iio: accel: Add buffer mode for Sensortek STK8312
authorTiberiu Breana <tiberiu.a.breana@intel.com>
Wed, 24 Jun 2015 14:01:48 +0000 (17:01 +0300)
committerJonathan Cameron <jic23@kernel.org>
Sun, 5 Jul 2015 13:42:53 +0000 (14:42 +0100)
Added triggered buffer mode support for the STK8312 accelerometer.

Additional changes:
- set_mode now sets operation mode directly, no longer masking
  the register's previous value
- read_accel now returns raw acceleration data instead of the
  sign_extend32 value
- read_raw will now enable/disable the sensor with each reading

Signed-off-by: Tiberiu Breana <tiberiu.a.breana@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
drivers/iio/accel/stk8312.c

index d211d9f..be58d66 100644 (file)
  */
 
 #include <linux/acpi.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
+#include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/delay.h>
+#include <linux/iio/buffer.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
 
 #define STK8312_REG_XOUT               0x00
 #define STK8312_REG_YOUT               0x01
 #define STK8312_REG_ZOUT               0x02
+#define STK8312_REG_INTSU              0x06
 #define STK8312_REG_MODE               0x07
 #define STK8312_REG_STH                        0x13
 #define STK8312_REG_RESET              0x20
 #define STK8312_REG_OTPDATA            0x3E
 #define STK8312_REG_OTPCTRL            0x3F
 
-#define STK8312_MODE_ACTIVE            1
-#define STK8312_MODE_STANDBY           0
-#define STK8312_MODE_MASK              0x01
+#define STK8312_MODE_ACTIVE            0x01
+#define STK8312_MODE_STANDBY           0x00
+#define STK8312_DREADY_BIT             0x10
+#define STK8312_INT_MODE               0xC0
 #define STK8312_RNG_MASK               0xC0
 #define STK8312_RNG_SHIFT              6
 #define STK8312_READ_RETRIES           16
+#define STK8312_ALL_CHANNEL_MASK       7
+#define STK8312_ALL_CHANNEL_SIZE       3
 
 #define STK8312_DRIVER_NAME            "stk8312"
+#define STK8312_GPIO                   "stk8312_gpio"
+#define STK8312_IRQ_NAME               "stk8312_event"
 
 /*
  * The accelerometer has two measurement ranges:
@@ -53,19 +65,27 @@ static const int stk8312_scale_table[][2] = {
        {0, 461600}, {1, 231100}
 };
 
-#define STK8312_ACCEL_CHANNEL(reg, axis) {                     \
+#define STK8312_ACCEL_CHANNEL(index, reg, axis) {              \
        .type = IIO_ACCEL,                                      \
        .address = reg,                                         \
        .modified = 1,                                          \
        .channel2 = IIO_MOD_##axis,                             \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
+       .scan_index = index,                                    \
+       .scan_type = {                                          \
+               .sign = 's',                                    \
+               .realbits = 8,                                  \
+               .storagebits = 8,                               \
+               .endianness = IIO_CPU,                          \
+       },                                                      \
 }
 
 static const struct iio_chan_spec stk8312_channels[] = {
-       STK8312_ACCEL_CHANNEL(STK8312_REG_XOUT, X),
-       STK8312_ACCEL_CHANNEL(STK8312_REG_YOUT, Y),
-       STK8312_ACCEL_CHANNEL(STK8312_REG_ZOUT, Z),
+       STK8312_ACCEL_CHANNEL(0, STK8312_REG_XOUT, X),
+       STK8312_ACCEL_CHANNEL(1, STK8312_REG_YOUT, Y),
+       STK8312_ACCEL_CHANNEL(2, STK8312_REG_ZOUT, Z),
+       IIO_CHAN_SOFT_TIMESTAMP(3),
 };
 
 struct stk8312_data {
@@ -73,6 +93,9 @@ struct stk8312_data {
        struct mutex lock;
        int range;
        u8 mode;
+       struct iio_trigger *dready_trig;
+       bool dready_trigger_on;
+       s8 buffer[16]; /* 3x8-bit channels + 5x8 padding + 64-bit timestamp */
 };
 
 static IIO_CONST_ATTR(in_accel_scale_available, STK8312_SCALE_AVAIL);
@@ -130,31 +153,19 @@ exit_err:
 static int stk8312_set_mode(struct stk8312_data *data, u8 mode)
 {
        int ret;
-       u8 masked_reg;
        struct i2c_client *client = data->client;
 
