--- /dev/null
+/*
+ * sca3000.c -- support VTI sca3000 series accelerometers
+ * via SPI
+ *
+ * Copyright (c) 2007 Jonathan Cameron <jic23@kernel.org>
+ *
+ * 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.
+ */
+#ifndef _SCA3000
+#define _SCA3000
+
+#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
+ * (approx 1 - 25Hz) and then a programmable threshold 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 access 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.
+ */
+#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 multiplexed registers (write to ctrl_data after select) */
+#define SCA3000_REG_ADDR_CTRL_DATA 0x22
+
+/*
+ * Measurement 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
+ * @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 work_struct interrupt_handler_ws;
+ s64 last_timestamp;
+ int mo_det_use_count;
+ struct mutex lock;
+ int bpse;
+ /* Can these share a cacheline ? */
+ u8 rx[2] ____cacheline_aligned;
+ u8 tx[6] ____cacheline_aligned;
+};
+
+/**
+ * struct sca3000_chip_info - model dependent parameters
+ * @scale: scale * 10^-6
+ * @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 {
+ unsigned int scale;
+ 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;
+ int mot_det_mult_xz[6];
+ int mot_det_mult_y[7];
+};
+
+int sca3000_read_data_short(struct sca3000_state *st,
+ u8 reg_address_high,
+ 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);
+
+#ifdef CONFIG_IIO_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_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
+#endif /* _SCA3000 */
Code Review / kvmfornfv.git / blobdiff