[PATCH 2/3] lm90: initialize parameters from devicetree

["Stéphan Kochen" <stephan-j6uo2F6POYhmR6Xm/wNWPw@public.gmane.org>]

Allow a device tree to set initial temperature sensor parameters.

Userspace can still override actual values through sysfs.

Signed-off-by: Stéphan Kochen <stephan-j6uo2F6POYhmR6Xm/wNWPw@public.gmane.org>
---
 Documentation/devicetree/bindings/hwmon/lm90.txt | 40 +++++++++++++++++
 drivers/hwmon/lm90.c                             | 55 ++++++++++++++++++++++--
 2 files changed, 92 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/hwmon/lm90.txt b/Documentation/devicetree/bindings/hwmon/lm90.txt
index e863248..045e94b 100644
--- a/Documentation/devicetree/bindings/hwmon/lm90.txt
+++ b/Documentation/devicetree/bindings/hwmon/lm90.txt
@@ -33,6 +33,38 @@ Optional properties:
               LM90 "-ALERT" pin output.
               See interrupt-controller/interrupts.txt for the format.
 
+- update-interval: Interval at which temperatures are sampled,
+  Type: unsigned   in milliseconds.
+  Size: one cell
+
+- local-low:      Valid temperature range for the chip internal sensor,
+  local-high:     outside which the alert will be set. Values are in
+  local-critical: millicelcius.
+  Type: signed
+  Size: one cell
+
+- remote-low:      Valid temperature range for the external sensor,
+  remote-high:     outside which the alert will be set. Values are in
+  remote-critical: millicelciius.
+  Type: signed
+  Size: one cell
+
+- remote-offset:   Where available, an external sensor temperature offset.
+  Type: signed
+  Size: one cell
+
+- local-emergency:  On max6659, max6695 and max6696, a configurable
+  remote-emergency: 3rd upper bound on temperature.
+  Type: signed
+  Size: one cell
+
+- remote2-low:      On max6695 and max6696, a second external sensor.
+  remote2-high:
+  remote2-critical:
+  remote2-emergency:
+  Type: signed
+  Size: one cell
+
 Example LM90 node:
 
 temp-sensor {
@@ -41,4 +73,12 @@ temp-sensor {
 	vcc-supply = <&palmas_ldo6_reg>;
 	interrupt-parent = <&gpio>;
 	interrupts = <TEGRA_GPIO(O, 4) IRQ_TYPE_LEVEL_LOW>;
+	update-interval = <500>;
+	local-low = <5000>;
+	local-high = <80000>;
+	local-critical = <90000>;
+	remote-low = <5000>;
+	remote-high = <80000>;
+	remote-critical = <90000>;
+	remote-offset = <(-62125)>;
 }
diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
index 88daf72..8ae8791 100644
--- a/drivers/hwmon/lm90.c
+++ b/drivers/hwmon/lm90.c
@@ -93,6 +93,7 @@
 #include <linux/hwmon.h>
 #include <linux/err.h>
 #include <linux/mutex.h>
+#include <linux/of.h>
 #include <linux/sysfs.h>
 #include <linux/interrupt.h>
 #include <linux/regulator/consumer.h>
@@ -1504,8 +1505,16 @@ static void lm90_restore_conf(struct i2c_client *client, struct lm90_data *data)
 static void lm90_init_client(struct lm90_data *data)
 {
 	struct i2c_client *client = data->client;
+	struct device *dev = &client->dev;
 	u8 config, convrate;
+	u32 ms;
+#ifdef CONFIG_OF
+	s32 temp;
+#endif
 
+	/*
+	 * Save old conversion rate.
+	 */
 	if (lm90_read_reg(client, LM90_REG_R_CONVRATE, &convrate) < 0) {
 		dev_warn(&client->dev, "Failed to read convrate register!\n");
 		convrate = LM90_DEF_CONVRATE_RVAL;
@@ -1515,14 +1524,24 @@ static void lm90_init_client(struct lm90_data *data)
 	/*
 	 * Start the conversions.
 	 */
-	lm90_set_convrate_locked(data, 500);  /* 500ms / 2Hz  */
+#ifdef CONFIG_OF
+	if (of_property_read_u32(dev->of_node, "update-interval", &ms) < 0)
+#endif
+		ms = 500;  /* default rate: 2Hz */
+	lm90_set_convrate_locked(data, ms);
+
+	/*
+	 * Save old config
+	 */
 	if (lm90_read_reg(client, LM90_REG_R_CONFIG1, &config) < 0) {
-		dev_warn(&client->dev, "Initialization failed!\n");
+		dev_warn(dev, "Initialization failed!\n");
 		return;
 	}
 	data->config_orig = config;
 
-	/* Check Temperature Range Select */
+	/*
+	 * Check Temperature Range Select
+	 */
 	if (data->kind == adt7461 || data->kind == tmp451) {
 		if (config & 0x04)
 			data->flags |= LM90_FLAG_ADT7461_EXT;
@@ -1545,6 +1564,36 @@ static void lm90_init_client(struct lm90_data *data)
 	config &= 0xBF;	/* run */
 	if (config != data->config_orig) /* Only write if changed */
 		i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1, config);
+
+#ifdef CONFIG_OF
+	/*
+	 * Set initial values from devicetree
+	 */
+#define INIT_REG(_property, _index, _bits) { \
+	if (of_property_read_s32(dev->of_node, _property, &temp) == 0) \
+		lm90_set_temp##_bits##_locked(data, _index, temp); \
+}
+	INIT_REG("local-low", LOCAL_LOW, 8);
+	INIT_REG("local-high", LOCAL_HIGH, 8);
+	INIT_REG("local-critical", LOCAL_CRIT, 8);
+	INIT_REG("remote-low", REMOTE_LOW, 11);
+	INIT_REG("remote-high", REMOTE_HIGH, 11);
+	INIT_REG("remote-critical", REMOTE_CRIT, 8);
+	if (data->flags & LM90_HAVE_OFFSET) {
+		INIT_REG("remote-offset", REMOTE_OFFSET, 11);
+	}
+	if (data->flags & LM90_HAVE_EMERGENCY) {
+		INIT_REG("local-emergency", LOCAL_EMERG, 8);
+		INIT_REG("remote-emergency", REMOTE_EMERG, 8);
+	}
+	if (data->flags & LM90_HAVE_TEMP3) {
+		INIT_REG("remote2-low", REMOTE2_LOW, 11);
+		INIT_REG("remote2-high", REMOTE2_HIGH, 11);
+		INIT_REG("remote2-critical", REMOTE2_CRIT, 8);
+		INIT_REG("remote2-emergency", REMOTE2_EMERG, 8);
+	}
+#undef INIT_REG
+#endif
 }
 
 static bool lm90_is_tripped(struct i2c_client *client, u16 *status)
-- 
2.5.0

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