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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Cobalt/SEAD3 LCD frame buffer driver.
*
* Copyright (C) 2008 Yoichi Yuasa <yuasa@linux-mips.org>
* Copyright (C) 2012 MIPS Technologies, Inc.
*/
#include <linux/delay.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/uaccess.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/sched/signal.h>
/*
* Cursor position address
* \X 0 1 2 ... 14 15
* Y+----+----+----+---+----+----+
* 0|0x00|0x01|0x02|...|0x0e|0x0f|
* +----+----+----+---+----+----+
* 1|0x40|0x41|0x42|...|0x4e|0x4f|
* +----+----+----+---+----+----+
*/
#define LCD_DATA_REG_OFFSET 0x10
#define LCD_XRES_MAX 16
#define LCD_YRES_MAX 2
#define LCD_CHARS_MAX 32
#define LCD_CLEAR 0x01
#define LCD_CURSOR_MOVE_HOME 0x02
#define LCD_RESET 0x06
#define LCD_OFF 0x08
#define LCD_CURSOR_OFF 0x0c
#define LCD_CURSOR_BLINK_OFF 0x0e
#define LCD_CURSOR_ON 0x0f
#define LCD_ON LCD_CURSOR_ON
#define LCD_CURSOR_MOVE_LEFT 0x10
#define LCD_CURSOR_MOVE_RIGHT 0x14
#define LCD_DISPLAY_LEFT 0x18
#define LCD_DISPLAY_RIGHT 0x1c
#define LCD_PRERESET 0x3f /* execute 4 times continuously */
#define LCD_BUSY 0x80
#define LCD_GRAPHIC_MODE 0x40
#define LCD_TEXT_MODE 0x80
#define LCD_CUR_POS_MASK 0x7f
#define LCD_CUR_POS(x) ((x) & LCD_CUR_POS_MASK)
#define LCD_TEXT_POS(x) ((x) | LCD_TEXT_MODE)
static inline void lcd_write_control(struct fb_info *info, u8 control)
{
writel((u32)control << 24, info->screen_base);
}
static inline u8 lcd_read_control(struct fb_info *info)
{
return readl(info->screen_base) >> 24;
}
static inline void lcd_write_data(struct fb_info *info, u8 data)
{
writel((u32)data << 24, info->screen_base + LCD_DATA_REG_OFFSET);
}
static inline u8 lcd_read_data(struct fb_info *info)
{
return readl(info->screen_base + LCD_DATA_REG_OFFSET) >> 24;
}
static int lcd_busy_wait(struct fb_info *info)
{
u8 val = 0;
int timeout = 10, retval = 0;
do {
val = lcd_read_control(info);
val &= LCD_BUSY;
if (val != LCD_BUSY)
break;
if (msleep_interruptible(1))
return -EINTR;
timeout--;
} while (timeout);
if (val == LCD_BUSY)
retval = -EBUSY;
return retval;
}
static void lcd_clear(struct fb_info *info)
{
int i;
for (i = 0; i < 4; i++) {
udelay(150);
lcd_write_control(info, LCD_PRERESET);
}
udelay(150);
lcd_write_control(info, LCD_CLEAR);
udelay(150);
lcd_write_control(info, LCD_RESET);
}
static const struct fb_fix_screeninfo cobalt_lcdfb_fix = {
.id = "cobalt-lcd",
.type = FB_TYPE_TEXT,
.type_aux = FB_AUX_TEXT_MDA,
.visual = FB_VISUAL_MONO01,
.line_length = LCD_XRES_MAX,
.accel = FB_ACCEL_NONE,
};
static ssize_t cobalt_lcdfb_read(struct fb_info *info, char __user *buf,
size_t count, loff_t *ppos)
{
char src[LCD_CHARS_MAX];
unsigned long pos;
int len, retval = 0;
pos = *ppos;
if (pos >= LCD_CHARS_MAX || count == 0)
return 0;
if (count > LCD_CHARS_MAX)
count = LCD_CHARS_MAX;
if (pos + count > LCD_CHARS_MAX)
count = LCD_CHARS_MAX - pos;
for (len = 0; len < count; len++) {
retval = lcd_busy_wait(info);
if (retval < 0)
break;
lcd_write_control(info, LCD_TEXT_POS(pos));
retval = lcd_busy_wait(info);
if (retval < 0)
break;
src[len] = lcd_read_data(info);
if (pos == 0x0f)
pos = 0x40;
else
pos++;
}
if (retval < 0 && signal_pending(current))
return -ERESTARTSYS;
if (copy_to_user(buf, src, len))
return -EFAULT;
*ppos += len;
return len;
}
