As3525 v1/v2 Add power savings menu

Allow user to select cpu undervolt

There have been quite a few issues across the SANSA AMS line related
to CPU undervolting while most players show greatly increased runtime
some crash.
Rather than constanly upping the voltage we now have a
setting with a safe value for all players and the option for lower voltages

I plan to add a few other options here later such as disk
timings and maybe some other clocks/experimental settings

Added: Disk Low speed option for AS3525v2 devices cuts
	frequency to 12 MHz from 24 MHz
Added: Disk Low speed option for AS3525v1 devices cuts
        frequency to 15.5 MHz from 31 MHz

Added: I2c Low Speed AS3525 devices, should be bigger improvement for v1 devices

Fixed: Debug menu for AS3525v2 No SDSLOT frequency,
	Showed IDE freq though it is unused

Added: DBOP and SSP underclocking affects display on v1/v2 respectively

Fixed: debug menu now has SSP frequency, and SSP_CPSR

Update: made settings menu more generic

Update: cleaned up code

Added: Clip v1 & Fuze v1 didn't have HAVE_ADJUSTABLE_CPU_VOLTAGE.
	not sure why but,  waiting on testing to confirm

Added: C200v2 and E200v2 devices and HAVE_ADJUSTABLE_CPU_VOLTAGE.

Fixed: v1 devices don't like display timing set lower (dbop)
       v1 devices don't have a divider set for ssp (causes divide by 0)

Fixed: ClipZip display lags with Max SSP divider changed from 0xFE to 0x32

Fixed: v1 devices didn't work properly with highspeed sd cards
	Added code from http://gerrit.rockbox.org/r/#/c/1704/
	Added powersave and IDE interface enable/disable

Added: V2 devices now have powersave enabled on sd interface

Update: cleaned up code, lang defines, added manual entries

Update ssp clock mechanism added calculated ssp divider to clipzip

Update turn display clock off when clip+ turns off display

Fixed: clipzip wrong register for SSP clock

Change-Id: I04137682243be92f0f8d8bf1cfa54fbb1965559b
TODO: add other players?

1 files changed, 22 insertions, 1 deletions

diff --git a/firmware/target/arm/as3525/sansa-clipplus/lcd-clip-plus.c b/firmware/target/arm/as3525/sansa-clipplus/lcd-clip-plus.c
index a50a9e5c80..7c0cfb5345 100644
--- a/firmware/target/arm/as3525/sansa-clipplus/lcd-clip-plus.c
+++ b/firmware/target/arm/as3525/sansa-clipplus/lcd-clip-plus.c
@@ -26,11 +26,25 @@
 #include "system.h"
 #include "cpu.h"
 
+static void ssp_set_prescaler(unsigned int prescaler)
+{
+    int oldlevel = disable_interrupt_save(IRQ_FIQ_STATUS);
+    /* must be on to write regs */
+    bool ssp_enabled = bitset32(&CGU_PERI, CGU_SSP_CLOCK_ENABLE) &
+                                           CGU_SSP_CLOCK_ENABLE;
+    SSP_CPSR = prescaler;
+
+    if (!ssp_enabled) /* put it back how we found it */
+        bitclr32(&CGU_PERI, CGU_SSP_CLOCK_ENABLE);
+
+    restore_irq(oldlevel);
+}
+
 int lcd_hw_init(void)
 {
     bitset32(&CGU_PERI, CGU_SSP_CLOCK_ENABLE);
 
-    SSP_CPSR = AS3525_SSP_PRESCALER;    /* OF = 0x10 */
+    ssp_set_prescaler(AS3525_SSP_PRESCALER);    /* OF = 0x10 */
     SSP_CR0 = (1<<7) | (1<<6) | 7;  /* Motorola SPI frame format, 8 bits */
     SSP_CR1 = (1<<3) | (1<<1);  /* SSP Operation enabled */
     SSP_IMSC = 0;       /* No interrupts */
@@ -115,3 +129,10 @@ void lcd_enable_power(bool onoff)
 #endif
 }
 
+#if defined(CONFIG_POWER_SAVING) && (CONFIG_POWER_SAVING & POWERSV_DISP)
+/* declared in system-as3525.c */
+void ams_ssp_set_low_speed(bool slow)
+{
+    ssp_set_prescaler(slow ? AS3525_SSP_PRESCALER_MAX : AS3525_SSP_PRESCALER);
+}
+#endif