linux-kernel - Re: [PATCH v3 1/2] gpio: designware: switch device node to fwnode

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Date:	Thu, 25 Feb 2016 19:58:16 +0800
From:	Jiang Qiu <qiujiang@...wei.com>
To:	Andy Shevchenko <andy.shevchenko@...il.com>
CC:	Linus Walleij <linus.walleij@...aro.org>,
	Alexandre Courbot <gnurou@...il.com>,
	Mika Westerberg <mika.westerberg@...ux.intel.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	<linuxarm@...wei.com>, <haifeng.wei@...wei.com>,
	<charles.chenxin@...wei.com>
Subject: Re: [PATCH v3 1/2] gpio: designware: switch device node to fwnode

在 2016/2/24 21:46, Andy Shevchenko 写道:
> On Wed, Feb 24, 2016 at 2:33 PM, qiujiang <qiujiang@...wei.com> wrote:
>> This patch switch device node to fwnode in dwapb_port_property,
>> so as to apply a unified data structure for DT and ACPI.
>>
>> This change also needs to be done in intel_quark_i2c_gpio driver,
>> since it depends on gpio-dwapb driver.
>>
>> Acked-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
>> Signed-off-by: qiujiang <qiujiang@...wei.com>
> 
> Yes, something like this.
> Though I have questions:
>  - why do you use fwnode_*() instead of device_property_*() calls?
> What prevents us to move to device property API directly?
Yes, it looks more reasonable by using devce_property. Howerver,
device_get_child_node_count was used here to find each child node. This
API output the fwnode_handle for each child node directly, but device
property APIs need 'dev' data instead. Actually, the effects of fwnode_*()
and device_*() are the same. So, I used fwnode_*() APIs here.

If there is any other more way to traverse child nodes, let me know.
Thank you.
> 
>> -       gpio->domain = irq_domain_add_linear(node, ngpio,
>> -                                            &irq_generic_chip_ops, gpio);
>> +       gpio->domain = irq_domain_create_linear(fwnode, ngpio,
>> +                                                &irq_generic_chip_ops, gpio);
> 
> Are they equivalent?
Yes, they are equivalent.
> 
>> @@ -415,7 +415,7 @@ static int dwapb_gpio_add_port(struct dwapb_gpio *gpio,
>>         }
>>
>>  #ifdef CONFIG_OF_GPIO
>> -       port->gc.of_node = pp->node;
>> +       port->gc.of_node = to_of_node(pp->fwnode);
> 
> If fwnode is not OF one?
> Perhaps, something like ... = is_of_node() ? to_of_node() : NULL;
> 
The way you suggested is more resonable, I will fixed it in next version.
> 
>> -       node = dev->of_node;
>> -       if (!IS_ENABLED(CONFIG_OF_GPIO) || !node)
>> +       if (!IS_ENABLED(CONFIG_OF_GPIO) || !(dev->of_node))
>>                 return ERR_PTR(-ENODEV);
> 
> So, since you converted to fwnode, do you still need this check?
>
Although this patch coverted device node to fwnode, only DTs binding was
supported here, and patch2 support ACPI will remove this check.
>>
>> -       nports = of_get_child_count(node);
>> +       nports = device_get_child_node_count(dev);
>>         if (nports == 0)
>>                 return ERR_PTR(-ENODEV);
> 
> ...I think this one fail if it will not found any child.
This one fail? yes, it will return to failure.
I am not very clear here.
> 
>> -               if (of_property_read_u32(port_np, "reg", &pp->idx) ||
>> +               if (fwnode_property_read_u32(fwnode, "reg", &pp->idx) ||
> 
> device_property_*() ?
> 
>>                     pp->idx >= DWAPB_MAX_PORTS) {
>>                         dev_err(dev, "missing/invalid port index for %s\n",
>> -                               port_np->full_name);
>> +                               to_of_node(fwnode)->full_name);
> 
> If it's not OF?
This is checked above, and patch2 will remove it.
> 
>> -               if (of_property_read_u32(port_np, "snps,nr-gpios",
>> +               if (fwnode_property_read_u32(fwnode, "snps,nr-gpios",
> 
> Ditto.
> 
>>                                          &pp->ngpio)) {
>>                         dev_info(dev, "failed to get number of gpios for %s\n",
>> -                                port_np->full_name);
>> +                                to_of_node(fwnode)->full_name);
> 
> Ditto.
> 
>>                 if (pp->idx == 0 &&
>> -                   of_property_read_bool(port_np, "interrupt-controller")) {
>> -                       pp->irq = irq_of_parse_and_map(port_np, 0);
>> +                       of_property_read_bool(to_of_node(fwnode),
>> +                               "interrupt-controller")) {
> 
> device_property_*() ?
> 
>> +                       pp->irq = irq_of_parse_and_map(to_of_node(fwnode), 0);
>>                         if (!pp->irq) {
>>                                 dev_warn(dev, "no irq for bank %s\n",
>> -                                        port_np->full_name);
>> +                                        to_of_node(fwnode)->full_name);
>>                         }
>>                 }
>>
>>                 pp->irq_shared  = false;
>>                 pp->gpio_base   = -1;
>> -               pp->name        = port_np->full_name;
>> +               pp->name = to_of_node(fwnode)->full_name;
>>         }
>>
>>         return pdata;
> 
>