From: Geert Uytterhoeven <geert+renesas@glider.be>
To: Linus Walleij <linus.walleij@linaro.org>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
Jonathan Corbet <corbet@lwn.net>,
Harish Jenny K N <harish_kandiga@mentor.com>,
Eugeniu Rosca <erosca@de.adit-jv.com>
Cc: Alexander Graf <graf@amazon.com>,
Peter Maydell <peter.maydell@linaro.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Phil Reid <preid@electromag.com.au>,
Marc Zyngier <marc.zyngier@arm.com>,
Christoffer Dall <christoffer.dall@arm.com>,
Magnus Damm <magnus.damm@gmail.com>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
linux-gpio@vger.kernel.org, linux-doc@vger.kernel.org,
linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org,
qemu-devel@nongnu.org,
Geert Uytterhoeven <geert+renesas@glider.be>
Subject: [PATCH v6 4/8] gpiolib: Add support for GPIO lookup by line name
Date: Tue, 24 Mar 2020 14:56:49 +0100 [thread overview]
Message-ID: <20200324135653.6676-4-geert+renesas@glider.be> (raw)
In-Reply-To: <20200324135653.6676-1-geert+renesas@glider.be>
Currently a GPIO lookup table can only refer to a specific GPIO by a
tuple, consisting of a GPIO controller label and a GPIO offset inside
the controller.
However, a GPIO may also carry a line name, defined by DT or ACPI.
If present, the line name is the most use-centric way to refer to a
GPIO. Hence add support for looking up GPIOs by line name.
Implement this by reusing the existing gpiod_lookup infrastructure.
Rename gpiod_lookup.chip_label to gpiod_lookup.key, to make it clear
that this field can have two meanings, and update the kerneldoc and
GPIO_LOOKUP*() macros.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Ulrich Hecht <uli+renesas@fpond.eu>
Reviewed-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Tested-by: Eugeniu Rosca <erosca@de.adit-jv.com>
---
v6:
- Update Documentation/driver-api/gpio/board.rst,
- Reword rationale,
v5:
- Add Reviewed-by, Tested-by,
v4:
- Add Reviewed-by,
- Rename gpiod_lookup.chip_label.
- Use U16_MAX instead of (u16)-1,
v3:
- New.
---
Documentation/driver-api/gpio/board.rst | 10 ++++++----
drivers/gpio/gpiolib.c | 22 +++++++++++++++++-----
include/linux/gpio/machine.h | 15 ++++++++-------
3 files changed, 31 insertions(+), 16 deletions(-)
diff --git a/Documentation/driver-api/gpio/board.rst b/Documentation/driver-api/gpio/board.rst
index ce91518bf9f48ded..0ad1f8cacf5e5d26 100644
--- a/Documentation/driver-api/gpio/board.rst
+++ b/Documentation/driver-api/gpio/board.rst
@@ -113,13 +113,15 @@ files that desire to do so need to include the following header::
GPIOs are mapped by the means of tables of lookups, containing instances of the
gpiod_lookup structure. Two macros are defined to help declaring such mappings::
- GPIO_LOOKUP(chip_label, chip_hwnum, con_id, flags)
- GPIO_LOOKUP_IDX(chip_label, chip_hwnum, con_id, idx, flags)
+ GPIO_LOOKUP(key, chip_hwnum, con_id, flags)
+ GPIO_LOOKUP_IDX(key, chip_hwnum, con_id, idx, flags)
where
- - chip_label is the label of the gpiod_chip instance providing the GPIO
- - chip_hwnum is the hardware number of the GPIO within the chip
+ - key is either the label of the gpiod_chip instance providing the GPIO, or
+ the GPIO line name
+ - chip_hwnum is the hardware number of the GPIO within the chip, or U16_MAX
+ to indicate that key is a GPIO line name
- con_id is the name of the GPIO function from the device point of view. It
can be NULL, in which case it will match any function.
- idx is the index of the GPIO within the function.
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 8d7366f4451fe695..c756602e249c052e 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -4643,7 +4643,7 @@ static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
if (!table)
return desc;
- for (p = &table->table[0]; p->chip_label; p++) {
+ for (p = &table->table[0]; p->key; p++) {
struct gpio_chip *chip;
/* idx must always match exactly */
@@ -4654,18 +4654,30 @@ static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
if (p->con_id && (!con_id || strcmp(p->con_id, con_id)))
continue;
- chip = find_chip_by_name(p->chip_label);
+ if (p->chip_hwnum == U16_MAX) {
+ desc = gpio_name_to_desc(p->key);
+ if (desc) {
+ *flags = p->flags;
+ return desc;
+ }
+
+ dev_warn(dev, "cannot find GPIO line %s, deferring\n",
+ p->key);
+ return ERR_PTR(-EPROBE_DEFER);
+ }
+
+ chip = find_chip_by_name(p->key);
if (!chip) {
/*
* As the lookup table indicates a chip with
- * p->chip_label should exist, assume it may
+ * p->key should exist, assume it may
* still appear later and let the interested
* consumer be probed again or let the Deferred
* Probe infrastructure handle the error.
