MPL115 supports shutdown gpio which can be used to set the state
to low power mode. Power from all internal circuits and
registers is removed. This is done by pulling the SHDN pin to low.
This patch enables runtime PM on MPL115 to increase power savings.
According to spec., a wakeup time period of ~5 ms exists between
waking up and actually communicating with the device. This is
implemented using sleep delay.
Signed-off-by: Rajat Khandelwal <[email protected]>
---
v4:
1. Using runtime PM for low power mode and not forcing shutdown pin
2. Changing patch comment
3. Increasing autosuspend timeout to 2 sec to make the driver more
responsive to user
drivers/iio/pressure/mpl115.c | 61 ++++++++++++++++++++++++++++++-
drivers/iio/pressure/mpl115.h | 5 +++
drivers/iio/pressure/mpl115_i2c.c | 1 +
drivers/iio/pressure/mpl115_spi.c | 1 +
4 files changed, 67 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/pressure/mpl115.c b/drivers/iio/pressure/mpl115.c
index 5bf5b9abe6f1..ec7527161844 100644
--- a/drivers/iio/pressure/mpl115.c
+++ b/drivers/iio/pressure/mpl115.c
@@ -4,12 +4,13 @@
*
* Copyright (c) 2014 Peter Meerwald <[email protected]>
*
- * TODO: shutdown pin
+ * TODO: synchronization with system suspend
*/
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
#include "mpl115.h"
@@ -27,6 +28,7 @@ struct mpl115_data {
s16 a0;
s16 b1, b2;
s16 c12;
+ struct gpio_desc *shutdown;
const struct mpl115_ops *ops;
};
@@ -102,16 +104,24 @@ static int mpl115_read_raw(struct iio_dev *indio_dev,
switch (mask) {
case IIO_CHAN_INFO_PROCESSED:
+ pm_runtime_get_sync(data->dev);
ret = mpl115_comp_pressure(data, val, val2);
if (ret < 0)
return ret;
+ pm_runtime_mark_last_busy(data->dev);
+ pm_runtime_put_autosuspend(data->dev);
+
return IIO_VAL_INT_PLUS_MICRO;
case IIO_CHAN_INFO_RAW:
+ pm_runtime_get_sync(data->dev);
/* temperature -5.35 C / LSB, 472 LSB is 25 C */
ret = mpl115_read_temp(data);
if (ret < 0)
return ret;
+ pm_runtime_mark_last_busy(data->dev);
+ pm_runtime_put_autosuspend(data->dev);
*val = ret >> 6;
+
return IIO_VAL_INT;
case IIO_CHAN_INFO_OFFSET:
*val = -605;
@@ -168,6 +178,8 @@ int mpl115_probe(struct device *dev, const char *name,
if (ret)
return ret;
+ dev_set_drvdata(dev, indio_dev);
+
ret = data->ops->read(data->dev, MPL115_A0);
if (ret < 0)
return ret;
@@ -185,10 +193,58 @@ int mpl115_probe(struct device *dev, const char *name,
return ret;
data->c12 = ret;
+ data->shutdown = devm_gpiod_get_optional(dev, "shutdown",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(data->shutdown))
+ return dev_err_probe(dev, PTR_ERR(data->shutdown),
+ "cannot get shutdown gpio\n");
+
+ if (data->shutdown) {
+ /* Enable runtime PM */
+ pm_runtime_get_noresume(dev);
+ pm_runtime_set_active(dev);
+ pm_runtime_enable(dev);
+
+ /*
+ * As the device takes 3 ms to come up with a fresh
+ * reading after power-on and 5 ms to actually power-on,
+ * do not shut it down unnecessarily. Set autosuspend to
+ * 2000 ms.
