| Message ID | 20241112-am64-overlay-bool-v1-1-b9d1faff444e@solid-run.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | of: add support for value "false" to of_property_read_bool | expand |
Am 12.11.24 um 08:41 schrieb Josua Mayer: > Boolean type properties are usually considered true if present and false > when they do not exist. This works well for many in-tree board dts and > existing drivers. > > When users need to overrride boolean values from included dts includes, > /delete-property/ is recommend. This however does not work in overlays > (addons). > > Several places use string "true" ([1], [2], [3]) and one uses string > "false" ([1]). This suggests that at some point the value of a type > string property was to be taken into account during evaluation. > > Change of_property_read_bool to only return true if a property is both > present, and not equal "false". > > Existing usage in drivers/of and include/linux/of.h are updated > accordingly. > Other places should be reviewed as needed wrt. changed semantics. > > [1] Documentation/devicetree/bindings/sound/rt5651.txt > [2] Documentation/devicetree/bindings/sound/pcm3060.txt > [3] arch/arm/boot/dts/ti/omap/am335x-baltos.dtsi > > Signed-off-by: Josua Mayer <josua@solid-run.com> > --- Please note this patch-set has only been tested to compile, I do not consider it ready for current merge window. I would however appreciate comments.
diff --git a/drivers/of/property.c b/drivers/of/property.c index 11b922fde7af167cc69f6dd89826219653cd1ee8..a51132b883fb3fa0b1a120bacb298abf72f67c5b 100644 --- a/drivers/of/property.c +++ b/drivers/of/property.c @@ -893,7 +893,7 @@ of_fwnode_device_get_dma_attr(const struct fwnode_handle *fwnode) static bool of_fwnode_property_present(const struct fwnode_handle *fwnode, const char *propname) { - return of_property_read_bool(to_of_node(fwnode), propname); + return of_property_present(to_of_node(fwnode), propname); } static int of_fwnode_property_read_int_array(const struct fwnode_handle *fwnode, diff --git a/include/linux/of.h b/include/linux/of.h index 85b60ac9eec50bb202aa774cab273e1d947e394d..ea65c7d1176194d6ce79432782361f2cdab84f8b 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -1247,14 +1247,15 @@ static inline int of_property_read_string_index(const struct device_node *np, * Search for a boolean property in a device node. Usage on non-boolean * property types is deprecated. * - * Return: true if the property exists false otherwise. + * Return: true if the property exists and value is not "false", + * false otherwise. */ static inline bool of_property_read_bool(const struct device_node *np, const char *propname) { - struct property *prop = of_find_property(np, propname, NULL); + int ret = of_property_match_string(np, propname, "false"); - return prop ? true : false; + return ret == -ENODATA ? true : false; } /** @@ -1268,7 +1269,9 @@ static inline bool of_property_read_bool(const struct device_node *np, */ static inline bool of_property_present(const struct device_node *np, const char *propname) { - return of_property_read_bool(np, propname); + struct property *prop = of_find_property(np, propname, NULL); + + return prop ? true : false; } /** @@ -1679,7 +1682,7 @@ static inline int of_reconfig_get_state_change(unsigned long action, * of_device_is_system_power_controller - Tells if system-power-controller is found for device_node * @np: Pointer to the given device_node * - * Return: true if present false otherwise + * Return: true if enabled, false otherwise */ static inline bool of_device_is_system_power_controller(const struct device_node *np) {
Boolean type properties are usually considered true if present and false when they do not exist. This works well for many in-tree board dts and existing drivers. When users need to overrride boolean values from included dts includes, /delete-property/ is recommend. This however does not work in overlays (addons). Several places use string "true" ([1], [2], [3]) and one uses string "false" ([1]). This suggests that at some point the value of a type string property was to be taken into account during evaluation. Change of_property_read_bool to only return true if a property is both present, and not equal "false". Existing usage in drivers/of and include/linux/of.h are updated accordingly. Other places should be reviewed as needed wrt. changed semantics. [1] Documentation/devicetree/bindings/sound/rt5651.txt [2] Documentation/devicetree/bindings/sound/pcm3060.txt [3] arch/arm/boot/dts/ti/omap/am335x-baltos.dtsi Signed-off-by: Josua Mayer <josua@solid-run.com> --- drivers/of/property.c | 2 +- include/linux/of.h | 13 ++++++++----- 2 files changed, 9 insertions(+), 6 deletions(-)