*/
dev_warn(dev, "cannot find GPIO chip %s, deferring\n",
- p->chip_label);
+ p->key);
return ERR_PTR(-EPROBE_DEFER);
}
@@ -4696,7 +4708,7 @@ static int platform_gpio_count(struct device *dev, const char *con_id)
if (!table)
return -ENOENT;
- for (p = &table->table[0]; p->chip_label; p++) {
+ for (p = &table->table[0]; p->key; p++) {
if ((con_id && p->con_id && !strcmp(con_id, p->con_id)) ||
(!con_id && !p->con_id))
count++;
diff --git a/include/linux/gpio/machine.h b/include/linux/gpio/machine.h
index 1ebe5be05d5f81fa..84c66fbf54fd5811 100644
--- a/include/linux/gpio/machine.h
+++ b/include/linux/gpio/machine.h
@@ -20,8 +20,9 @@ enum gpio_lookup_flags {
/**
* struct gpiod_lookup - lookup table
- * @chip_label: name of the chip the GPIO belongs to
- * @chip_hwnum: hardware number (i.e. relative to the chip) of the GPIO
+ * @key: either the name of the chip the GPIO belongs to, or the GPIO line name
+ * @chip_hwnum: hardware number (i.e. relative to the chip) of the GPIO, or
+ * U16_MAX to indicate that @key is a GPIO line name
* @con_id: name of the GPIO from the device's point of view
* @idx: index of the GPIO in case several GPIOs share the same name
* @flags: bitmask of gpio_lookup_flags GPIO_* values
@@ -30,7 +31,7 @@ enum gpio_lookup_flags {
* functions using platform data.
*/
struct gpiod_lookup {
- const char *chip_label;
+ const char *key;
u16 chip_hwnum;
const char *con_id;
unsigned int idx;
@@ -63,17 +64,17 @@ struct gpiod_hog {
/*
* Simple definition of a single GPIO under a con_id
*/
-#define GPIO_LOOKUP(_chip_label, _chip_hwnum, _con_id, _flags) \
- GPIO_LOOKUP_IDX(_chip_label, _chip_hwnum, _con_id, 0, _flags)
+#define GPIO_LOOKUP(_key, _chip_hwnum, _con_id, _flags) \
+ GPIO_LOOKUP_IDX(_key, _chip_hwnum, _con_id, 0, _flags)
/*
* Use this macro if you need to have several GPIOs under the same con_id.
* Each GPIO needs to use a different index and can be accessed using
* gpiod_get_index()
*/
-#define GPIO_LOOKUP_IDX(_chip_label, _chip_hwnum, _con_id, _idx, _flags) \
+#define GPIO_LOOKUP_IDX(_key, _chip_hwnum, _con_id, _idx, _flags) \
{ \
- .chip_label = _chip_label, \
+ .key = _key, \
.chip_hwnum = _chip_hwnum, \
.con_id = _con_id, \
.idx = _idx, \
--
2.17.1
next prev parent reply other threads:[~2020-03-24 13:57 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-24 13:53 [PATCH v6 0/8] gpio: Add GPIO Aggregator Geert Uytterhoeven
2020-03-24 13:56 ` [PATCH v6 1/8] ARM: integrator: impd1: Use GPIO_LOOKUP() helper macro Geert Uytterhoeven
2020-03-24 13:56 ` [PATCH v6 2/8] i2c: i801: " Geert Uytterhoeven
2020-03-25 9:14 ` Jean Delvare
2020-04-15 10:57 ` Wolfram Sang
2020-03-24 13:56 ` [PATCH v6 3/8] mfd: sm501: Use GPIO_LOOKUP_IDX() " Geert Uytterhoeven
2020-04-15 9:25 ` Lee Jones
2020-03-24 13:56 ` Geert Uytterhoeven [this message]
2020-03-26 21:18 ` [PATCH v6 4/8] gpiolib: Add support for GPIO lookup by line name Linus Walleij
2020-05-11 10:18 ` Geert Uytterhoeven
2020-03-24 13:56 ` [PATCH v6 5/8] gpiolib: Introduce gpiod_set_config() Geert Uytterhoeven
2020-03-26 21:26 ` Linus Walleij
2020-03-27 8:45 ` Geert Uytterhoeven
2020-03-27 21:33 ` Linus Walleij
2020-03-27 21:37 ` Linus Walleij
2020-03-24 13:56 ` [PATCH v6 6/8] gpio: Add GPIO Aggregator Geert Uytterhoeven
2020-03-24 13:56 ` [PATCH v6 7/8] docs: gpio: Add GPIO Aggregator documentation Geert Uytterhoeven
2020-03-24 13:56 ` [PATCH v6 8/8] MAINTAINERS: Add GPIO Aggregator section Geert Uytterhoeven
2020-03-26 21:07 ` [PATCH v6 1/8] ARM: integrator: impd1: Use GPIO_LOOKUP() helper macro Linus Walleij
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200324135653.6676-4-geert+renesas@glider.be \
--to=geert+renesas@glider.be \
--cc=bgolaszewski@baylibre.com \
--cc=christoffer.dall@arm.com \
--cc=corbet@lwn.net \
--cc=erosca@de.adit-jv.com \
--cc=graf@amazon.com \
--cc=harish_kandiga@mentor.com \
--cc=linus.walleij@linaro.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-gpio@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-renesas-soc@vger.kernel.org \
--cc=magnus.damm@gmail.com \
--cc=marc.zyngier@arm.com \
--cc=mark.rutland@arm.com \
--cc=pbonzini@redhat.com \
--cc=peter.maydell@linaro.org \
--cc=preid@electromag.com.au \
--cc=qemu-devel@nongnu.org \
--cc=robh+dt@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).