-       if (mode > 1)
-               return -EINVAL;
-       else if (mode == data->mode)
+       if (mode == data->mode)
                return 0;
 
-       ret = i2c_smbus_read_byte_data(client, STK8312_REG_MODE);
-       if (ret < 0) {
-               dev_err(&client->dev, "failed to change sensor mode\n");
-               return ret;
-       }
-       masked_reg = ret & (~STK8312_MODE_MASK);
-       masked_reg |= mode;
-
-       ret = i2c_smbus_write_byte_data(client,
-                       STK8312_REG_MODE, masked_reg);
+       ret = i2c_smbus_write_byte_data(client, STK8312_REG_MODE, mode);
        if (ret < 0) {
                dev_err(&client->dev, "failed to change sensor mode\n");
                return ret;
        }
 
        data->mode = mode;
-       if (mode == STK8312_MODE_ACTIVE) {
+       if (mode & STK8312_MODE_ACTIVE) {
                /* Need to run OTP sequence before entering active mode */
                usleep_range(1000, 5000);
                ret = stk8312_otp_init(data);
@@ -163,6 +174,52 @@ static int stk8312_set_mode(struct stk8312_data *data, u8 mode)
        return ret;
 }
 
+static int stk8312_set_interrupts(struct stk8312_data *data, u8 int_mask)
+{
+       int ret;
+       u8 mode;
+       struct i2c_client *client = data->client;
+
+       mode = data->mode;
+       /* We need to go in standby mode to modify registers */
+       ret = stk8312_set_mode(data, STK8312_MODE_STANDBY);
+       if (ret < 0)
+               return ret;
+
+       ret = i2c_smbus_write_byte_data(client, STK8312_REG_INTSU, int_mask);
+       if (ret < 0)
+               dev_err(&client->dev, "failed to set interrupts\n");
+
+       return stk8312_set_mode(data, mode);
+}
+
+static int stk8312_data_rdy_trigger_set_state(struct iio_trigger *trig,
+                                             bool state)
+{
+       struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+       struct stk8312_data *data = iio_priv(indio_dev);
+       int ret;
+
+       if (state)
+               ret = stk8312_set_interrupts(data, STK8312_DREADY_BIT);
+       else
+               ret = stk8312_set_interrupts(data, 0x00);
+
+       if (ret < 0) {
+               dev_err(&data->client->dev, "failed to set trigger state\n");
+               return ret;
+       }
+
+       data->dready_trigger_on = state;
+
+       return ret;
+}
+
+static const struct iio_trigger_ops stk8312_trigger_ops = {
+       .set_trigger_state = stk8312_data_rdy_trigger_set_state,
+       .owner = THIS_MODULE,
+};
+
 static int stk8312_set_range(struct stk8312_data *data, u8 range)
 {
        int ret;
@@ -208,12 +265,10 @@ static int stk8312_read_accel(struct stk8312_data *data, u8 address)
                return -EINVAL;
 
        ret = i2c_smbus_read_byte_data(client, address);
-       if (ret < 0) {
+       if (ret < 0)
                dev_err(&client->dev, "register read failed\n");
-               return ret;
-       }
 
-       return sign_extend32(ret, 7);
+       return ret;
 }
 
 static int stk8312_read_raw(struct iio_dev *indio_dev,
@@ -221,14 +276,27 @@ static int stk8312_read_raw(struct iio_dev *indio_dev,
                            int *val, int *val2, long mask)
 {
        struct stk8312_data *data = iio_priv(indio_dev);
-
-       if (chan->type != IIO_ACCEL)
-               return -EINVAL;
+       int ret;
 
        switch (mask) {
        case IIO_CHAN_INFO_RAW:
+               if (iio_buffer_enabled(indio_dev))
+                       return -EBUSY;
                mutex_lock(&data->lock);
-               *val = stk8312_read_accel(data, chan->address);
+               ret = stk8312_set_mode(data, data->mode | STK8312_MODE_ACTIVE);
+               if (ret < 0) {
+                       mutex_unlock(&data->lock);
+                       return -EINVAL;
+               }
+               ret = stk8312_read_accel(data, chan->address);
+               if (ret < 0) {
+                       stk8312_set_mode(data,
+                                        data->mode & (~STK8312_MODE_ACTIVE));
+                       mutex_unlock(&data->lock);
+                       return -EINVAL;
+               }
+               *val = sign_extend32(ret, 7);
+               stk8312_set_mode(data, data->mode & (~STK8312_MODE_ACTIVE));
                mutex_unlock(&data->lock);
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
@@ -277,6 +345,109 @@ static const struct iio_info stk8312_info = {
        .attrs                  = &stk8312_attribute_group,
 };
 
