Re: [RFC v2 3/3] iio: chemical: add Atlas pH-SM sensor support

[Adriana Reus <adriana.reus@intel.com>]

On 15.12.2015 17:19, Matt Ranostay wrote:
> On Tue, Dec 15, 2015 at 3:03 AM, Adriana Reus <adriana.reus@intel.com> wrote:
>>
>>
>> On 15.12.2015 11:26, Matt Ranostay wrote:
>>>
>>> Add support for the Atlas Scientific pH-SM chemical sensor that can
>>> detect pH levels of solutions in the range of 0-14.
>>>
>>> Signed-off-by: Matt Ranostay <mranostay@gmail.com>
>>> ---
>>>    .../bindings/iio/chemical/atlas,ph-sm.txt          |  22 ++
>>>    drivers/iio/chemical/Kconfig                       |  13 +
>>>    drivers/iio/chemical/Makefile                      |   1 +
>>>    drivers/iio/chemical/atlas-ph-sensor.c             | 431
>>> +++++++++++++++++++++
>>>    4 files changed, 467 insertions(+)
>>>    create mode 100644
>>> Documentation/devicetree/bindings/iio/chemical/atlas,ph-sm.txt
>>>    create mode 100644 drivers/iio/chemical/atlas-ph-sensor.c
>>>
>>> diff --git
>>> a/Documentation/devicetree/bindings/iio/chemical/atlas,ph-sm.txt
>>> b/Documentation/devicetree/bindings/iio/chemical/atlas,ph-sm.txt
>>> new file mode 100644
>>> index 0000000..cffa190
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/iio/chemical/atlas,ph-sm.txt
>>> @@ -0,0 +1,22 @@
>>> +* Atlas Scientific pH-SM OEM sensor
>>> +
>>>
>>> +http://www.atlas-scientific.com/_files/_datasheets/_oem/pH_oem_datasheet.pdf
>>> +
>>> +Required properties:
>>> +
>>> +  - compatible: must be "atlas,ph-sm"
>>> +  - reg: the I2C address of the sensor
>>> +  - interrupt-parent: should be the phandle for the interrupt controller
>>> +  - interrupts: the sole interrupt generated by the device
>>> +
>>> +  Refer to interrupt-controller/interrupts.txt for generic interrupt
>>> client
>>> +  node bindings.
>>> +
>>> +Example:
>>> +
>>> +atlas@65 {
>>> +       compatible = "atlas,ph-sm";
>>> +       reg = <0x65>;
>>> +       interrupt-parent = <&gpio1>;
>>> +       interrupts = <16 2>;
>>> +};
>>> diff --git a/drivers/iio/chemical/Kconfig b/drivers/iio/chemical/Kconfig
>>> index 3061b72..a358e4b 100644
>>> --- a/drivers/iio/chemical/Kconfig
>>> +++ b/drivers/iio/chemical/Kconfig
>>> @@ -4,6 +4,19 @@
>>>
>>>    menu "Chemical Sensors"
>>>
>>> +config ATLAS_PH_SENSOR
>>> +       tristate "Atlas Scientific OEM pH-SM sensor"
>>> +       depends on I2C
>>> +       select REGMAP_I2C
>>> +       select IIO_BUFFER
>>> +       select IIO_TRIGGERED_BUFFER
>>> +       help
>>> +        Say Y here to build I2C interface support for the Atlas
>>> +        Scientific OEM pH-SM sensor.
>>> +
>>> +        To compile this driver as module, choose M here: the
>>> +        module will be called atlas-ph-sensor.
>>> +
>>>    config VZ89X
>>>          tristate "SGX Sensortech MiCS VZ89X VOC sensor"
>>>          depends on I2C
>>> diff --git a/drivers/iio/chemical/Makefile b/drivers/iio/chemical/Makefile
>>> index 7292f2d..e9eb852 100644
>>> --- a/drivers/iio/chemical/Makefile
>>> +++ b/drivers/iio/chemical/Makefile
>>> @@ -3,4 +3,5 @@
>>>    #
>>>
>>>    # When adding new entries keep the list in alphabetical order
>>> +obj-$(CONFIG_ATLAS_PH_SENSOR)  += atlas-ph-sensor.o
>>>    obj-$(CONFIG_VZ89X)           += vz89x.o
>>> diff --git a/drivers/iio/chemical/atlas-ph-sensor.c
>>> b/drivers/iio/chemical/atlas-ph-sensor.c
>>> new file mode 100644
>>> index 0000000..63da26b
>>> --- /dev/null
>>> +++ b/drivers/iio/chemical/atlas-ph-sensor.c
>>> @@ -0,0 +1,431 @@
>>> +/*
>>> + * atlas-ph-sensor.c - Support for Atlas Scientific OEM pH-SM sensor
>>> + *
>>> + * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com>
>>> + *
>>> + * This program is free software; you can redistribute it and/or modify
>>> + * it under the terms of the GNU General Public License as published by
>>> + * the Free Software Foundation; either version 2 of the License, or
>>> + * (at your option) any later version.
