The Texas Instruments TMP121 is a SPI temperature sensor very similar
to the LM70, with slightly higher resolution. This patch extends the
LM70 driver to support the TMP121. Chip type is determined by
platform data.
Signed-off-by: Manuel Lauss <mano at roarinelk.homelinux.net>
---
Documentation/hwmon/lm70 | 7 +++++-
drivers/hwmon/Kconfig | 5 ++-
drivers/hwmon/lm70.c | 56 ++++++++++++++++++++++++++++++++++++++++-----
include/linux/spi/lm70.h | 15 ++++++++++++
4 files changed, 73 insertions(+), 10 deletions(-)
create mode 100644 include/linux/spi/lm70.h
diff --git a/Documentation/hwmon/lm70 b/Documentation/hwmon/lm70
index 2bdd3fe..88f4322 100644
--- a/Documentation/hwmon/lm70
+++ b/Documentation/hwmon/lm70
@@ -1,9 +1,11 @@
Kernel driver lm70
==================
-Supported chip:
+Supported chips:
* National Semiconductor LM70
Datasheet: http://www.national.com/pf/LM/LM70.html
+ * Texas Instruments TMP121/TMP123
+ Datasheet: http://www.ti.com/lit/gpn/tmp121
Author:
Kaiwan N Billimoria <kaiwan at designergraphix.com>
@@ -25,6 +27,9 @@ complement digital temperature (sent via the SIO line), is available in the
driver for interpretation. This driver makes use of the kernel's in-core
SPI support.
+The TMP121 is very similar; main differences are 4 wire SPI interface,
+and 13bit temperature data (0.0625 celsius resolution).
+
Thanks to
---------
Jean Delvare <khali at linux-fr.org> for mentoring the hwmon-side driver
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index d402e8d..56a84e0 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -407,11 +407,12 @@ config SENSORS_LM63
will be called lm63.
config SENSORS_LM70
- tristate "National Semiconductor LM70"
+ tristate "National Semiconductor LM70 / Texas Instruments TMP121"
depends on SPI_MASTER && EXPERIMENTAL
help
If you say yes here you get support for the National Semiconductor
- LM70 digital temperature sensor chip.
+ LM70 and Texas Instruments TMP121/TMP123 digital temperature
+ sensor chips.
This driver can also be built as a module. If so, the module
will be called lm70.
diff --git a/drivers/hwmon/lm70.c b/drivers/hwmon/lm70.c
index d435f00..9ab0479 100644
--- a/drivers/hwmon/lm70.c
+++ b/drivers/hwmon/lm70.c
@@ -33,13 +33,14 @@
#include <linux/hwmon.h>
#include <linux/mutex.h>
#include <linux/spi/spi.h>
-
+#include <linux/spi/lm70.h>
#define DRVNAME "lm70"
struct lm70 {
struct device *hwmon_dev;
struct mutex lock;
+ unsigned int chip;
};
/* sysfs hook function */
@@ -67,10 +68,8 @@ static ssize_t lm70_sense_temp(struct device *dev,
}
dev_dbg(dev, "rxbuf[1] : 0x%x rxbuf[0] : 0x%x\n", rxbuf[1], rxbuf[0]);
- raw = (rxbuf[1] << 8) + rxbuf[0];
- dev_dbg(dev, "raw=0x%x\n", raw);
-
/*
+ * LM70:
* The "raw" temperature read into rxbuf[] is a 16-bit signed 2's
* complement value. Only the MSB 11 bits (1 sign + 10 temperature
* bits) are meaningful; the LSB 5 bits are to be discarded.
@@ -80,8 +79,27 @@ static ssize_t lm70_sense_temp(struct device *dev,
* by 0.25. Also multiply by 1000 to represent in millidegrees
* Celsius.
* So it's equivalent to multiplying by 0.25 * 1000 = 250.
+ *
+ * TMP121:
+ * 13bits of 2's complement data, discard lower 3 bits. Chip
+ * transmits high byte first. Resolution 0.0625 celsius.
*/
- val = ((int)raw/32) * 250;
+ switch (p_lm70->chip) {
+ case LM70_CHIP_LM70:
+ raw = (rxbuf[1] << 8) + rxbuf[0];
+ dev_dbg(dev, "raw=0x%x\n", raw);
+ val = ((int)raw/32) * 250;
+ break;
+
+ case LM70_CHIP_TMP121:
+ raw = (rxbuf[0] << 8) + rxbuf[1];
+ dev_dbg(dev, "raw=0x%x\n", raw);
+ val = (raw / 8) * 625 / 10;
+ break;
+
+ default:
+ raw = 0;
+ }
status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */
out:
mutex_unlock(&p_lm70->lock);
@@ -93,7 +111,21 @@ static DEVICE_ATTR(temp1_input, S_IRUGO, lm70_sense_temp, NULL);
static ssize_t lm70_show_name(struct device *dev, struct device_attribute
*devattr, char *buf)
{
- return sprintf(buf, "lm70\n");
+ struct spi_device *spi = to_spi_device(dev);
+ struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);
+ int ret;
+
+ switch (p_lm70->chip) {
+ case LM70_CHIP_LM70:
+ ret = sprintf(buf, "lm70\n");
+ break;
+ case LM70_CHIP_TMP121:
+ ret = sprintf(buf, "tmp121\n");
+ break;
+ default:
+ ret = -EINVAL;
+ }
+ return ret;
}
static DEVICE_ATTR(name, S_IRUGO, lm70_show_name, NULL);
@@ -102,11 +134,20 @@ static DEVICE_ATTR(name, S_IRUGO, lm70_show_name, NULL);
static int __devinit lm70_probe(struct spi_device *spi)
{
+ struct lm70_platform_data *pdata;
struct lm70 *p_lm70;
int status;
+ unsigned int chip;
+
+ pdata = spi->dev.platform_data;
+ if (pdata)
+ chip = pdata->chip;
+ else
+ chip = LM70_CHIP_LM70;
/* signaling is SPI_MODE_0 on a 3-wire link (shared SI/SO) */
- if ((spi->mode & (SPI_CPOL|SPI_CPHA)) || !(spi->mode & SPI_3WIRE))
+ if ((chip == LM70_CHIP_LM70) &&
+ ((spi->mode & (SPI_CPOL|SPI_CPHA)) || !(spi->mode & SPI_3WIRE)))
return -EINVAL;
p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL);
@@ -114,6 +155,7 @@ static int __devinit lm70_probe(struct spi_device *spi)
return -ENOMEM;
mutex_init(&p_lm70->lock);
+ p_lm70->chip = chip;
/* sysfs hook */
p_lm70->hwmon_dev = hwmon_device_register(&spi->dev);
diff --git a/include/linux/spi/lm70.h b/include/linux/spi/lm70.h
new file mode 100644
index 0000000..986c35a
--- /dev/null
+++ b/include/linux/spi/lm70.h
@@ -0,0 +1,15 @@
+/*
+ * LM70 platform data
+ */
+
+#ifndef _LM70_H_
+#define _LM70_H_
+
+#define LM70_CHIP_LM70 0
+#define LM70_CHIP_TMP121 1
+
+struct lm70_platform_data {
+ unsigned int chip;
+};
+
+#endif
--
1.6.0.1
