On Tue, Jun 04, 2024 at 09:27:26PM +0800, Hui Wang wrote:
> Certain designs connect a gpio to the reset pin, and the reset pin
GPIO
> needs to be setup correctly before accessing the chip.
>
> Here adding a function to handle the chip reset. If the reset-gpios is
> defined in the dt, do the hard reset through this gpio, othwerwise do
DT
> the soft reset as before.
...
> +static int sc16is7xx_reset(struct device *dev, struct regmap *regmaps[])
> +{
> + struct gpio_desc *reset_gpiod;
> + reset_gpiod = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
> + if (!reset_gpiod)
> + /* soft reset device, purging any pending irq / data */
> + regmap_write(regmaps[0], SC16IS7XX_IOCONTROL_REG,
> + SC16IS7XX_IOCONTROL_SRESET_BIT);
> + else if (!IS_ERR(reset_gpiod)) {
> + /* delay 5 us (at least 3 us) and deassert the gpio to exit the hard reset */
> + udelay(5);
> + gpiod_set_value_cansleep(reset_gpiod, 0);
> + } else
> + return PTR_ERR(reset_gpiod);
You can do better here.
reset_gpiod = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
if (IS_ERR(reset_gpiod))
return PTR_ERR(reset_gpiod);
if (reset_gpiod) {
/* delay 5 us (at least 3 us) and deassert the GPIO to exit the hard reset */
fsleep(5);
gpiod_set_value_cansleep(reset_gpiod, 0);
} else {
/* soft reset device, purging any pending IRQ / data */
regmap_write(regmaps[0], SC16IS7XX_IOCONTROL_REG,
SC16IS7XX_IOCONTROL_SRESET_BIT);
}
> + return 0;
> +}
--
With Best Regards,
Andy Shevchenko