>>> + *
>>> + * 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.
>>> + *
>>> + */
>>> +
>>> +#include <linux/module.h>
>>> +#include <linux/init.h>
>>> +#include <linux/interrupt.h>
>>> +#include <linux/delay.h>
>>> +#include <linux/mutex.h>
>>> +#include <linux/err.h>
>>> +#include <linux/irq.h>
>>> +#include <linux/gpio.h>
>>> +#include <linux/i2c.h>
>>> +#include <linux/regmap.h>
>>> +#include <linux/iio/iio.h>
>>> +#include <linux/iio/buffer.h>
>>> +#include <linux/iio/trigger.h>
>>> +#include <linux/iio/trigger_consumer.h>
>>> +#include <linux/iio/triggered_buffer.h>
>>> +#include <linux/pm_runtime.h>
>>> +
>>> +#define ATLAS_REGMAP_NAME      "atlas_ph_regmap"
>>> +#define ATLAS_DRV_NAME         "atlas_ph"
>>> +
>>> +#define ATLAS_REG_DEV_TYPE             0x00
>>> +#define ATLAS_REG_DEV_VERSION          0x01
>>> +
>>> +#define ATLAS_REG_INT_CONTROL          0x04
>>> +#define ATLAS_REG_INT_CONTROL_EN       BIT(2)
>>> +
>>> +#define ATLAS_REG_PWR_CONTROL          0x06
>>> +
>>> +#define ATLAS_REG_TEMP_DATA            0x0e
>>> +#define ATLAS_REG_PH_DATA              0x16
>>> +
>>> +#define ATLAS_PH_INT_TIME_IN_US                450000
>>> +
>>> +struct atlas_data {
>>> +       struct i2c_client *client;
>>> +       struct iio_trigger *trig;
>>> +       struct regmap *regmap;
>>> +
>>> +       __be32 buffer[4]; /* 32-bit pH data + 32-bit pad + 64-bit
>>> timestamp */
>>> +};
>>> +
>>> +static bool atlas_is_volatile_reg(struct device *dev, unsigned int reg)
>>> +{
>>> +       if (reg == ATLAS_REG_INT_CONTROL)
>>> +               return true;
>>> +
>>> +       return false;
>>> +}
>>> +
>>> +static const struct regmap_config atlas_regmap_config = {
>>> +       .name = ATLAS_REGMAP_NAME,
>>> +
>>> +       .reg_bits = 8,
>>> +       .val_bits = 8,
>>> +
>>> +       .volatile_reg = atlas_is_volatile_reg,
>>> +       .max_register = ATLAS_REG_PH_DATA + 4,
>>> +       .cache_type = REGCACHE_FLAT,
>>> +
>>> +};
>>> +
>>> +static const struct iio_chan_spec atlas_channels[] = {
>>> +       {
>>> +               .type = IIO_PH,
>>> +               .info_mask_separate =
>>> +                       BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
>>> +               .scan_index = 0,
>>> +               .scan_type = {
>>> +                       .sign = 'u',
>>> +                       .realbits = 32,
>>> +                       .storagebits = 32,
>>> +                       .endianness = IIO_BE,
>>> +               },
>>> +       },
>>> +       {
>>> +               .type = IIO_TEMP,
>>> +               .address = ATLAS_REG_TEMP_DATA,
>>> +               .info_mask_separate =
>>> +                       BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
>>> +               .output = 1,
>>> +               .scan_index = -1
>>> +       },
>>> +};
>>> +
>>> +static int atlas_set_powermode(struct atlas_data *data, int on)
>>> +{
>>> +       return regmap_write(data->regmap, ATLAS_REG_PWR_CONTROL, on);
>>> +}
>>> +
>>> +static int atlas_set_interrupt(struct atlas_data *data, bool state)
>>> +{
>>> +       return regmap_update_bits(data->regmap, ATLAS_REG_INT_CONTROL,
>>> +                                 ATLAS_REG_INT_CONTROL_EN,
>>> +                                 state ? ATLAS_REG_INT_CONTROL_EN : 0);
>>> +}
>>> +
>>> +static int atlas_buffer_postenable(struct iio_dev *indio_dev)
>>> +{
>>> +       struct atlas_data *data = iio_priv(indio_dev);
>>> +
>>> +       pm_runtime_get_sync(&data->client->dev);
>>
>> ^ pm_runtime_get_sync may return errors
>>
>>> +
>>> +       return atlas_set_interrupt(data, true);
>>> +}
>>> +
>>> +static int atlas_buffer_predisable(struct iio_dev *indio_dev)
>>> +{
>>> +       struct atlas_data *data = iio_priv(indio_dev);
>>> +       int ret;
>>> +
>>> +       ret = atlas_set_interrupt(data, false);
>>> +       if (ret)
>>> +               return ret;
