Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 574fb258 authored by Jonathan Cameron's avatar Jonathan Cameron Committed by Greg Kroah-Hartman
Browse files

Staging: IIO: VTI sca3000 series accelerometer driver (spi) 



Example of how a device with a hardware ring buffer is
handled within IIO.

Changes since V2:
* Moved to new registration functions giving much cleaner
  interface.

Signed-off-by: default avatarJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 7026ea4b

drivers/staging/iio/accel/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -17,3 +17,11 @@ config LIS3L02DQ 
	  Say yes here to build SPI support for the ST microelectronics

	  accelerometer. The driver supplies direct access via sysfs files

	  and an event interface via a character device.



config SCA3000

       depends on IIO_RING_BUFFER

       depends on SPI

       tristate "VTI SCA3000 series accelerometers"

       help

         Say yes here to build support for the VTI SCA3000 series of SPI

	 accelerometers. These devices use a hardware ring buffer.
 
 No newline at end of file

drivers/staging/iio/accel/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -5,3 +5,6 @@ obj-$(CONFIG_KXSD9) += kxsd9.o 


lis3l02dq-y		:= lis3l02dq_core.o

obj-$(CONFIG_LIS3L02DQ)	+= lis3l02dq.o



sca3000-y		:= sca3000_core.o sca3000_ring.o

obj-$(CONFIG_SCA3000)	+= sca3000.o
 
 No newline at end of file

drivers/staging/iio/accel/sca3000.h

0 → 100644
+298 −0
Original line number Diff line number Diff line 
/*

 * sca3000.c -- support VTI sca3000 series accelerometers

 *              via SPI

 *

 * Copyright (c) 2007 Jonathan Cameron <jic23@cam.ac.uk>

 *

 * Partly based upon tle62x0.c

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * Initial mode is direct measurement.

 *

 * Untested things

 *

 * Temperature reading (the e05 I'm testing with doesn't have a sensor)

 *

 * Free fall detection mode - supported but untested as I'm not droping my

 * dubious wire rig far enough to test it.

 *

 * Unsupported as yet

 *

 * Time stamping of data from ring. Various ideas on how to do this but none

 * are remotely simple. Suggestions welcome.

 *

 * Individual enabling disabling of channels going into ring buffer

 *

 * Overflow handling (this is signaled for all but 8 bit ring buffer mode.)

 *

 * Motion detector using AND combinations of signals.

 *

 * Note: Be very careful about not touching an register bytes marked

 * as reserved on the data sheet. They really mean it as changing convents of

 * some will cause the device to lock up.

 *

 * Known issues - on rare occasions the interrupts lock up. Not sure why as yet.

 * Can probably alleviate this by reading the interrupt register on start, but

 * that is really just brushing the problem under the carpet.

 */

#define SCA3000_WRITE_REG(a) (((a) << 2) | 0x02)

#define SCA3000_READ_REG(a) ((a) << 2)



#define SCA3000_REG_ADDR_REVID			0x00

#define SCA3000_REVID_MAJOR_MASK		0xf0

#define SCA3000_REVID_MINOR_MASK		0x0f



#define SCA3000_REG_ADDR_STATUS			0x02

#define SCA3000_LOCKED				0x20

#define SCA3000_EEPROM_CS_ERROR			0x02

#define SCA3000_SPI_FRAME_ERROR			0x01



/* All reads done using register decrement so no need to directly access LSBs */

#define SCA3000_REG_ADDR_X_MSB			0x05

#define SCA3000_REG_ADDR_Y_MSB			0x07

#define SCA3000_REG_ADDR_Z_MSB			0x09



#define SCA3000_REG_ADDR_RING_OUT		0x0f



/* Temp read untested - the e05 doesn't have the sensor */

#define SCA3000_REG_ADDR_TEMP_MSB		0x13



#define SCA3000_REG_ADDR_MODE			0x14

#define SCA3000_MODE_PROT_MASK			0x28



#define SCA3000_RING_BUF_ENABLE			0x80

#define SCA3000_RING_BUF_8BIT			0x40

/* Free fall detection triggers an interrupt if the acceleration

 * is below a threshold for equivalent of 25cm drop

 */

#define SCA3000_FREE_FALL_DETECT		0x10

#define SCA3000_MEAS_MODE_NORMAL		0x00

#define SCA3000_MEAS_MODE_OP_1			0x01

#define SCA3000_MEAS_MODE_OP_2			0x02



/* In motion detection mode the accelerations are band pass filtered

 * (aprox 1 - 25Hz) and then a programmable theshold used to trigger

 * and interrupt.

