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SubjectRe: [PATCH v2 1/1] gpio: mvebu: Add support for multiple PWM lines per GPIO chip
>  static int mvebu_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
> {
> struct mvebu_pwm *mvpwm = to_mvebu_pwm(chip);
> struct mvebu_gpio_chip *mvchip = mvpwm->mvchip;
> struct gpio_desc *desc;
> + struct mvebu_pwm *counter;
> unsigned long flags;
> int ret = 0;
>
> spin_lock_irqsave(&mvpwm->lock, flags);
>
> - if (mvpwm->gpiod) {
> - ret = -EBUSY;
> - } else {
> - desc = gpiochip_request_own_desc(&mvchip->chip,
> - pwm->hwpwm, "mvebu-pwm");
> - if (IS_ERR(desc)) {
> - ret = PTR_ERR(desc);
> + counter = mvpwm;
> + if (counter->gpiod) {
> + counter = mvebu_pwm_get_avail_counter();
> + if (!counter) {
> + ret = -EBUSY;

I don't understand this bit of code. Please could you explain what is
going on.

> goto out;
> }
>
> - ret = gpiod_direction_output(desc, 0);
> - if (ret) {
> - gpiochip_free_own_desc(desc);
> - goto out;
> - }
> + pwm->chip_data = counter;
> + }
>
> - mvpwm->gpiod = desc;
> + desc = gpiochip_request_own_desc(&mvchip->chip,
> + pwm->hwpwm, "mvebu-pwm");
> + if (IS_ERR(desc)) {
> + ret = PTR_ERR(desc);
> + goto out;
> }
> +
> + ret = gpiod_direction_output(desc, 0);
> + if (ret) {
> + gpiochip_free_own_desc(desc);
> + goto out;
> + }
> +
> + regmap_update_bits(mvchip->regs, GPIO_BLINK_CNT_SELECT_OFF +
> + mvchip->offset, BIT(pwm->hwpwm),
> + counter->id ? BIT(pwm->hwpwm) : 0);
> + regmap_read(mvchip->regs, GPIO_BLINK_CNT_SELECT_OFF +
> + mvchip->offset, &counter->blink_select);
> +
> + counter->gpiod = desc;
> out:
> spin_unlock_irqrestore(&mvpwm->lock, flags);
> return ret;
> @@ -632,6 +666,11 @@ static void mvebu_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
> struct mvebu_pwm *mvpwm = to_mvebu_pwm(chip);
> unsigned long flags;
>
> + if (pwm->chip_data) {
> + mvpwm = (struct mvebu_pwm *) pwm->chip_data;
> + pwm->chip_data = NULL;
> + }
> +
> spin_lock_irqsave(&mvpwm->lock, flags);
> gpiochip_free_own_desc(mvpwm->gpiod);
> mvpwm->gpiod = NULL;
> @@ -648,6 +687,9 @@ static void mvebu_pwm_get_state(struct pwm_chip *chip,
> unsigned long flags;
> u32 u;
>
> + if (pwm->chip_data)
> + mvpwm = (struct mvebu_pwm *) pwm->chip_data;
> +

You should not need a cast here, if chip_data is a void *.

What is pwm->chip_data is a NULL? Don't you then use an uninitialized
mvpwm?

Andrew

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