On Wed, Dec 2, 2020 at 12:33 AM Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
>
> This adds a driver for the Richtek RT8515 dual channel
> torch/flash white LED driver.
>
> This LED driver is found in some mobile phones from
> Samsung such as the GT-S7710 and GT-I8190.
>
> A V4L interface is added.
>
> We do not have a proper datasheet for the RT8515 but
> it turns out that RT9387A has a public datasheet and
> is essentially the same chip. We designed the driver
> in accordance with this datasheet. The day someone
> needs to drive a RT9387A this driver can probably
> easily be augmented to handle that chip too.
...
> +#include <linux/of.h>
As far as I can see you are using fwnode API, so above better to be
replaced with
#include <linux/property.h>
For the ID table you probably need mod_devicetable.h.
...
> +#define RT8515_MIN_IOUT_MA 15
> +#define RT8515_MAX_IOUT_MA 700
MA -> mA ?
...
> +#define RT8515_TIMEOUT_DEFAULT 250000U /* 250ms */
> +#define RT8515_MAX_TIMEOUT_DEFAULT 300000U /* 300ms */
MAX and DEFAULT in the same sentence sound confusing.
Also, instead of comments can you use units in the name, like _US?
(I guess _DEFAULT can be replaced by _US)
...
> +struct rt8515 {
> + struct device *dev;
> + struct led_classdev_flash fled;
If you make this first member you will effectively eliminate overhead
of container_of().
> + struct v4l2_flash *v4l2_flash;
> +};
...
> + if (brightness == LED_OFF) {
> + /* Off */
> + gpiod_set_value(rt->enable_flash, 0);
> + gpiod_set_value(rt->enable_torch, 0);
These two together are repeated at least three times in the driver, perhaps
static void rt8515_gpio_led_off(... *rt)
{
gpiod_set_value(rt->enable_flash, 0);
gpiod_set_value(rt->enable_torch, 0);
}
> + } else if (brightness < RT8515_TORCH_MAX) {
> + /* Step it up to movie mode brightness using the flash pin */
> + rt8515_gpio_brightness_commit(rt->enable_torch, brightness);
> + } else {
> + /* Max torch brightness requested */
> + gpiod_set_value(rt->enable_torch, 1);
> + }
...
> + ret1 = fwnode_property_read_u32(rt->dev->fwnode, resistance, &res);
> + ret2 = fwnode_property_read_u32(led, max_ua_prop, &ua);
> +
> + /* No info in DT, OK go with hardware maxima */
> + if (ret1 && ret2) {
> + max_ma = RT8515_MAX_IOUT_MA;
> + max_intensity = hw_max;
> + goto out_assign_max;
> + }
> +
> + if (ret1 || ret2) {
> + dev_err(rt->dev,
> + "either %s or %s missing from DT, using HW max\n",
> + resistance, max_ua_prop);
> + max_ma = RT8515_MAX_IOUT_MA;
> + max_intensity = hw_max;
> + goto out_assign_max;
> + }
Dup. Can be rewritten as (taking into account that resistance can't be 0):
u32 res = 0; /* Can't be 0, used as undefined value */
...
fwnode_property_read_u32(rt->dev->fwnode, resistance, &res);
ret = fwnode_property_read_u32(led, max_ua_prop, &ua);
if (ret || res == 0) {
/* No info in DT, OK go with hardware maxima */
if (!(ret && res == 0)) {
dev_err(rt->dev,
"either %s or %s missing from DT, using HW max\n",
// or resistance is 0, the case your original code is missing
resistance, max_ua_prop);
}
max_ma = RT8515_MAX_IOUT_MA;
max_intensity = hw_max;
goto out_assign_max;
}
But please double check.
> + /*
> + * Formula from datasheet, this is the maximum current
the datasheet
> + * defined by the hardware.
> + */
> + max_ma = (5500 * 1000) / res;
> + /*
> + * Calculate max intensity (linear scaling)
> + * Formula is ((ua / 1000) / max_ma) * 100, then simplified
> + */
> + max_intensity = (ua / 10) / max_ma;
> +
> + dev_info(rt->dev,
> + "current restricted from %u to %u mA, max intensity %d/100\n",
> + max_ma, (ua / 1000), max_intensity);
> +
> +out_assign_max:
> + dev_info(rt->dev, "max intensity %d/%d = %d mA\n",
> + max_intensity, hw_max, max_ma);
> + *max_intensity_setting = max_intensity;
> +}
...
> + /* ENF - Enable Flash line */
> + rt->enable_flash = devm_gpiod_get(dev, "enf", GPIOD_OUT_LOW);
> + if (IS_ERR(rt->enable_flash)) {
> + dev_err(dev, "cannot get ENF (enable flash) GPIO\n");
> + return PTR_ERR(rt->enable_flash);
Shouldn't it be dev_err_probe() to avoid spam in certain cases?
> + }
> +
> + /* ENT - Enable Torch line */
> + rt->enable_torch = devm_gpiod_get(dev, "ent", GPIOD_OUT_LOW);
> + if (IS_ERR(rt->enable_torch)) {
> + dev_err(dev, "cannot get ENT (enable torch) GPIO\n");
> + return PTR_ERR(rt->enable_torch);
Shouldn't it be dev_err_probe() to avoid spam in certain cases?
> + }
...
> + rt->v4l2_flash = v4l2_flash_init(dev, child, fled, NULL, &v4l2_sd_cfg);
> + if (IS_ERR(rt->v4l2_flash)) {
> + ret = PTR_ERR(rt->v4l2_flash);
> + dev_err(dev, "failed to register V4L2 flash device (%d)\n",
> + ret);
> + /*
> + * Continue without the V4L2 flash
> + * (we still have the classdev)
> + */
> + }
> + return 0;
In conjunction with above can be
return PTR_ERR_OR_ZERO(rt->v4l2_flash);
...
> +static const struct of_device_id rt8515_match[] = {
> + { .compatible = "richtek,rt8515", },
> + { /* sentinel */ },
Comma is not needed.
> +};
--
With Best Regards,
Andy Shevchenko
