diff mbox

[v5,5/5] iio: humidity: si7020: add No Hold read mode

Message ID 1446118467-26453-5-git-send-email-nicola@corna.info (mailing list archive)
State New, archived
Headers show

Commit Message

Nicola Corna Oct. 29, 2015, 11:34 a.m. UTC 
The Si7013/20/21 modules support 2 read modes:
 * Hold mode (blocking), where the device stretches the clock until the end
of the measurement
 * No Hold mode (non-blocking), where the device replies NACK for every I2C
call during the measurement
Here the No Hold mode is implemented, selectable with the blocking_io
variable within si7020_platform_data. The default mode is Hold, unless the
adapter does not support clock stretching, in which case the No Hold mode
is used.

Signed-off-by: Nicola Corna <nicola@corna.info>
---
This patch depends on patch "[PATCH v4 1/2] iio: humidity: si7020: replaced
bitmask on humidity values with range check"
 drivers/iio/humidity/si7020.c        | 75 ++++++++++++++++++++++++++++++++----
 include/linux/platform_data/si7020.h | 21 ++++++++++
 2 files changed, 89 insertions(+), 7 deletions(-)
 create mode 100644 include/linux/platform_data/si7020.h

Comments

Jonathan Cameron Oct. 31, 2015, 10:21 a.m. UTC | #1 
On 29/10/15 11:34, Nicola Corna wrote:
> The Si7013/20/21 modules support 2 read modes:
>  * Hold mode (blocking), where the device stretches the clock until the end
> of the measurement
>  * No Hold mode (non-blocking), where the device replies NACK for every I2C
> call during the measurement
> Here the No Hold mode is implemented, selectable with the blocking_io
> variable within si7020_platform_data. The default mode is Hold, unless the
> adapter does not support clock stretching, in which case the No Hold mode
> is used.
> 
> Signed-off-by: Nicola Corna <nicola@corna.info>
I'm fine with this.  The dependency below should I think show up in the
coming merge window, so this lot might as well go via Wolfram.

