[PATCH v1 09/15] auxdisplay: linedisp: Add support for overriding character mapping

Andy Shevchenko
2024-02-08T18:49:34Z

There is already the driver using character mapping table for
7 or 14 segment display. It is possible to override it. Make
the similar in the line display library to allow other drivers
to utilise the same functionality.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
drivers/auxdisplay/line-display.c | 111 +++++++++++++++++++++++++++++-
drivers/auxdisplay/line-display.h | 31 +++++++++
2 files changed, 140 insertions(+), 2 deletions(-)

diff --git a/drivers/auxdisplay/line-display.c b/drivers/auxdisplay/line-display.c
index 62e8a911bb12..da47fc59f6cb 100644
--- a/drivers/auxdisplay/line-display.c
+++ b/drivers/auxdisplay/line-display.c
@@ -22,6 +22,9 @@
#include <linux/sysfs.h>
#include <linux/timer.h>

+#include <linux/map_to_7segment.h>
+#include <linux/map_to_14segment.h>
+
#include "line-display.h"

#define DEFAULT_SCROLL_RATE (HZ / 2)
@@ -188,12 +191,71 @@ static ssize_t scroll_step_ms_store(struct device *dev,

static DEVICE_ATTR_RW(scroll_step_ms);

+static ssize_t map_seg_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct linedisp *linedisp = container_of(dev, struct linedisp, dev);
+ struct linedisp_map *map = linedisp->map;
+
+ memcpy(buf, &map->map, map->size);
+ return map->size;
+}
+
+static ssize_t map_seg_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct linedisp *linedisp = container_of(dev, struct linedisp, dev);
+ struct linedisp_map *map = linedisp->map;
+
+ if (count != map->size)
+ return -EINVAL;
+
+ memcpy(&map->map, buf, count);
+ return count;
+}
+
+static const SEG7_DEFAULT_MAP(initial_map_seg7);
+static DEVICE_ATTR(map_seg7, 0644, map_seg_show, map_seg_store);
+
+static const SEG14_DEFAULT_MAP(initial_map_seg14);
+static DEVICE_ATTR(map_seg14, 0644, map_seg_show, map_seg_store);
+
static struct attribute *linedisp_attrs[] = {
&dev_attr_message.attr,
&dev_attr_scroll_step_ms.attr,
- NULL,
+ &dev_attr_map_seg7.attr,
+ &dev_attr_map_seg14.attr,
+ NULL
};
-ATTRIBUTE_GROUPS(linedisp);
+
+static umode_t linedisp_attr_is_visible(struct kobject *kobj, struct attribute *attr, int n)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ struct linedisp *linedisp = container_of(dev, struct linedisp, dev);
+ struct linedisp_map *map = linedisp->map;
+ umode_t mode = attr->mode;
+
+ if (attr == &dev_attr_map_seg7.attr) {
+ if (!map)
+ return 0;
+ if (map->type != LINEDISP_MAP_SEG7)
+ return 0;
+ }
+
+ if (attr == &dev_attr_map_seg14.attr) {
+ if (!map)
+ return 0;
+ if (map->type != LINEDISP_MAP_SEG14)
+ return 0;
+ }
+
+ return mode;
+};
+
+static const struct attribute_group linedisp_group = {
+ .is_visible = linedisp_attr_is_visible,
+ .attrs = linedisp_attrs,
+};
+__ATTRIBUTE_GROUPS(linedisp);

static DEFINE_IDA(linedisp_id);

@@ -201,6 +263,7 @@ static void linedisp_release(struct device *dev)
{
struct linedisp *linedisp = container_of(dev, struct linedisp, dev);

+ kfree(linedisp->map);
kfree(linedisp->message);
ida_free(&linedisp_id, linedisp->id);
}
@@ -210,6 +273,44 @@ static const struct device_type linedisp_type = {
.release = linedisp_release,
};

+static int linedisp_init_map(struct linedisp *linedisp)
+{
+ struct linedisp_map *map;
+ int err;
+
+ if (!linedisp->ops->get_map_type)
+ return 0;
+
+ err = linedisp->ops->get_map_type(linedisp);
+ if (err < 0)
+ return err;
+
+ map = kmalloc(sizeof(*map), GFP_KERNEL);
+ if (!map)
+ return -ENOMEM;
+
+ map->type = err;
+
+ /* assign initial mapping */
+ switch (map->type) {
+ case LINEDISP_MAP_SEG7:
+ map->map.seg7 = initial_map_seg7;
+ map->size = sizeof(map->map.seg7);
+ break;
+ case LINEDISP_MAP_SEG14:
+ map->map.seg14 = initial_map_seg14;
+ map->size = sizeof(map->map.seg14);
+ break;
+ default:
+ kfree(map);
+ return -EINVAL;
+ }
+
+ linedisp->map = map;
+
+ return 0;
+}
+
/**
* linedisp_register - register a character line display
* @linedisp: pointer to character line display structure
@@ -241,6 +342,11 @@ int linedisp_register(struct linedisp *linedisp, struct device *parent,
device_initialize(&linedisp->dev);
dev_set_name(&linedisp->dev, "linedisp.%u", linedisp->id);

+ /* initialise a character mapping, if required */
+ err = linedisp_init_map(linedisp);
+ if (err)
+ goto out_put_device;
+
/* initialise a timer for scrolling the message */
timer_setup(&linedisp->timer, linedisp_scroll, 0);

@@ -259,6 +365,7 @@ int linedisp_register(struct linedisp *linedisp, struct device *parent,
device_del(&linedisp->dev);
out_del_timer:
del_timer_sync(&linedisp->timer);
+out_put_device:
put_device(&linedisp->dev);
return err;
}
diff --git a/drivers/auxdisplay/line-display.h b/drivers/auxdisplay/line-display.h
index a4f0d1bf5848..65d782111f53 100644
--- a/drivers/auxdisplay/line-display.h
+++ b/drivers/auxdisplay/line-display.h
@@ -14,13 +14,43 @@
#include <linux/device.h>
#include <linux/timer_types.h>

+#include <linux/map_to_7segment.h>
+#include <linux/map_to_14segment.h>
+
struct linedisp;

+/**
+ * enum linedisp_map_type - type of the character mapping
+ * @LINEDISP_MAP_SEG7: Map characters to 7 segment display
+ * @LINEDISP_MAP_SEG14: Map characters to 14 segment display
+ */
+enum linedisp_map_type {
+ LINEDISP_MAP_SEG7,
+ LINEDISP_MAP_SEG14,
+};
+
+/**
+ * struct linedisp_map - character mapping
+ * @type: type of the character mapping
+ * @map: conversion character mapping
+ * @size: size of the @map
+ */
+struct linedisp_map {
+ enum linedisp_map_type type;
+ union {
+ struct seg7_conversion_map seg7;
+ struct seg14_conversion_map seg14;
+ } map;
+ unsigned int size;
+};
+
/**
* struct linedisp_ops - character line display operations
+ * @get_map_type: Function called to get the character mapping, if required
* @update: Function called to update the display. This must not sleep!
*/
struct linedisp_ops {
+ int (*get_map_type)(struct linedisp *linedisp);
void (*update)(struct linedisp *linedisp);
};

@@ -42,6 +72,7 @@ struct linedisp {
unsigned int id;
struct timer_list timer;
const struct linedisp_ops *ops;
+ struct linedisp_map *map;
char *buf;
char *message;
unsigned int num_chars;
--
2.43.0.rc1.1.gbec44491f096