[patch FYI] twl4030 dumps revision info

[David Brownell <david-b@pacbell.net>]

This is a diagnostic patch, dumping the IDCODE of the
TWL4030/TWL5030/... family chips.

Not for merging, at least for now.  Later this may be
useful to make sure the reduced-functionality catalog
parts (TPS series) don't go registering components that
don't exist, like the battery charger.

The main curiousity we've uncovered is that TWL5030 ES1.0
mis-identifies itself as TWL4030 ES1.0 ... unclear just now
whether that's also true of ES1.1 and later parts.

- Dave

---
 drivers/mfd/twl4030-core.c |   62 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

--- a/drivers/mfd/twl4030-core.c
+++ b/drivers/mfd/twl4030-core.c
@@ -748,6 +748,66 @@ static int twl4030_remove(struct i2c_cli
 	return 0;
 }
 
+struct es_desc {
+	u8	nibble;
+	char	name[4];
+};
+
+static const struct es_desc twl4030_es[] = {
+	{ 0, "1.0", },
+	{ 1, "2.x", },
+	{ 4, "3.0", },
+	{ 5, "3.1", },
+	{ },
+};
+static const struct es_desc twl5030_es[] = {
+	{ 0, "1.0", },
+	{ 1, "1.1", },
+	{ },
+};
+
+static u32 twl_id(struct device *dev)
+{
+	const u32 mask = ((1 << 16) - 1) << 12;
+	union { u8 bytes[4]; u32 word; } idcode;
+	int status;
+	u8 nibble;
+	char *chip;
+	const struct es_desc *desc;
+
+	status = twl4030_i2c_read(TWL4030_MODULE_INTBR,
+			idcode.bytes, 0, 4);
+	if (status < 0)
+		return 0;
+
+	idcode.word = le32_to_cpu(idcode.word),
+	nibble = idcode.word >> 28;
+
+	/* NOTE:  TWL5030 / TPS65930 ES1.0 mis-identifies as TWL4030 */
+
+	if ((idcode.word & mask) == (0x0009002F & mask)) {
+		chip = "TWL4030";
+		desc = twl4030_es;
+	} else if ((idcode.word & mask) == (0x0009802F & mask)) {
+		chip = "TWL5030";
+		desc = twl5030_es;
+	} else {
+		chip = "unrecognized";
+		desc = NULL;
+	}
+
+	while (desc && desc->name[0]) {
+		if (desc->nibble == nibble) {
+			dev_info(dev, "%s ES %s; idcode %08x\n",
+					chip, desc->name, idcode.word);
+			return idcode.word;
+		}
+		desc++;
+	}
+	dev_info(dev, "%s; idcode %08x\n", chip, idcode.word);
+	return idcode.word;
+}
+
 /* NOTE:  this driver only handles a single twl4030/tps659x0 chip */
 static int
 twl4030_probe(struct i2c_client *client, const struct i2c_device_id *id)
@@ -795,6 +855,8 @@ twl4030_probe(struct i2c_client *client,
 
 	if(0)dumpit();
 
+	twl_id(&client->dev);
+
 	/* setup clock framework */
 	clocks_init();