diff options
| -rw-r--r-- | drivers/gpio/gpio-bcm-kona.c | 67 |
1 files changed, 55 insertions, 12 deletions
diff --git a/drivers/gpio/gpio-bcm-kona.c b/drivers/gpio/gpio-bcm-kona.c index 77bd4ec93a23..17f3f210fee9 100644 --- a/drivers/gpio/gpio-bcm-kona.c +++ b/drivers/gpio/gpio-bcm-kona.c @@ -69,6 +69,22 @@ struct bcm_kona_gpio { struct bcm_kona_gpio_bank { int id; int irq; + /* + * Used to keep track of lock/unlock operations for each GPIO in the + * bank. + * + * All GPIOs are locked by default (see bcm_kona_gpio_reset), and the + * unlock count for all GPIOs is 0 by default. Each unlock increments + * the counter, and each lock decrements the counter. + * + * The lock function only locks the GPIO once its unlock counter is + * down to 0. This is necessary because the GPIO is unlocked in two + * places in this driver: once for requested GPIOs, and once for + * requested IRQs. Since it is possible for a GPIO to be requested + * as both a GPIO and an IRQ, we need to ensure that we don't lock it + * too early. + */ + u8 gpio_unlock_count[GPIO_PER_BANK]; /* Used in the interrupt handler */ struct bcm_kona_gpio *kona_gpio; }; @@ -87,14 +103,23 @@ static void bcm_kona_gpio_lock_gpio(struct bcm_kona_gpio *kona_gpio, unsigned long flags; int bank_id = GPIO_BANK(gpio); int bit = GPIO_BIT(gpio); + struct bcm_kona_gpio_bank *bank = &kona_gpio->banks[bank_id]; - raw_spin_lock_irqsave(&kona_gpio->lock, flags); + if (bank->gpio_unlock_count[bit] == 0) { + dev_err(kona_gpio->gpio_chip.parent, + "Unbalanced locks for GPIO %u\n", gpio); + return; + } - val = readl(kona_gpio->reg_base + GPIO_PWD_STATUS(bank_id)); - val |= BIT(bit); - bcm_kona_gpio_write_lock_regs(kona_gpio->reg_base, bank_id, val); + if (--bank->gpio_unlock_count[bit] == 0) { + raw_spin_lock_irqsave(&kona_gpio->lock, flags); - raw_spin_unlock_irqrestore(&kona_gpio->lock, flags); + val = readl(kona_gpio->reg_base + GPIO_PWD_STATUS(bank_id)); + val |= BIT(bit); + bcm_kona_gpio_write_lock_regs(kona_gpio->reg_base, bank_id, val); + + raw_spin_unlock_irqrestore(&kona_gpio->lock, flags); + } } static void bcm_kona_gpio_unlock_gpio(struct bcm_kona_gpio *kona_gpio, @@ -104,14 +129,19 @@ static void bcm_kona_gpio_unlock_gpio(struct bcm_kona_gpio *kona_gpio, unsigned long flags; int bank_id = GPIO_BANK(gpio); int bit = GPIO_BIT(gpio); + struct bcm_kona_gpio_bank *bank = &kona_gpio->banks[bank_id]; - raw_spin_lock_irqsave(&kona_gpio->lock, flags); + if (bank->gpio_unlock_count[bit] == 0) { + raw_spin_lock_irqsave(&kona_gpio->lock, flags); - val = readl(kona_gpio->reg_base + GPIO_PWD_STATUS(bank_id)); - val &= ~BIT(bit); - bcm_kona_gpio_write_lock_regs(kona_gpio->reg_base, bank_id, val); + val = readl(kona_gpio->reg_base + GPIO_PWD_STATUS(bank_id)); + val &= ~BIT(bit); + bcm_kona_gpio_write_lock_regs(kona_gpio->reg_base, bank_id, val); - raw_spin_unlock_irqrestore(&kona_gpio->lock, flags); + raw_spin_unlock_irqrestore(&kona_gpio->lock, flags); + } + + ++bank->gpio_unlock_count[bit]; } static int bcm_kona_gpio_get_dir(struct gpio_chip *chip, unsigned gpio) @@ -362,6 +392,7 @@ static void bcm_kona_gpio_irq_mask(struct irq_data *d) kona_gpio = irq_data_get_irq_chip_data(d); reg_base = kona_gpio->reg_base; + raw_spin_lock_irqsave(&kona_gpio->lock, flags); val = readl(reg_base + GPIO_INT_MASK(bank_id)); @@ -384,6 +415,7 @@ static void bcm_kona_gpio_irq_unmask(struct irq_data *d) kona_gpio = irq_data_get_irq_chip_data(d); reg_base = kona_gpio->reg_base; + raw_spin_lock_irqsave(&kona_gpio->lock, flags); val = readl(reg_base + GPIO_INT_MSKCLR(bank_id)); @@ -479,15 +511,26 @@ static void bcm_kona_gpio_irq_handler(struct irq_desc *desc) static int bcm_kona_gpio_irq_reqres(struct irq_data *d) { struct bcm_kona_gpio *kona_gpio = irq_data_get_irq_chip_data(d); + unsigned int gpio = d->hwirq; + + /* + * We need to unlock the GPIO before any other operations are performed + * on the relevant GPIO configuration registers + */ + bcm_kona_gpio_unlock_gpio(kona_gpio, gpio); - return gpiochip_reqres_irq(&kona_gpio->gpio_chip, d->hwirq); + return gpiochip_reqres_irq(&kona_gpio->gpio_chip, gpio); } static void bcm_kona_gpio_irq_relres(struct irq_data *d) { struct bcm_kona_gpio *kona_gpio = irq_data_get_irq_chip_data(d); + unsigned int gpio = d->hwirq; + + /* Once we no longer use it, lock the GPIO again */ + bcm_kona_gpio_lock_gpio(kona_gpio, gpio); - gpiochip_relres_irq(&kona_gpio->gpio_chip, d->hwirq); + gpiochip_relres_irq(&kona_gpio->gpio_chip, gpio); } static struct irq_chip bcm_gpio_irq_chip = { |