392 lines
8.9 KiB
C
392 lines
8.9 KiB
C
/*
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* 1-Wire implementation for the ds2438 chip
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*
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* Copyright (c) 2017 Mariusz Bialonczyk <manio@skyboo.net>
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/types.h>
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#include <linux/delay.h>
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#include <linux/w1.h>
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#define W1_FAMILY_DS2438 0x26
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#define W1_DS2438_RETRIES 3
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/* Memory commands */
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#define W1_DS2438_READ_SCRATCH 0xBE
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#define W1_DS2438_WRITE_SCRATCH 0x4E
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#define W1_DS2438_COPY_SCRATCH 0x48
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#define W1_DS2438_RECALL_MEMORY 0xB8
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/* Register commands */
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#define W1_DS2438_CONVERT_TEMP 0x44
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#define W1_DS2438_CONVERT_VOLTAGE 0xB4
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#define DS2438_PAGE_SIZE 8
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#define DS2438_ADC_INPUT_VAD 0
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#define DS2438_ADC_INPUT_VDD 1
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#define DS2438_MAX_CONVERSION_TIME 10 /* ms */
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/* Page #0 definitions */
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#define DS2438_STATUS_REG 0x00 /* Status/Configuration Register */
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#define DS2438_STATUS_IAD (1 << 0) /* Current A/D Control Bit */
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#define DS2438_STATUS_CA (1 << 1) /* Current Accumulator Configuration */
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#define DS2438_STATUS_EE (1 << 2) /* Current Accumulator Shadow Selector bit */
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#define DS2438_STATUS_AD (1 << 3) /* Voltage A/D Input Select Bit */
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#define DS2438_STATUS_TB (1 << 4) /* Temperature Busy Flag */
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#define DS2438_STATUS_NVB (1 << 5) /* Nonvolatile Memory Busy Flag */
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#define DS2438_STATUS_ADB (1 << 6) /* A/D Converter Busy Flag */
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#define DS2438_TEMP_LSB 0x01
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#define DS2438_TEMP_MSB 0x02
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#define DS2438_VOLTAGE_LSB 0x03
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#define DS2438_VOLTAGE_MSB 0x04
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#define DS2438_CURRENT_LSB 0x05
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#define DS2438_CURRENT_MSB 0x06
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#define DS2438_THRESHOLD 0x07
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int w1_ds2438_get_page(struct w1_slave *sl, int pageno, u8 *buf)
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{
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unsigned int retries = W1_DS2438_RETRIES;
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u8 w1_buf[2];
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u8 crc;
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size_t count;
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while (retries--) {
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crc = 0;
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if (w1_reset_select_slave(sl))
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continue;
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w1_buf[0] = W1_DS2438_RECALL_MEMORY;
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w1_buf[1] = 0x00;
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w1_write_block(sl->master, w1_buf, 2);
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if (w1_reset_select_slave(sl))
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continue;
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w1_buf[0] = W1_DS2438_READ_SCRATCH;
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w1_buf[1] = 0x00;
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w1_write_block(sl->master, w1_buf, 2);
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count = w1_read_block(sl->master, buf, DS2438_PAGE_SIZE + 1);
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if (count == DS2438_PAGE_SIZE + 1) {
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crc = w1_calc_crc8(buf, DS2438_PAGE_SIZE);
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/* check for correct CRC */
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if ((u8)buf[DS2438_PAGE_SIZE] == crc)
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return 0;
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}
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}
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return -1;
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}
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int w1_ds2438_get_temperature(struct w1_slave *sl, int16_t *temperature)
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{
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unsigned int retries = W1_DS2438_RETRIES;
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u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/];
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unsigned int tm = DS2438_MAX_CONVERSION_TIME;
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unsigned long sleep_rem;
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int ret;
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mutex_lock(&sl->master->bus_mutex);
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while (retries--) {
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if (w1_reset_select_slave(sl))
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continue;
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w1_write_8(sl->master, W1_DS2438_CONVERT_TEMP);
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mutex_unlock(&sl->master->bus_mutex);
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sleep_rem = msleep_interruptible(tm);
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if (sleep_rem != 0) {
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ret = -1;
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goto post_unlock;
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}
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if (mutex_lock_interruptible(&sl->master->bus_mutex) != 0) {
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ret = -1;
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goto post_unlock;
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}
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break;
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}
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if (w1_ds2438_get_page(sl, 0, w1_buf) == 0) {
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*temperature = (((int16_t) w1_buf[DS2438_TEMP_MSB]) << 8) | ((uint16_t) w1_buf[DS2438_TEMP_LSB]);
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ret = 0;
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} else
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ret = -1;
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mutex_unlock(&sl->master->bus_mutex);
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post_unlock:
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return ret;
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}
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int w1_ds2438_change_config_bit(struct w1_slave *sl, u8 mask, u8 value)
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{
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unsigned int retries = W1_DS2438_RETRIES;
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u8 w1_buf[3];
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u8 status;
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int perform_write = 0;
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while (retries--) {
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if (w1_reset_select_slave(sl))
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continue;
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w1_buf[0] = W1_DS2438_RECALL_MEMORY;
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w1_buf[1] = 0x00;
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w1_write_block(sl->master, w1_buf, 2);
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if (w1_reset_select_slave(sl))
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continue;
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w1_buf[0] = W1_DS2438_READ_SCRATCH;
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w1_buf[1] = 0x00;
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w1_write_block(sl->master, w1_buf, 2);
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/* reading one byte of result */
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status = w1_read_8(sl->master);
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/* if bit0=1, set a value to a mask for easy compare */
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if (value)
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value = mask;
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if ((status & mask) == value)
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return 0; /* already set as requested */
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else {
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/* changing bit */
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status ^= mask;
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perform_write = 1;
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}
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break;
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}
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if (perform_write) {
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retries = W1_DS2438_RETRIES;
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while (retries--) {
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if (w1_reset_select_slave(sl))
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continue;
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w1_buf[0] = W1_DS2438_WRITE_SCRATCH;
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w1_buf[1] = 0x00;
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w1_buf[2] = status;
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w1_write_block(sl->master, w1_buf, 3);
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if (w1_reset_select_slave(sl))
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continue;
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w1_buf[0] = W1_DS2438_COPY_SCRATCH;
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w1_buf[1] = 0x00;
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w1_write_block(sl->master, w1_buf, 2);
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return 0;
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}
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}
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return -1;
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}
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uint16_t w1_ds2438_get_voltage(struct w1_slave *sl, int adc_input, uint16_t *voltage)
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{
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unsigned int retries = W1_DS2438_RETRIES;
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u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/];
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unsigned int tm = DS2438_MAX_CONVERSION_TIME;
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unsigned long sleep_rem;
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int ret;
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mutex_lock(&sl->master->bus_mutex);
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if (w1_ds2438_change_config_bit(sl, DS2438_STATUS_AD, adc_input)) {
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ret = -1;
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goto pre_unlock;
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}
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while (retries--) {
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if (w1_reset_select_slave(sl))
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continue;
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w1_write_8(sl->master, W1_DS2438_CONVERT_VOLTAGE);
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mutex_unlock(&sl->master->bus_mutex);
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sleep_rem = msleep_interruptible(tm);
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if (sleep_rem != 0) {
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ret = -1;
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goto post_unlock;
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}
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if (mutex_lock_interruptible(&sl->master->bus_mutex) != 0) {
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ret = -1;
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goto post_unlock;
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}
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break;
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}
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if (w1_ds2438_get_page(sl, 0, w1_buf) == 0) {
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*voltage = (((uint16_t) w1_buf[DS2438_VOLTAGE_MSB]) << 8) | ((uint16_t) w1_buf[DS2438_VOLTAGE_LSB]);
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ret = 0;
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} else
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ret = -1;
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pre_unlock:
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mutex_unlock(&sl->master->bus_mutex);
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post_unlock:
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return ret;
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}
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static ssize_t iad_write(struct file *filp, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf,
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loff_t off, size_t count)
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{
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struct w1_slave *sl = kobj_to_w1_slave(kobj);
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int ret;
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if (count != 1 || off != 0)
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return -EFAULT;
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mutex_lock(&sl->master->bus_mutex);
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if (w1_ds2438_change_config_bit(sl, DS2438_STATUS_IAD, *buf & 0x01) == 0)
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ret = 1;
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else
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ret = -EIO;
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mutex_unlock(&sl->master->bus_mutex);
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return ret;
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}
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static ssize_t page0_read(struct file *filp, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf,
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loff_t off, size_t count)
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{
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struct w1_slave *sl = kobj_to_w1_slave(kobj);
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int ret;
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u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/];
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if (off != 0)
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return 0;
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if (!buf)
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return -EINVAL;
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mutex_lock(&sl->master->bus_mutex);
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if (w1_ds2438_get_page(sl, 0, w1_buf) == 0) {
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memcpy(buf, &w1_buf, DS2438_PAGE_SIZE);
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ret = DS2438_PAGE_SIZE;
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} else
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ret = -EIO;
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mutex_unlock(&sl->master->bus_mutex);
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return ret;
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}
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static ssize_t temperature_read(struct file *filp, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf,
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loff_t off, size_t count)
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{
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struct w1_slave *sl = kobj_to_w1_slave(kobj);
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int ret;
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ssize_t c = PAGE_SIZE;
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int16_t temp;
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if (off != 0)
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return 0;
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if (!buf)
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return -EINVAL;
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if (w1_ds2438_get_temperature(sl, &temp) == 0) {
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c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", temp);
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ret = PAGE_SIZE - c;
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} else
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ret = -EIO;
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return ret;
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}
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static ssize_t vad_read(struct file *filp, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf,
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loff_t off, size_t count)
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{
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struct w1_slave *sl = kobj_to_w1_slave(kobj);
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int ret;
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ssize_t c = PAGE_SIZE;
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uint16_t voltage;
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if (off != 0)
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return 0;
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if (!buf)
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return -EINVAL;
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if (w1_ds2438_get_voltage(sl, DS2438_ADC_INPUT_VAD, &voltage) == 0) {
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c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", voltage);
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ret = PAGE_SIZE - c;
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} else
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ret = -EIO;
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return ret;
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}
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static ssize_t vdd_read(struct file *filp, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf,
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loff_t off, size_t count)
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{
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struct w1_slave *sl = kobj_to_w1_slave(kobj);
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int ret;
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ssize_t c = PAGE_SIZE;
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uint16_t voltage;
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if (off != 0)
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return 0;
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if (!buf)
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return -EINVAL;
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if (w1_ds2438_get_voltage(sl, DS2438_ADC_INPUT_VDD, &voltage) == 0) {
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c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", voltage);
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ret = PAGE_SIZE - c;
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} else
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ret = -EIO;
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return ret;
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}
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static BIN_ATTR(iad, S_IRUGO | S_IWUSR | S_IWGRP, NULL, iad_write, 1);
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static BIN_ATTR_RO(page0, DS2438_PAGE_SIZE);
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static BIN_ATTR_RO(temperature, 0/* real length varies */);
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static BIN_ATTR_RO(vad, 0/* real length varies */);
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static BIN_ATTR_RO(vdd, 0/* real length varies */);
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static struct bin_attribute *w1_ds2438_bin_attrs[] = {
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&bin_attr_iad,
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&bin_attr_page0,
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&bin_attr_temperature,
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&bin_attr_vad,
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&bin_attr_vdd,
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NULL,
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};
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static const struct attribute_group w1_ds2438_group = {
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.bin_attrs = w1_ds2438_bin_attrs,
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};
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static const struct attribute_group *w1_ds2438_groups[] = {
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&w1_ds2438_group,
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NULL,
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};
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static struct w1_family_ops w1_ds2438_fops = {
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.groups = w1_ds2438_groups,
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};
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static struct w1_family w1_ds2438_family = {
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.fid = W1_FAMILY_DS2438,
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.fops = &w1_ds2438_fops,
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};
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module_w1_family(w1_ds2438_family);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>");
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MODULE_DESCRIPTION("1-wire driver for Maxim/Dallas DS2438 Smart Battery Monitor");
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MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2438));
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