| Message ID | 20180622183114.GA92912@dtor-ws (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 22 Jun 2018, Dmitry Torokhov wrote: > On Fri, Jun 22, 2018 at 01:42:28PM +0200, Matthias Brugger wrote: > > The drivers gets probed from a mfd devices. So the driver runs > > probe although no DT node exists. This leads to a NULL pointer > > dereference in the probe function. Check if a node exists and > > error out in case none is present. > > Hmm, if a cell specifies of_compatible and no such node is present in DT > maybe we should bail out in mfd_add_device() instead of pushing the > check into individual drivers? Something like: > > diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c > index 94e3f32ce935..36a5fd98000d 100644 > --- a/drivers/mfd/mfd-core.c > +++ b/drivers/mfd/mfd-core.c > @@ -137,6 +137,18 @@ static inline void mfd_acpi_add_device(const struct mfd_cell *cell, > } > #endif > > +static struct device_node *mfd_get_node_for_cell(struct device *parent, > + const struct mfd_cell *cell) > +{ > + struct device_node *np; > + > + for_each_child_of_node(parent->of_node, np) > + if (of_device_is_compatible(np, cell->of_compatible)) > + return np; > + > + return NULL; > +} > + > static int mfd_add_device(struct device *parent, int id, > const struct mfd_cell *cell, atomic_t *usage_count, > struct resource *mem_base, > @@ -144,7 +156,6 @@ static int mfd_add_device(struct device *parent, int id, > { > struct resource *res; > struct platform_device *pdev; > - struct device_node *np = NULL; > int ret = -ENOMEM; > int platform_id; > int r; > @@ -176,11 +187,11 @@ static int mfd_add_device(struct device *parent, int id, > goto fail_res; > > 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)) { > - pdev->dev.of_node = np; > - break; > - } > + pdev->dev.of_node = mfd_get_node_for_cell(parent, cell); > + if (!pdev->dev.of_node) { > + dev_err(parent, "unable to locate node for %s (%s)\n", > + cell->name, cell->of_compatible); > + goto fail_res; > } > } > > Lee? This change results the wrong semantics. MFD overrides Device Tree, such that if a device is supplied and registered using mfd_add_device(s) it should be probed. The only reason we provide a pointer to the of_node is for the child device to pull properties from. If a device should only be probed if an OF node exists, then it should not be registered at the MFD level. > > Fixes: 3e9f0b3e2b27 ("input: Add MediaTek PMIC keys support") > > Signed-off-by: Matthias Brugger <mbrugger@suse.com> > > --- > > drivers/input/keyboard/mtk-pmic-keys.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/drivers/input/keyboard/mtk-pmic-keys.c b/drivers/input/keyboard/mtk-pmic-keys.c > > index 02c67a1749fc..388043e1939c 100644 > > --- a/drivers/input/keyboard/mtk-pmic-keys.c > > +++ b/drivers/input/keyboard/mtk-pmic-keys.c > > @@ -257,6 +257,9 @@ static int mtk_pmic_keys_probe(struct platform_device *pdev) > > const struct of_device_id *of_id = > > of_match_device(of_mtk_pmic_keys_match_tbl, &pdev->dev); > > > > + if (of_id == NULL) > > + return -ENODEV; > > + > > keys = devm_kzalloc(&pdev->dev, sizeof(*keys), GFP_KERNEL); > > if (!keys) > > return -ENOMEM; > > Thanks. >
diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c index 94e3f32ce935..36a5fd98000d 100644 --- a/drivers/mfd/mfd-core.c +++ b/drivers/mfd/mfd-core.c @@ -137,6 +137,18 @@ static inline void mfd_acpi_add_device(const struct mfd_cell *cell, } #endif +static struct device_node *mfd_get_node_for_cell(struct device *parent, + const struct mfd_cell *cell) +{ + struct device_node *np; + + for_each_child_of_node(parent->of_node, np) + if (of_device_is_compatible(np, cell->of_compatible)) + return np; + + return NULL; +} + static int mfd_add_device(struct device *parent, int id, const struct mfd_cell *cell, atomic_t *usage_count, struct resource *mem_base, @@ -144,7 +156,6 @@ static int mfd_add_device(struct device *parent, int id, { struct resource *res; struct platform_device *pdev; - struct device_node *np = NULL; int ret = -ENOMEM; int platform_id; int r; @@ -176,11 +187,11 @@ static int mfd_add_device(struct device *parent, int id, goto fail_res; 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)) { - pdev->dev.of_node = np; - break; - } + pdev->dev.of_node = mfd_get_node_for_cell(parent, cell); + if (!pdev->dev.of_node) { + dev_err(parent, "unable to locate node for %s (%s)\n", + cell->name, cell->of_compatible); + goto fail_res; } }