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

[Matt Ranostay <mranostay@gmail.com>]

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 ?


>
>> +
>> +       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");
>>
>