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/*
* AD7280A Lithium Ion Battery Monitoring System
*
* Copyright 2011 Analog Devices Inc.
*
* Licensed under the GPL-2.
*/
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/spi/spi.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/events.h>
#include "ad7280a.h"
/* Registers */
#define AD7280A_CELL_VOLTAGE_1 0x0 /* D11 to D0, Read only */
#define AD7280A_CELL_VOLTAGE_2 0x1 /* D11 to D0, Read only */
#define AD7280A_CELL_VOLTAGE_3 0x2 /* D11 to D0, Read only */
#define AD7280A_CELL_VOLTAGE_4 0x3 /* D11 to D0, Read only */
#define AD7280A_CELL_VOLTAGE_5 0x4 /* D11 to D0, Read only */
#define AD7280A_CELL_VOLTAGE_6 0x5 /* D11 to D0, Read only */
#define AD7280A_AUX_ADC_1 0x6 /* D11 to D0, Read only */
#define AD7280A_AUX_ADC_2 0x7 /* D11 to D0, Read only */
#define AD7280A_AUX_ADC_3 0x8 /* D11 to D0, Read only */
#define AD7280A_AUX_ADC_4 0x9 /* D11 to D0, Read only */
#define AD7280A_AUX_ADC_5 0xA /* D11 to D0, Read only */
#define AD7280A_AUX_ADC_6 0xB /* D11 to D0, Read only */
#define AD7280A_SELF_TEST 0xC /* D11 to D0, Read only */
#define AD7280A_CONTROL_HB 0xD /* D15 to D8, Read/write */
#define AD7280A_CONTROL_LB 0xE /* D7 to D0, Read/write */
#define AD7280A_CELL_OVERVOLTAGE 0xF /* D7 to D0, Read/write */
#define AD7280A_CELL_UNDERVOLTAGE 0x10 /* D7 to D0, Read/write */
#define AD7280A_AUX_ADC_OVERVOLTAGE 0x11 /* D7 to D0, Read/write */
#define AD7280A_AUX_ADC_UNDERVOLTAGE 0x12 /* D7 to D0, Read/write */
#define AD7280A_ALERT 0x13 /* D7 to D0, Read/write */
#define AD7280A_CELL_BALANCE 0x14 /* D7 to D0, Read/write */
#define AD7280A_CB1_TIMER 0x15 /* D7 to D0, Read/write */
#define AD7280A_CB2_TIMER 0x16 /* D7 to D0, Read/write */
#define AD7280A_CB3_TIMER 0x17 /* D7 to D0, Read/write */
#define AD7280A_CB4_TIMER 0x18 /* D7 to D0, Read/write */
#define AD7280A_CB5_TIMER 0x19 /* D7 to D0, Read/write */
#define AD7280A_CB6_TIMER 0x1A /* D7 to D0, Read/write */
#define AD7280A_PD_TIMER 0x1B /* D7 to D0, Read/write */
#define AD7280A_READ 0x1C /* D7 to D0, Read/write */
#define AD7280A_CNVST_CONTROL 0x1D /* D7 to D0, Read/write */
/* Bits and Masks */
#define AD7280A_CTRL_HB_CONV_INPUT_ALL 0
#define AD7280A_CTRL_HB_CONV_INPUT_6CELL_AUX1_3_4 BIT(6)
#define AD7280A_CTRL_HB_CONV_INPUT_6CELL BIT(7)
#define AD7280A_CTRL_HB_CONV_INPUT_SELF_TEST (BIT(7) | BIT(6))
#define AD7280A_CTRL_HB_CONV_RES_READ_ALL 0
#define AD7280A_CTRL_HB_CONV_RES_READ_6CELL_AUX1_3_4 BIT(4)
#define AD7280A_CTRL_HB_CONV_RES_READ_6CELL BIT(5)
#define AD7280A_CTRL_HB_CONV_RES_READ_NO (BIT(5) | BIT(4))
#define AD7280A_CTRL_HB_CONV_START_CNVST 0
#define AD7280A_CTRL_HB_CONV_START_CS BIT(3)
#define AD7280A_CTRL_HB_CONV_AVG_DIS 0
#define AD7280A_CTRL_HB_CONV_AVG_2 BIT(1)
#define AD7280A_CTRL_HB_CONV_AVG_4 BIT(2)
#define AD7280A_CTRL_HB_CONV_AVG_8 (BIT(2) | BIT(1))
#define AD7280A_CTRL_HB_CONV_AVG(x) ((x) << 1)
#define AD7280A_CTRL_HB_PWRDN_SW BIT(0)
#define AD7280A_CTRL_LB_SWRST BIT(7)
#define AD7280A_CTRL_LB_ACQ_TIME_400ns 0
#define AD7280A_CTRL_LB_ACQ_TIME_800ns BIT(5)
