linux-kernel - Re: [PATCH v4 2/3] leds: Add driver for the TLC5925 LED controller

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Date:   Tue, 14 Jun 2022 16:49:13 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Jean-Jacques Hiblot <jjhiblot@...phandler.com>
Cc:     Pavel Machek <pavel@....cz>, krzk+dt@...nel.org,
        Rob Herring <robh+dt@...nel.org>,
        Linux LED Subsystem <linux-leds@...r.kernel.org>,
        devicetree <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 2/3] leds: Add driver for the TLC5925 LED controller

On Tue, Jun 14, 2022 at 4:27 PM Jean-Jacques Hiblot
<jjhiblot@...phandler.com> wrote:
>
> The TLC5925 is a 16-channels constant-current LED sink driver.
> It is controlled via SPI but doesn't offer a register-based interface.
> Instead it contains a shift register and latches that convert the
> serial input into a parallel output.
>
> Datasheet: https://www.ti.com/lit/ds/symlink/tlc5925.pdf

>

No blank lines are allowed in the tag block.

> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@...phandler.com>

...

> +#include <linux/err.h>
> +#include <linux/leds.h>
> +#include <linux/module.h>
> +#include <linux/property.h>
> +#include <linux/spi/spi.h>

This misses a few headers that this code is direct user of:
container_of.h
gpio/consumer.h
types.h

...

> +       // assign_bit() is atomic, no need for lock

Comment is useless, since it's a pattern that is used in the kernel:
__op is non-atomic, op is atomic.

...

> +
> +

One blank line is enough

...

> +
> +

Ditto.

...

> +       gpios = devm_gpiod_get_array(dev, "output-enable-b", GPIOD_OUT_LOW);
> +       if (IS_ERR(gpios)) {
> +               return dev_err_probe(dev, PTR_ERR(gpios),
> +                             "Unable to get the 'output-enable-b' gpios\n");
> +       }

{} are not needed, and you may put the return on one line.

...

> +       count = device_get_child_node_count(dev);
> +       if (!count) {
> +               dev_err(dev, "no led defined.\n");
> +               return -ENODEV;
> +       }

It's fine to use return dev_err_probe() in such cases like above, it's
written in the documentation.

...

> +               ret = fwnode_property_read_u32(child, "reg", &idx);
> +               if (ret || idx >= max_num_leds) {
> +                       dev_warn(dev, "%s: invalid reg value. Ignoring.\n",
> +                               fwnode_get_name(child));

%pfw / %pfwP ?

> +                       fwnode_handle_put(child);
> +                       continue;
> +               }

...

> +               ret = devm_led_classdev_register_ext(dev, cdev, &init_data);
> +               if (ret) {
> +                       dev_warn(dev, "%s: cannot create LED device.\n",
> +                               fwnode_get_name(child));

Ditto.

> +                       fwnode_handle_put(child);
> +                       continue;
> +               }

-- 
With Best Regards,
Andy Shevchenko