diff options
Diffstat (limited to 'drivers/w1/slaves/w1_ds28e17.c')
| -rw-r--r-- | drivers/w1/slaves/w1_ds28e17.c | 771 |
1 files changed, 771 insertions, 0 deletions
diff --git a/drivers/w1/slaves/w1_ds28e17.c b/drivers/w1/slaves/w1_ds28e17.c new file mode 100644 index 000000000000..e78b63ea4daf --- /dev/null +++ b/drivers/w1/slaves/w1_ds28e17.c @@ -0,0 +1,771 @@ +/* + * w1_ds28e17.c - w1 family 19 (DS28E17) driver + * + * Copyright (c) 2016 Jan Kandziora <jjj@gmx.de> + * + * This source code is licensed under the GNU General Public License, + * Version 2. See the file COPYING for more details. + */ + +#include <linux/crc16.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/i2c.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/uaccess.h> + +#define CRC16_INIT 0 + +#include <linux/w1.h> + +#define W1_FAMILY_DS28E17 0x19 + +/* Module setup. */ +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Jan Kandziora <jjj@gmx.de>"); +MODULE_DESCRIPTION("w1 family 19 driver for DS28E17, 1-wire to I2C master bridge"); +MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS28E17)); + + +/* Default I2C speed to be set when a DS28E17 is detected. */ +static int i2c_speed = 100; +module_param_named(speed, i2c_speed, int, (S_IRUSR | S_IWUSR)); +MODULE_PARM_DESC(speed, "Default I2C speed to be set when a DS28E17 is detected"); + +/* Default I2C stretch value to be set when a DS28E17 is detected. */ +static char i2c_stretch = 1; +module_param_named(stretch, i2c_stretch, byte, (S_IRUSR | S_IWUSR)); +MODULE_PARM_DESC(stretch, "Default I2C stretch value to be set when a DS28E17 is detected"); + +/* DS28E17 device command codes. */ +#define W1_F19_WRITE_DATA_WITH_STOP 0x4B +#define W1_F19_WRITE_DATA_NO_STOP 0x5A +#define W1_F19_WRITE_DATA_ONLY 0x69 +#define W1_F19_WRITE_DATA_ONLY_WITH_STOP 0x78 +#define W1_F19_READ_DATA_WITH_STOP 0x87 +#define W1_F19_WRITE_READ_DATA_WITH_STOP 0x2D +#define W1_F19_WRITE_CONFIGURATION 0xD2 +#define W1_F19_READ_CONFIGURATION 0xE1 +#define W1_F19_ENABLE_SLEEP_MODE 0x1E +#define W1_F19_READ_DEVICE_REVISION 0xC4 + +/* DS28E17 status bits */ +#define W1_F19_STATUS_CRC 0x01 +#define W1_F19_STATUS_ADDRESS 0x02 +#define W1_F19_STATUS_START 0x08 + +/* + * Maximum number of I2C bytes to transfer within one CRC16 protected onewire + * command. + * */ +#define W1_F19_WRITE_DATA_LIMIT 255 + +/* Maximum number of I2C bytes to read with one onewire command. */ +#define W1_F19_READ_DATA_LIMIT 255 + +/* Constants for calculating the busy sleep. */ +#define W1_F19_BUSY_TIMEBASES { 90, 23, 10 } +#define W1_F19_BUSY_GRATUITY 1000 + +/* Number of checks for the busy flag before timeout. */ +#define W1_F19_BUSY_CHECKS 1000 + + +/* Slave specific data. */ +struct w1_f19_data { + u8 speed; + u8 stretch; + struct i2c_adapter adapter; +}; + + +/* Wait a while until the busy flag clears. */ +static int w1_f19_i2c_busy_wait(struct w1_slave *sl, size_t count) +{ + const unsigned long timebases[3] = W1_F19_BUSY_TIMEBASES; + struct w1_f19_data *data = sl->family_data; + unsigned int checks; + + /* Check the busy flag first in any case.