 */

#define SCA3000_MEAS_MODE_MOT_DET		0x03



#define SCA3000_REG_ADDR_BUF_COUNT		0x15



#define SCA3000_REG_ADDR_INT_STATUS		0x16



#define SCA3000_INT_STATUS_THREE_QUARTERS	0x80

#define SCA3000_INT_STATUS_HALF			0x40



#define SCA3000_INT_STATUS_FREE_FALL		0x08

#define SCA3000_INT_STATUS_Y_TRIGGER		0x04

#define SCA3000_INT_STATUS_X_TRIGGER		0x02

#define SCA3000_INT_STATUS_Z_TRIGGER		0x01



/* Used to allow accesss to multiplexed registers */

#define SCA3000_REG_ADDR_CTRL_SEL		0x18

/* Only available for SCA3000-D03 and SCA3000-D01 */

#define SCA3000_REG_CTRL_SEL_I2C_DISABLE	0x01

#define SCA3000_REG_CTRL_SEL_MD_CTRL		0x02

#define SCA3000_REG_CTRL_SEL_MD_Y_TH		0x03

#define SCA3000_REG_CTRL_SEL_MD_X_TH		0x04

#define SCA3000_REG_CTRL_SEL_MD_Z_TH		0x05

/* BE VERY CAREFUL WITH THIS, IF 3 BITS ARE NOT SET the device

   will not function */

#define SCA3000_REG_CTRL_SEL_OUT_CTRL		0x0B

#define SCA3000_OUT_CTRL_PROT_MASK		0xE0

#define SCA3000_OUT_CTRL_BUF_X_EN		0x10

#define SCA3000_OUT_CTRL_BUF_Y_EN		0x08

#define SCA3000_OUT_CTRL_BUF_Z_EN		0x04

#define SCA3000_OUT_CTRL_BUF_DIV_4		0x02

#define SCA3000_OUT_CTRL_BUF_DIV_2		0x01



/* Control which motion detector interrupts are on.

 * For now only OR combinations are supported.x

 */

#define SCA3000_MD_CTRL_PROT_MASK		0xC0

#define SCA3000_MD_CTRL_OR_Y			0x01

#define SCA3000_MD_CTRL_OR_X			0x02

#define SCA3000_MD_CTRL_OR_Z			0x04

/* Currently unsupported */

#define SCA3000_MD_CTRL_AND_Y			0x08

#define SCA3000_MD_CTRL_AND_X			0x10

#define SAC3000_MD_CTRL_AND_Z			0x20



/* Some control registers of complex access methods requiring this register to

 * be used to remove a lock.

 */

#define SCA3000_REG_ADDR_UNLOCK			0x1e



#define SCA3000_REG_ADDR_INT_MASK		0x21

#define SCA3000_INT_MASK_PROT_MASK		0x1C



#define SCA3000_INT_MASK_RING_THREE_QUARTER	0x80

#define SCA3000_INT_MASK_RING_HALF		0x40



#define SCA3000_INT_MASK_ALL_INTS		0x02

#define SCA3000_INT_MASK_ACTIVE_HIGH		0x01

#define SCA3000_INT_MASK_ACTIVE_LOW		0x00



/* Values of mulipexed registers (write to ctrl_data after select) */

#define SCA3000_REG_ADDR_CTRL_DATA		0x22



/* Measurment modes available on some sca3000 series chips. Code assumes others

 * may become available in the future.

 *

 * Bypass - Bypass the low-pass filter in the signal channel so as to increase

 *          signal bandwidth.

 *

 * Narrow - Narrow low-pass filtering of the signal channel and half output

 *          data rate by decimation.

 *

 * Wide - Widen low-pass filtering of signal channel to increase bandwidth

 */

#define SCA3000_OP_MODE_BYPASS			0x01

#define SCA3000_OP_MODE_NARROW			0x02

#define SCA3000_OP_MODE_WIDE			0x04

#define SCA3000_MAX_TX 6

#define SCA3000_MAX_RX 2



/**

 * struct sca3000_state - device instance state information

 * @us: 	 		the associated spi device

 * @info: 	  		chip variant information

 * @indio_dev: 	 		device information used by the IIO core

 * @interrupt_handler_ws: 	event interrupt handler for all events

 * @last_timestamp: 		the timestamp of the last event

 * @mo_det_use_count: 		reference counter for the motion detection unit

 * @lock: 		 	lock used to protect elements of sca3000_state

 * 	 			and the underlying device state.