+static irqreturn_t stk8312_trigger_handler(int irq, void *p)
+{
+       struct iio_poll_func *pf = p;
+       struct iio_dev *indio_dev = pf->indio_dev;
+       struct stk8312_data *data = iio_priv(indio_dev);
+       int bit, ret, i = 0;
+       u8 buffer[STK8312_ALL_CHANNEL_SIZE];
+
+       mutex_lock(&data->lock);
+       /*
+        * Do a bulk read if all channels are requested,
+        * from 0x00 (XOUT) to 0x02 (ZOUT)
+        */
+       if (*(indio_dev->active_scan_mask) == STK8312_ALL_CHANNEL_MASK) {
+               ret = i2c_smbus_read_i2c_block_data(data->client,
+                                                   STK8312_REG_XOUT,
+                                                   STK8312_ALL_CHANNEL_SIZE,
+                                                   buffer);
+               if (ret < STK8312_ALL_CHANNEL_SIZE) {
+                       dev_err(&data->client->dev, "register read failed\n");
+                       mutex_unlock(&data->lock);
+                       goto err;
+               }
+               data->buffer[0] = buffer[0];
+               data->buffer[1] = buffer[1];
+               data->buffer[2] = buffer[2];
+       } else {
+               for_each_set_bit(bit, indio_dev->active_scan_mask,
+                          indio_dev->masklength) {
+                       ret = stk8312_read_accel(data, bit);
+                       if (ret < 0) {
+                               mutex_unlock(&data->lock);
+                               goto err;
+                       }
+                       data->buffer[i++] = ret;
+               }
+       }
+       mutex_unlock(&data->lock);
+
+       iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
+                                          pf->timestamp);
+err:
+       iio_trigger_notify_done(indio_dev->trig);
+
+       return IRQ_HANDLED;
+}
+
+static irqreturn_t stk8312_data_rdy_trig_poll(int irq, void *private)
+{
+       struct iio_dev *indio_dev = private;
+       struct stk8312_data *data = iio_priv(indio_dev);
+
+       if (data->dready_trigger_on)
+               iio_trigger_poll(data->dready_trig);
+
+       return IRQ_HANDLED;
+}
+
+static int stk8312_buffer_preenable(struct iio_dev *indio_dev)
+{
+       struct stk8312_data *data = iio_priv(indio_dev);
+
+       return stk8312_set_mode(data, data->mode | STK8312_MODE_ACTIVE);
+}
+
+static int stk8312_buffer_postdisable(struct iio_dev *indio_dev)
+{
+       struct stk8312_data *data = iio_priv(indio_dev);
+
+       return stk8312_set_mode(data, data->mode & (~STK8312_MODE_ACTIVE));
+}
+
+static const struct iio_buffer_setup_ops stk8312_buffer_setup_ops = {
+       .preenable   = stk8312_buffer_preenable,
+       .postenable  = iio_triggered_buffer_postenable,
+       .predisable  = iio_triggered_buffer_predisable,
+       .postdisable = stk8312_buffer_postdisable,
+};
+
+static int stk8312_gpio_probe(struct i2c_client *client)
+{
+       struct device *dev;
+       struct gpio_desc *gpio;
+       int ret;
+
+       if (!client)
+               return -EINVAL;
+
+       dev = &client->dev;
+
+       /* data ready gpio interrupt pin */
+       gpio = devm_gpiod_get_index(dev, STK8312_GPIO, 0, GPIOD_IN);
+       if (IS_ERR(gpio)) {
+               dev_err(dev, "acpi gpio get index failed\n");
+               return PTR_ERR(gpio);
+       }
+
+       ret = gpiod_to_irq(gpio);
+       dev_dbg(dev, "GPIO resource, no:%d irq:%d\n", desc_to_gpio(gpio), ret);
+
+       return ret;
+}
+
 static int stk8312_probe(struct i2c_client *client,
                         const struct i2c_device_id *id)
 {
@@ -312,26 +483,85 @@ static int stk8312_probe(struct i2c_client *client,
        if (ret < 0)
                return ret;
 
