Hi Simon,
On 09/24/2015 03:32 PM, Simon Guinot wrote:
On Thu, Sep 24, 2015 at 02:19:56PM +0200, Jacek Anaszewski wrote:
Hi Simon,
Hi Jacek,
Thanks again for the review. Please see my comments below.
On 09/22/2015 10:24 AM, Simon Guinot wrote:
This patch adds device tree support for the netxbig LEDs.
This also introduces a additionnal DT binding for the GPIO extension bus
(netxbig-gpio-ext) used to configure the LEDs. Since this bus could also
be used to control other devices, then it seems more suitable to have it
in a separate DT binding.
Signed-off-by: Simon Guinot <simon.guinot@xxxxxxxxxxxx>
Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
.../devicetree/bindings/gpio/netxbig-gpio-ext.txt | 22 ++
.../devicetree/bindings/leds/leds-netxbig.txt | 92 +++++++
drivers/leds/leds-netxbig.c | 265 +++++++++++++++++++--
include/dt-bindings/leds/leds-netxbig.h | 18 ++
.../linux/platform_data/leds-kirkwood-netxbig.h | 1 +
5 files changed, 376 insertions(+), 22 deletions(-)
create mode 100644 Documentation/devicetree/bindings/gpio/netxbig-gpio-ext.txt
create mode 100644 Documentation/devicetree/bindings/leds/leds-netxbig.txt
create mode 100644 include/dt-bindings/leds/leds-netxbig.h
Changes for v2:
- Check timer mode value retrieved from DT.
- In netxbig_leds_get_of_pdata, don't use unsigned long variables to get
timer delay values from DT with function of_property_read_u32_index.
Instead, use a temporary u32 variable. This allows to silence a static
checker warning.
- Make timer property optional in the binding documentation. It is now
aligned with the driver code.
Changes for v3:
- Fix pointer usage with the temporary u32 variable while calling
of_property_read_u32_index.
Changes for v4:
- In DT binding document netxbig-gpio-ext.txt, detail byte order for
registers and latch mechanism for "enable-gpio".
- In leds-netxbig.c, add some error messages.
- In leds-netxbig.c, fix some "sizeof" style issues.
- In leds-netxbig.c, in netxbig_leds_get_of_pdata(), move the
of_property_read_string() calls after the error-prone checks.
- Add some Acked-by.
Changes for v5:
- Rename DT property "bright-max" into the more common "max-brightness".
- Make use of the "max-brightness" DT property. Instead of counting the
data pins of the GPIO extension bus, use "max-brightness" to get the
maximum brightness level.
...
@@ -333,7 +339,7 @@ create_netxbig_led(struct platform_device *pdev,
led_dat->mode_addr = template->mode_addr;
led_dat->mode_val = template->mode_val;
led_dat->bright_addr = template->bright_addr;
- led_dat->bright_max = (1 << pdata->gpio_ext->num_data) - 1;
+ led_dat->bright_max = template->bright_max;
Could you explain please, why in netxbig_led_set() led_dat->bright_max
is multiplied by the brightness value to be set as shown below?
void netxbig_led_set(struct led_classdev *led_cdev,
enum led_brightness value)
{
...
if (set_brightness) {
bright_val = DIV_ROUND_UP(value * led_dat->bright_max,
LED_FULL);
gpio_ext_set_value(led_dat->gpio_ext,
led_dat->bright_addr, bright_val);
}
...
}
Hardware values for brightness levels are in a range 0 to bright_max
(with bright_max = 7).
Software values for brightness levels are in a range 0 to 255.
Here, we are simply converting a software brightness value into an
hardware one. And the resulting value can be written directly into the
CPLD hardware bright register via the gpio-ext bus.
This conversion isn't required, as max_brightness property was
introduced to allow overriding LED_FULL value. I know that this is
in this form for a long time in this driver, just aside note.
+ led = leds;
+ for_each_child_of_node(np, child) {
+ const char *string;
+ int *mode_val;
+ int num_modes;
+
+ if (of_property_read_u32(child, "mode-addr",
+ &led->mode_addr))
+ return -EINVAL;
Since for_each_child_of_node uses of_get_next_child underneath,
the user is responsible for releasing current child in case
they are going to break the iteration. In other words you
need to execute of_node_put(child) then. Assigning error codes
to ret and following it with "goto exit_for_each" would do here,
where exit_for_each is defined as follows:
exit_for_each:
of_node_put(child);
return ret;
OK, good caught. I'll do that for the next version. Note that a bunch of
other LED drivers are needing a such fix too.
Right, but this is not an urgent issue since AFAICT no LED class driver
depends on CONFIG_OF_DYNAMIC, which turns of node ref counting on.
Nonetheless it shouldn't discourage us from producing new code free
of the potential issues, we are aware of.
--
Best Regards,
Jacek Anaszewski
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