>>> +
>>> +       pm_runtime_mark_last_busy(&data->client->dev);
>>> +       return pm_runtime_put_autosuspend(&data->client->dev);
>>> +}
>>> +
>>> +static const struct iio_trigger_ops atlas_interrupt_trigger_ops = {
>>> +       .owner = THIS_MODULE,
>>> +};
>>> +
>>> +static const struct iio_buffer_setup_ops atlas_buffer_setup_ops = {
>>> +       .postenable = atlas_buffer_postenable,
>>> +       .predisable = atlas_buffer_predisable,
>>> +};
>>> +
>>> +static irqreturn_t atlas_trigger_handler(int irq, void *private)
>>> +{
>>> +       struct iio_dev *indio_dev = private;
>>> +       struct atlas_data *data = iio_priv(indio_dev);
>>> +       int ret;
>>> +
>>> +       ret = i2c_smbus_read_i2c_block_data(data->client,
>>> ATLAS_REG_PH_DATA,
>>> +                               sizeof(data->buffer[0]), (u8 *)
>>> &data->buffer);
>>> +
>>> +       if (ret > 0)
>>> +               iio_push_to_buffers_with_timestamp(indio_dev,
>>> data->buffer,
>>> +                               iio_get_time_ns());
>>> +
>>> +       iio_trigger_notify_done(indio_dev->trig);
>>> +
>>> +       return IRQ_HANDLED;
>>> +}
>>> +
>>> +static irqreturn_t atlas_interrupt_handler(int irq, void *private)
>>> +{
>>> +       struct iio_dev *indio_dev = private;
>>> +       struct atlas_data *data = iio_priv(indio_dev);
>>> +
>>> +       /* re-enable interrupt */
>>> +       atlas_set_interrupt(data, true);
>>> +
>>> +       return IRQ_HANDLED;
>>> +}
>>> +
>>> +static int atlas_read_ph_measurement(struct atlas_data *data, __be32
>>> *val)
>>> +{
>>> +       struct device *dev = &data->client->dev;
>>> +       int suspended = pm_runtime_suspended(dev);
>>> +       int ret;
>>> +
>>> +       ret = pm_runtime_get_sync(dev);
>>> +       if (ret)
>>> +               return ret;
>>
>> ^ pm_runtime_get_sync can also return 1 (if the device is already
>> active).. in which case you definitely don't want to return here.
>> Also if this does return an error you may want to call put_noidle
>> because get_sync increments the device usage_count before it tries to
>> resume and you can end up with an unbalanced count there.
>>>
>>> +
>>> +       if (suspended)
>>> +               usleep_range(ATLAS_PH_INT_TIME_IN_US,
>>> +                            ATLAS_PH_INT_TIME_IN_US + 100000);
>>> +
>>> +       ret = i2c_smbus_read_i2c_block_data(data->client,
>>> ATLAS_REG_PH_DATA,
>>> +                                           sizeof(*val), (u8 *) val);
>>> +
>>> +       pm_runtime_mark_last_busy(dev);
>>> +       pm_runtime_put_autosuspend(dev);
>>
>> ^ also may return err code
>
> What would be proper handling of it here though? *_put_noidle ?

No need for *_put_noidle AFAICT in this case, so just returning the
error code should be ok.
>
>
>>
>>> +
>>> +       return ret == sizeof(*val) ? 0 : -EINVAL;
>>> +}
>>> +
>>> +static int atlas_read_raw(struct iio_dev *indio_dev,
>>> +                         struct iio_chan_spec const *chan,
>>> +                         int *val, int *val2, long mask)
>>> +{
>>> +       struct atlas_data *data = iio_priv(indio_dev);
>>> +
>>> +       switch (mask) {
>>> +       case IIO_CHAN_INFO_RAW: {
>>> +               int ret;
>>> +               __be32 reg;
>>> +
>>> +               mutex_lock(&indio_dev->mlock);
>>> +
>>> +               if (iio_buffer_enabled(indio_dev)) {
>>> +                       ret = -EBUSY;
>>> +                       goto error_busy;
>>> +               }
>>> +
>>> +               switch (chan->type) {
>>> +               case IIO_TEMP:
>>> +                       ret = regmap_bulk_read(data->regmap,
>>> chan->address,
>>> +                                             (u8 *) &reg, sizeof(reg));
>>
>> ^ what would happen if temp is read while the chip is suspended
>> runtime-pm wise? Unless I am missing something the chip may be powered
>> off at this point.
