[PATCH 2/3] leds: leds-lp5569: Place the LED mapping table in the lower half of the SRAM

[Arthur Crepin Leblond]

The LED mapping instructions (map_start, load_end, map_addr, ...) take
a 7-bits absolute SRAM address, so the mapping table must be in the
lower half of the SRAM (0-127).
The driver placed the muxing info after the engine programs, which
these instructions cannot reach.

Place the mapping tables in pages 0-2 and the engine programs after
them.

This changes the SRAM layout seen by userspace:

  - The program of engines 1/2/3 now starts at address 0x30/0x70/0xb0
    instead of 0x00/0x40/0x80 (ENGINEx_PROG_START).
  - The mapping of engines 1/2/3 is at address 0x00/0x10/0x20.

Programs loaded through engineN_load or the firmware interface are not
affected, since they are written relative to the start of the engine.
Programs that use absolute SRAM addresses (map_start, load_end,
load_addr, map_addr) must be updated to the new layout.

Fixes: 30c6743cc89c ("leds: leds-lp5569: Add support for Texas Instruments LP5569")
Signed-off-by: Arthur Crepin Leblond <arthur@xxxxxxxxxxxxx>
---
 drivers/leds/leds-lp5569.c | 53 +++++++++++++++++++++++++++++-----------------
 1 file changed, 34 insertions(+), 19 deletions(-)

diff --git a/drivers/leds/leds-lp5569.c b/drivers/leds/leds-lp5569.c
index 15beac7b34ea..a4d9787c4158 100644
--- a/drivers/leds/leds-lp5569.c
+++ b/drivers/leds/leds-lp5569.c
@@ -21,17 +21,21 @@
 
 #define LP5569_MAX_LEDS			9
 
-/* Memory is used like this:
- * 0x00 engine 1 program (4 pages)
- * 0x40 engine 2 program (4 pages)
- * 0x80 engine 3 program (4 pages)
- * 0xc0 engine 1 muxing info (1 page)
- * 0xd0 engine 2 muxing info (1 page)
- * 0xe0 engine 3 muxing info (1 page)
+/*
+ * Memory is used like this (a page is 16 instructions).
+ * The LED mapping rows must be in the lower half of the SRAM (0x00-0x7f) to be
+ * reachable by the map_* instructions, so they are placed before the engine
+ * programs:
+ * 0x00 engine 1 muxing info (1 page)
+ * 0x10 engine 2 muxing info (1 page)
+ * 0x20 engine 3 muxing info (1 page)
+ * 0x30 engine 1 program (4 pages)
+ * 0x70 engine 2 program (4 pages)
+ * 0xb0 engine 3 program (4 pages)
  */
 #define LP5569_PAGES_PER_ENGINE		4
-#define LP5569_PROG_PAGE_BASE		0
-#define LP5569_MUX_PAGE_BASE		12
+#define LP5569_MUX_PAGE_BASE		0
+#define LP5569_PROG_PAGE_BASE		3
 
 #define LP5569_REG_ENABLE		0x00
 #define   LP5569_ENABLE			BIT(6)
@@ -88,12 +92,12 @@
 #define   LP5569_LED_FAULT1		BIT(1)
 #define   LP5569_LED_FAULT0		BIT(0)
 
-#define LP5569_ENG1_PROG_ADDR		0x0
-#define LP5569_ENG2_PROG_ADDR		0x40
-#define LP5569_ENG3_PROG_ADDR		0x80
-#define LP5569_ENG1_MUX_ADDR		0xc0
-#define LP5569_ENG2_MUX_ADDR		0xd0
-#define LP5569_ENG3_MUX_ADDR		0xe0
+#define LP5569_ENG1_MUX_ADDR		0x00
+#define LP5569_ENG2_MUX_ADDR		0x10
+#define LP5569_ENG3_MUX_ADDR		0x20
+#define LP5569_ENG1_PROG_ADDR		0x30
+#define LP5569_ENG2_PROG_ADDR		0x70
+#define LP5569_ENG3_PROG_ADDR		0xb0
 
 #define LP5569_STARTUP_SLEEP		500
 
@@ -119,11 +123,22 @@ static int lp5569_init_program_engine(struct lp55xx_chip *chip)
 	int j;
 	int ret;
 	u8 status;
-	/* Precompiled pattern per ENGINE setting LED MUX start and stop addresses */
+	/*
+	 * Precompiled program run by each ENGINE, setting the start and end of
+	 * the LED mapping table to the row of the engine (bit 7 of the operand
+	 * selects load_end instead of map_start):
+	 *   map_start MUX_ADDR
+	 *   load_end  MUX_ADDR
+	 *   map_next
+	 *   end
+	 */
 	static const u8 pattern[][LP55xx_BYTES_PER_PAGE] =  {
-		{ 0x9c, LP5569_ENG1_MUX_ADDR, 0x9c, 0xb0, 0x9d, 0x80, 0xd8, 0x00, 0},
-		{ 0x9c, LP5569_ENG2_MUX_ADDR, 0x9c, 0xc0, 0x9d, 0x80, 0xd8, 0x00, 0},
-		{ 0x9c, LP5569_ENG3_MUX_ADDR, 0x9c, 0xd0, 0x9d, 0x80, 0xd8, 0x00, 0},
+		{ 0x9c, LP5569_ENG1_MUX_ADDR, 0x9c, 0x80 | LP5569_ENG1_MUX_ADDR,
+		  0x9d, 0x80, 0xd8, 0x00, 0},
+		{ 0x9c, LP5569_ENG2_MUX_ADDR, 0x9c, 0x80 | LP5569_ENG2_MUX_ADDR,
+		  0x9d, 0x80, 0xd8, 0x00, 0},
+		{ 0x9c, LP5569_ENG3_MUX_ADDR, 0x9c, 0x80 | LP5569_ENG3_MUX_ADDR,
+		  0x9d, 0x80, 0xd8, 0x00, 0},
 	};
 
 	/* Setup each ENGINE program start address */

-- 
2.56.0