diff options
Diffstat (limited to 'drivers/w1/slaves/w1_ds2438.c')
| -rw-r--r-- | drivers/w1/slaves/w1_ds2438.c | 430 |
1 files changed, 430 insertions, 0 deletions
diff --git a/drivers/w1/slaves/w1_ds2438.c b/drivers/w1/slaves/w1_ds2438.c new file mode 100644 index 000000000..b005dda9c --- /dev/null +++ b/drivers/w1/slaves/w1_ds2438.c @@ -0,0 +1,430 @@ +/* + * 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] = (u8)pageno; + 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] = (u8)pageno; + 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 int 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 int w1_ds2438_get_current(struct w1_slave *sl, int16_t *voltage) +{ + u8 w1_buf[DS2438_PAGE_SIZE + 1 /*for CRC*/]; + int ret; + + mutex_lock(&sl->master->bus_mutex); + + if (w1_ds2438_get_page(sl, 0, w1_buf) == 0) { + /* The voltage measured across current sense resistor RSENS. */ + *voltage = (((int16_t) w1_buf[DS2438_CURRENT_MSB]) << 8) | ((int16_t) w1_buf[DS2438_CURRENT_LSB]); + ret = 0; + } else + ret = -1; + + mutex_unlock(&sl->master->bus_mutex); + + 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 iad_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; + int16_t voltage; + + if (off != 0) + return 0; + if (!buf) + return -EINVAL; + + if (w1_ds2438_get_current(sl, &voltage) == 0) { + ret = snprintf(buf, count, "%i\n", voltage); + } else + ret = -EIO; + + 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); + + /* Read no more than page0 size */ + if (count > DS2438_PAGE_SIZE) + count = DS2438_PAGE_SIZE; + + if (w1_ds2438_get_page(sl, 0, w1_buf) == 0) { + memcpy(buf, &w1_buf, count); + ret = count; + } 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; + int16_t temp; + + if (off != 0) + return 0; + if (!buf) + return -EINVAL; + + if (w1_ds2438_get_temperature(sl, &temp) == 0) { + ret = snprintf(buf, count, "%i\n", temp); + } 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; + uint16_t voltage; + + if (off != 0) + return 0; + if (!buf) + return -EINVAL; + + if (w1_ds2438_get_voltage(sl, DS2438_ADC_INPUT_VAD, &voltage) == 0) { + ret = snprintf(buf, count, "%u\n", voltage); + } 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; + uint16_t voltage; + + if (off != 0) + return 0; + if (!buf) + return -EINVAL; + + if (w1_ds2438_get_voltage(sl, DS2438_ADC_INPUT_VDD, &voltage) == 0) { + ret = snprintf(buf, count, "%u\n", voltage); + } else + ret = -EIO; + + return ret; +} + +static BIN_ATTR(iad, S_IRUGO | S_IWUSR | S_IWGRP, iad_read, iad_write, 0); +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)); |