+ */
+ pm_runtime_set_autosuspend_delay(dev, 2000);
+ pm_runtime_use_autosuspend(dev);
+ pm_runtime_put(dev);
+
+ dev_dbg(dev, "low-power mode enabled");
+ } else
+ dev_dbg(dev, "low-power mode disabled");
+
return devm_iio_device_register(dev, indio_dev);
}
EXPORT_SYMBOL_NS_GPL(mpl115_probe, IIO_MPL115);
+static int mpl115_runtime_suspend(struct device *dev)
+{
+ struct mpl115_data *data = iio_priv(dev_get_drvdata(dev));
+
+ gpiod_set_value(data->shutdown, 1);
+
+ return 0;
+}
+
+static int mpl115_runtime_resume(struct device *dev)
+{
+ struct mpl115_data *data = iio_priv(dev_get_drvdata(dev));
+
+ gpiod_set_value(data->shutdown, 0);
+ usleep_range(5000, 6000);
+
+ return 0;
+}
+
+DEFINE_RUNTIME_DEV_PM_OPS(mpl115_dev_pm_ops, mpl115_runtime_suspend,
+ mpl115_runtime_resume, NULL);
+
MODULE_AUTHOR("Peter Meerwald <[email protected]>");
MODULE_DESCRIPTION("Freescale MPL115 pressure/temperature driver");
MODULE_LICENSE("GPL");
diff --git a/drivers/iio/pressure/mpl115.h b/drivers/iio/pressure/mpl115.h
index 57d55eb8e661..78a0068a17bb 100644
--- a/drivers/iio/pressure/mpl115.h
+++ b/drivers/iio/pressure/mpl115.h
@@ -6,6 +6,8 @@
* Copyright (c) 2016 Akinobu Mita <[email protected]>
*/
+#include <linux/pm_runtime.h>
+
#ifndef _MPL115_H_
#define _MPL115_H_
@@ -18,4 +20,7 @@ struct mpl115_ops {
int mpl115_probe(struct device *dev, const char *name,
const struct mpl115_ops *ops);
+/*PM ops */
+extern const struct dev_pm_ops mpl115_dev_pm_ops;
+
#endif
diff --git a/drivers/iio/pressure/mpl115_i2c.c b/drivers/iio/pressure/mpl115_i2c.c
index 099ab1c6832c..555bda1146fb 100644
--- a/drivers/iio/pressure/mpl115_i2c.c
+++ b/drivers/iio/pressure/mpl115_i2c.c
@@ -53,6 +53,7 @@ MODULE_DEVICE_TABLE(i2c, mpl115_i2c_id);
static struct i2c_driver mpl115_i2c_driver = {
.driver = {
.name = "mpl115",
+ .pm = pm_ptr(&mpl115_dev_pm_ops),
},
.probe = mpl115_i2c_probe,
.id_table = mpl115_i2c_id,
diff --git a/drivers/iio/pressure/mpl115_spi.c b/drivers/iio/pressure/mpl115_spi.c
index 7feec87e2704..58d218fd90dc 100644
--- a/drivers/iio/pressure/mpl115_spi.c
+++ b/drivers/iio/pressure/mpl115_spi.c
@@ -92,6 +92,7 @@ MODULE_DEVICE_TABLE(spi, mpl115_spi_ids);
static struct spi_driver mpl115_spi_driver = {
.driver = {
.name = "mpl115",
+ .pm = pm_ptr(&mpl115_dev_pm_ops),
},
.probe = mpl115_spi_probe,
.id_table = mpl115_spi_ids,
--
2.34.1
Hi Rajat,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on jic23-iio/togreg]
[also build test ERROR on linus/master v6.0 next-20220930]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Rajat-Khandelwal/iio-pressure-mpl115-Implementing-low-power-mode-by-shutdown-gpio/20221003-133904
base: https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
config: x86_64-randconfig-a005-20221003
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/284b52f6eb0616aeb44203d7114c4fb1e80b785d
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Rajat-Khandelwal/iio-pressure-mpl115-Implementing-low-power-mode-by-shutdown-gpio/20221003-133904
git checkout 284b52f6eb0616aeb44203d7114c4fb1e80b785d
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>, old ones prefixed by <<):
>> ERROR: modpost: "mpl115_dev_pm_ops" [drivers/iio/pressure/mpl115_spi.ko] undefined!
--
0-DAY CI Kernel Test Service
https://01.org/lkp
On Mon, 3 Oct 2022 18:17:57 +0800
kernel test robot <[email protected]> wrote:
> Hi Rajat,
>
> Thank you for the patch! Yet something to improve:
>
> [auto build test ERROR on jic23-iio/togreg]
> [also build test ERROR on linus/master v6.0 next-20220930]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
>
> url: https://github.com/intel-lab-lkp/linux/commits/Rajat-Khandelwal/iio-pressure-mpl115-Implementing-low-power-mode-by-shutdown-gpio/20221003-133904
> base: https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
> config: x86_64-randconfig-a005-20221003
> compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
> reproduce (this is a W=1 build):
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # https://github.com/intel-lab-lkp/linux/commit/284b52f6eb0616aeb44203d7114c4fb1e80b785d
> git remote add linux-review https://github.com/intel-lab-lkp/linux
> git fetch --no-tags linux-review Rajat-Khandelwal/iio-pressure-mpl115-Implementing-low-power-mode-by-shutdown-gpio/20221003-133904
> git checkout 284b52f6eb0616aeb44203d7114c4fb1e80b785d
> # save the config file
> mkdir build_dir && cp config build_dir/.config
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash
>
> If you fix the issue, kindly add following tag where applicable
> | Reported-by: kernel test robot <[email protected]>
>
> All errors (new ones prefixed by >>, old ones prefixed by <<):
>
> >> ERROR: modpost: "mpl115_dev_pm_ops" [drivers/iio/pressure/mpl115_spi.ko] undefined!
>
You have probably figured this out, but you need the
EXPORT_NS_RUNTIME_DEV_PM_OPS()
with appropriate namespace set.
Thanks,
Jonathan