diff options
| -rw-r--r-- | Documentation/devicetree/bindings/hwmon/jc42.txt | 4 | ||||
| -rw-r--r-- | drivers/hwmon/jc42.c | 21 |
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; |