| Message ID | 20190713075259.243565-3-dmitry.torokhov@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Make gpiolib work with static device properties | expand |
On Sat, Jul 13, 2019 at 9:53 AM Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote: > Now that static device properties understand notion of child nodes, let's > teach gpiolib to tie such children and machine GPIO descriptor tables. > We will continue using a single table for entire device, but instead of > using connection ID as a lookup key in the GPIO descriptor table directly, > we will perform additional translation: fwnode_get_named_gpiod() when > dealing with property_set-backed fwnodes will try parsing string property > with name matching connection ID and use result of the lookup as the key in > the table: > > static const struct property_entry dev_child1_props[] __initconst = { > ... > PROPERTY_ENTRY_STRING("gpios", "child-1-gpios"), > { } > }; > > static struct gpiod_lookup_table dev_gpiod_table = { > .dev_id = "some-device", > .table = { > ... > GPIO_LOOKUP_IDX("B", 1, "child-1-gpios", 1, GPIO_ACTIVE_LOW), > ... > }, > }; > > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> I'm pretty grateful for this since I think at one point I provoked this whole series. :) > +static struct gpio_desc *__fwnode_get_named_gpiod(struct fwnode_handle *fwnode, I am allergic to __underscore_with_unclear_semantics() so I will change this when applying to something with meaning (I even like "inner_" better.) Otherwise it's good to go when I get an ACK on the first patch. Yours, Linus Walleij
Hi Dmitry, On Sat, Jul 13, 2019 at 12:52:59AM -0700, Dmitry Torokhov wrote: > Now that static device properties understand notion of child nodes, let's > teach gpiolib to tie such children and machine GPIO descriptor tables. > We will continue using a single table for entire device, but instead of > using connection ID as a lookup key in the GPIO descriptor table directly, > we will perform additional translation: fwnode_get_named_gpiod() when > dealing with property_set-backed fwnodes will try parsing string property > with name matching connection ID and use result of the lookup as the key in > the table: > > static const struct property_entry dev_child1_props[] __initconst = { > ... > PROPERTY_ENTRY_STRING("gpios", "child-1-gpios"), > { } > }; > > static struct gpiod_lookup_table dev_gpiod_table = { > .dev_id = "some-device", > .table = { > ... > GPIO_LOOKUP_IDX("B", 1, "child-1-gpios", 1, GPIO_ACTIVE_LOW), > ... > }, > }; We don't need struct gpiod_lookup_table anymore. We can mimic DT with the software nodes now that we have those "reference properties". A gpio reference with the software nodes would look something like this: enum { GPIO_CONTROLLER, MY_DEVICE }; static const struct software_node nodes[]; static const struct software_node_ref_args reset_gpio_ref = { .node = &nodes[GPIO_CONTROLLER], .nargs = 2, .args = { 14, /* line number */ GPIO_ACTIVE_HIGH /* flags */ } }; static const struct software_node_reference my_refs[] = { { "reset-gpios", 1, &reset_gpio_ref } }; /* Optionally, we could support gpiochip finding by name... */ static const struct property_entry my_props[] = { PROPERTY_ENTRY_STRING("gpio-controller", "name_of_the_controller") }; static const struct software_node nodes[] = { [GPIO_CONTROLLER] = { "gpio_controller" }, [MY_DEVICE] = { "my_device", NULL, my_props, my_refs } }; void my_init(void) { ... ret = software_node_register_nodes(nodes); ... } In gpiolib we should now be able to access that reference with fwnode_property_get_references_args(): static int gpiochip_match_fwnode(struct gpio_chip *chip, void *fwnode) { /* The fwnode member needs to be added to struct gpio_chip */ return chip->fwnode == fwnode; } static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id, unsigned int idx, unsigned long flags) { struct fwnode_reference_args args; struct gpio_chip *chip; struct gpio_desc *desc; const char *name; int ret; ret = fwnode_property_get_refernce_args(dev_fwnode(dev), con_id, NULL, idx, &args); ... /* Let's find the gpiochip */ chip = gpiochip_find(args.fwnode, gpiochip_match_fwnode); ... /* Or optionally with find_chip_by_name() */ //ret = device_property_read_string(dev, "gpio-controller", &name); ... //chip = find_chip_by_name(name); ... /* I'm assuming hwnum is the same as line number? */ desc = gpiochip_get_desc(chip, args.args[0]); *flags = args.args[1]; return desc; } The above is just an example, but I'm pretty sure that something like it (with a little bit of tuning) is all that we need. thanks,
