reset: qcom-pon: Add support for gen2 pon

Add support for gen2 pon register so "reboot bootloader" can
work on pixel3 and db845.

Cc: Andy Gross <agross@kernel.org>
Cc: David Brown <david.brown@linaro.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Amit Pundir <amit.pundir@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: linux-arm-msm@vger.kernel.org
Cc: devicetree@vger.kernel.org
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>

v2:
* Split out dts changes into separate path
* Minor cleanups and remove unused variables
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/reset/qcom-pon.c

@@ -14,11 +14,15 @@
 
 #define PON_SOFT_RB_SPARE		0x8f
 
+#define GEN1_REASON_SHIFT		2
+#define GEN2_REASON_SHIFT		1
+
 struct pm8916_pon {
 	struct device *dev;
 	struct regmap *regmap;
 	u32 baseaddr;
 	struct reboot_mode_driver reboot_mode;
+	long reason_shift;
 };
 
 static int pm8916_reboot_mode_write(struct reboot_mode_driver *reboot,
@@ -30,7 +34,7 @@ static int pm8916_reboot_mode_write(struct reboot_mode_driver *reboot,
 
 	ret = regmap_update_bits(pon->regmap,
 				 pon->baseaddr + PON_SOFT_RB_SPARE,
-				 0xfc, magic << 2);
+				 0xfc, magic << pon->reason_shift);
 	if (ret < 0)
 		dev_err(pon->dev, "update reboot mode bits failed\n");
 
@@ -60,6 +64,7 @@ static int pm8916_pon_probe(struct platform_device *pdev)
 		return error;
 
 	pon->reboot_mode.dev = &pdev->dev;
+	pon->reason_shift = (long)of_device_get_match_data(&pdev->dev);
 	pon->reboot_mode.write = pm8916_reboot_mode_write;
 	error = devm_reboot_mode_register(&pdev->dev, &pon->reboot_mode);
 	if (error) {
@@ -73,8 +78,9 @@ static int pm8916_pon_probe(struct platform_device *pdev)
 }
 
 static const struct of_device_id pm8916_pon_id_table[] = {
-	{ .compatible = "qcom,pm8916-pon" },
-	{ .compatible = "qcom,pms405-pon" },
+	{ .compatible = "qcom,pm8916-pon", .data = (void *)GEN1_REASON_SHIFT },
+	{ .compatible = "qcom,pms405-pon", .data = (void *)GEN1_REASON_SHIFT },
+	{ .compatible = "qcom,pm8998-pon", .data = (void *)GEN2_REASON_SHIFT },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, pm8916_pon_id_table);