-       ret = stk8312_set_mode(data, STK8312_MODE_ACTIVE);
+       ret = stk8312_set_mode(data, STK8312_INT_MODE | STK8312_MODE_ACTIVE);
        if (ret < 0)
                return ret;
 
+       if (client->irq < 0)
+               client->irq = stk8312_gpio_probe(client);
+
+       if (client->irq >= 0) {
+               ret = devm_request_threaded_irq(&client->dev, client->irq,
+                                               stk8312_data_rdy_trig_poll,
+                                               NULL,
+                                               IRQF_TRIGGER_RISING |
+                                               IRQF_ONESHOT,
+                                               STK8312_IRQ_NAME,
+                                               indio_dev);
+               if (ret < 0) {
+                       dev_err(&client->dev, "request irq %d failed\n",
+                               client->irq);
+                       goto err_power_off;
+               }
+
+               data->dready_trig = devm_iio_trigger_alloc(&client->dev,
+                                                          "%s-dev%d",
+                                                          indio_dev->name,
+                                                          indio_dev->id);
+               if (!data->dready_trig) {
+                       ret = -ENOMEM;
+                       goto err_power_off;
+               }
+
+               data->dready_trig->dev.parent = &client->dev;
+               data->dready_trig->ops = &stk8312_trigger_ops;
+               iio_trigger_set_drvdata(data->dready_trig, indio_dev);
+               ret = iio_trigger_register(data->dready_trig);
+               if (ret) {
+                       dev_err(&client->dev, "iio trigger register failed\n");
+                       goto err_power_off;
+               }
+       }
+
+       ret = iio_triggered_buffer_setup(indio_dev,
+                                        iio_pollfunc_store_time,
+                                        stk8312_trigger_handler,
+                                        &stk8312_buffer_setup_ops);
+       if (ret < 0) {
+               dev_err(&client->dev, "iio triggered buffer setup failed\n");
+               goto err_trigger_unregister;
+       }
+
        ret = iio_device_register(indio_dev);
        if (ret < 0) {
                dev_err(&client->dev, "device_register failed\n");
-               stk8312_set_mode(data, STK8312_MODE_STANDBY);
+               goto err_buffer_cleanup;
        }
 
        return ret;
+
+err_buffer_cleanup:
+       iio_triggered_buffer_cleanup(indio_dev);
+err_trigger_unregister:
+       if (data->dready_trig)
+               iio_trigger_unregister(data->dready_trig);
+err_power_off:
+       stk8312_set_mode(data, STK8312_MODE_STANDBY);
+       return ret;
 }
 
 static int stk8312_remove(struct i2c_client *client)
 {
        struct iio_dev *indio_dev = i2c_get_clientdata(client);
+       struct stk8312_data *data = iio_priv(indio_dev);
 
        iio_device_unregister(indio_dev);
+       iio_triggered_buffer_cleanup(indio_dev);
 
-       return stk8312_set_mode(iio_priv(indio_dev), STK8312_MODE_STANDBY);
+       if (data->dready_trig)
+               iio_trigger_unregister(data->dready_trig);
+
+       return stk8312_set_mode(data, STK8312_MODE_STANDBY);
 }
 
 #ifdef CONFIG_PM_SLEEP
@@ -341,7 +571,7 @@ static int stk8312_suspend(struct device *dev)
 
        data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
 
-       return stk8312_set_mode(data, STK8312_MODE_STANDBY);
+       return stk8312_set_mode(data, data->mode & (~STK8312_MODE_ACTIVE));
 }
 
 static int stk8312_resume(struct device *dev)
@@ -350,7 +580,7 @@ static int stk8312_resume(struct device *dev)
 
        data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
 
-       return stk8312_set_mode(data, STK8312_MODE_ACTIVE);
+       return stk8312_set_mode(data, data->mode | STK8312_MODE_ACTIVE);
 }
 
 static SIMPLE_DEV_PM_OPS(stk8312_pm_ops, stk8312_suspend, stk8312_resume);