Re: [PATCH v5 1/2] iio: accel: Add buffer mode for Sensortek STK8312

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On 24/06/15 15:01, Tiberiu Breana wrote:
> 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@xxxxxxxxx>
Applied to the togreg branch of iio.git

Thanks,
> ---
> v5:
> - iio_triggered_buffer_cleanup will now be called in _remove
>   unconditionally
> v4:
> - removed trigger_handler's local buffer, as it was unnecessary
> - cleaner approach for mutex_unlock in trigger_handler
> v3:
> - added a bulk read optimization for reading all channels at once
> v2:
> - addressed Jonathan's comments
> - added the GPIOD_IN flag to devm_gpiod_get_index
> ---
>  drivers/iio/accel/stk8312.c | 300 ++++++++++++++++++++++++++++++++++++++------
>  1 file changed, 265 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/iio/accel/stk8312.c b/drivers/iio/accel/stk8312.c
> index d211d9f3..be58d66 100644
> --- a/drivers/iio/accel/stk8312.c
> +++ b/drivers/iio/accel/stk8312.c
> @@ -11,16 +11,23 @@
>   */
>  
>  #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
> @@ -29,14 +36,19 @@
>  #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);
> 

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