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misc: panel: Abstract temporary backlight handling

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Currently the periodic scan timer is used for three purposes,
entangling keypad and display handling, which are both optional:
  1. Scanning the keypad,
  2. Flashing the backlight when a key is pressed,
  3. Disabling temporary backlighting after a fixed period of time.

Abstract the second purpose using a new lcd_poke() function.
Make the non-periodic temporary backlight handling independent from
keypad handling by converting it to a delayed workqueue.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Geert Uytterhoeven 2017-02-06 15:38:10 +01:00 committed by Greg Kroah-Hartman
parent 204a4f6d67
commit fda4ae1819
1 changed files with 60 additions and 41 deletions
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101
drivers/misc/panel.c
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@ -56,6 +56,7 @@
#include <linux/list.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/workqueue.h>
#include <generated/utsrelease.h>
#include <linux/io.h>
@ -75,8 +76,8 @@
/* a key repeats this times INPUT_POLL_TIME */
#define KEYPAD_REP_DELAY (2)
/* keep the light on this times INPUT_POLL_TIME for each flash */
#define FLASH_LIGHT_TEMPO (200)
/* keep the light on this many seconds for each flash */
#define FLASH_LIGHT_TEMPO (4)
/* converts an r_str() input to an active high, bits string : 000BAOSE */
#define PNL_PINPUT(a) ((((unsigned char)(a)) ^ 0x7F) >> 3)
@ -252,7 +253,10 @@ static struct {
int hwidth;
int charset;
int proto;
int light_tempo;
struct delayed_work bl_work;
struct mutex bl_tempo_lock; /* Protects access to bl_tempo */
bool bl_tempo;
/* TODO: use union here? */
struct {
@ -657,8 +661,6 @@ static void lcd_get_bits(unsigned int port, int *val)
}
}
static void init_scan_timer(void);
/* sets data port bits according to current signals values */
static int set_data_bits(void)
{
@ -790,11 +792,8 @@ static void lcd_send_serial(int byte)
}
/* turn the backlight on or off */
static void lcd_backlight(int on)
static void __lcd_backlight(int on)
{
if (lcd.pins.bl == PIN_NONE)
return;
/* The backlight is activated by setting the AUTOFEED line to +5V */
spin_lock_irq(&pprt_lock);
if (on)
@ -805,6 +804,44 @@ static void lcd_backlight(int on)
spin_unlock_irq(&pprt_lock);
}
static void lcd_backlight(int on)
{
if (lcd.pins.bl == PIN_NONE)
return;
mutex_lock(&lcd.bl_tempo_lock);
if (!lcd.bl_tempo)
__lcd_backlight(on);
mutex_unlock(&lcd.bl_tempo_lock);
}
static void lcd_bl_off(struct work_struct *work)
{
mutex_lock(&lcd.bl_tempo_lock);
if (lcd.bl_tempo) {
lcd.bl_tempo = false;
if (!(lcd.flags & LCD_FLAG_L))
__lcd_backlight(0);
}
mutex_unlock(&lcd.bl_tempo_lock);
}
/* turn the backlight on for a little while */
static void lcd_poke(void)
{
if (lcd.pins.bl == PIN_NONE)
return;
cancel_delayed_work_sync(&lcd.bl_work);
mutex_lock(&lcd.bl_tempo_lock);
if (!lcd.bl_tempo && !(lcd.flags & LCD_FLAG_L))
__lcd_backlight(1);
lcd.bl_tempo = true;
schedule_delayed_work(&lcd.bl_work, FLASH_LIGHT_TEMPO * HZ);
mutex_unlock(&lcd.bl_tempo_lock);
}
/* send a command to the LCD panel in serial mode */
static void lcd_write_cmd_s(int cmd)
{
@ -1099,13 +1136,8 @@ static inline int handle_lcd_special_code(void)
processed = 1;
break;
case '*':
/* flash back light using the keypad timer */
if (scan_timer.function) {
if (lcd.light_tempo == 0 &&
((lcd.flags & LCD_FLAG_L) == 0))
lcd_backlight(1);
lcd.light_tempo = FLASH_LIGHT_TEMPO;
}
/* flash back light */
lcd_poke();
processed = 1;
break;
case 'f': /* Small Font */
@ -1275,16 +1307,8 @@ static inline int handle_lcd_special_code(void)
? LCD_CMD_TWO_LINES
: 0));
/* check whether L flag was changed */
else if ((oldflags ^ lcd.flags) & (LCD_FLAG_L)) {
if (lcd.flags & (LCD_FLAG_L))
lcd_backlight(1);
else if (lcd.light_tempo == 0)
/*
* switch off the light only when the tempo
* lighting is gone
*/
lcd_backlight(0);
}
else if ((oldflags ^ lcd.flags) & (LCD_FLAG_L))
lcd_backlight(!!(lcd.flags & LCD_FLAG_L));
}
return processed;
@ -1615,8 +1639,10 @@ static void lcd_init(void)
else
lcd_char_conv = NULL;
if (lcd.pins.bl != PIN_NONE)
init_scan_timer();
if (lcd.pins.bl != PIN_NONE) {
mutex_init(&lcd.bl_tempo_lock);
INIT_DELAYED_WORK(&lcd.bl_work, lcd_bl_off);
}
pin_to_bits(lcd.pins.e, lcd_bits[LCD_PORT_D][LCD_BIT_E],
lcd_bits[LCD_PORT_C][LCD_BIT_E]);
@ -1984,19 +2010,8 @@ static void panel_scan_timer(void)
panel_process_inputs();
}
if (lcd.enabled && lcd.initialized) {
if (keypressed) {
if (lcd.light_tempo == 0 &&
((lcd.flags & LCD_FLAG_L) == 0))
lcd_backlight(1);
lcd.light_tempo = FLASH_LIGHT_TEMPO;
} else if (lcd.light_tempo > 0) {
lcd.light_tempo--;
if (lcd.light_tempo == 0 &&
((lcd.flags & LCD_FLAG_L) == 0))
lcd_backlight(0);
}
}
if (keypressed && lcd.enabled && lcd.initialized)
lcd_poke();
mod_timer(&scan_timer, jiffies + INPUT_POLL_TIME);
}
@ -2265,6 +2280,10 @@ static void panel_detach(struct parport *port)
if (lcd.enabled) {
panel_lcd_print("\x0cLCD driver unloaded.\x1b[Lc\x1b[Lb\x1b[L-");
misc_deregister(&lcd_dev);
if (lcd.pins.bl != PIN_NONE) {
cancel_delayed_work_sync(&lcd.bl_work);
__lcd_backlight(0);
}
lcd.initialized = false;
}