>>
>>> +                       break;
>>> +               case IIO_PH:
>>> +                       ret = atlas_read_ph_measurement(data, &reg);
>>> +                       break;
>>> +               default:
>>> +                       ret = -EINVAL;
>>> +               }
>>> +
>>> +               if (!ret) {
>>> +                       *val = be32_to_cpu(reg);
>>> +                       ret = IIO_VAL_INT;
>>> +               }
>>> +error_busy:
>>> +               mutex_unlock(&indio_dev->mlock);
>>> +               return ret;
>>> +       }
>>> +       case IIO_CHAN_INFO_SCALE:
>>> +               *val = 0; /* 0.001 */
>>> +               *val2 = 1000;
>>> +               return IIO_VAL_INT_PLUS_MICRO;
>>> +       }
>>> +
>>> +       return -EINVAL;
>>> +}
>>> +
>>> +static int atlas_write_raw(struct iio_dev *indio_dev,
>>> +                          struct iio_chan_spec const *chan,
>>> +                          int val, int val2, long mask)
>>> +{
>>> +       struct atlas_data *data = iio_priv(indio_dev);
>>> +       __be32 reg = cpu_to_be32(val);
>>> +
>>> +       if (val2 != 0)
>>> +               return -EINVAL;
>>> +
>>> +       if (mask != IIO_CHAN_INFO_RAW || chan->type != IIO_TEMP)
>>> +               return -EINVAL;
>>> +
>>> +       return regmap_bulk_write(data->regmap, chan->address, &reg, 4);
>>> +}
>>> +
>>> +static const struct iio_info atlas_info = {
>>> +       .driver_module = THIS_MODULE,
>>> +       .read_raw = atlas_read_raw,
>>> +       .write_raw = atlas_write_raw,
>>> +};
>>> +
>>> +static int atlas_probe(struct i2c_client *client,
>>> +                      const struct i2c_device_id *id)
>>> +{
>>> +       struct atlas_data *data;
>>> +       struct iio_trigger *trig;
>>> +       struct iio_dev *indio_dev;
>>> +       int ret;
>>> +
>>> +       indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
>>> +       if (!indio_dev)
>>> +               return -ENOMEM;
>>> +
>>> +       indio_dev->info = &atlas_info;
>>> +       indio_dev->name = ATLAS_DRV_NAME;
>>> +       indio_dev->channels = atlas_channels;
>>> +       indio_dev->modes = INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE;
>>> +       indio_dev->setup_ops = &atlas_buffer_setup_ops;
>>> +       indio_dev->dev.parent = &client->dev;
>>> +
>>> +       trig = devm_iio_trigger_alloc(&client->dev, "%s-dev%d",
>>> +                                     indio_dev->name, indio_dev->id);
>>> +
>>> +       if (!trig)
>>> +               return -ENOMEM;
>>> +
>>> +       data = iio_priv(indio_dev);
>>> +       data->client = client;
>>> +       data->trig = trig;
>>> +       trig->dev.parent = indio_dev->dev.parent;
>>> +       trig->ops = &atlas_interrupt_trigger_ops;
>>> +       iio_trigger_set_drvdata(trig, indio_dev);
>>> +
>>> +       i2c_set_clientdata(client, indio_dev);
>>> +
>>> +       data->regmap = devm_regmap_init_i2c(client, &atlas_regmap_config);
>>> +       if (IS_ERR(data->regmap)) {
>>> +               dev_err(&client->dev, "regmap initialization failed\n");
>>> +               return PTR_ERR(data->regmap);
>>> +       }
>>> +
>>> +       ret = pm_runtime_set_active(&client->dev);
>>> +       if (ret)
>>> +               return ret;
>>> +
>>> +       if (client->irq <= 0) {
>>> +               dev_err(&client->dev, "no valid irq defined\n");
>>> +               return -EINVAL;
>>> +       }
>>> +
>>> +       ret = iio_trigger_register(trig);
>>> +       if (ret) {
>>> +               dev_err(&client->dev, "failed to register trigger\n");
>>> +               return ret;
>>> +       }
>>> +
>>> +       ret = iio_triggered_buffer_setup(indio_dev, NULL,
>>> +               &atlas_trigger_handler, NULL);
>>> +
