[PATCH v2] arm: rockchip-rk3568-evb: add hardware id detection

[Michael Riesch <michael.riesch@wolfvision.net>]

The RK3568 EVB uses a voltage divider to determine the hardware ID of
the board. At the moment, the voltage levels for seven EVB variants are
defined. This commit adds a late_initcall to the board code that reads
out the voltage and populates the hardware ID as environment variable.

Signed-off-by: Michael Riesch <michael.riesch@wolfvision.net>
---
v2:
- add compatible check
- return early in case the voltage cannot be read
- populate hardware ID as environment variable

 arch/arm/boards/rockchip-rk3568-evb/board.c | 56 +++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/arch/arm/boards/rockchip-rk3568-evb/board.c b/arch/arm/boards/rockchip-rk3568-evb/board.c
index 57c24ed3c..f8b257e57 100644
--- a/arch/arm/boards/rockchip-rk3568-evb/board.c
+++ b/arch/arm/boards/rockchip-rk3568-evb/board.c
@@ -2,7 +2,13 @@
 #include <common.h>
 #include <init.h>
 #include <mach/bbu.h>
+#include <aiodev.h>
 #include <bootsource.h>
+#include <environment.h>
+#include <globalvar.h>
+#include <magicvar.h>
+
+static bool machine_is_rk3568_evb = false;
 
 static int rk3568_evb_probe(struct device_d *dev)
 {
@@ -11,6 +17,7 @@ static int rk3568_evb_probe(struct device_d *dev)
 
 	barebox_set_model("Rockchip RK3568 EVB");
 	barebox_set_hostname("rk3568-evb");
+	machine_is_rk3568_evb = true;
 
 	if (bootsource == BOOTSOURCE_MMC && instance == 1)
 		of_device_enable_path("/chosen/environment-sd");
@@ -34,3 +41,52 @@ static struct driver_d rk3568_evb_board_driver = {
 	.of_compatible = rk3568_evb_of_match,
 };
 coredevice_platform_driver(rk3568_evb_board_driver);
+
+static int rk3568_evb_detect_hwid(void)
+{
+	int ret;
+	int evb_hwid_voltage;
+	struct aiochannel *evb_hwid_chan;
+	char *evb_hwid;
+
+	if (!machine_is_rk3568_evb)
+		return 0;
+
+	evb_hwid_chan = aiochannel_by_name("aiodev0.in_value1_mV");
+	if (IS_ERR(evb_hwid_chan)) {
+		ret = PTR_ERR(evb_hwid_chan);
+		goto err_hwid;
+	}
+
+	ret = aiochannel_get_value(evb_hwid_chan, &evb_hwid_voltage);
+	if (ret)
+		goto err_hwid;
+
+	if (evb_hwid_voltage > 1650) {
+		evb_hwid = "1";
+	} else if (evb_hwid_voltage > 1350) {
+		evb_hwid = "2";
+	} else if (evb_hwid_voltage > 1050) {
+		evb_hwid = "3";
+	} else if (evb_hwid_voltage > 750) {
+		evb_hwid = "4";
+	} else if (evb_hwid_voltage > 450) {
+		evb_hwid = "5";
+	} else if (evb_hwid_voltage > 150) {
+		evb_hwid = "6";
+	} else {
+		evb_hwid = "7";
+	}
+	pr_info("Detected RK3568 EVB%s\n", evb_hwid);
+
+	globalvar_add_simple("board.hwid", evb_hwid);
+
+	return 0;
+
+err_hwid:
+	pr_err("couldn't retrieve hardware ID");
+	return ret;
+}
+late_initcall(rk3568_evb_detect_hwid);
+
+BAREBOX_MAGICVAR(global.board.hwid, "The board hardware ID");
-- 
2.20.1


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