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authorTakashi Iwai <tiwai@suse.de>2018-07-10 16:07:11 +0200
committerTakashi Iwai <tiwai@suse.de>2018-07-10 16:07:16 +0200
commit79590b7f6a188d1c05106f03c71d72cbe494e2cf (patch)
tree0329645dd6fbff3af4d9ddcadf9c5ce50d7a2b4a
parent0ac71df4c76bf516449658756e35c142322eb7a8 (diff)
hwmon: (jc42) optionally try to disable the SMBUS timeout
(bsc#1051510). suse-commit: 8e86453aac0e1519db95d26b1bc1c4bd1e5be913
-rw-r--r--Documentation/devicetree/bindings/hwmon/jc42.txt4
-rw-r--r--drivers/hwmon/jc42.c21
2 files changed, 25 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/hwmon/jc42.txt b/Documentation/devicetree/bindings/hwmon/jc42.txt
index 07a250498fbb..f569db58f64a 100644
--- a/Documentation/devicetree/bindings/hwmon/jc42.txt
+++ b/Documentation/devicetree/bindings/hwmon/jc42.txt
@@ -34,6 +34,10 @@ Required properties:
- reg: I2C address
+Optional properties:
+- smbus-timeout-disable: When set, the smbus timeout function will be disabled.
+ This is not supported on all chips.
+
Example:
temp-sensor@1a {
diff --git a/drivers/hwmon/jc42.c b/drivers/hwmon/jc42.c
index 1bf22eff0b08..0f1f6421845f 100644
--- a/drivers/hwmon/jc42.c
+++ b/drivers/hwmon/jc42.c
@@ -22,6 +22,7 @@
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
+#include <linux/bitops.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
@@ -45,6 +46,7 @@ static const unsigned short normal_i2c[] = {
#define JC42_REG_TEMP 0x05
#define JC42_REG_MANID 0x06
#define JC42_REG_DEVICEID 0x07
+#define JC42_REG_SMBUS 0x22 /* NXP and Atmel, possibly others? */
/* Status bits in temperature register */
#define JC42_ALARM_CRIT_BIT 15
@@ -73,6 +75,9 @@ static const unsigned short normal_i2c[] = {
#define ONS_MANID 0x1b09 /* ON Semiconductor */
#define STM_MANID 0x104a /* ST Microelectronics */
+/* SMBUS register */
+#define SMBUS_STMOUT BIT(7) /* SMBus time-out, active low */
+
/* Supported chips */
/* Analog Devices */
@@ -476,6 +481,22 @@ static int jc42_probe(struct i2c_client *client, const struct i2c_device_id *id)
data->extended = !!(cap & JC42_CAP_RANGE);
+ if (device_property_read_bool(dev, "smbus-timeout-disable")) {
+ int smbus;
+
+ /*
+ * Not all chips support this register, but from a
+ * quick read of various datasheets no chip appears
+ * incompatible with the below attempt to disable
+ * the timeout. And the whole thing is opt-in...
+ */
+ smbus = i2c_smbus_read_word_swapped(client, JC42_REG_SMBUS);
+ if (smbus < 0)
+ return smbus;
+ i2c_smbus_write_word_swapped(client, JC42_REG_SMBUS,
+ smbus | SMBUS_STMOUT);
+ }
+
config = i2c_smbus_read_word_swapped(client, JC42_REG_CONFIG);
if (config < 0)
return config;