static ssize_t cobalt_lcdfb_write(struct fb_info *info, const char __user *buf,
size_t count, loff_t *ppos)
{
char dst[LCD_CHARS_MAX];
unsigned long pos;
int len, retval = 0;
pos = *ppos;
if (pos >= LCD_CHARS_MAX || count == 0)
return 0;
if (count > LCD_CHARS_MAX)
count = LCD_CHARS_MAX;
if (pos + count > LCD_CHARS_MAX)
count = LCD_CHARS_MAX - pos;
if (copy_from_user(dst, buf, count))
return -EFAULT;
for (len = 0; len < count; len++) {
retval = lcd_busy_wait(info);
if (retval < 0)
break;
lcd_write_control(info, LCD_TEXT_POS(pos));
retval = lcd_busy_wait(info);
if (retval < 0)
break;
lcd_write_data(info, dst[len]);
if (pos == 0x0f)
pos = 0x40;
else
pos++;
}
if (retval < 0 && signal_pending(current))
return -ERESTARTSYS;
*ppos += len;
return len;
}
static int cobalt_lcdfb_blank(int blank_mode, struct fb_info *info)
{
int retval;
retval = lcd_busy_wait(info);
if (retval < 0)
return retval;
switch (blank_mode) {
case FB_BLANK_UNBLANK:
lcd_write_control(info, LCD_ON);
break;
default:
lcd_write_control(info, LCD_OFF);
break;
}
return 0;
}
static int cobalt_lcdfb_cursor(struct fb_info *info, struct fb_cursor *cursor)
{
u32 x, y;
int retval;
switch (cursor->set) {
case FB_CUR_SETPOS:
x = cursor->image.dx;
y = cursor->image.dy;
if (x >= LCD_XRES_MAX || y >= LCD_YRES_MAX)
return -EINVAL;
retval = lcd_busy_wait(info);
if (retval < 0)
return retval;
lcd_write_control(info,
LCD_TEXT_POS(info->fix.line_length * y + x));
break;
default:
return -EINVAL;
}
retval = lcd_busy_wait(info);
if (retval < 0)
return retval;
if (cursor->enable)
lcd_write_control(info, LCD_CURSOR_ON);
else
lcd_write_control(info, LCD_CURSOR_OFF);
return 0;
}
static const struct fb_ops cobalt_lcd_fbops = {
.owner = THIS_MODULE,
.fb_read = cobalt_lcdfb_read,
.fb_write = cobalt_lcdfb_write,
.fb_blank = cobalt_lcdfb_blank,
.fb_cursor = cobalt_lcdfb_cursor,
};
static int cobalt_lcdfb_probe(struct platform_device *dev)
{
struct fb_info *info;
struct resource *res;
int retval;
info = framebuffer_alloc(0, &dev->dev);
if (!info)
return -ENOMEM;
res = platform_get_resource(dev, IORESOURCE_MEM, 0);
if (!res) {
framebuffer_release(info);
return -EBUSY;
}
info->screen_size = resource_size(res);
info->screen_base = devm_ioremap(&dev->dev, res->start,
info->screen_size);
if (!info->screen_base) {
framebuffer_release(info);
return -ENOMEM;
}
info->fbops = &cobalt_lcd_fbops;
info->fix = cobalt_lcdfb_fix;
info->fix.smem_start = res->start;
info->fix.smem_len = info->screen_size;
info->pseudo_palette = NULL;
info->par = NULL;
info->flags = FBINFO_DEFAULT;
retval = register_framebuffer(info);
if (retval < 0) {
framebuffer_release(info);
return retval;
}
platform_set_drvdata(dev, info);
lcd_clear(info);
fb_info(info, "Cobalt server LCD frame buffer device\n");
return 0;
}
static int cobalt_lcdfb_remove(struct platform_device *dev)
{
struct fb_info *info;
info = platform_get_drvdata(dev);
if (info) {
unregister_framebuffer(info);
framebuffer_release(info);
}
return 0;
}
static struct platform_driver cobalt_lcdfb_driver = {
.probe = cobalt_lcdfb_probe,
.remove = cobalt_lcdfb_remove,
.driver = {
.name = "cobalt-lcd",
},
};
module_platform_driver(cobalt_lcdfb_driver);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Yoichi Yuasa");
MODULE_DESCRIPTION("Cobalt server LCD frame buffer driver");
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