Update TODO and I2C interface description

README.i2c-intf

@@ -35,6 +35,7 @@ General ranges:
    bit 1: Flashing mode
    bit 2: Self-test features
    bit 3: Stock firmware flag (only stock firmware should have this set)
+   bit 4: Charger register read/writes are supported
    
 0x06: bits 3-0: number of rows, bits 7-4 number of cols
 0x07: CRC8 of keyboard data from 0x08-0x13
@@ -44,29 +45,28 @@ General ranges:
 
 0x20: System configuration
    bit 0: disable KB scanning (1: scanning disabled, 0: scanning enabled)
-   bit 1: poll mode
-          1: don't rely on row change detection, poll the matrix periodically
-             (prevents MCU power down)
-          0: power down the MCU when no key is pressed, and rely on change
-             detection on row inupts to wake the MCU up
-   bit 2: enable USB debug interface
+   bit 1: enable USB debug interface
           1: enabled
           0: disabled
 
-0x21: System command
+0x21: Charger register address
+0x22: Charger register value
+
+0x23: System command
       Writing values into this register causes the firmware to perform
       certain one-shot actions:
 
-      0x52 ('R') - reset the MCU
-      0x63 ('c') - run a column self-test
-      0x72 ('r') - run a row self-test
-                   (results for both tests will be stored in test-result
-                    registers)
+      0x72 ('r') - reset the MCU
+      0x69 ('i') - jump to USB bootloader
+      0x74 ('t') - run a self-test
+                   (results are as a text in debug log)
+      0x91       - read charger register
+      0xA1       - write charger register
 
       The register is set to 0x00 or 0xff after the operation completes.
       0xff means error.
 
-0x22: Writing value 0x53 ('S') to this register stops the main app from
+0x24: Writing value 0x53 ('S') to this register stops the main app from
       jumping to the user app.
 
 
@@ -147,7 +147,7 @@ is flashed.
 
 After MCU powerup or reset, stock firmware will listen for 1s on I2C interface,
 before passing control to the user firmware. If 0x53 is not written to register
-0x22 during that time, this will prevent execution of the user's firmware.
+0x24 during that time, this will prevent execution of the user's firmware.
 
 If the user firmware execution is not prevented in this way, stock firmware
 will redirect interrupt vectors from 0x0000+offset to 0x4000+offset and jump
@@ -172,12 +172,12 @@ Flashing steps:
    ... repeat 1-5 for all memory locations to be flashed
 6) Write command 0x43 to reg 0xf4
 7) Poll 0xf4 for result (either 0x00 or 0xff)
-8) Reset the MCU by writing command 0x52 to reg 0x21
+8) Reset the MCU by writing command 0x72 to reg 0x23
 
 
 Self-tests
 ----------
 
-1) Write command 'r' or 'c' to reg 0x21
+1) Write command 't' to reg 0x23
 2) Read repeatedly from register 0xff to get the self-test results
    in human readable text form

README.testing

@@ -0,0 +1,43 @@
+Firmware testing
+----------------
+
+Situations/features to test:
+
+- factory firmware
+  - USB debugging
+    - is disabled by default after start
+    - can be enabled/disabled at runtime
+      - via I2C
+      - if Pine + F + U is pressed  (status is reflected over I2C
+        in a control register)
+  - scanning block works
+    - switching it on/off works at runtime
+    - no interrupts are fired when blocked
+    - no keys appear pressed during a block
+  - USB bootloader jump works
+    - if Pine + F + B is pressed
+    - via USB debugger mode
+    - via I2C command
+  - reset over I2C works
+  - I2C debug log readout works
+  - selftest works
+    - shows result via I2C debug log
+  - exposed GPIOs are accessible over I2C
+    - direction configuration works
+    - readout/setting works
+
+- interrupt
+  - 10us pulse visible on logical probe capture
+  - POGO interrupt is received on the SoC
+
+- charger
+  - I2C A communication works
+  - I2C A timeout mechanism works when the bus is blocked
+
+- user firmware
+  - flashing works
+  - reading works
+  - deletion works
+  - is not jumped to unless it's commited after flashing
+  - can be executed
+    - starts automatically unless Pine+F+H is held on powerup

TODO

@@ -1,37 +1,22 @@
 Firmware
 --------
 
-- allow to stay in factory FW by holding a key combo on powerup
-  - choose combo
-  - document
+- check that the charger's INT pin is high prior to I2C A communication
+  and return error if it is not (P87 must have pull-up enabled, and
+  it is low if charger is free to communicate)
 
-- test I2C interface using FX2
+- trigger POGO interrupt on P84 (open drain mode)
+
+- implement special key combos:
+  - Pine + F + H  (stay in main FW if pressed during powerup)
+  - Pine + F + U  (enable USB debugger)
+  - Pine + F + B  (jump to USB bootloader)
 
 - first I2C TX after switch to USER firmware after flashing over I2C fails,
   subsequent ones work
   - also power consumption indicates power consumption of the sotck firmware
     so maybe we just sleep in stock instead of switching after flashing?
 
-------------
-
-- implement I2C configuration options
-  - disable keyboard matrix scanning
-- only enable USB in stock FW upon request over I2C (idling USB stack takes
-  about 0.6mA on top of 1.8mA baseline)
-
-Charger behavior
-----------------
-
-- does the charger turn off VOUT after some period of low load?
-- does it enable it again to see if there's a need for it?
-- this auto-off behavior will kill the power to the keyboard
-  controller, so we need a way to detect it and power the controller
-  from the pinephone side by enabling VBUS.
-  - tricky!
-  - or make the user keep pressing the kb power button to use the
-    keyboard for a while, like in a train conductor has to in a train :)
-    - not good!
-
 
 Userspace input device daemon
 -----------------------------

firmware/registers.h

@@ -48,10 +48,10 @@
 
 #define REG_SYS_COMMAND		0x23
 #define REG_SYS_COMMAND_MCU_RESET	'r'
-#define REG_SYS_COMMAND_SELFTEST	't'
 #define REG_SYS_COMMAND_USB_IAP		'i'
-#define REG_SYS_COMMAND_I2CA_READ	'R'
-#define REG_SYS_COMMAND_I2CA_WRITE	'W'
+#define REG_SYS_COMMAND_SELFTEST	't'
+#define REG_SYS_COMMAND_I2CA_READ	0x91
+#define REG_SYS_COMMAND_I2CA_WRITE	0xA1
 
 #define REG_SYS_USER_APP_BLOCK	0x24
 #define REG_SYS_USER_APP_BLOCK_MAGIC	0x53