Hi Mark
On Wed, Nov 27, 2013 at 10:40 PM, Mark Rutland <mark.rutland@xxxxxxx> wrote:
> Hi,
>
> On Wed, Nov 27, 2013 at 03:49:52AM +0000, 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 using dipsw and LED using LED framework.
>>
>> Signed-off-by: Tien Hock Loh <thloh@xxxxxxxxxx>
>> ---
>> .../devicetree/bindings/gpio/gpio-altera.txt | 35 ++
>> drivers/gpio/Kconfig | 7 +
>> drivers/gpio/Makefile | 1 +
>> drivers/gpio/gpio-altera.c | 395 +++++++++++++++++++++
>> 4 files changed, 438 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/gpio/gpio-altera.txt
>> create mode 100644 drivers/gpio/gpio-altera.c
>>
>> diff --git a/Documentation/devicetree/bindings/gpio/gpio-altera.txt b/Documentation/devicetree/bindings/gpio/gpio-altera.txt
>> new file mode 100644
>> index 0000000..6c57d84
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/gpio/gpio-altera.txt
>> @@ -0,0 +1,35 @@
>> +Altera GPIO controller bindings
>> +
>> +Required properties:
>> +- compatible:
>> + - "altr,pio-1.0"
>> +- 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 local interrupt offset number to the GPIO controller.
>
> Huh? This line doesn't make much sense immediately after the description
> of interrupt-controller. Presumably this is associated iwth
> #interrupt-cells?
Yes, it must have got displaced when I was editing the text. I'll get
this fixed.
>
>> +
>> +Altera GPIO specific properties:
>> +- altr,gpio-bank-width: Width of the GPIO bank. This defines how many pins the
>> + GPIO device has. Ranges between 1-32.
>
> The code appears to handle this as an optional property, such that this
> proeprty is only required if the GPIO controller does not have 32 GPIOs.
> It would be worth notign that this is optional, and describing when this
> is expected in the binding.
>
Noted. Will add a note on required and optional parameters.
>> +- altr,interrupt_trigger: Specifies the interrupt trigger type the GPIO
>> + hardware is synthesized. This field is required if the Altera GPIO controller
>> + used has IRQ enabled as the interrupt type is not software controlled,
>> + but hardware synthesized.
>
> s/_/-/
>
> What type is this, and what values are expected?
>
> The description implies that this is an optional property, but the code
> seems to require it.
This isn't always required, but only required when the controller is
used as an interrupt controller. I'll specify that this is a required
field if GPIO is used as an interrupt controller. I'll add in the
expected values as well.
>
>> +
>> +Example:
>> +
>> +gpio_altr: gpio_altr {
>> + compatible = "altr,pio-1.0";
>> + reg = <0xff200000 0x10>;
>> + interrupts = <0 45 4>;
>> + altr,gpio-bank-width = <32>;
>> + altr,interrupt_trigger = <0>;
>
> The description doesn't tell me what this porperty in the example
> means...
Noted, I'll put the supported interrupt trigger to the description
above. This is the value of interrupt trigger as defined in
<dt-bindings/interrupt-controller/irq.h>.
>
>> + #gpio-cells = <1>;
>> + gpio-controller;
>> + #interrupt-cells = <1>;
>> + interrupt-controller;
>> +};
>
> [...]
>
>> +int altera_gpio_probe(struct platform_device *pdev)
>> +{
>> + struct device_node *node = pdev->dev.of_node;
>> + int id, reg, ret;
>> + struct altera_gpio_chip *altera_gc = devm_kzalloc(&pdev->dev,
>> + sizeof(*altera_gc), GFP_KERNEL);
>> + if (altera_gc == NULL) {
>> + pr_err("%s: out of memory\n", node->full_name);
>> + return -ENOMEM;
>> + }
>> + altera_gc->irq = 0;
>> +
>> + spin_lock_init(&altera_gc->gpio_lock);
>> +
>> + id = pdev->id;
>> +
>> + if (of_property_read_u32(node, "altr,gpio-bank-width", ®))
>> + /*By default assume full GPIO controller*/
>> + altera_gc->mmchip.gc.ngpio = 32;
>> + else
>> + altera_gc->mmchip.gc.ngpio = reg;
>
> As mentioned above, the binding doesn't describe this as optional, yet
> it's treated as such.
I'll get this fixed in the documentation.
>
>> +
>> + if (altera_gc->mmchip.gc.ngpio > 32) {
>> + pr_warn("%s: ngpio is greater than 32, defaulting to 32\n",
>> + node->full_name);
>> + altera_gc->mmchip.gc.ngpio = 32;
>> + }
>> +
>> + altera_gc->mmchip.gc.direction_input = altera_gpio_direction_input;
>> + altera_gc->mmchip.gc.direction_output = altera_gpio_direction_output;
>> + altera_gc->mmchip.gc.get = altera_gpio_get;
>> + altera_gc->mmchip.gc.set = altera_gpio_set;
>> + altera_gc->mmchip.gc.to_irq = altera_gpio_to_irq;
>> + altera_gc->mmchip.gc.owner = THIS_MODULE;
>> +
>> + ret = of_mm_gpiochip_add(node, &altera_gc->mmchip);
>> + if (ret) {
>> + pr_err("%s: Failed adding memory mapped gpiochip\n",
>> + node->full_name);
>> + return ret;
>> + }
>> +
>> + platform_set_drvdata(pdev, altera_gc);
>> +
>> + altera_gc->mapped_irq = irq_of_parse_and_map(node, 0);
>> +
>> + if (!altera_gc->mapped_irq)
>> + goto skip_irq;
>
> It seems odd to jump directly to a return 0. Why not just return 0 here
> (or initialise ret to 0 and combine the two return cases)?
Noted. I'll return 0 here.
>
> Thanks,
> Mark.
Thanks for the comments. I'll post a patch v5.
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