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SubjectRe: [PATCH 13/16] regulator: mc13xxx: Use of_get_child_by_name
Hi

This patch breaks DT-Enabled kernel run on non-DT board:
[ 0.822977] Unable to handle kernel NULL pointer dereference at
virtual address 0000001c
(...)
[ 0.880320] [<c02f3e94>] (of_get_next_child) from [<c02f5420>]
(of_get_child_by_name+0x38/0x50)
[ 0.881449] [<c02f5420>] (of_get_child_by_name) from [<c01f6258>]
(mc13xxx_get_num_regulators_dt+0x18/0x64)
[ 0.882707] [<c01f6258>] (mc13xxx_get_num_regulators_dt) from
[<c01f5d38>] (mc13783_regulator_probe+0x34/0x17c)
[ 0.884011] [<c01f5d38>] (mc13783_regulator_probe) from [<c021fed0>]
(platform_drv_probe+0x20/0x54)
[ 0.885182] [<c021fed0>] (platform_drv_probe) from [<c021e674>]
(driver_probe_device+0x144/0x360)
(...)

Because mc13783-regulator do in its probe:
static int mc13783_regulator_probe(struct platform_device *pdev)
{
(...)
int i, num_regulators;

num_regulators = mc13xxx_get_num_regulators_dt(pdev);
if (num_regulators <= 0 && pdata)
num_regulators = pdata->num_regulators


and mc13xxx_get_num_regulators_dt() do, before your patch:

parent = of_find_node_by_name(pdev->dev.parent->of_node, "regulators");
if (!parent)
return -ENODEV;

of_find_node_by_name will return NULL if the node passed is NULL and the
DT is non-existant.

But, with your change we use this:
parent = of_get_child_by_name(pdev->dev.parent->of_node, "regulators");

Which will OOPS as it does not expect to have a NULL node passed as
argument.

So please revert this patch.

Regards,

Philippe



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