[lm-sensors] [PATCH RESEND] hwmon: lm70: TI TMP121 support.

David Brownell david-b at pacbell.net
Thu Oct 23 18:53:00 CEST 2008


On Thursday 23 October 2008, Manuel Lauss wrote:
> > Ah, yes, the lack of an i2c_driver.id_table parameter was why I originally
> > wrote a separate driver.  I suppose I could add another struct spi_driver
> > for the TMP121 and sort out chip types internally.
> 
> Does this look acceptable?

Much better, thanks.  The SPI framework doesn't currently
identify chips other than as a driver name.  Hasn't needed to.


> --- 
> 
> From: Manuel Lauss <mano at roarinelk.homelinux.net>
> Subject: [PATCH] hwmon: Extend LM70 with TMP121/TMP123 support.
> 
> 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.
> 
> Signed-off-by: Manuel Lauss <mano at roarinelk.homelinux.net>
> ---
>  Documentation/hwmon/lm70 |    7 +++-
>  drivers/hwmon/Kconfig    |    5 ++-
>  drivers/hwmon/lm70.c     |   85 +++++++++++++++++++++++++++++++++++++++-------
>  3 files changed, 81 insertions(+), 16 deletions(-)
> 
> diff --git a/Documentation/hwmon/lm70 b/Documentation/hwmon/lm70
> index 2bdd3fe..80716d2 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
> +    Information: http://focus.ti.com/docs/prod/folders/print/tmp121.html
>  
>  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 13-bit temperature data (0.0625 degrees celsius resolution).

Instead of saying "4 wire SPI" I'd say "output-only SPI" ... since
in fact it only uses three wires.  An unlike the LM70, it's not
using the data wire for half duplex  transfers, it just spits out
the temperature reading.


> +
>  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 6de1e0f..f86923d 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"

TMP121 and TMP123 ...

>  	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..8c7651b 100644
> --- a/drivers/hwmon/lm70.c
> +++ b/drivers/hwmon/lm70.c
> @@ -37,9 +37,13 @@
>  
>  #define DRVNAME		"lm70"
>  
> +#define LM70_CHIP_LM70		0
> +#define LM70_CHIP_TMP121	1

Obviously TMP123 doesn't need a different identifier, since
the difference is only in the electrical connections used
for pins 1 & 2.  But a comment to that effect might be wise.


> +
>  struct lm70 {
>  	struct device *hwmon_dev;
>  	struct mutex lock;
> +	unsigned int chip;
>  };
>  
>  /* sysfs hook function */
> @@ -47,7 +51,7 @@ static ssize_t lm70_sense_temp(struct device *dev,
>  		struct device_attribute *attr, char *buf)
>  {
>  	struct spi_device *spi = to_spi_device(dev);
> -	int status, val;
> +	int status, val = 0;
>  	u8 rxbuf[2];
>  	s16 raw=0;
>  	struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);
> @@ -67,10 +71,8 @@ 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 +82,23 @@ 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:
> +	 * 13 bits of 2's complement data, discard LSB 3 bits.  Chip
> +	 * transmits high byte first.  Resolution 0.0625 degrees celsius.

For SPI, everything is MSB first ... else insist (spi->mode & SPI_LSB_FIRST)
is true.  Please strike the comment implying it might not be MSB first.


>  	 */
> -	val = ((int)raw/32) * 250;
> +	switch (p_lm70->chip) {
> +	case LM70_CHIP_LM70:
> +		raw = (rxbuf[1] << 8) + rxbuf[0];
> +		val = ((int)raw/32) * 250;
> +		break;
> +
> +	case LM70_CHIP_TMP121:
> +		raw = (rxbuf[0] << 8) + rxbuf[1];
> +		val = (raw / 8) * 625 / 10;
> +		break;
> +	}
> +	dev_dbg(dev, "raw=0x%x\n", raw);
>  	status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */
>  out:
>  	mutex_unlock(&p_lm70->lock);
> @@ -93,27 +110,37 @@ 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 lm70 *p_lm70 = dev_get_drvdata(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);
>  
>  /*----------------------------------------------------------------------*/
>  
> -static int __devinit lm70_probe(struct spi_device *spi)
> +static int __devinit common_probe(struct spi_device *spi, int chip)
>  {
>  	struct lm70 *p_lm70;
>  	int status;
>  
> -	/* signaling is SPI_MODE_0 on a 3-wire link (shared SI/SO) */
> -	if ((spi->mode & (SPI_CPOL|SPI_CPHA)) || !(spi->mode & SPI_3WIRE))
> -		return -EINVAL;
> -
>  	p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL);
>  	if (!p_lm70)
>  		return -ENOMEM;
>  
>  	mutex_init(&p_lm70->lock);
> +	p_lm70->chip = chip;
>  
>  	/* sysfs hook */
>  	p_lm70->hwmon_dev = hwmon_device_register(&spi->dev);
> @@ -141,6 +168,20 @@ out_dev_reg_failed:
>  	return status;
>  }
>  
> +static int __devinit lm70_probe(struct spi_device *spi)
> +{
> +	/* signaling is SPI_MODE_0 on a 3-wire link (shared SI/SO) */
> +	if ((spi->mode & (SPI_CPOL|SPI_CPHA)) || !(spi->mode & SPI_3WIRE))
> +		return -EINVAL;
> +
> +	return common_probe(spi, LM70_CHIP_LM70);
> +}
> +
> +static int __devinit tmp121_probe(struct spi_device *spi)
> +{

For symmetry you might verify the CPOL and CPHA settings are right;
that'd mostly help catch user configuration bugs.

> +	return common_probe(spi, LM70_CHIP_TMP121);
> +}
> +
>  static int __devexit lm70_remove(struct spi_device *spi)
>  {
>  	struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);
> @@ -154,6 +195,15 @@ static int __devexit lm70_remove(struct spi_device *spi)
>  	return 0;
>  }
>  
> +static struct spi_driver tmp121_driver = {
> +	.driver = {
> +		.name	= "tmp121",
> +		.owner	= THIS_MODULE,
> +	},
> +	.probe	= tmp121_probe,
> +	.remove	= __devexit_p(lm70_remove),
> +};
> +
>  static struct spi_driver lm70_driver = {
>  	.driver = {
>  		.name	= "lm70",
> @@ -165,17 +215,26 @@ static struct spi_driver lm70_driver = {
>  
>  static int __init init_lm70(void)
>  {
> -	return spi_register_driver(&lm70_driver);
> +	int ret = spi_register_driver(&lm70_driver);
> +	if (ret)
> +		return ret;
> +
> +	ret = spi_register_driver(&tmp121_driver);
> +	if (ret)
> +		spi_unregister_driver(&lm70_driver);
> +
> +	return ret;
>  }
>  
>  static void __exit cleanup_lm70(void)
>  {
>  	spi_unregister_driver(&lm70_driver);
> +	spi_unregister_driver(&tmp121_driver);
>  }
>  
>  module_init(init_lm70);
>  module_exit(cleanup_lm70);
>  
>  MODULE_AUTHOR("Kaiwan N Billimoria");
> -MODULE_DESCRIPTION("National Semiconductor LM70 Linux driver");
> +MODULE_DESCRIPTION("National Semiconductor LM70 / TI TMP121 Linux driver");
>  MODULE_LICENSE("GPL");
> -- 
> 1.6.0.2
> 
> 






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