[PATCH v6 06/10] mfd: bcm590xx: Add PMU ID/revision parsing function

[Artur Weber <aweber.kernel@gmail.com>]

The BCM590xx PMUs have two I2C registers for reading the PMU ID
and revision. The revision is useful for subdevice drivers, since
different revisions may have slight differences in behavior (for
example - BCM59054 has different regulator configurations for
revision A0 and A1).

Check the PMU ID register and make sure it matches the DT compatible.
Fetch the digital and analog revision from the PMUREV register
so that it can be used in subdevice drivers.

Also add some known revision values to bcm590xx.h, for convenience
when writing subdevice drivers.

Signed-off-by: Artur Weber <aweber.kernel@gmail.com>
---
Changes in v6:
- Adapt to PMUID being passed as device type value
- Rename rev_dig and rev_ana to rev_digital and rev_analog
- Rewrite commit message

Changes in v5:
- Add REG_ prefix to register offset constant names

Changes in v4:
- Added this commit
---
 drivers/mfd/bcm590xx.c       | 63 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/mfd/bcm590xx.h | 14 ++++++++++
 2 files changed, 77 insertions(+)

diff --git a/drivers/mfd/bcm590xx.c b/drivers/mfd/bcm590xx.c
index 4620eed0066fbf1dd691a2e392e967747b4d125b..74dc4ae5ecd5db7fadc56918f63110c1265d4a76 100644
--- a/drivers/mfd/bcm590xx.c
+++ b/drivers/mfd/bcm590xx.c
@@ -17,6 +17,15 @@
 #include <linux/regmap.h>
 #include <linux/slab.h>
 
+/* Under primary I2C address: */
+#define BCM590XX_REG_PMUID		0x1e
+
+#define BCM590XX_REG_PMUREV		0x1f
+#define BCM590XX_PMUREV_DIG_MASK	0xF
+#define BCM590XX_PMUREV_DIG_SHIFT	0
+#define BCM590XX_PMUREV_ANA_MASK	0xF0
+#define BCM590XX_PMUREV_ANA_SHIFT	4
+
 static const struct mfd_cell bcm590xx_devs[] = {
 	{
 		.name = "bcm590xx-vregs",
@@ -37,6 +46,56 @@ static const struct regmap_config bcm590xx_regmap_config_sec = {
 	.cache_type	= REGCACHE_MAPLE,
 };
 
+/* Map PMU ID value to model name string */
+static const char * const bcm590xx_names[] = {
+	[BCM590XX_PMUID_BCM59054] = "BCM59054",
+	[BCM590XX_PMUID_BCM59056] = "BCM59056",
+};
+
+/*
+ * Parse the version from version registers and make sure it matches
+ * the device type passed to the compatible.
+ */
+static int bcm590xx_parse_version(struct bcm590xx *bcm590xx)
+{
+	unsigned int id, rev;
+	int ret;
+
+	/* Get PMU ID and verify that it matches compatible */
+	ret = regmap_read(bcm590xx->regmap_pri, BCM590XX_REG_PMUID, &id);
+	if (ret) {
+		dev_err(bcm590xx->dev, "failed to read PMU ID: %d\n", ret);
+		return ret;
+	}
+
+	if (id != bcm590xx->pmu_id) {
+		dev_err(bcm590xx->dev,
+			"Incorrect ID for %s: expected %x, got %x. Check your DT compatible.\n",
+			bcm590xx_names[bcm590xx->pmu_id], bcm590xx->pmu_id, id);
+		return -EINVAL;
+	}
+
+	/* Get PMU revision and store it in the info struct */
+	ret = regmap_read(bcm590xx->regmap_pri, BCM590XX_REG_PMUREV, &rev);
+	if (ret) {
+		dev_err(bcm590xx->dev, "failed to read PMU revision: %d\n",
+			ret);
+		return ret;
+	}
+
+	bcm590xx->rev_digital = (rev & BCM590XX_PMUREV_DIG_MASK)
+				     >> BCM590XX_PMUREV_DIG_SHIFT;
+
+	bcm590xx->rev_analog = (rev & BCM590XX_PMUREV_ANA_MASK)
+				    >> BCM590XX_PMUREV_ANA_SHIFT;
+
+	dev_info(bcm590xx->dev, "PMU ID 0x%x (%s), revision: digital %d, analog %d",
+		 id, bcm590xx_names[id],
+		 bcm590xx->rev_digital, bcm590xx->rev_analog);
+
+	return 0;
+}
+
 static int bcm590xx_i2c_probe(struct i2c_client *i2c_pri)
 {
 	struct bcm590xx *bcm590xx;
@@ -78,6 +137,10 @@ static int bcm590xx_i2c_probe(struct i2c_client *i2c_pri)
 		goto err;
 	}
 
+	ret = bcm590xx_parse_version(bcm590xx);
+	if (ret)
+		goto err;
+
 	ret = devm_mfd_add_devices(&i2c_pri->dev, -1, bcm590xx_devs,
 				   ARRAY_SIZE(bcm590xx_devs), NULL, 0, NULL);
 	if (ret < 0) {
diff --git a/include/linux/mfd/bcm590xx.h b/include/linux/mfd/bcm590xx.h
index 8d146e3b102a7dbce6f4dbab9f8ae5a9c4e68c0e..fbc458e94bef923ca1b69afe2cac944adf6fedf8 100644
--- a/include/linux/mfd/bcm590xx.h
+++ b/include/linux/mfd/bcm590xx.h
@@ -17,6 +17,16 @@
 #define BCM590XX_PMUID_BCM59054		0x54
 #define BCM590XX_PMUID_BCM59056		0x56
 
+/* Known chip revision IDs */
+#define BCM59054_REV_DIGITAL_A1		1
+#define BCM59054_REV_ANALOG_A1		2
+
+#define BCM59056_REV_DIGITAL_A0		1
+#define BCM59056_REV_ANALOG_A0		1
+
+#define BCM59056_REV_DIGITAL_B0		2
+#define BCM59056_REV_ANALOG_B0		2
+
 /* max register address */
 #define BCM590XX_MAX_REGISTER_PRI	0xe7
 #define BCM590XX_MAX_REGISTER_SEC	0xf0
@@ -30,6 +40,10 @@ struct bcm590xx {
 
 	/* PMU ID value; also used as device type */
 	u8 pmu_id;
+
+	/* Chip revision, read from PMUREV reg */
+	u8 rev_digital;
+	u8 rev_analog;
 };
 
 #endif /*  __LINUX_MFD_BCM590XX_H */

-- 
2.48.1