[PATCH v3] firmware: meson_sm: populate platform devices from sm device tree data

[Dmitry Rokosov <ddrokosov@sberdevices.ru>]

In some meson boards, secure monitor device has children, for example,
power secure controller. By default, secure monitor isn't the bus in terms
of device tree subsystem, so the of_platform initialization code doesn't
populate its device tree data. As a result, secure monitor's children
aren't probed at all.

Run the 'of_platform_populate()' routine manually to resolve such issues.

Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
---
Changes v3 since v2 at [2]:
    - unmap meson sm shmem region if devm_of_platform_populate() failed
    - move pr_info() log about successfully enabled secure-monitor to
      the end of probe() routine

Changes v2 since v1 at [1]:
    - decline the device tree /firmware based solution
    - introduce devm_of_platform_populate() solution in the meson sm driver

Links:
    [1] https://lore.kernel.org/all/20230323185548.13731-1-ddrokosov@sberdevices.ru/
    [2] https://lore.kernel.org/linux-amlogic/20230324140141.6743-1-ddrokosov@sberdevices.ru/
---
 drivers/firmware/meson/meson_sm.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/meson/meson_sm.c b/drivers/firmware/meson/meson_sm.c
index 77aa5c6398aa..1a99dbc274fa 100644
--- a/drivers/firmware/meson/meson_sm.c
+++ b/drivers/firmware/meson/meson_sm.c
@@ -311,11 +311,14 @@ static int __init meson_sm_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, fw);
 
-	pr_info("secure-monitor enabled\n");
+	if (devm_of_platform_populate(dev))
+		goto out_in_base;
 
 	if (sysfs_create_group(&pdev->dev.kobj, &meson_sm_sysfs_attr_group))
 		goto out_in_base;
 
+	pr_info("secure-monitor enabled\n");
+
 	return 0;
 
 out_in_base:
-- 
2.36.0