[...] > > create child: /dcsr@20000000/dcsr-atbrepl@3a8000 > > create child: /dcsr@20000000/dcsr-tsgen-ctrl@3a9000 > > create child: /dcsr@20000000/dcsr-tsgen-read@3aa000 > > create child: /regulators/regulator@0 > > ... > > > > As default the Linux will create all the platform device for each DT node, > which > > Can be found from "drivers/of/platform.c". > > > > So we can get the pdev node using the specified DT node, and feel safe to > use > > it as Pankaj's patch does. > > > > I mean before the devices are populated from device tree. > For example, we usually call of_platform_populate in .init_machine. > Before it, we may not be able to get it's device, isn't it? >
Yes, right. For this case, we'd better create the pdev or dev manually for the first time We use it, right ? Thanks, BRs Xiubo > Regards > Dong Aisheng > > > And also we must make sure that the 'syscon' DT nodes has the compatible > prop. > > > > Thanks, > > > > BRs > > Xiubo > > > > > > > Regards > > > Dong Aisheng > > > > > > > ---- > > > > static struct syscon *of_syscon_register(struct device_node *np) > > > > { > > > > + struct platform_device *pdev; > > > > struct syscon *syscon; > > > > struct regmap *regmap; > > > > void __iomem *base; > > > > @@ -142,7 +144,11 @@ static struct syscon *of_syscon_register(struct > > > > device_node *np) > > > > if (!base) > > > > return ERR_PTR(-ENOMEM); > > > > > > > > - regmap = regmap_init_mmio(NULL, base, &syscon_regmap_config); > > > > + pdev = of_find_device_by_node(np); > > > > + if (!(&pdev->dev)) > > > > + return ERR_PTR(-ENODEV); > > > > + > > > > + regmap = regmap_init_mmio(&pdev->dev, base, > &syscon_regmap_config); > > > > if (IS_ERR(regmap)) { > > > > pr_err("regmap init failed\n"); > > > > return ERR_CAST(regmap); > > > > ------- > > > > > > > > I have tested this in linux-next and it works well. In this way there > won't > > > > be any issues of > > > > dereferencing NULL pointer in regmap.c and at the same time, if DT has > > > > {big,little}-endian > > > > optional property in syscon device node, it will be taken care. > > > > > > > > So I would wait for Arnd's opinion about above mentioned changes and > then > > > > post a new > > > > change after addressing Arnd's minor comment along with this fix in next > > > > revision. > > > > > > > > > > > > Thanks, > > > > Pankaj Dubey > > > > > Maybe we could consider create device structure for each syscon > compatible > > > > device in > > > > > syscon driver in of_syscon_register in first time which seems to be > > > > reasonable. > > > > > > > > > > Regards > > > > > Dong Aisheng > > > > > > > > > > > -------------------------------------------- > > > > > > Subject: [PATCH] regmap: fix NULL pointer dereference in > > > > > > regmap_get_val_endian > > > > > > > > > > > > Recent commits for getting reg endianess causing NULL pointer > > > > > > dereference if dev is passed NULL in regmap_init_mmio. This patch > > > > > > fixes this issue, and allows to parse reg endianess only if dev and > > > > > > dev->of_node exist. > > > > > > > > > > > > Signed-off-by: Pankaj Dubey <pankaj.du...@samsung.com> > > > > > > --- > > > > > > drivers/base/regmap/regmap.c | 23 ++++++++++++++--------- > > > > > > 1 file changed, 14 insertions(+), 9 deletions(-) > > > > > > > > > > > > diff --git a/drivers/base/regmap/regmap.c > > > > > > b/drivers/base/regmap/regmap.c index f2281af..455a877 100644 > > > > > > --- a/drivers/base/regmap/regmap.c > > > > > > +++ b/drivers/base/regmap/regmap.c > > > > > > @@ -477,7 +477,7 @@ static enum regmap_endian > > > > > > regmap_get_val_endian(struct device *dev, > > > > > > const struct regmap_bus *bus, > > > > > > const struct regmap_config > > > > > > *config) > > > > { > > > > > > - struct device_node *np = dev->of_node; > > > > > > + struct device_node *np; > > > > > > enum regmap_endian endian; > > > > > > > > > > > > /* Retrieve the endianness specification from the regmap config > > > */ > > > > > > @@ -487,15 +487,20 @@ static enum regmap_endian > > > > > > regmap_get_val_endian(struct device *dev, > > > > > > if (endian != REGMAP_ENDIAN_DEFAULT) > > > > > > return endian; > > > > > > > > > > > > - /* Parse the device's DT node for an endianness specification */ > > > > > > - if (of_property_read_bool(np, "big-endian")) > > > > > > - endian = REGMAP_ENDIAN_BIG; > > > > > > - else if (of_property_read_bool(np, "little-endian")) > > > > > > - endian = REGMAP_ENDIAN_LITTLE; > > > > > > + /* If the dev and dev->of_node exist try to get endianness from > > > DT > > > > > > */ > > > > > > + if (dev && dev->of_node) { > > > > > > + np = dev->of_node; > > > > > > > > > > > > - /* If the endianness was specified in DT, use that */ > > > > > > - if (endian != REGMAP_ENDIAN_DEFAULT) > > > > > > - return endian; > > > > > > + /* Parse the device's DT node for an endianness > > > > > > specification */ > > > > > > + if (of_property_read_bool(np, "big-endian")) > > > > > > + endian = REGMAP_ENDIAN_BIG; > > > > > > + else if (of_property_read_bool(np, "little-endian")) > > > > > > + endian = REGMAP_ENDIAN_LITTLE; > > > > > > + > > > > > > + /* If the endianness was specified in DT, use that */ > > > > > > + if (endian != REGMAP_ENDIAN_DEFAULT) > > > > > > + return endian; > > > > > > + } > > > > > > > > > > > > /* Retrieve the endianness specification from the bus config */ > > > > > > if (bus && bus->val_format_endian_default) > > > > > > -- > > > > > > > > > > > > Thanks, > > > > > > Pankaj Dubey > > > > > > > > > > > > > Regards > > > > > > > Dong Aisheng > > > > > > > > > > > > > > > > > > > > > > > Thanks, > > > > > > > > Pankaj Dubey > > > > > > > > > > > > > > > > > Regards > > > > > > > > > Dong Aisheng > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > _______________________________________________ > > > > > > > > > > linux-arm-kernel mailing list > > > > > > > > > > linux-arm-ker...@lists.infradead.org > > > > > > > > > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > > > > > > > > > > > > > > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/