*/ + if (w1_touch_bit(sl->master, 1) == 0) + return 0; + + /* + * Do a generously long sleep in the beginning, + * as we have to wait at least this time for all + * the I2C bytes at the given speed to be transferred. + */ + usleep_range(timebases[data->speed] * (data->stretch) * count, + timebases[data->speed] * (data->stretch) * count + + W1_F19_BUSY_GRATUITY); + + /* Now continusly check the busy flag sent by the DS28E17. */ + checks = W1_F19_BUSY_CHECKS; + while ((checks--) > 0) { + /* Return success if the busy flag is cleared. */ + if (w1_touch_bit(sl->master, 1) == 0) + return 0; + + /* Wait one non-streched byte timeslot. */ + udelay(timebases[data->speed]); + } + + /* Timeout. */ + dev_warn(&sl->dev, "busy timeout\n"); + return -ETIMEDOUT; +} + + +/* Utility function: result. */ +static size_t w1_f19_error(struct w1_slave *sl, u8 w1_buf[]) +{ + /* Warnings. */ + if (w1_buf[0] & W1_F19_STATUS_CRC) + dev_warn(&sl->dev, "crc16 mismatch\n"); + if (w1_buf[0] & W1_F19_STATUS_ADDRESS) + dev_warn(&sl->dev, "i2c device not responding\n"); + if ((w1_buf[0] & (W1_F19_STATUS_CRC | W1_F19_STATUS_ADDRESS)) == 0 + && w1_buf[1] != 0) { + dev_warn(&sl->dev, "i2c short write, %d bytes not acknowledged\n", + w1_buf[1]); + } + + /* Check error conditions. */ + if (w1_buf[0] & W1_F19_STATUS_ADDRESS) + return -ENXIO; + if (w1_buf[0] & W1_F19_STATUS_START) + return -EAGAIN; + if (w1_buf[0] != 0 || w1_buf[1] != 0) + return -EIO; + + /* All ok. */ + return 0; +} + + +/* Utility function: write data to I2C slave, single chunk. */ +static int __w1_f19_i2c_write(struct w1_slave *sl, + const u8 *command, size_t command_count, + const u8 *buffer, size_t count) +{ + u16 crc; + int error; + u8 w1_buf[2]; + + /* Send command and I2C data to DS28E17. */ + crc = crc16(CRC16_INIT, command, command_count); + w1_write_block(sl->master, command, command_count); + + w1_buf[0] = count; + crc = crc16(crc, w1_buf, 1); + w1_write_8(sl->master, w1_buf[0]); + + crc = crc16(crc, buffer, count); + w1_write_block(sl->master, buffer, count); + + w1_buf[0] = ~(crc & 0xFF); + w1_buf[1] = ~((crc >> 8) & 0xFF); + w1_write_block(sl->master, w1_buf, 2); + + /* Wait until busy flag clears (or timeout). */ + if (w1_f19_i2c_busy_wait(sl, count + 1) < 0) + return -ETIMEDOUT; + + /* Read status from DS28E17. */ + w1_read_block(sl->master, w1_buf, 2); + + /* Check error conditions. */ + error = w1_f19_error(sl, w1_buf); + if (error < 0) + return error; + + /* Return number of bytes written. */ + return count; +} + + +/* Write data to I2C slave. */ +static int w1_f19_i2c_write(struct w1_slave *sl, u16 i2c_address, + const u8 *buffer, size_t count, bool stop) +{ + int result; + int remaining = count; + const u8 *p; + u8 command[2]; + + /* Check input. */ + if (count == 0) + return -EOPNOTSUPP; + + /* Check whether we need multiple commands. */ + if (count <= W1_F19_WRITE_DATA_LIMIT) { + /* + * Small data amount. Data can be sent with + * a single onewire command. + */ + + /* Send all data to DS28E17. */ + command[0] = (stop ? W1_F19_WRITE_DATA_WITH_STOP + : W1_F19_WRITE_DATA_NO_STOP); + command[1] = i2c_address << 1; + result = __w1_f19_i2c_write(sl, command, 2, buffer, count); + } else { + /* Large data amount. Data has to be sent in multiple chunks. */ + + /* Send first chunk to DS28E17. */ + p = buffer; + command[0] = W1_F19_WRITE_DATA_NO_STOP; + command[1] = i2c_address << 1; + result = __w1_f19_i2c_write(sl, command, 2, p, + W1_F19_WRITE_DATA_LIMIT); + if (result < 0) + return result; + + /* Resume to same DS28E17. */ + if (w1_reset_resume_command(sl->master)) + return -EIO; + + /* Next data chunk. */ + p += W1_F19_WRITE_DATA_LIMIT; + remaining -= W1_F19_WRITE_DATA_LIMIT; + + while (remaining > W1_F19_WRITE_DATA_LIMIT) { + /* Send intermediate chunk to DS28E17. */ + command[0] = W1_F19_WRITE_DATA_ONLY; + result = __w1_f19_i2c_write(sl, command, 1, p, + W1_F19_WRITE_DATA_LIMIT); + if (result < 0) + return result; + + /* Resume to same DS28E17. */ + if (w1_reset_resume_command(sl->master)) + return -EIO; + + /* Next data chunk. */ + p += W1_F19_WRITE_DATA_LIMIT; + remaining -= W1_F19_WRITE_DATA_LIMIT; + } + + /* Send final chunk to DS28E17. */ + command[0] = (stop ? W1_F19_WRITE_DATA_ONLY_WITH_STOP + : W1_F19_WRITE_DATA_ONLY); + result = __w1_f19_i2c_write(sl, command, 1, p, remaining); + } + + return result; +} + + +/* Read data from I2C slave. */ +static int w1_f19_i2c_read(struct w1_slave *sl, u16 i2c_address, + u8 *buffer, size_t count) +{ + u16 crc; + int error; + u8 w1_buf[5]; + + /* Check input. */ + if (count == 0) + return -EOPNOTSUPP; + + /* Send command to DS28E17. */ + w1_buf[0] = W1_F19_READ_DATA_WITH_STOP; + w1_buf[1] = i2c_address << 1 | 0x01; + w1_buf[2] = count; + crc = crc16(CRC16_INIT, w1_buf, 3); + w1_buf[3] = ~(crc & 0xFF); + w1_buf[4] = ~((crc >> 8) & 0xFF); + w1_write_block(sl->master, w1_buf, 5); + + /* Wait until busy flag clears (or timeout). */ + if (w1_f19_i2c_busy_wait(sl, count + 1) < 0) + return -ETIMEDOUT; + + /* Read status from DS28E17. */ + w1_buf[0] = w1_read_8(sl->master); + w1_buf[1] = 0; + + /* Check error conditions. */ + error = w1_f19_error(sl, w1_buf); + if (error < 0) + return error; + + /* Read received I2C data from DS28E17. */ + return w1_read_block(sl->master, buffer, count); +} + + +/* Write to, then read data from I2C slave. */ +static int w1_f19_i2c_write_read(struct w1_slave *sl, u16 i2c_address, + const u8 *wbuffer, size_t wcount, u8 *rbuffer, size_t rcount) +{ + u16 crc; + int error; + u8 w1_buf[3]; + + /* Check input. */ + if (wcount == 0 || rcount == 0) + return -EOPNOTSUPP; + + /* Send command and I2C data to DS28E17. */ + w1_buf[0] = W1_F19_WRITE_READ_DATA_WITH_STOP; + w1_buf[1] = i2c_address << 1; + w1_buf[2] = wcount; + crc = crc16(CRC16_INIT, w1_buf, 3); + w1_write_block(sl->master, w1_buf, 3); + + crc = crc16(crc, wbuffer, wcount); + w1_write_block(sl->master, wbuffer, wcount); + + w1_buf[0] = rcount; + crc = crc16(crc, w1_buf, 1); + w1_buf[1] = ~(crc & 0xFF); + w1_buf[2] = ~((crc >> 8) & 0xFF); + w1_write_block(sl->master, w1_buf, 3); + + /* Wait until busy flag clears (or timeout). */ + if (w1_f19_i2c_busy_wait(sl, wcount + rcount + 2) < 0) + return -ETIMEDOUT; + + /* Read status from DS28E17. */ + w1_read_block(sl->master, w1_buf, 2); + + /* Check error conditions. */ + error = w1_f19_error(sl, w1_buf); + if (error < 0) + return error; + + /* Read received I2C data from DS28E17. */ + return w1_read_block(sl->master, rbuffer, rcount); +} + + +/* Do an I2C master transfer. */ +static int w1_f19_i2c_master_transfer(struct i2c_adapter *adapter, + struct i2c_msg *msgs, int num) +{ + struct w1_slave *sl = (struct w1_slave *) adapter->algo_data; + int i = 0; + int result = 0; + + /* Start onewire transaction. */ + mutex_lock(&sl->master->bus_mutex); + + /* Select DS28E17. */ + if (w1_reset_select_slave(sl)) { + i = -EIO; + goto error; + } + + /* Loop while there are still messages to transfer. */ + while (i < num) { + /* + * Check for special case: Small write followed + * by read to same I2C device. + */ + if (i < (num-1) + && msgs[i].addr == msgs[i+1].addr + && !