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

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On 15.12.2015 17:19, Matt Ranostay wrote:
On Tue, Dec 15, 2015 at 3:03 AM, Adriana Reus <adriana.reus@xxxxxxxxx> 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@xxxxxxxxx>
---
   .../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@xxxxxxxxx>
+ *
+ * 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@xxxxxxxxx>");
+MODULE_DESCRIPTION("Atlas Scientific pH-SM sensor");
+MODULE_LICENSE("GPL");


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