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index e013d417a936..b6574febe2b8 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -4307,39 +4307,44 @@ struct gpio_desc *gpiod_get_from_of_node(struct device_node *node, } EXPORT_SYMBOL(gpiod_get_from_of_node); -/** - * fwnode_get_named_gpiod - obtain a GPIO from firmware node - * @fwnode: handle of the firmware node - * @propname: name of the firmware property representing the GPIO - * @index: index of the GPIO to obtain for the consumer - * @dflags: GPIO initialization flags - * @label: label to attach to the requested GPIO - * - * This function can be used for drivers that get their configuration - * from opaque firmware. - * - * The function properly finds the corresponding GPIO using whatever is the - * underlying firmware interface and then makes sure that the GPIO - * descriptor is requested before it is returned to the caller. - * - * Returns: - * On successful request the GPIO pin is configured in accordance with - * provided @dflags. - * - * In case of error an ERR_PTR() is returned. - */ -struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode, - const char *propname, int index, - enum gpiod_flags dflags, - const char *label) +static struct gpio_desc * +software_node_get_gpiod(struct fwnode_handle *fwnode, + const char *propname, int index, unsigned long *flags) +{ + struct device *dev; + const char *con_id; + + dev = software_node_get_linked_device(fwnode); + if (IS_ERR_OR_NULL(dev)) + return ERR_PTR(-EINVAL); + + if (fwnode_property_read_string(fwnode, propname, &con_id)) { + /* + * We could not find string mapping property name to + * entry in gpio lookup table. Let's see if we are + * dealing with firmware node corresponding to the + * device (and not a child node): for such nodes we can + * try doing lookup directly with property name. + */ + if (fwnode_get_parent(fwnode)) + return ERR_PTR(-ENOENT); + + con_id = propname; + } + + return gpiod_find(dev, con_id, index, flags); +} + +static struct gpio_desc *__fwnode_get_named_gpiod(struct fwnode_handle *fwnode, + const char *propname, + int index, + enum gpiod_flags dflags, + const char *label) { unsigned long lflags = GPIO_LOOKUP_FLAGS_DEFAULT; struct gpio_desc *desc = ERR_PTR(-ENODEV); int ret; - if (!fwnode) - return ERR_PTR(-EINVAL); - if (is_of_node(fwnode)) { desc = gpiod_get_from_of_node(to_of_node(fwnode), propname, index, @@ -4355,9 +4360,13 @@ struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode, acpi_gpio_update_gpiod_flags(&dflags, &info); acpi_gpio_update_gpiod_lookup_flags(&lflags, &info); + } else if (is_software_node(fwnode)) { + desc = software_node_get_gpiod(fwnode, propname, index, + &lflags); + if (IS_ERR(desc)) + return desc; } - /* Currently only ACPI takes this path */ ret = gpiod_request(desc, label); if (ret) return ERR_PTR(ret); @@ -4370,6 +4379,47 @@ struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode, return desc; } + +/** + * fwnode_get_named_gpiod - obtain a GPIO from firmware node + * @fwnode: handle of the firmware node + * @propname: name of the firmware property representing the GPIO + * @index: index of the GPIO to obtain for the consumer + * @dflags: GPIO initialization flags + * @label: label to attach to the requested GPIO + * + * This function can be used for drivers that get their configuration + * from opaque firmware. + * + * The function properly finds the corresponding GPIO using whatever is the + * underlying firmware interface and then makes sure that the GPIO + * descriptor is requested before it is returned to the caller. + * + * Returns: + * On successful request the GPIO pin is configured in accordance with + * provided @dflags. + * + * In case of error an ERR_PTR() is returned. + */ +struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode, + const char *propname, int index, + enum gpiod_flags dflags, + const char *label) +{ + struct gpio_desc *desc; + + if (!fwnode) + return ERR_PTR(-EINVAL); + + desc = __fwnode_get_named_gpiod(fwnode, propname, index, dflags, label); + if (IS_ERR(desc) && PTR_ERR(desc) == -ENOENT && + !IS_ERR_OR_NULL(fwnode->secondary)) { + desc = __fwnode_get_named_gpiod(fwnode->secondary, + propname, index, dflags, label); + } + + return desc; +} EXPORT_SYMBOL_GPL(fwnode_get_named_gpiod); /**
Now that static device properties understand notion of child nodes, let's teach gpiolib to tie such children and machine GPIO descriptor tables. We will continue using a single table for entire device, but instead of using connection ID as a lookup key in the GPIO descriptor table directly, we will perform additional translation: fwnode_get_named_gpiod() when dealing with property_set-backed fwnodes will try parsing string property with name matching connection ID and use result of the lookup as the key in the table: static const struct property_entry dev_child1_props[] __initconst = { ... PROPERTY_ENTRY_STRING("gpios", "child-1-gpios"), { } }; static struct gpiod_lookup_table dev_gpiod_table = { .dev_id = "some-device", .table = { ... GPIO_LOOKUP_IDX("B", 1, "child-1-gpios", 1, GPIO_ACTIVE_LOW), ... }, }; Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> --- drivers/gpio/gpiolib.c | 108 ++++++++++++++++++++++++++++++----------- 1 file changed, 79 insertions(+), 29 deletions(-)