(msgs[i].flags & I2C_M_RD) + && (msgs[i+1].flags & I2C_M_RD) + && (msgs[i].len <= W1_F19_WRITE_DATA_LIMIT)) { + /* + * The DS28E17 has a combined transfer + * for small write+read. + */ + result = w1_f19_i2c_write_read(sl, msgs[i].addr, + msgs[i].buf, msgs[i].len, + msgs[i+1].buf, msgs[i+1].len); + if (result < 0) { + i = result; + goto error; + } + + /* + * Check if we should interpret the read data + * as a length byte. The DS28E17 unfortunately + * has no read without stop, so we can just do + * another simple read in that case. + */ + if (msgs[i+1].flags & I2C_M_RECV_LEN) { + result = w1_f19_i2c_read(sl, msgs[i+1].addr, + &(msgs[i+1].buf[1]), msgs[i+1].buf[0]); + if (result < 0) { + i = result; + goto error; + } + } + + /* Eat up read message, too. */ + i++; + } else if (msgs[i].flags & I2C_M_RD) { + /* Read transfer. */ + result = w1_f19_i2c_read(sl, msgs[i].addr, + msgs[i].buf, msgs[i].len); + if (result < 0) { + i = result; + goto error; + } + + /* + * Check if we should interpret the read data + * as a length byte. The DS28E17 unfortunately + * has no read without stop, so we can just do + * another simple read in that case. + */ + if (msgs[i].flags & I2C_M_RECV_LEN) { + result = w1_f19_i2c_read(sl, + msgs[i].addr, + &(msgs[i].buf[1]), + msgs[i].buf[0]); + if (result < 0) { + i = result; + goto error; + } + } + } else { + /* + * Write transfer. + * Stop condition only for last + * transfer. + */ + result = w1_f19_i2c_write(sl, + msgs[i].addr, + msgs[i].buf, + msgs[i].len, + i == (num-1)); + if (result < 0) { + i = result; + goto error; + } + } + + /* Next message. */ + i++; + + /* Are there still messages to send/receive? */ + if (i < num) { + /* Yes. Resume to same DS28E17. */ + if (w1_reset_resume_command(sl->master)) { + i = -EIO; + goto error; + } + } + } + +error: + /* End onewire transaction. */ + mutex_unlock(&sl->master->bus_mutex); + + /* Return number of messages processed or error. */ + return i; +} + + +/* Get I2C adapter functionality. */ +static u32 w1_f19_i2c_functionality(struct i2c_adapter *adapter) +{ + /* + * Plain I2C functions only. + * SMBus is emulated by the kernel's I2C layer. + * No "I2C_FUNC_SMBUS_QUICK" + * No "I2C_FUNC_SMBUS_READ_BLOCK_DATA" + * No "I2C_FUNC_SMBUS_BLOCK_PROC_CALL" + */ + return I2C_FUNC_I2C | + I2C_FUNC_SMBUS_BYTE | + I2C_FUNC_SMBUS_BYTE_DATA | + I2C_FUNC_SMBUS_WORD_DATA | + I2C_FUNC_SMBUS_PROC_CALL | + I2C_FUNC_SMBUS_WRITE_BLOCK_DATA | + I2C_FUNC_SMBUS_I2C_BLOCK | + I2C_FUNC_SMBUS_PEC; +} + + +/* I2C adapter quirks. */ +static const struct i2c_adapter_quirks w1_f19_i2c_adapter_quirks = { + .max_read_len = W1_F19_READ_DATA_LIMIT, +}; + +/* I2C algorithm. */ +static const struct i2c_algorithm w1_f19_i2c_algorithm = { + .master_xfer = w1_f19_i2c_master_transfer, + .functionality = w1_f19_i2c_functionality, +}; + + +/* Read I2C speed from DS28E17. */ +static int w1_f19_get_i2c_speed(struct w1_slave *sl) +{ + struct w1_f19_data *data = sl->family_data; + int result = -EIO; + + /* Start onewire transaction. */ + mutex_lock(&sl->master->bus_mutex); + + /* Select slave. */ + if (w1_reset_select_slave(sl)) + goto error; + + /* Read slave configuration byte. */ + w1_write_8(sl->master, W1_F19_READ_CONFIGURATION); + result = w1_read_8(sl->master); + if (result < 0 || result > 2) { + result = -EIO; + goto error; + } + + /* Update speed in slave specific data. */ + data->speed = result; + +error: + /* End onewire transaction. */ + mutex_unlock(&sl->master->bus_mutex); + + return result; +} + + +/* Set I2C speed on DS28E17. */ +static int __w1_f19_set_i2c_speed(struct w1_slave *sl, u8 speed) +{ + struct w1_f19_data *data = sl->family_data; + const int i2c_speeds[3] = { 100, 400, 900 }; + u8 w1_buf[2]; + + /* Select slave. */ + if (w1_reset_select_slave(sl)) + return -EIO; + + w1_buf[0] = W1_F19_WRITE_CONFIGURATION; + w1_buf[1] = speed; + w1_write_block(sl->master, w1_buf, 2); + + /* Update speed in slave specific data. */ + data->speed = speed; + + dev_info(&sl->dev, "i2c speed set to %d kBaud\n", i2c_speeds[speed]); + + return 0; +} + +static int w1_f19_set_i2c_speed(struct