Re: [PATCH 3/3] gpio: msm: Add device tree and irqdomain supportfor gpio-msm-v2

[Rohit Vaswani]

On 5/22/2013 2:36 AM, Stanimir Varbanov wrote:
> Hi, Rohit
>
> Thanks for the patch!
Thanks for the comments... more below
> On 05/21/2013 09:32 PM, Rohit Vaswani wrote:
> > This cleans up the gpio-msm-v2 driver of all the global define usage.
> > The number of gpios are now defined in the device tree. This enables
> > adding irqdomain support as well.
> >
> > Signed-off-by: Rohit Vaswani <rvaswani@xxxxxxxxxxxxxx>
> > ---
> <cut>
>
> >   
> >   static DEFINE_SPINLOCK(tlmm_lock);
> > @@ -168,18 +173,20 @@ static void msm_gpio_free(struct gpio_chip *chip, unsigned offset)
> >   
> >   static int msm_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
> >   {
> > -	return MSM_GPIO_TO_INT(chip->base + offset);
> > +	struct msm_gpio_dev *g_dev = to_msm_gpio_dev(chip);
> > +	struct irq_domain *domain = g_dev->domain;
> > +	return irq_create_mapping(domain, offset);
> IMO here you should use irq_find_mapping() and create irq mapping once
> in .probe. See below comment.
Looking at this more, I  would prefer to get rid of the entire for loop 
and the irq_create_mapping in probe and
just have the irq_create_mapping in msm_gpio_to_irq. This way we are not 
allocating a descriptor for every gpio and only for the ones that call 
the msm_gpio_to_irq.

> >   }
> >   
> <cut>
>
> > -static int msm_gpio_probe(struct platform_device *dev)
> > +static struct lock_class_key msm_gpio_lock_class;
> > +
> > +static int msm_gpio_irq_domain_map(struct irq_domain *d, unsigned int irq,
> > +				   irq_hw_number_t hwirq)
> > +{
> > +	irq_set_lockdep_class(irq, &msm_gpio_lock_class);
> > +	irq_set_chip_and_handler(irq, &msm_gpio_irq_chip,
> > +			handle_level_irq);
> > +	set_irq_flags(irq, IRQF_VALID);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct irq_domain_ops msm_gpio_irq_domain_ops = {
> > +	.xlate = irq_domain_xlate_twocell,
> > +	.map = msm_gpio_irq_domain_map,
> > +};
> > +
> > +static int msm_gpio_irqdomain_init(struct device_node *node, int ngpio)
> >   {
> > -	int i, irq, ret;
> > +	msm_gpio.domain = irq_domain_add_linear(node, ngpio,
> > +			&msm_gpio_irq_domain_ops, &msm_gpio);
> > +	if (!msm_gpio.domain) {
> > +		WARN(1, "Cannot allocate irq_domain\n");
> Are you sure that we want to WARN if no memory? I'd return an error and
> fail the probe if the driver can't works without interrupts.
Done.
> > +		return -ENOMEM;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static int msm_gpio_probe(struct platform_device *pdev)
> > +{
> > +	int i, irq, ret, ngpio;
> > +	struct resource *res;
> > +
> > +	msm_gpio.gpio_chip.label = pdev->name;
> > +	msm_gpio.gpio_chip.dev = &pdev->dev;
> > +	of_property_read_u32(pdev->dev.of_node, "ngpio", &ngpio);
> > +	msm_gpio.gpio_chip.ngpio = ngpio;
> > +
> > +	res = platform_get_resource(&pdev->dev, IORESOURCE_MEM, 0);
> > +	if (!res) {
> > +		dev_err(&pdev->dev, "%s: no mem resource\n", __func__);
> > +		return -EINVAL;
> > +	}
> > +
> > +	msm_tlmm_base = devm_ioremap_resource(pdev->dev, res);
> > +	if (!msm_tlmm_base) {
> > +		dev_err(&pdev->dev, "Couldn't allocate memory for msm tlmm base\n");
> > +		return -ENOMEM;
> > +	}
> > +
> > +	msm_gpio.enabled_irqs = devm_kzalloc(&pdev->dev,
> > +						sizeof(unsigned long) * ngpio,
> > +						GFP_KERNEL);
> > +	msm_gpio.wake_irqs = devm_kzalloc(&pdev->dev,
> > +						sizeof(unsigned long) * ngpio,
> > +						GFP_KERNEL);
> > +	msm_gpio.dual_edge_irqs = devm_kzalloc(&pdev->dev,
> > +						sizeof(unsigned long) * ngpio,
> > +						GFP_KERNEL);
> > +	bitmap_zero(msm_gpio.enabled_irqs, ngpio);
> > +	bitmap_zero(msm_gpio.wake_irqs, ngpio);
> > +	bitmap_zero(msm_gpio.dual_edge_irqs, ngpio);
> >   
> > -	bitmap_zero(msm_gpio.enabled_irqs, NR_GPIO_IRQS);
> > -	bitmap_zero(msm_gpio.wake_irqs, NR_GPIO_IRQS);
> > -	bitmap_zero(msm_gpio.dual_edge_irqs, NR_GPIO_IRQS);
> > -	msm_gpio.gpio_chip.label = dev->name;
> >   	ret = gpiochip_add(&msm_gpio.gpio_chip);
> > -	if (ret < 0)
> > +	if (ret < 0) {
> > +		dev_err(&pdev->dev, "gpiochip_add failed with error %d\n", ret);
> >   		return ret;
> > +	}
> > +
> > +	summary_irq = platform_get_irq(pdev, 0);
> > +	if (summary_irq < 0) {
> > +		dev_err(&pdev->dev, "No Summary irq defined for msmgpio\n");
> > +		return summary_irq;
> > +	}
> > +
> > +	msm_gpio_irqdomain_init(pdev->dev.of_node, msm_gpio.gpio_chip.ngpio);
> Adding irqdomain might fail, could you check the return value. And if
> irqdomain init fail do we need to set up chained handler for summary_irq
> at all?
Done.
> >   
> >   	for (i = 0; i < msm_gpio.gpio_chip.ngpio; ++i) {
> >   		irq = msm_gpio_to_irq(&msm_gpio.gpio_chip, i);
> I'd call irq_create_mapping() instead. This way the mapping will be
> created once in .probe and use irq_find_mapping() in gpio_to_irq.
Will get rid of this for loop as mentioned above. Thanks for catching this.

> > +		irq_set_lockdep_class(irq, &msm_gpio_lock_class);
> >   		irq_set_chip_and_handler(irq, &msm_gpio_irq_chip,
> >   					 handle_level_irq);
> >   		set_irq_flags(irq, IRQF_VALID);
> These three function calls are not needed anymore because
> irq_create_mapping() will call internally irqdomain .map operation. The
> .map already calls these three functions.
Done.
> >   	}
> >   
> > -	irq_set_chained_handler(TLMM_SCSS_SUMMARY_IRQ,
> > -				msm_summary_irq_handler);
> > +	irq_set_chained_handler(summary_irq, msm_summary_irq_handler);
> > +
> >   	return 0;
> >   }
> >   
> - Stan


Thanks,
Rohit Vaswani

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