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alistair23-linux/drivers/video/fbdev/cobalt_lcdfb.c
Jani Nikula 8a48ac3393 video: constify fb ops across all drivers 
Now that the fbops member of struct fb_info is const, we can start
making the ops const as well.

This does not cover all drivers; some actually modify the fbops struct,
for example to adjust for different configurations, and others do more
involved things that I'd rather not touch in practically obsolete
drivers. Mostly this is the low hanging fruit where we can add "const"
and be done with it.

v3:
- un-constify atyfb, mb862xx, nvidia and uvesabf (0day)

v2:
- fix typo (Christophe de Dinechin)
- use "static const" instead of "const static" in mx3fb.c
- also constify smscufx.c

Cc: linux-fbdev@vger.kernel.org
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/ce67f14435f3af498f2e8bf35ce4be11f7504132.1575390740.git.jani.nikula@intel.com
2019-12-05 10:57:53 +02:00

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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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