On Mon, Aug 18, 2025 at 09:56:07AM +0300, Matti Vaittinen wrote:

On 18/08/2025 09:54, Matti Vaittinen wrote:

quoted

On 18/08/2025 01:47, Dmitry Torokhov wrote:

quoted

Refactor the rohm-bd71828 MFD driver to use software nodes for
instantiating the gpio-keys child device, replacing the old
platform_data mechanism.

Thanks for doing this Dmitry! I believe I didn't understand how
providing the IRQs via swnode works... :)

If I visit the ROHM office this week, then I will try to test this using
the PMIC HW. (Next week I'll be in ELCE, and after it I have probably
already forgotten this...)

quoted

The power key's properties are now defined using software nodes and
property entries. The IRQ is passed as a resource attached to the
platform device.

This will allow dropping support for using platform data for configuring
gpio-keys in the future.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
  drivers/mfd/rohm-bd71828.c | 81 +++++++++++++++++++++++++++-----------
  1 file changed, 58 insertions(+), 23 deletions(-)

diff --git a/drivers/mfd/rohm-bd71828.c b/drivers/mfd/rohm-bd71828.c
index a14b7aa69c3c..c29dde9996b7 100644
--- a/drivers/mfd/rohm-bd71828.c
+++ b/drivers/mfd/rohm-bd71828.c

@@ -4,7 +4,6 @@

// ...snip

quoted

+static int bd71828_reg_cnt;
+
+static int bd71828_i2c_register_swnodes(void)
+{
+    int error;
+
+    if (bd71828_reg_cnt == 0) {

Isn't this check racy...

quoted

+        error = software_node_register_node_group(bd71828_swnodes);
+        if (error)
+            return error;
+    }
+
+    bd71828_reg_cnt++;

... with this...

quoted

+    return 0;
+}
+
+static void bd71828_i2c_unregister_swnodes(void *dummy)
+{
+    if (bd71828_reg_cnt != 0) {

...this...

quoted

+        software_node_unregister_node_group(bd71828_swnodes);
+        bd71828_reg_cnt--;

...and this? Perhaps add a mutex or use atomics?

Also, shouldn't the software_node_unregister_node_group() be only called
for the last instance to exit (Eg, "if (bd71828_reg_cnt == 0)" instead
of the "if (bd71828_reg_cnt != 0) {")?

Oh. Probably "if (bd71828_reg_cnt == 1)".

You are right, I am not sure what I was thinking when I wrote this.

I actually doubt that sharing of nodes between devices would work well.
But I believe these devices are singletons, it should not be possible to
have several of them in a single system, right? So maybe the best way is
to simply instantiate them in probe and bail out if they are already
registered.

Thanks.

-- 
Dmitry