Acked-by: Jonathan Cameron <jic23@kernel.org>
> ---
> This patch depends on patch "[PATCH v4 1/2] iio: humidity: si7020: replaced
> bitmask on humidity values with range check"
>  drivers/iio/humidity/si7020.c        | 75 ++++++++++++++++++++++++++++++++----
>  include/linux/platform_data/si7020.h | 21 ++++++++++
>  2 files changed, 89 insertions(+), 7 deletions(-)
>  create mode 100644 include/linux/platform_data/si7020.h
> 
> diff --git a/drivers/iio/humidity/si7020.c b/drivers/iio/humidity/si7020.c
> index 12128d1..674a61a 100644
> --- a/drivers/iio/humidity/si7020.c
> +++ b/drivers/iio/humidity/si7020.c
> @@ -2,6 +2,7 @@
>   * si7020.c - Silicon Labs Si7013/20/21 Relative Humidity and Temp Sensors
>   * Copyright (c) 2013,2014  Uplogix, Inc.
>   * David Barksdale <dbarksdale@uplogix.com>
> + * Copyright (c) 2015 Nicola Corna <nicola@corna.info>
>   *
>   * This program is free software; you can redistribute it and/or modify it
>   * under the terms and conditions of the GNU General Public License,
> @@ -30,33 +31,78 @@
>  #include <linux/module.h>
>  #include <linux/slab.h>
>  #include <linux/sysfs.h>
> +#include <linux/jiffies.h>
>  
>  #include <linux/iio/iio.h>
>  #include <linux/iio/sysfs.h>
> +#include <linux/platform_data/si7020.h>
>  
>  /* Measure Relative Humidity, Hold Master Mode */
>  #define SI7020CMD_RH_HOLD	0xE5
> +/* Measure Relative Humidity, No Hold Master Mode */
> +#define SI7020CMD_RH_NO_HOLD	0xF5
>  /* Measure Temperature, Hold Master Mode */
>  #define SI7020CMD_TEMP_HOLD	0xE3
> +/* Measure Temperature, No Hold Master Mode */
> +#define SI7020CMD_TEMP_NO_HOLD	0xF3
>  /* Software Reset */
>  #define SI7020CMD_RESET		0xFE
> +/* Relative humidity measurement timeout (us) */
> +#define SI7020_RH_TIMEOUT	22800
> +/* Temperature measurement timeout (us) */
> +#define SI7020_TEMP_TIMEOUT	10800
> +/* Minimum delay between retries (No Hold Mode) in us */
> +#define SI7020_NOHOLD_SLEEP_MIN	2000
> +/* Maximum delay between retries (No Hold Mode) in us */
> +#define SI7020_NOHOLD_SLEEP_MAX	6000
>  
>  static int si7020_read_raw(struct iio_dev *indio_dev,
>  			   struct iio_chan_spec const *chan, int *val,
>  			   int *val2, long mask)
>  {
>  	struct i2c_client **client = iio_priv(indio_dev);
> +	struct si7020_platform_data *pdata;
>  	int ret;
> +	bool holdmode;
> +	unsigned char buf[2];
> +	unsigned long start;
>  
>  	switch (mask) {
>  	case IIO_CHAN_INFO_RAW:
> -		ret = i2c_smbus_read_word_data(*client,
> -					       chan->type == IIO_TEMP ?
> -					       SI7020CMD_TEMP_HOLD :
> -					       SI7020CMD_RH_HOLD);
> -		if (ret < 0)
> -			return ret;
> -		*val = ret >> 2;
> +		pdata = dev_get_platdata(&(*client)->dev);
> +		if (pdata)
> +			holdmode = pdata->blocking_io;
> +		else
> +			holdmode = !i2c_check_quirks((*client)->adapter,
> +				   I2C_AQ_NO_CLK_STRETCH);
> +		if (holdmode) {
> +			ret = i2c_smbus_read_word_data(*client,
> +						       chan->type == IIO_TEMP ?
> +						       SI7020CMD_TEMP_HOLD :
> +						       SI7020CMD_RH_HOLD);
> +			if (ret < 0)
> +				return ret;
> +			*val = ret >> 2;
> +		} else {
> +			ret = i2c_smbus_write_byte(*client,
> +						   chan->type == IIO_TEMP ?
> +						   SI7020CMD_TEMP_NO_HOLD :
> +						   SI7020CMD_RH_NO_HOLD);
> +			if (ret < 0)
> +				return ret;
> +			start = jiffies;
> +			while ((ret = i2c_master_recv(*client, buf, 2)) < 0) {
> +				if (time_after(jiffies, start +
> +					       usecs_to_jiffies(
> +							chan->type == IIO_TEMP ?
> +							SI7020_TEMP_TIMEOUT :
> +							SI7020_RH_TIMEOUT)))
> +					return ret;
> +				usleep_range(SI7020_NOHOLD_SLEEP_MIN,
> +					     SI7020_NOHOLD_SLEEP_MAX);
> +			}
> +			*val = ((buf[0] << 8) | buf[1]) >> 2;
> +		}
>  		/*
>  		 * Humidity values can slightly exceed the 0-100%RH
>  		 * range and should be corrected by software
> @@ -116,6 +162,7 @@ static int si7020_probe(struct i2c_client *client,
>  {
>  	struct iio_dev *indio_dev;
>  	struct i2c_client **data;
> +	struct si7020_platform_data *pdata;
>  	int ret;
>  
>  	if (!i2c_check_functionality(client->adapter,
> @@ -123,6 +170,20 @@ static int si7020_probe(struct i2c_client *client,
>  				     I2C_FUNC_SMBUS_READ_WORD_DATA))
>  		return -ENODEV;
>  
> +	pdata = dev_get_platdata(&client->dev);
> +	if (pdata) {
> +		if (pdata->blocking_io) {
> +			if (i2c_check_quirks(client->adapter,
> +			   I2C_AQ_NO_CLK_STRETCH))
> +				return -ENODEV;
> +		} else if (!i2c_check_functionality(client->adapter,
> +			  I2C_FUNC_I2C))
> +			return -ENODEV;
> +	} else
> +		if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C) &&
> +		   i2c_check_quirks(client->adapter, I2C_AQ_NO_CLK_STRETCH))
> +			return -ENODEV;
> +
>  	/* Reset device, loads default settings. */
>  	ret = i2c_smbus_write_byte(client, SI7020CMD_RESET);
>  	if (ret < 0)
> diff --git a/include/linux/platform_data/si7020.h b/include/linux/platform_data/si7020.h
> new file mode 100644
> index 0000000..8bb5848
> --- /dev/null
> +++ b/include/linux/platform_data/si7020.h
> @@ -0,0 +1,21 @@
> +/*
> + * Copyright (C) 2015 Nicola Corna <nicola@corna.info>
> + *
> + * This software is licensed under the terms of the GNU General Public
> + * License version 2, as published by the Free Software Foundation, and
> + * may be copied, distributed, and modified under those terms.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#ifndef __SI7020_H_
> +#define __SI7020_H_
> +
> +struct si7020_platform_data {
> +	bool blocking_io;
> +};
> +#endif /* __SI7020_H_ */
>
Wolfram Sang Nov. 30, 2015, 5:33 p.m. UTC | #2 
On Sat, Oct 31, 2015 at 10:21:56AM +0000, Jonathan Cameron wrote:
> On 29/10/15 11:34, Nicola Corna wrote:
> > The Si7013/20/21 modules support 2 read modes:
> >  * Hold mode (blocking), where the device stretches the clock until the end
> > of the measurement
> >  * No Hold mode (non-blocking), where the device replies NACK for every I2C
> > call during the measurement
> > Here the No Hold mode is implemented, selectable with the blocking_io
> > variable within si7020_platform_data. The default mode is Hold, unless the
> > adapter does not support clock stretching, in which case the No Hold mode
> > is used.
> > 
> > Signed-off-by: Nicola Corna <nicola@corna.info>
> I'm fine with this.  The dependency below should I think show up in the
> coming merge window, so this lot might as well go via Wolfram.
> 
> Acked-by: Jonathan Cameron <jic23@kernel.org>

