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[v2,0/4] gpio: sifive: Module support

Message ID 20230719163446.1398961-1-samuel.holland@sifive.com
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Series gpio: sifive: Module support | expand

Message

Samuel Holland July 19, 2023, 4:34 p.m. UTC 
With the call to of_irq_count() removed, the SiFive GPIO driver can be
built as a module. This helps to minimize the size of a multiplatform
kernel, and is required by some downstream distributions (Android GKI).

This series removes the rest of the of_* API usage in the process.

Changes in v2:
 - Add 3 new patches removing of_* API usage
 - Add MODULE_AUTHOR and MODULE_DESCRIPTION

Samuel Holland (4):
  gpio: sifive: Directly use the device's fwnode
  gpio: sifive: Look up IRQs only once during probe
  gpio: sifive: Get the parent IRQ's domain from its irq_data
  gpio: sifive: Allow building the driver as a module

 drivers/gpio/Kconfig       |  2 +-
 drivers/gpio/gpio-sifive.c | 45 +++++++++++++-------------------------
 2 files changed, 16 insertions(+), 31 deletions(-)

Comments

Andy Shevchenko July 19, 2023, 4:44 p.m. UTC | #1 
On Wed, Jul 19, 2023 at 09:34:42AM -0700, Samuel Holland wrote:
> There is no need to convert dev->of_node back to a fwnode_handle.

...

> -	girq->fwnode = of_node_to_fwnode(node);
> +	girq->fwnode = dev->fwnode;

	dev_fwnode(dev)

...and include property.h here
Andy Shevchenko July 19, 2023, 4:54 p.m. UTC | #2 
On Wed, Jul 19, 2023 at 09:34:44AM -0700, Samuel Holland wrote:
> Do not parse the devicetree again when the data is already available
> from the IRQ subsystem. This follows the example of the ThunderX and
> X-Gene GPIO drivers. The ngpio check is needed to avoid a possible
> out-of-bounds read.

...

> -	girq->parent_domain = parent;
> +	girq->parent_domain = irq_get_irq_data(chip->irq_number[0])->domain;

For the sake of readability I would like to leave parent variable
and assign it beforehand somewhere upper in the code.

Also, can irq_get_irq_data() return NULL? Needs a comment on top
of that assignment or an additional check.
Andy Shevchenko July 19, 2023, 5:21 p.m. UTC | #3 
On Wed, Jul 19, 2023 at 12:03:46PM -0500, Samuel Holland wrote:
> On 2023-07-19 11:54 AM, Andy Shevchenko wrote:
> > On Wed, Jul 19, 2023 at 09:34:44AM -0700, Samuel Holland wrote:

...

> > Also, can irq_get_irq_data() return NULL? Needs a comment on top
> > of that assignment or an additional check.
> 
> No, the earlier loop already verified the IRQ number was valid. I don't think it
> can later become invalid. In any case, we already dereference the result of
> irq_get_irq_data(irq_number[foo]) in sifive_gpio_child_to_parent_hwirq().

Thanks for explanation, just add a comment.