linux-kernel - [PATCH 1/1] mfd: mfd-core: Honour Device Tree's request to disable a child-device

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Date:   Thu,  7 Nov 2019 11:19:50 +0000
From:   Lee Jones <lee.jones@...aro.org>
To:     daniel.thompson@...aro.org, broonie@...nel.org, arnd@...db.de,
        linus.walleij@...aro.org
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        baohua@...nel.org, stephan@...hold.net,
        Lee Jones <lee.jones@...aro.org>,
        Barry Song <Baohua.Song@....com>
Subject: [PATCH 1/1] mfd: mfd-core: Honour Device Tree's request to disable a child-device

Until now, MFD has assumed all child devices passed to it (via
mfd_cells) are to be registered. It does not take into account
requests from Device Tree and the like to disable child devices
on a per-platform basis.

Well now it does.

Link: https://www.spinics.net/lists/arm-kernel/msg366309.html
Link: https://lkml.org/lkml/2019/8/22/1350

Reported-by: Barry Song <Baohua.Song@....com>
Reported-by: Stephan Gerhold <stephan@...hold.net>
Signed-off-by: Lee Jones <lee.jones@...aro.org>
---
 drivers/mfd/mfd-core.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index cb3e0a14bbdd..f5a73af60dd4 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -152,6 +152,11 @@ static int mfd_add_device(struct device *parent, int id,
 	if (parent->of_node && cell->of_compatible) {
 		for_each_child_of_node(parent->of_node, np) {
 			if (of_device_is_compatible(np, cell->of_compatible)) {
+				if (!of_device_is_available(np)) {
+					/* Ignore disabled devices error free */
+					ret = 0;
+					goto fail_alias;
+				}
 				pdev->dev.of_node = np;
 				pdev->dev.fwnode = &np->fwnode;
 				break;
-- 
2.24.0