 * @bpse: 		 	number of bits per scan element

 * @tx: 		 	dma-able transmit buffer

 * @rx: 		 	dma-able receive buffer

 **/

struct sca3000_state {

	struct spi_device		*us;

	const struct sca3000_chip_info	*info;

	struct iio_dev			*indio_dev;

	struct work_struct		interrupt_handler_ws;

	s64				last_timestamp;

	int				mo_det_use_count;

	struct mutex			lock;

	int				bpse;

	u8				*tx;

	/* not used during a ring buffer read */

	u8				*rx;

};



/**

 * struct sca3000_chip_info - model dependant parameters

 * @name: 			model identification

 * @temp_output:		some devices have temperature sensors.

 * @measurement_mode_freq:	normal mode sampling frequency

 * @option_mode_1:		first optional mode. Not all models have one

 * @option_mode_1_freq:		option mode 1 sampling frequency

 * @option_mode_2:		second optional mode. Not all chips have one

 * @option_mode_2_freq:		option mode 2 sampling frequency

 *

 * This structure is used to hold information about the functionality of a given

 * sca3000 variant.

 **/

struct sca3000_chip_info {

	const char		*name;

	bool			temp_output;

	int			measurement_mode_freq;

	int			option_mode_1;

	int			option_mode_1_freq;

	int			option_mode_2;

	int			option_mode_2_freq;

};



/**

 * sca3000_read_data() read a series of values from the device

 * @dev:		device

 * @reg_address_high:	start address (decremented read)

 * @rx:			pointer where recieved data is placed. Callee

 *			responsible for freeing this.

 * @len:		number of bytes to read

 *

 * The main lock must be held.

 **/

int sca3000_read_data(struct sca3000_state *st,

		      u8 reg_address_high,

		      u8 **rx_p,

		      int len);



/**

 * sca3000_write_reg() write a single register

 * @address:	address of register on chip

 * @val:	value to be written to register

 *

 * The main lock must be held.

 **/

int sca3000_write_reg(struct sca3000_state *st, u8 address, u8 val);



/* Conversion function for use with the ring buffer when in 11bit mode */

static inline int sca3000_11bit_convert(uint8_t msb, uint8_t lsb)

{

	int16_t val;



	val = ((lsb >> 3) & 0x1C) | (msb << 5);

	val |= (val & (1 << 12)) ? 0xE000 : 0;



	return val;

};



static inline int sca3000_13bit_convert(uint8_t msb, uint8_t lsb)

{

	s16 val;



	val = ((lsb >> 3) & 0x1F) | (msb << 5);

	/* sign fill */

	val |= (val & (1 << 12)) ? 0xE000 : 0;



	return val;

};





#ifdef CONFIG_IIO_RING_BUFFER

/**

 * sca3000_register_ring_funcs() setup the ring state change functions

 **/

void sca3000_register_ring_funcs(struct iio_dev *indio_dev);



/**

 * sca3000_configure_ring() - allocate and configure ring buffer

 * @indio_dev: iio-core device whose ring is to be configured

 *

 * The hardware ring buffer needs far fewer ring buffer functions than

 * a software one as a lot of things are handled automatically.

 * This function also tells the iio core that our device supports a

 * hardware ring buffer mode.

 **/

int sca3000_configure_ring(struct iio_dev *indio_dev);



/**

 * sca3000_unconfigure_ring() - deallocate the ring buffer

 * @indio_dev: iio-core device whose ring we are freeing

 **/

void sca3000_unconfigure_ring(struct iio_dev *indio_dev);



/**

 * sca3000_ring_int_process() handles ring related event pushing and escalation

 * @val:	the event code

 **/

void sca3000_ring_int_process(u8 val, struct iio_ring_buffer *ring);



#else

static inline void sca3000_register_ring_funcs(struct iio_dev *indio_dev) {};



static inline

int sca3000_register_ring_access_and_init(struct iio_dev *indio_dev)

{

	return 0;

};



static inline void sca3000_ring_int_process(u8 val, void *ring) {};



#endif