mfd: qcom-spmi-pmic: read fab id on supported PMICs

The PMI8998 and PM660 expose the fab_id, this is needed by drivers like
the RRADC to calibrate ADC values.

Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Tested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220429220904.137297-4-caleb.connolly@linaro.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/mfd/qcom-spmi-pmic.c

@@ -19,6 +19,7 @@
 #define PMIC_REV4		0x103
 #define PMIC_TYPE		0x104
 #define PMIC_SUBTYPE		0x105
+#define PMIC_FAB_ID		0x1f2
 
 #define PMIC_TYPE_VALUE		0x51
 
@@ -157,6 +158,12 @@ static int pmic_spmi_load_revid(struct regmap *map, struct device *dev,
 	if (ret < 0)
 		return ret;
 
+	if (pmic->subtype == PMI8998_SUBTYPE || pmic->subtype == PM660_SUBTYPE) {
+		ret = regmap_read(map, PMIC_FAB_ID, &pmic->fab_id);
+		if (ret < 0)
+			return ret;
+	}
+
 	/*
 	 * In early versions of PM8941 and PM8226, the major revision number
 	 * started incrementing from 0 (eg 0 = v1.0, 1 = v2.0).

include/soc/qcom/qcom-spmi-pmic.h

@@ -52,6 +52,7 @@ struct qcom_spmi_pmic {
 	unsigned int major;
 	unsigned int minor;
 	unsigned int rev2;
+	unsigned int fab_id;
 	const char *name;
 };