[PATCH RFC] sunxi: pinephone: detect existed magnetometer and fixup dtb

[Andrey Skvortsov]

In newer 1.2 PinePhone board revisions LIS3MDL magnetometer was replaced by
AF8133J. They use the same PB1 pin in different modes.

LIS3MDL uses it as an gpio input to handle interrupt.
AF8133J uses it as an gpio output as a reset signal.

It wasn't possible at runtime to enable both device tree
nodes and detect supported sensor at probe time.

AF8133J has reset pin (PB1) connected to the SoC. By default AF8133J
is in a reset state and don't respond to probe request on I2C
bus. Extra code would be needed to handle reset signal. Therefore this
code uses LIS3MDL magnetometer instead of AF8133J.

Introducing new dts 1.2b with AF8133J sensor would require probing in
SPL. That would lead to pulling in into SPL I2C controller driver,
RSB controller driver, introducing new AXP803 driver to power-up
sensors for probe. It's working, but SPL is pretty size-constrained on
A64 and doesn't have much space. Therefore fdt fixup is done in U-Boot
proper without introducing new board revision and new dts.

Signed-off-by: Andrey Skvortsov <andrej.skvortzov at gmail.com>
---

AF8133J's driver isn't upstreamed yet, but it will be soon. Therefore this
is RFC patch. I'd like to know whether selected approach will be accepted
in u-boot before submiting coresponding dts changes to the Linux kernel.
Any feedback on this change would be very welcome.

 board/sunxi/board.c         | 26 ++++++++++++++++++++++++++
 configs/pinephone_defconfig |  1 +
 2 files changed, 27 insertions(+)

diff --git a/board/sunxi/board.c b/board/sunxi/board.c
index 1305302060..a4bfa24400 100644
--- a/board/sunxi/board.c
+++ b/board/sunxi/board.c
@@ -15,6 +15,7 @@
 #include <dm.h>
 #include <env.h>
 #include <hang.h>
+#include <i2c.h>
 #include <image.h>
 #include <init.h>
 #include <log.h>
@@ -920,6 +921,28 @@ static void bluetooth_dt_fixup(void *blob)
 			   "local-bd-address", bdaddr, ETH_ALEN, 1);
 }
 
+#ifdef CONFIG_PINEPHONE_DT_SELECTION
+
+#define PINEPHONE_LIS3MDL_I2C_ADDR	0x1E
+#define PINEPHONE_LIS3MDL_I2C_BUS	1 /* I2C1 */
+
+static	void board_dt_fixup(void *blob)
+{
+	struct udevice *bus, *dev;
+
+	if (!fdt_node_check_compatible(blob, 0, "pine64,pinephone-1.2"))
+		if (!uclass_get_device_by_seq(UCLASS_I2C, PINEPHONE_LIS3MDL_I2C_BUS, &bus)) {
+			dm_i2c_probe(bus, PINEPHONE_LIS3MDL_I2C_ADDR, 0, &dev);
+			fdt_set_status_by_compatible(
+				blob, "st,lis3mdl-magn",
+				dev ? FDT_STATUS_OKAY  : FDT_STATUS_DISABLED);
+			fdt_set_status_by_compatible(
+				blob, "voltafield,af8133j",
+				dev ? FDT_STATUS_DISABLED : FDT_STATUS_OKAY);
+		}
+}
+#endif
+
 int ft_board_setup(void *blob, struct bd_info *bd)
 {
 	int __maybe_unused r;
@@ -934,6 +957,9 @@ int ft_board_setup(void *blob, struct bd_info *bd)
 
 	bluetooth_dt_fixup(blob);
 
+#ifdef CONFIG_PINEPHONE_DT_SELECTION
+	board_dt_fixup(blob);
+#endif
 #ifdef CONFIG_VIDEO_DT_SIMPLEFB
 	r = sunxi_simplefb_setup(blob);
 	if (r)
diff --git a/configs/pinephone_defconfig b/configs/pinephone_defconfig
index eebc676901..457e7ee1e7 100644
--- a/configs/pinephone_defconfig
+++ b/configs/pinephone_defconfig
@@ -12,6 +12,7 @@ CONFIG_MMC_SUNXI_SLOT_EXTRA=2
 CONFIG_PINEPHONE_DT_SELECTION=y
 # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
 CONFIG_OF_LIST="sun50i-a64-pinephone-1.1 sun50i-a64-pinephone-1.2"
+CONFIG_SYS_I2C_MVTWSI=y
 CONFIG_LED_STATUS=y
 CONFIG_LED_STATUS_GPIO=y
 CONFIG_LED_STATUS0=y
-- 
2.43.0