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Optimize lcd-ssd1303 driver (clip series)

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Saves 100+ bytes (50 of it in iram), saves a bit of power

Internal LCD clock decreased but with added efficiency of drawing routines
loses only around 2 Hz on the scanrate (~75Hz) while fps is slightly increased

Column offsets are now calculated outside the loops saving a few instructions

Passing a LCD_NOP command after lcd_update turns off Data/Cmd# gpio
saving a bit more power

Added a function lcd_write_cmd_triple() that allows 3 commands to be sent at once
when enabled with LCD_USE_FIFO_FOR_COMMANDS it sends them back to back without
checking FIFO status in between or sending to thhe D/C# Gpio.
Makes an assumption about the FIFO being large enough to
accept 3 commands after being emptied which should be the case on the
clipv1, clipv2, clipplus. I have only enabled it for the clip plus
as thats the only device I have to test it on.

On clip+ the SSP clock is now turned off when screen is off

Change-Id: Ib5fd24697bfe4ac8b8ee017361e789e4a7910d21
This commit is contained in:
William Wilgus 2017-12-14 06:22:04 +01:00
parent 056d4b0ec0
commit dcd71e66bd
5 changed files with 224 additions and 78 deletions
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32
firmware/target/arm/as3525/sansa-clipplus/lcd-clip-plus.c
View file

@ -64,6 +64,31 @@ void lcd_write_command(int byte)
;
}
void lcd_write_cmd_triplet(int cmd1, int cmd2, int cmd3)
{
#ifndef LCD_USE_FIFO_FOR_COMMANDS
lcd_write_command(cmd1);
lcd_write_command(cmd2);
lcd_write_command(cmd3);
#else
/* combine writes to data register */
while(SSP_SR & (1<<4)) /* BSY flag */
;
/* FIFO is empty at this point */
/* LCD command mode */
GPIOB_PIN(2) = 0;
/* !!makes assumption FIFO is at least (3) levels deep!! */
SSP_DATA = cmd1;
SSP_DATA = cmd2;
SSP_DATA = cmd3;
while(SSP_SR & (1<<4)) /* BSY flag */
;
#endif
}
void lcd_write_data(const fb_data* p_bytes, int count)
{
/* LCD data mode */
@ -80,6 +105,13 @@ void lcd_write_data(const fb_data* p_bytes, int count)
void lcd_enable_power(bool onoff)
{
#ifndef BOOTLOADER
if (onoff)
bitset32(&CGU_PERI, CGU_SSP_CLOCK_ENABLE);
else
bitclr32(&CGU_PERI, CGU_SSP_CLOCK_ENABLE);
#else
(void) onoff;
#endif
}