[PATCH v5 08/11] rtc: isl1208: Add support for the built-in RTC on the PMIC RAA215300

[Biju Das <biju.das.jz@xxxxxxxxxxxxxx>]

The built-in RTC found on PMIC RAA215300 is the same as ISL1208.
However, the external oscillator bit is inverted on PMIC version
0x11. The PMIC driver detects PMIC version and instantiates the
RTC device based on i2c_device_id.

The internal oscillator is enabled or not is determined by the
parent clock name.

Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
---
v4->v5:
 * Updated commit description.
 * Replaced "unsigned long"->"kernel_ulong_t" in isl1208_id[].
 * -ENOENT means clock not present, so any other errors are propagated.
 * Dropped bool inverted parameter from isl1208_set_xtoscb() instead
   using xor to compute the value of xtoscb.
v3->v4:
 * Added support for internal oscillator enable/disable.
v2->v3:
 * RTC device is instantiated by PMIC driver and dropped isl1208_probe_helper().
 * Added "TYPE_RAA215300_RTC_A0" to handle inverted oscillator bit case.
RFC->v2:
 * Dropped compatible "renesas,raa215300-isl1208" and "renesas,raa215300-pmic" property.
 * Updated the comment polarity->bit for External Oscillator.
 * Added raa215300_rtc_probe_helper() for registering raa215300_rtc device and
   added the helper function isl1208_probe_helper() to share the code.
---
 drivers/rtc/rtc-isl1208.c | 48 +++++++++++++++++++++++++++++++--------
 1 file changed, 39 insertions(+), 9 deletions(-)

diff --git a/drivers/rtc/rtc-isl1208.c b/drivers/rtc/rtc-isl1208.c
index 6ca977595977..5c68120ff543 100644
--- a/drivers/rtc/rtc-isl1208.c
+++ b/drivers/rtc/rtc-isl1208.c
@@ -74,6 +74,7 @@ struct isl1208_config {
 	unsigned int	nvmem_length;
 	unsigned	has_tamper:1;
 	unsigned	has_timestamp:1;
+	unsigned	has_inverted_osc_bit:1;
 };
 
 static const struct isl1208_config config_isl1208 = {
@@ -100,11 +101,19 @@ static const struct isl1208_config config_isl1219 = {
 	.has_timestamp = true
 };
 
+static const struct isl1208_config config_raa215300_a0 = {
+	.nvmem_length = 2,
+	.has_tamper = false,
+	.has_timestamp = false,
+	.has_inverted_osc_bit = true
+};
+
 static const struct i2c_device_id isl1208_id[] = {
 	{ "isl1208", .driver_data = (kernel_ulong_t)&config_isl1208 },
 	{ "isl1209", .driver_data = (kernel_ulong_t)&config_isl1209 },
 	{ "isl1218", .driver_data = (kernel_ulong_t)&config_isl1218 },
 	{ "isl1219", .driver_data = (kernel_ulong_t)&config_isl1219 },
+	{ "raa215300_a0", .driver_data = (kernel_ulong_t)&config_raa215300_a0 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, isl1208_id);
@@ -852,17 +861,37 @@ isl1208_probe(struct i2c_client *client)
 		isl1208->config = (struct isl1208_config *)id->driver_data;
 	}
 
-	xin = devm_clk_get_optional(&client->dev, "xin");
-	if (IS_ERR(xin))
-		return PTR_ERR(xin);
+	if (client->dev.parent->type == &i2c_client_type) {
+		xin = of_clk_get_by_name(client->dev.parent->of_node, "xin");
+		if (IS_ERR(xin)) {
+			if (PTR_ERR(xin) != -ENOENT)
+				return PTR_ERR(xin);
+
+			clkin = of_clk_get_by_name(client->dev.parent->of_node,
+						   "clkin");
+			if (IS_ERR(clkin)) {
+				if (PTR_ERR(clkin) != -ENOENT)
+					return PTR_ERR(xin);
+			} else {
+				xtosb_val = 0;
+				clk_put(clkin);
+			}
+		} else {
+			clk_put(xin);
+		}
+	} else {
+		xin = devm_clk_get_optional(&client->dev, "xin");
+		if (IS_ERR(xin))
+			return PTR_ERR(xin);
 
-	if (!xin) {
-		clkin = devm_clk_get_optional(&client->dev, "clkin");
-		if (IS_ERR(clkin))
-			return PTR_ERR(clkin);
+		if (!xin) {
+			clkin = devm_clk_get_optional(&client->dev, "clkin");
+			if (IS_ERR(clkin))
+				return PTR_ERR(clkin);
 
-		if (clkin)
-			xtosb_val = 0;
+			if (clkin)
+				xtosb_val = 0;
+		}
 	}
 
 	isl1208->rtc = devm_rtc_allocate_device(&client->dev);
@@ -882,6 +911,7 @@ isl1208_probe(struct i2c_client *client)
 		return sr;
 	}
 
+	xtosb_val ^= isl1208->config->has_inverted_osc_bit ? 1 : 0;
 	rc = isl1208_set_xtoscb(client, sr, xtosb_val);
 	if (rc)
 		return rc;
-- 
2.25.1