Messages in this thread | | | Date | Fri, 17 Apr 2020 08:34:09 +0200 | From | Michael Walle <> | Subject | Re: [PATCH v2 10/16] gpio: add a reusable generic gpio_chip using regmap |
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Hi Linus,
Am 2020-04-16 11:27, schrieb Linus Walleij: > On Thu, Apr 2, 2020 at 10:37 PM Michael Walle <michael@walle.cc> wrote: > >> There are quite a lot simple GPIO controller which are using regmap to >> access the hardware. This driver tries to be a base to unify existing >> code into one place. This won't cover everything but it should be a >> good >> starting point. >> >> It does not implement its own irq_chip because there is already a >> generic one for regmap based devices. Instead, the irq_chip will be >> instanciated in the parent driver and its irq domain will be associate >> to this driver. >> >> For now it consists of the usual registers, like set (and an optional >> clear) data register, an input register and direction registers. >> Out-of-the-box, it supports consecutive register mappings and mappings >> where the registers have gaps between them with a linear mapping >> between >> GPIO offset and bit position. For weirder mappings the user can >> register >> its own .xlate(). >> >> Signed-off-by: Michael Walle <michael@walle.cc> > > Overall I really like this driver and I think we should merge is as > soon > as it is in reasonable shape and then improve on top so we can start > migrating drivers to it. > >> +static int gpio_regmap_to_irq(struct gpio_chip *chip, unsigned int >> offset) >> +{ >> + struct gpio_regmap_data *data = gpiochip_get_data(chip); >> + struct gpio_regmap *gpio = data->gpio; >> + >> + /* the user might have its own .to_irq callback */ >> + if (gpio->to_irq) >> + return gpio->to_irq(gpio, offset); >> + >> + return irq_create_mapping(gpio->irq_domain, offset); > > I think that should at least be irq_find_mapping(), the mapping should > definately not be created by the .to_irq() callback since that is just > a convenience function.
what do you mean by conenience function? are there other ways? if you use irq_find_mapping() who will create the mappings? most gpio drivers use a similar function like gpio_regmap_to_irq().
> >> + if (gpio->irq_domain) >> + chip->to_irq = gpio_regmap_to_irq; > > I don't know about this. > (...) >> + * @irq_domain: (Optional) IRQ domain if the >> controller is >> + * interrupt-capable > (...) >> + struct irq_domain *irq_domain; > > I don't think this is a good storage place for the irqdomain, we > already have > gpio_irq_chip inside gpio_chip and that has an irqdomain, we should > strive to reuse that infrastructure also for regmap GPIO I think, for > now > I would just leave .to_irq() out of this and let the driver deal with > any > irqs.
How would a driver attach the to_irq callback then? At the moment, the gpio_regmap doesn't expose the gpio_chip. So either we have to do that or the config still have to have a .to_irq property.
-michael
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