Sorry for the spam, had a bad copy and paste in previous email.
On Mon, Jun 17, 2013 at 2:38 PM, Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
> On Thu, Jun 6, 2013 at 10:05 AM, <thloh@xxxxxxxxxx> wrote:
>
>> From: Tien Hock Loh <thloh@xxxxxxxxxx>
>>
>> Add driver support for Altera GPIO soft IP, including interrupts and I/O.
>> Tested on Altera CV SoC board.
>>
>> Signed-off-by: Tien Hock Loh <thloh@xxxxxxxxxx>
> (...)
>
> This is looking much better, some remaining comments.
>
>> +++ b/Documentation/devicetree/bindings/gpio/gpio-altera.txt
>> @@ -0,0 +1,36 @@
>> +Altera GPIO controller bindings
>> +
>> +Required properties:
>> +- compatible:
>> + - "altr,pio-1.0"
>
> I asked you to add this prefix to
> Documentation/devicetree/bindings/vendor-prefixes.txt
>
Noted, missed that out.
>> +- reg: Physical base address and length of the controller's registers.
>> +- #gpio-cells : Should be 1
>> + - first cell is the gpio offset number
>> +- gpio-controller : Marks the device node as a GPIO controller.
>> +- #interrupt-cells : Should be 1.
>> +- interrupts: Specify the interrupt.
>> +- interrupt-controller: Mark the device node as an interrupt controller
>> + The first cell is the GPIO number.
>
> How can that cell be the "GPIO number"? Surely it is the local
> interrupt offset number on the GPIO controller?
>
Yup, bad documentation. I'll update this.
> (...)
>> +++ b/drivers/gpio/gpio-altera.c
>
>> +static int altera_gpio_get(struct gpio_chip *gc, unsigned offset)
>> +{
>> + struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
>> +
>> + return (readl(mm_gc->regs + ALTERA_GPIO_DATA) >> offset) & 1;
>
> I usually would write that like this:
>
> #include <linux/bitops.h>
>
> return !!(readl(mm_gc->regs + ALTERA_GPIO_DATA) & BIT(offset));
>
> But no big deal.
>
>> + gpio_ddr |= (1 << offset);
>
> And with <linux/bitops.h> I would just:
>
> gpio_ddr |= BIT(offset);
Noted, that looks cleaner.
>
>> +static void altera_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
>> +{
>> + struct altera_gpio_chip *altera_gc = irq_desc_get_handler_data(desc);
>> + struct irq_chip *chip = irq_desc_get_chip(desc);
>> + struct of_mm_gpio_chip *mm_gc = &altera_gc->mmchip;
>> + unsigned long status;
>> +
>> + int base;
>> + chip->irq_mask(&desc->irq_data);
>> +
>> + if (altera_gc->level_trigger) {
>> + status = __raw_readl(mm_gc->regs + ALTERA_GPIO_DATA);
>> + status &= __raw_readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
>> +
>> + for (base = 0; base < mm_gc->gc.ngpio; base++) {
>> + if ((1 << base) & status) {
>> + generic_handle_irq(irq_linear_revmap(
>> + altera_gc->irq, base));
>> + }
>> + }
>> + } else {
>> + while ((status =
>> + (__raw_readl(mm_gc->regs + ALTERA_GPIO_EDGE_CAP) &
>> + __raw_readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK)))) {
>> + __raw_writel(status,
>> + mm_gc->regs + ALTERA_GPIO_EDGE_CAP);
>> + for (base = 0; base < mm_gc->gc.ngpio; base++) {
>> + if ((1 << base) & status) {
>> + generic_handle_irq(irq_linear_revmap(
>> + altera_gc->irq, base));
>> + }
>> + }
>> + }
>> + }
>> +
>> + chip->irq_eoi(irq_desc_get_irq_data(desc));
>> + chip->irq_unmask(&desc->irq_data);
>> +}
>
> Why is the above code using __raw_* accessors?
>
> Atleast use readl_relaxed() instead of __raw.
Noted.
A question regarding readl_relaxed(), is that because the endianess
swapping? If that's the case, should codes in other functions use
readl_relaxed()/writel_relaxed() as well?
>
>> + if (of_get_property(node, "interrupts", ®) == NULL)
>> + goto skip_irq;
>> + altera_gc->hwirq = irq_of_parse_and_map(node, 0);
>
> But wait. How can a hardware IRQ be something coming out
> of irq_of_parse_and_map()???
>
> The entire point of mapping an IRQ is to move it into some
> free Linux IRQ slot, it is as far away from a HW IRQ you
> ever get.
>
> Either rename the variable or rethink what you're doing here.
The variable naming came from gpio-mpc8xxx.c, I'll update this to a better name.
>
> Yours,
> Linus Walleij
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