Not sure, will think about it...
Jonathan Cameron Dec. 5, 2015, 6:24 p.m. UTC | #3 
On 30/11/15 17:33, Wolfram Sang wrote:
> On Sat, Oct 31, 2015 at 10:21:56AM +0000, Jonathan Cameron wrote:
>> On 29/10/15 11:34, Nicola Corna wrote:
>>> The Si7013/20/21 modules support 2 read modes:
>>>  * Hold mode (blocking), where the device stretches the clock until the end
>>> of the measurement
>>>  * No Hold mode (non-blocking), where the device replies NACK for every I2C
>>> call during the measurement
>>> Here the No Hold mode is implemented, selectable with the blocking_io
>>> variable within si7020_platform_data. The default mode is Hold, unless the
>>> adapter does not support clock stretching, in which case the No Hold mode
>>> is used.
>>>
>>> Signed-off-by: Nicola Corna <nicola@corna.info>
>> I'm fine with this.  The dependency below should I think show up in the
>> coming merge window, so this lot might as well go via Wolfram.
>>
>> Acked-by: Jonathan Cameron <jic23@kernel.org>
> 
> Not sure, will think about it...
> 
Nicola,

If Wolfram doesn't pick this up, please ping me after the next merge window.
Whilst I'll still have it in my queue, it'll be so long ago by then I'll probably
miss it!

Jonathan
Wolfram Sang Dec. 5, 2015, 7:01 p.m. UTC | #4 
> If Wolfram doesn't pick this up, please ping me after the next merge window.

I tried to pick it a second ago, but it could not be applied (my branch
is based on 4.4-rc3). So, I really think it's better you pick it and
handle the conflicts.
diff mbox

Patch

diff --git a/drivers/iio/humidity/si7020.c b/drivers/iio/humidity/si7020.c
index 12128d1..674a61a 100644
--- a/drivers/iio/humidity/si7020.c
+++ b/drivers/iio/humidity/si7020.c
@@ -2,6 +2,7 @@ 
  * si7020.c - Silicon Labs Si7013/20/21 Relative Humidity and Temp Sensors
  * Copyright (c) 2013,2014  Uplogix, Inc.
  * David Barksdale <dbarksdale@uplogix.com>
+ * Copyright (c) 2015 Nicola Corna <nicola@corna.info>
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -30,33 +31,78 @@ 
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/sysfs.h>
+#include <linux/jiffies.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
+#include <linux/platform_data/si7020.h>
 
