On Sat, Jul 16, 2011 at 01:45:50PM +0530, Tarun Kanti DebBarma wrote:
> Call runtime pm APIs pm_runtime_get_sync() and pm_runtime_put_sync()
> for enabling/disabling clocks appropriately. Remove syscore_ops and
> instead use dev_pm_ops now.
>
...
> @@ -481,6 +483,22 @@ static int omap_gpio_request(struct gpio_chip *chip, unsigned offset)
>
> spin_lock_irqsave(&bank->lock, flags);
>
> + /*
> + * If this is the first gpio_request for the bank,
> + * enable the bank module.
> + */
> + if (!bank->mod_usage) {
> + if (IS_ERR_VALUE(pm_runtime_get_sync(bank->dev) < 0)) {
> + dev_err(bank->dev, "%s: GPIO bank %d "
> + "pm_runtime_get_sync failed\n",
> + __func__, bank->id);
> + return -EINVAL;
Must spin_unlock_irqrestore() first.
> + }
> +
> + /* Initialize the gpio bank registers to init time value */
> + omap_gpio_mod_init(bank);
omap_gpio_mod_init calls mpuio_init calls platform_driver_register
which can't be called in an IRQs off and spinlocked atomic context,
for example, device_private_init calls kzalloc with GFP_KERNEL.
Concurrency protection for this will need to happen prior to the
spinlock (assuming it really does need to be an IRQ saving spinlock
and not a mutex). Possibly a new mutex is needed to protect the
check for first usage and init'ing the bank (and blocking a racing
second caller until the init is done).
The omap_gpio_mod_init may be unbalanced with the code performed below
on last free of a GPIO for the bank? If all GPIOs are freed and then
a new GPIO used, does omap_gpio_mod_init do the right thing? Need a
separate flag to indicate whether one-time init has ever been
performed, vs. needing runtime PM enable/disable?
> + }
> +
> /* Set trigger to none. You need to enable the desired trigger with
> * request_irq() or set_irq_type().
> */
> @@ -517,7 +535,6 @@ static void omap_gpio_free(struct gpio_chip *chip, unsigned offset)
> unsigned long flags;
>
> spin_lock_irqsave(&bank->lock, flags);
> -
> if (bank->regs->wkup_status)
> /* Disable wake-up during idle for dynamic tick */
> _gpio_rmw(base, bank->regs->wkup_status, 1 << offset, 0);
> @@ -535,6 +552,18 @@ static void omap_gpio_free(struct gpio_chip *chip, unsigned offset)
> }
>
> _reset_gpio(bank, bank->chip.base + offset);
> +
> + /*
> + * If this is the last gpio to be freed in the bank,
> + * disable the bank module.
> + */
> + if (!bank->mod_usage) {
> + if (IS_ERR_VALUE(pm_runtime_put_sync(bank->dev) < 0)) {
> + dev_err(bank->dev, "%s: GPIO bank %d "
> + "pm_runtime_put_sync failed\n",
> + __func__, bank->id);
> + }
> + }
> spin_unlock_irqrestore(&bank->lock, flags);
Todd
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