On 06/21/2013 03:42 AM, Javier Martinez Canillas wrote:
> When an OMAP GPIO is used as an IRQ line, a call to gpio_request()
> has to be made to initialize the OMAP GPIO bank before a driver
> request the IRQ. Otherwise the call to request_irq() fails.
>
> Drives should not be aware of this neither care whether an IRQ line
> is a GPIO or not. They should just request the IRQ and this has to
> be handled by the irq_chip driver.
>
> With the current OMAP GPIO DT binding, if we define:
>
> gpio6: gpio@49058000 {
> compatible = "ti,omap3-gpio";
> reg = <0x49058000 0x200>;
> interrupts = <34>;
> ti,hwmods = "gpio6";
> gpio-controller;
> #gpio-cells = <2>;
> interrupt-controller;
> #interrupt-cells = <2>;
> };
>
> interrupt-parent = <&gpio6>;
> interrupts = <16 8>;
>
> The GPIO is correctly mapped as an IRQ but a call to gpio_request()
> is never made. So, let's add a custom .map function handler that
> setups and configures the GPIO as input automatically.
>
> Many thanks to Jon Hunter and Grant Likely for their feedback and
> suggestions on how to solve this.
>
> Signed-off-by: Javier Martinez Canillas <[email protected]>
> ---
>
> NOTE: Ideally this has to be handled by the IRQ core instead
> each irq_chip driver implementing a custom .map or .xlate
> function handler. There are some work-in-progress to add this
> logic to the core but until this general solution gets into
> mainline let's add this temporary solution that can be later
> reverted when is not needed anymore.
>
> Tested on a OMAP3 DM3735 board (IGEPv2) to make its smsc911x
> LAN chip to work with DeviceTree booting.
>
> drivers/gpio/gpio-omap.c | 29 ++++++++++++++++++++++++++++-
> 1 files changed, 28 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
> index d3f7d2d..b3e5f75 100644
> --- a/drivers/gpio/gpio-omap.c
> +++ b/drivers/gpio/gpio-omap.c
> @@ -1086,6 +1086,33 @@ static void omap_gpio_chip_init(struct gpio_bank *bank)
>
> static const struct of_device_id omap_gpio_match[];
>
> +static int omap_gpio_irq_map(struct irq_domain *d, unsigned int virq,
> + irq_hw_number_t hwirq)
> +{
> + struct gpio_bank *bank = d->host_data;
> + int gpio;
> + int ret;
> +
> + if (!bank)
> + return -EINVAL;
> +
> + gpio = irq_to_gpio(bank, hwirq);
> +
> + ret = gpio_request_one(gpio, GPIOF_IN, NULL);
> +
> + if (ret) {
> + dev_err(bank->dev, "Could not request GPIO%d\n", gpio);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static struct irq_domain_ops omap_gpio_irq_ops = {
> + .xlate = irq_domain_xlate_onetwocell,
> + .map = omap_gpio_irq_map,
> +};
> +
> static int omap_gpio_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> @@ -1137,7 +1164,7 @@ static int omap_gpio_probe(struct platform_device *pdev)
>
>
> bank->domain = irq_domain_add_linear(node, bank->width,
> - &irq_domain_simple_ops, NULL);
> + &omap_gpio_irq_ops, bank);
> if (!bank->domain)
> return -ENODEV;
>
>
Actually, I've been doing more testing and I found that this solution is wrong.
Grant suggested to add this logic in a custom .map function handler instead of a
.xlate since .map will be called just once on irq_create_mapping() and .xlate
will be called many times.
Now, this works if irq_create_mapping() is only called from
irq_create_of_mapping() when defining a GPIO-IRQ using DT but the gpio-omap
driver calls irq_create_mapping() for all GPIO in a bank on
omap_gpio_chip_init()
static void omap_gpio_chip_init(struct gpio_bank *bank)
{
...
for (j = 0; j < bank->width; j++) {
int irq = irq_create_mapping(bank->domain, j);
irq_set_lockdep_class(irq, &gpio_lock_class);
irq_set_chip_data(irq, bank);
if (bank->is_mpuio) {
omap_mpuio_alloc_gc(bank, irq, bank->width);
} else {
irq_set_chip_and_handler(irq, &gpio_irq_chip,
handle_simple_irq);
set_irq_flags(irq, IRQF_VALID);
}
}
..
}
So, this not only configures all GPIO as input but avoids outside code such as
drivers or board code to setup and configure a GPIO, since calling
gpio_request() will return -EBUSY.
There is no need to create this mapping for all GPIO on probe() and this logic
can be moved to the custom .map handler function. I'll send a v2 of this patch
that does this.
Thanks a lot and best regards,
Javier
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