>>> +       if (ret) {
>>> +               dev_err(&client->dev, "cannot setup iio trigger\n");
>>> +               goto unregister_trigger;
>>> +       }
>>> +
>>> +       ret = devm_request_threaded_irq(&client->dev, client->irq,
>>> +                                       NULL, atlas_interrupt_handler,
>>> +                                       IRQF_TRIGGER_FALLING |
>>> IRQF_ONESHOT,
>>> +                                       "atlas_irq",
>>> +                                       indio_dev);
>>> +       if (ret) {
>>> +               dev_err(&client->dev, "request irq (%d) failed\n",
>>> client->irq);
>>> +               goto unregister_buffer;
>>> +       }
>>> +
>>> +       ret = atlas_set_powermode(data, 1);
>>> +       if (ret) {
>>> +               dev_err(&client->dev, "cannot power device on");
>>> +               goto unregister_buffer;
>>> +       }
>>> +
>>> +       pm_runtime_enable(&client->dev);
>>> +       pm_runtime_set_autosuspend_delay(&client->dev, 2500);
>>> +       pm_runtime_use_autosuspend(&client->dev);
>>> +
>>> +       ret = iio_device_register(indio_dev);
>>> +       if (ret) {
>>> +               dev_err(&client->dev, "unable to register device\n");
>>> +               goto unregister_buffer;
>>> +       }
>>> +
>>> +       return 0;
>>> +
>>> +unregister_buffer:
>>> +       iio_triggered_buffer_cleanup(indio_dev);
>>> +
>>> +unregister_trigger:
>>> +       iio_trigger_unregister(data->trig);
>>> +
>>> +       return ret;
>>> +}
>>> +
>>> +static int atlas_remove(struct i2c_client *client)
>>> +{
>>> +       struct iio_dev *indio_dev = i2c_get_clientdata(client);
>>> +       struct atlas_data *data = iio_priv(indio_dev);
>>> +
>>> +       iio_device_unregister(indio_dev);
>>> +       iio_triggered_buffer_cleanup(indio_dev);
>>> +       iio_trigger_unregister(data->trig);
>>> +
>>> +       pm_runtime_disable(&client->dev);
>>> +       pm_runtime_set_suspended(&client->dev);
>>> +       pm_runtime_put_noidle(&client->dev);
>>> +
>>> +       return atlas_set_powermode(data, 0);
>>> +}
>>> +
>>> +#ifdef CONFIG_PM
>>> +static int atlas_runtime_suspend(struct device *dev)
>>> +{
>>> +       struct atlas_data *data =
>>> +                    iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
>>> +
>>> +       return atlas_set_powermode(data, 0);
>>> +}
>>> +
>>> +static int atlas_runtime_resume(struct device *dev)
>>> +{
>>> +       struct atlas_data *data =
>>> +                    iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
>>> +
>>> +       return atlas_set_powermode(data, 1);
>>> +}
>>> +#endif
>>> +
>>> +static const struct dev_pm_ops atlas_pm_ops = {
>>> +       SET_RUNTIME_PM_OPS(atlas_runtime_suspend,
>>> +                          atlas_runtime_resume, NULL)
>>> +};
>>> +
>>> +static const struct i2c_device_id atlas_id[] = {
>>> +       { "atlas-ph-sm", 0 },
>>> +       {}
>>> +};
>>> +MODULE_DEVICE_TABLE(i2c, atlas_id);
>>> +
>>> +static const struct of_device_id atlas_dt_ids[] = {
>>> +       { .compatible = "atlas,ph-sm" },
>>> +       { }
>>> +};
>>> +MODULE_DEVICE_TABLE(of, atlas_dt_ids);
>>> +
>>> +static struct i2c_driver atlas_driver = {
>>> +       .driver = {
>>> +               .name   = ATLAS_DRV_NAME,
>>> +               .of_match_table = of_match_ptr(atlas_dt_ids),
>>> +               .pm     = &atlas_pm_ops,
>>> +       },
>>> +       .probe          = atlas_probe,
>>> +       .remove         = atlas_remove,
>>> +       .id_table       = atlas_id,
>>> +};
>>> +module_i2c_driver(atlas_driver);
>>> +
>>> +MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
>>> +MODULE_DESCRIPTION("Atlas Scientific pH-SM sensor");
>>> +MODULE_LICENSE("GPL");
>>>
>>