 /* Measure Relative Humidity, Hold Master Mode */
 #define SI7020CMD_RH_HOLD	0xE5
+/* Measure Relative Humidity, No Hold Master Mode */
+#define SI7020CMD_RH_NO_HOLD	0xF5
 /* Measure Temperature, Hold Master Mode */
 #define SI7020CMD_TEMP_HOLD	0xE3
+/* Measure Temperature, No Hold Master Mode */
+#define SI7020CMD_TEMP_NO_HOLD	0xF3
 /* Software Reset */
 #define SI7020CMD_RESET		0xFE
+/* Relative humidity measurement timeout (us) */
+#define SI7020_RH_TIMEOUT	22800
+/* Temperature measurement timeout (us) */
+#define SI7020_TEMP_TIMEOUT	10800
+/* Minimum delay between retries (No Hold Mode) in us */
+#define SI7020_NOHOLD_SLEEP_MIN	2000
+/* Maximum delay between retries (No Hold Mode) in us */
+#define SI7020_NOHOLD_SLEEP_MAX	6000
 
 static int si7020_read_raw(struct iio_dev *indio_dev,
 			   struct iio_chan_spec const *chan, int *val,
 			   int *val2, long mask)
 {
 	struct i2c_client **client = iio_priv(indio_dev);
+	struct si7020_platform_data *pdata;
 	int ret;
+	bool holdmode;
+	unsigned char buf[2];
+	unsigned long start;
 
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
-		ret = i2c_smbus_read_word_data(*client,
-					       chan->type == IIO_TEMP ?
-					       SI7020CMD_TEMP_HOLD :
-					       SI7020CMD_RH_HOLD);
-		if (ret < 0)
-			return ret;
-		*val = ret >> 2;
+		pdata = dev_get_platdata(&(*client)->dev);
+		if (pdata)
+			holdmode = pdata->blocking_io;
+		else
+			holdmode = !i2c_check_quirks((*client)->adapter,
+				   I2C_AQ_NO_CLK_STRETCH);
+		if (holdmode) {
+			ret = i2c_smbus_read_word_data(*client,
+						       chan->type == IIO_TEMP ?
+						       SI7020CMD_TEMP_HOLD :
+						       SI7020CMD_RH_HOLD);
+			if (ret < 0)
+				return ret;
+			*val = ret >> 2;
+		} else {
+			ret = i2c_smbus_write_byte(*client,
+						   chan->type == IIO_TEMP ?
+						   SI7020CMD_TEMP_NO_HOLD :
+						   SI7020CMD_RH_NO_HOLD);
+			if (ret < 0)
+				return ret;
+			start = jiffies;
+			while ((ret = i2c_master_recv(*client, buf, 2)) < 0) {
+				if (time_after(jiffies, start +
+					       usecs_to_jiffies(
+							chan->type == IIO_TEMP ?
+							SI7020_TEMP_TIMEOUT :
+							SI7020_RH_TIMEOUT)))
+					return ret;
+				usleep_range(SI7020_NOHOLD_SLEEP_MIN,
+					     SI7020_NOHOLD_SLEEP_MAX);
+			}
+			*val = ((buf[0] << 8) | buf[1]) >> 2;
+		}
 		/*
 		 * Humidity values can slightly exceed the 0-100%RH
 		 * range and should be corrected by software
@@ -116,6 +162,7 @@  static int si7020_probe(struct i2c_client *client,
 {
 	struct iio_dev *indio_dev;
 	struct i2c_client **data;
+	struct si7020_platform_data *pdata;
 	int ret;
 
 	if (!i2c_check_functionality(client->adapter,
@@ -123,6 +170,20 @@  static int si7020_probe(struct i2c_client *client,
 				     I2C_FUNC_SMBUS_READ_WORD_DATA))
 		return -ENODEV;
 
+	pdata = dev_get_platdata(&client->dev);
+	if (pdata) {
+		if (pdata->blocking_io) {
+			if (i2c_check_quirks(client->adapter,
+			   I2C_AQ_NO_CLK_STRETCH))
+				return -ENODEV;
+		} else if (!i2c_check_functionality(client->adapter,
+			  I2C_FUNC_I2C))
+			return -ENODEV;
+	} else
+		if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C) &&
+		   i2c_check_quirks(client->adapter, I2C_AQ_NO_CLK_STRETCH))
+			return -ENODEV;
+
 	/* Reset device, loads default settings. */
 	ret = i2c_smbus_write_byte(client, SI7020CMD_RESET);
 	if (ret < 0)
diff --git a/include/linux/platform_data/si7020.h b/include/linux/platform_data/si7020.h
new file mode 100644
index 0000000..8bb5848
--- /dev/null
+++ b/include/linux/platform_data/si7020.h
@@ -0,0 +1,21 @@ 
+/*
+ * Copyright (C) 2015 Nicola Corna <nicola@corna.info>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef __SI7020_H_
+#define __SI7020_H_
+
+struct si7020_platform_data {
+	bool blocking_io;
+};
+#endif /* __SI7020_H_ */