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Message-ID: <20250630130358.40352-1-brgl@bgdev.pl>
Date: Mon, 30 Jun 2025 15:03:57 +0200
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Kent Gibson <warthog618@...il.com>,
Linus Walleij <linus.walleij@...aro.org>,
Jonathan Corbet <corbet@....net>
Cc: linux-gpio@...r.kernel.org,
linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org,
Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: [PATCH] gpio: sim: allow to mark simulated lines as invalid
From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Add a new line-level, boolean property to the gpio-sim configfs
interface called 'valid'. It's set by default and the user can unset it
to make the line be included in the standard `gpio-reserved-ranges`
property when the chip is registered with GPIO core. This allows users
to specify which lines should not be available for requesting as GPIOs.
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
---
Documentation/admin-guide/gpio/gpio-sim.rst | 7 +-
drivers/gpio/gpio-sim.c | 83 ++++++++++++++++++++-
2 files changed, 86 insertions(+), 4 deletions(-)
diff --git a/Documentation/admin-guide/gpio/gpio-sim.rst b/Documentation/admin-guide/gpio/gpio-sim.rst
index 35d49ccd49e0..f5135a14ef2e 100644
--- a/Documentation/admin-guide/gpio/gpio-sim.rst
+++ b/Documentation/admin-guide/gpio/gpio-sim.rst
@@ -50,8 +50,11 @@ the number of lines exposed by this bank.
**Attribute:** ``/config/gpio-sim/gpio-device/gpio-bankX/lineY/name``
-This group represents a single line at the offset Y. The 'name' attribute
-allows to set the line name as represented by the 'gpio-line-names' property.
+**Attribute:** ``/config/gpio-sim/gpio-device/gpio-bankX/lineY/valid``
+
+This group represents a single line at the offset Y. The ``valid`` attribute
+indicates whether the line can be used as GPIO. The ``name`` attribute allows
+to set the line name as represented by the 'gpio-line-names' property.
**Item:** ``/config/gpio-sim/gpio-device/gpio-bankX/lineY/hog``
diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c
index f638219a7c4f..9503296422fd 100644
--- a/drivers/gpio/gpio-sim.c
+++ b/drivers/gpio/gpio-sim.c
@@ -39,7 +39,7 @@
#include "dev-sync-probe.h"
#define GPIO_SIM_NGPIO_MAX 1024
-#define GPIO_SIM_PROP_MAX 4 /* Max 3 properties + sentinel. */
+#define GPIO_SIM_PROP_MAX 5 /* Max 4 properties + sentinel. */
#define GPIO_SIM_NUM_ATTRS 3 /* value, pull and sentinel */
static DEFINE_IDA(gpio_sim_ida);
@@ -629,6 +629,7 @@ struct gpio_sim_line {
unsigned int offset;
char *name;
+ bool valid;
/* There can only be one hog per line. */
struct gpio_sim_hog *hog;
@@ -744,6 +745,36 @@ gpio_sim_set_line_names(struct gpio_sim_bank *bank, char **line_names)
}
}
+static unsigned int gpio_sim_get_reserved_ranges_size(struct gpio_sim_bank *bank)
+{
+ struct gpio_sim_line *line;
+ unsigned int size = 0;
+
+ list_for_each_entry(line, &bank->line_list, siblings) {
+ if (line->valid)
+ continue;
+
+ size += 2;
+ }
+
+ return size;
+}
+
+static void gpio_sim_set_reserved_ranges(struct gpio_sim_bank *bank,
+ u32 *ranges)
+{
+ struct gpio_sim_line *line;
+ int i = 0;
+
+ list_for_each_entry(line, &bank->line_list, siblings) {
+ if (line->valid)
+ continue;
+
+ ranges[i++] = line->offset;
+ ranges[i++] = 1;
+ }
+}
+
static void gpio_sim_remove_hogs(struct gpio_sim_device *dev)
{
struct gpiod_hog *hog;
@@ -844,9 +875,10 @@ static struct fwnode_handle *
gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
struct fwnode_handle *parent)
{
+ unsigned int prop_idx = 0, line_names_size, ranges_size;
struct property_entry properties[GPIO_SIM_PROP_MAX];
- unsigned int prop_idx = 0, line_names_size;
char **line_names __free(kfree) = NULL;
+ u32 *ranges __free(kfree) = NULL;
memset(properties, 0, sizeof(properties));
@@ -870,6 +902,19 @@ gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
line_names, line_names_size);
}
+ ranges_size = gpio_sim_get_reserved_ranges_size(bank);
+ if (ranges_size) {
+ ranges = kcalloc(ranges_size, sizeof(u32), GFP_KERNEL);
+ if (!ranges)
+ return ERR_PTR(-ENOMEM);
+
+ gpio_sim_set_reserved_ranges(bank, ranges);
+
+ properties[prop_idx++] = PROPERTY_ENTRY_U32_ARRAY_LEN(
+ "gpio-reserved-ranges",
+ ranges, ranges_size);
+ }
+
return fwnode_create_software_node(properties, parent);
}
@@ -1189,8 +1234,41 @@ static ssize_t gpio_sim_line_config_name_store(struct config_item *item,
CONFIGFS_ATTR(gpio_sim_line_config_, name);
+static ssize_t
+gpio_sim_line_config_valid_show(struct config_item *item, char *page)
+{
+ struct gpio_sim_line *line = to_gpio_sim_line(item);
+ struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
+
+ guard(mutex)(&dev->lock);
+
+ return sprintf(page, "%c\n", line->valid ? '1' : '0');
+}
+
+static ssize_t gpio_sim_line_config_valid_store(struct config_item *item,
+ const char *page, size_t count)
+{
+ struct gpio_sim_line *line = to_gpio_sim_line(item);
+ struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
+ bool valid;
+ int ret;
+
+ ret = kstrtobool(page, &valid);
+ if (ret)
+ return ret;
+
+ guard(mutex)(&dev->lock);
+
+ line->valid = valid;
+
+ return count;
+}
+
+CONFIGFS_ATTR(gpio_sim_line_config_, valid);
+
static struct configfs_attribute *gpio_sim_line_config_attrs[] = {
&gpio_sim_line_config_attr_name,
+ &gpio_sim_line_config_attr_valid,
NULL
};
@@ -1399,6 +1477,7 @@ gpio_sim_bank_config_make_line_group(struct config_group *group,
line->parent = bank;
line->offset = offset;
+ line->valid = true;
list_add_tail(&line->siblings, &bank->line_list);
return &line->group;
--
2.48.1
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