#define AD7280A_CTRL_LB_ACQ_TIME_1200ns BIT(6)
#define AD7280A_CTRL_LB_ACQ_TIME_1600ns (BIT(6) | BIT(5))
#define AD7280A_CTRL_LB_ACQ_TIME(x) ((x) << 5)
#define AD7280A_CTRL_LB_MUST_SET BIT(4)
#define AD7280A_CTRL_LB_THERMISTOR_EN BIT(3)
#define AD7280A_CTRL_LB_LOCK_DEV_ADDR BIT(2)
#define AD7280A_CTRL_LB_INC_DEV_ADDR BIT(1)
#define AD7280A_CTRL_LB_DAISY_CHAIN_RB_EN BIT(0)
#define AD7280A_ALERT_GEN_STATIC_HIGH BIT(6)
#define AD7280A_ALERT_RELAY_SIG_CHAIN_DOWN (BIT(7) | BIT(6))
#define AD7280A_ALL_CELLS (0xAD << 16)
#define AD7280A_MAX_SPI_CLK_HZ 700000 /* < 1MHz */
#define AD7280A_MAX_CHAIN 8
#define AD7280A_CELLS_PER_DEV 6
#define AD7280A_BITS 12
#define AD7280A_NUM_CH (AD7280A_AUX_ADC_6 - \
AD7280A_CELL_VOLTAGE_1 + 1)
#define AD7280A_DEVADDR_MASTER 0
#define AD7280A_DEVADDR_ALL 0x1F
/* 5-bit device address is sent LSB first */
static unsigned int ad7280a_devaddr(unsigned int addr)
{
return ((addr & 0x1) << 4) |
((addr & 0x2) << 3) |
(addr & 0x4) |
((addr & 0x8) >> 3) |
((addr & 0x10) >> 4);
}
/* During a read a valid write is mandatory.
* So writing to the highest available address (Address 0x1F)
* and setting the address all parts bit to 0 is recommended
* So the TXVAL is AD7280A_DEVADDR_ALL + CRC
*/
#define AD7280A_READ_TXVAL 0xF800030A
/*
* AD7280 CRC
*
* P(x) = x^8 + x^5 + x^3 + x^2 + x^1 + x^0 = 0b100101111 => 0x2F
*/
#define POLYNOM 0x2F
#define POLYNOM_ORDER 8
#define HIGHBIT (1 << (POLYNOM_ORDER - 1))
struct ad7280_state {
struct spi_device *spi;
struct iio_chan_spec *channels;
struct iio_dev_attr *iio_attr;
int slave_num;
int scan_cnt;
int readback_delay_us;
unsigned char crc_tab[256];
unsigned char ctrl_hb;
unsigned char ctrl_lb;
unsigned char cell_threshhigh;
unsigned char cell_threshlow;
unsigned char aux_threshhigh;
unsigned char aux_threshlow;
unsigned char cb_mask[AD7280A_MAX_CHAIN];
struct mutex lock; /* protect sensor state */
__be32 buf[2] ____cacheline_aligned;
};
static void ad7280_crc8_build_table(unsigned char *crc_tab)
{
unsigned char bit, crc;
int cnt, i;
for (cnt = 0; cnt < 256; cnt++) {
crc = cnt;
for (i = 0; i < 8; i++) {
bit = crc & HIGHBIT;
crc <<= 1;
if (bit)
crc ^= POLYNOM;
}
crc_tab[cnt] = crc;
}
}
static unsigned char ad7280_calc_crc8(unsigned char *crc_tab, unsigned int val)
{
unsigned char crc;
crc = crc_tab[val >> 16 & 0xFF];
crc = crc_tab[crc ^ (val >> 8 & 0xFF)];
return crc ^ (val & 0xFF);
}
static int ad7280_check_crc(struct ad7280_state *st, unsigned int val)
{
unsigned char crc = ad7280_calc_crc8(st->crc_tab, val >> 10);
if (crc != ((val >> 2) & 0xFF))
return -EIO;
return 0;
}
/* After initiating a conversion sequence we need to wait until the
* conversion is done. The delay is typically in the range of 15..30 us
* however depending an the number of devices in the daisy chain and the
* number of averages taken, conversion delays and acquisition time options
* it may take up to 250us, in this case we better sleep instead of busy
* wait.
*/
static void ad7280_delay(struct ad7280_state *st)
{
if
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