On 10/9/23 9:34 AM, Dipen Patel wrote:

On 10/8/23 11:48 PM, Bartosz Golaszewski wrote:

quoted

On Thu, Oct 5, 2023 at 9:43 PM Dipen Patel [off-list ref] wrote:

quoted

On 10/5/23 12:05 PM, Bartosz Golaszewski wrote:

quoted

On Thu, Oct 5, 2023 at 8:12 PM Dipen Patel [off-list ref] wrote:

quoted

On 10/5/23 6:48 AM, Bartosz Golaszewski wrote:

quoted

On Thu, Oct 5, 2023 at 1:52 AM Dipen Patel [off-list ref] wrote:

quoted

On 10/4/23 3:54 PM, Dipen Patel wrote:

quoted

On 10/4/23 1:33 PM, Dipen Patel wrote:

quoted

On 10/4/23 1:30 PM, Dipen Patel wrote:

quoted

On 10/4/23 5:00 AM, Bartosz Golaszewski wrote:

quoted

On Thu, Sep 7, 2023 at 9:28 AM Linus Walleij [off-list ref] wrote:

quoted

On Tue, Sep 5, 2023 at 8:53 PM Bartosz Golaszewski [off-list ref] wrote:

quoted

From: Bartosz Golaszewski <redacted>

Using struct gpio_chip is not safe as it will disappear if the
underlying driver is unbound for any reason. Switch to using reference
counted struct gpio_device and its dedicated accessors.

Signed-off-by: Bartosz Golaszewski <redacted>

As Andy points out add <linux/cleanup.h>, with that fixed:
Reviewed-by: Linus Walleij <redacted>

I think this can be merged into the gpio tree after leaving some
slack for the HTE maintainer to look at it, things look so much
better after this.

Yours,
Linus Walleij

Dipen,

if you could give this patch a test and possibly ack it for me to take
it through the GPIO tree (or go the immutable tag from HTE route) then
it would be great. This is the last user of gpiochip_find() treewide,
so with it we could remove it entirely for v6.7.

Progress so far for the RFT...

I tried applying the patch series on 6.6-rc1 and it did not apply cleanly,
some patches I needed to manually apply and correct. With all this, it failed
compilation at some spi/spi-bcm2835 driver. I disabled that and was able to
compile. I thought I should let you know this part.

Now, I tried to test the hte and it seems to fail finding the gpio device,
roughly around this place [1]. I thought it would be your patch series so
tried to just use 6.6rc1 without your patches and it still failed at the
same place. I have to trace back now from which kernel version it broke.

[1].
https://git.kernel.org/pub/scm/linux/kernel/git/pateldipen1984/linux.git/tree/drivers/hte/hte-tegra194.c?h=for-next#n781

of course with your patches it would fail for the gdev instead of the chip.

Small update:

I put some debugging prints in the gpio match function in the hte-tegra194.c as
below:

static int tegra_gpiochip_match(struct gpio_chip *chip, void *data)
 {
+       struct device_node *node = data;
+       struct fwnode_handle *fw = of_node_to_fwnode(data);
+       if (!fw || !chip->fwnode)
+               pr_err("dipen patel: fw is null\n");

-       pr_err("%s:%d\n", __func__, __LINE__);
+       pr_err("dipen patel, %s:%d: %s, %s, %s, match?:%d, fwnode name:%s\n",
__func__, __LINE__, chip->label, node->name, node->full_name, (chip->fwnode ==
fw), fw->dev->init_name);
        return chip->fwnode == of_node_to_fwnode(data);
 }

The output of the printfs looks like below:
[    3.955194] dipen patel: fw is null -----> this message started appearing
when I added !chip->fwnode test in the if condition line.

[    3.958864] dipen patel, tegra_gpiochip_match:689: tegra234-gpio, gpio,
gpio@c2f0000, match?:0, fwnode name:(null)

I conclude that chip->fwnode is empty. Any idea in which conditions that node
would be empty?

sorry for spamming, one last message before I sign off for the day....

Seems, adding below in the tegra gpio driver resolved the issue I am facing, I
was able to verify your patch series.

diff --git a/drivers/gpio/gpio-tegra186.c b/drivers/gpio/gpio-tegra186.c
index d87dd06db40d..a56c159d7136 100644
--- a/drivers/gpio/gpio-tegra186.c
+++ b/drivers/gpio/gpio-tegra186.c

@@ -989,6 +989,8 @@ static int tegra186_gpio_probe(struct platform_device *pdev)
                offset += port->pins;
        }

+       gpio->gpio.fwnode = of_node_to_fwnode(pdev->dev.of_node);
+
        return devm_gpiochip_add_data(&pdev->dev, &gpio->gpio, gpio);
 }

Now, few follow up questions:
1) is this the correct way of setting the chip fwnode in the gpio driver?

You shouldn't need this. This driver already does:

    gpio->gpio.parent = &pdev->dev;

so fwnode should be assigned in gpiochip_add_data_with_key(). Can you
check why this doesn't happen?

I do not see anywhere chip->fwnode being set in the gpiochip_add_* function.
The only reference I see is here [1]. Does it mean I need to change my match
function from:

chip->fwnode == of_node_to_fwnode(data)

to:
dev_fwnode(chip->parent) == of_node_to_fwnode(data)?

No! chip->fwnode is only used to let GPIOLIB know which fwnode to
assign to the GPIO device (struct gpio_device).

What do you suggest I should use for the match as I do not see chip->fwnode
being set?

This is most likely going to be a longer discussion. I suggest that in
the meantime you just assign the gc->fwnode pointer explicitly from
the platform device in the tegra GPIO driver and use it in the lookup
function. Note that this is NOT wrong or a hack. It's just that most
devices don't need to be looked up using gpio_device_find().

Sure, at the same time, I am also find to use any other method/s.

(Correction) I am also fine*

With patch
https://patchwork.ozlabs.org/project/linux-gpio/patch/20231009173858.723686-1-dipenp@nvidia.com/

Tested-by: Dipen Patel <dipenp@nvidia.com>

quoted

Bart

quoted

quoted

Bart

quoted

[1]:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpio/gpiolib.c?h=v6.6-rc1#n767

quoted

Bart

quoted

2) Or should I use something else in hte matching function instead of fwnode so
to avoid adding above line in the gpio driver?

quoted

quoted

quoted

quoted

Bart

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel