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