszewski
Hi!
> > @@ -112,11 +113,11 @@ tlc591xx_brightness_set(struct led_classdev *led_cdev,
> > struct tlc591xx_priv *priv = led->priv;
> > int err;
> >
> > - switch (brightness) {
> > + switch ((int)brightness) {
> > case 0:
Can we get a rid of the cast here? Do we need to move away from the
enum for the brightness?
> Added tag:
>
> Fixes: e370d010a5fe ("leds: tlc591xx: Driver for the TI 8/16 Channel i2c
> LED driver")
>
> and applied to the for-5.5 branch.
Actually, careful with the Fixes tag. -stable people will want to
apply it, and it may not be a good idea in this case. Maximum
brightness of 256 is pretty unusual, so I'd call this "a bit risky".
Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
On 10/13/19 1:45 PM, Pavel Machek wrote:
> Hi!
>
>>> @@ -112,11 +113,11 @@ tlc591xx_brightness_set(struct led_classdev *led_cdev,
>>> struct tlc591xx_priv *priv = led->priv;
>>> int err;
>>>
>>> - switch (brightness) {
>>> + switch ((int)brightness) {
>>> case 0:
>
> Can we get a rid of the cast here? Do we need to move away from the
> enum for the brightness?
I at first also wanted to ask for dropping the cast but first tried
to do it myself. Then I found out compiler (or sparse, I don't recall
exactly) complains about TLC591XX_MAX_BRIGHTNESS not being a value of
enum led_brighteess type. That's the reason for the cast Jean added,
I presume.
>> Added tag:
>>
>> Fixes: e370d010a5fe ("leds: tlc591xx: Driver for the TI 8/16 Channel i2c
>> LED driver")
>>
>> and applied to the for-5.5 branch.
>
> Actually, careful with the Fixes tag. -stable people will want to
> apply it, and it may not be a good idea in this case. Maximum
> brightness of 256 is pretty unusual, so I'd call this "a bit risky".
I entirely disagree. Not seeing anything risky in that since
max_brightness is also initialized to this value. If userspace properly
uses the ABI, then it will be safe.
> Best regards,
> Pavel
>
--
Best regards,
Jacek Anaszewski
On 13/10/2019 18:36, Jacek Anaszewski wrote:
> On 10/13/19 1:45 PM, Pavel Machek wrote:
>> Hi!
>>
>>>> @@ -112,11 +113,11 @@ tlc591xx_brightness_set(struct led_classdev *led_cdev,
>>>> struct tlc591xx_priv *priv = led->priv;
>>>> int err;
>>>>
>>>> - switch (brightness) {
>>>> + switch ((int)brightness) {
>>>> case 0:
>> Can we get a rid of the cast here? Do we need to move away from the
>> enum for the brightness?
> I at first also wanted to ask for dropping the cast but first tried
> to do it myself. Then I found out compiler (or sparse, I don't recall
> exactly) complains about TLC591XX_MAX_BRIGHTNESS not being a value of
> enum led_brighteess type. That's the reason for the cast Jean added,
> I presume.
Indeed that cast is to fix the warning.
JJ
>>> Added tag:
>>>
>>> Fixes: e370d010a5fe ("leds: tlc591xx: Driver for the TI 8/16 Channel i2c
>>> LED driver")
>>>
>>> and applied to the for-5.5 branch.
>> Actually, careful with the Fixes tag. -stable people will want to
>> apply it, and it may not be a good idea in this case. Maximum
>> brightness of 256 is pretty unusual, so I'd call this "a bit risky".
> I entirely disagree. Not seeing anything risky in that since
> max_brightness is also initialized to this value. If userspace properly
> uses the ABI, then it will be safe.
>
>> Best regards,
>> Pavel
>>