w1_slave *sl, u8 speed) +{ + int result; + + /* Start onewire transaction. */ + mutex_lock(&sl->master->bus_mutex); + + /* Set I2C speed on DS28E17. */ + result = __w1_f19_set_i2c_speed(sl, speed); + + /* End onewire transaction. */ + mutex_unlock(&sl->master->bus_mutex); + + return result; +} + + +/* Sysfs attributes. */ + +/* I2C speed attribute for a single chip. */ +static ssize_t speed_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct w1_slave *sl = dev_to_w1_slave(dev); + int result; + + /* Read current speed from slave. Updates data->speed. */ + result = w1_f19_get_i2c_speed(sl); + if (result < 0) + return result; + + /* Return current speed value. */ + return sprintf(buf, "%d\n", result); +} + +static ssize_t speed_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct w1_slave *sl = dev_to_w1_slave(dev); + int error; + + /* Valid values are: "100", "400", "900" */ + if (count < 3 || count > 4 || !buf) + return -EINVAL; + if (count == 4 && buf[3] != '\n') + return -EINVAL; + if (buf[1] != '0' || buf[2] != '0') + return -EINVAL; + + /* Set speed on slave. */ + switch (buf[0]) { + case '1': + error = w1_f19_set_i2c_speed(sl, 0); + break; + case '4': + error = w1_f19_set_i2c_speed(sl, 1); + break; + case '9': + error = w1_f19_set_i2c_speed(sl, 2); + break; + default: + return -EINVAL; + } + + if (error < 0) + return error; + + /* Return bytes written. */ + return count; +} + +static DEVICE_ATTR_RW(speed); + + +/* Busy stretch attribute for a single chip. */ +static ssize_t stretch_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct w1_slave *sl = dev_to_w1_slave(dev); + struct w1_f19_data *data = sl->family_data; + + /* Return current stretch value. */ + return sprintf(buf, "%d\n", data->stretch); +} + +static ssize_t stretch_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct w1_slave *sl = dev_to_w1_slave(dev); + struct w1_f19_data *data = sl->family_data; + + /* Valid values are '1' to '9' */ + if (count < 1 || count > 2 || !buf) + return -EINVAL; + if (count == 2 && buf[1] != '\n') + return -EINVAL; + if (buf[0] < '1' || buf[0] > '9') + return -EINVAL; + + /* Set busy stretch value. */ + data->stretch = buf[0] & 0x0F; + + /* Return bytes written. */ + return count; +} + +static DEVICE_ATTR_RW(stretch); + + +/* All attributes. */ +static struct attribute *w1_f19_attrs[] = { + &dev_attr_speed.attr, + &dev_attr_stretch.attr, + NULL, +}; + +static const struct attribute_group w1_f19_group = { + .attrs = w1_f19_attrs, +}; + +static const struct attribute_group *w1_f19_groups[] = { + &w1_f19_group, + NULL, +}; + + +/* Slave add and remove functions. */ +static int w1_f19_add_slave(struct w1_slave *sl) +{ + struct w1_f19_data *data = NULL; + + /* Allocate memory for slave specific data. */ + data = devm_kzalloc(&sl->dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + sl->family_data = data; + + /* Setup default I2C speed on slave. */ + switch (i2c_speed) { + case 100: + __w1_f19_set_i2c_speed(sl, 0); + break; + case 400: + __w1_f19_set_i2c_speed(sl, 1); + break; + case 900: + __w1_f19_set_i2c_speed(sl, 2); + break; + default: + /* + * A i2c_speed module parameter of anything else + * than 100, 400, 900 means not to touch the + * speed of the DS28E17. + * We assume 400kBaud, the power-on value. + */ + data->speed = 1; + } + + /* + * Setup default busy stretch + * configuration for the DS28E17. + */ + data->stretch = i2c_stretch; + + /* Setup I2C adapter. */ + data->adapter.owner = THIS_MODULE; + data->adapter.algo = &w1_f19_i2c_algorithm; + data->adapter.algo_data = sl; + strcpy(data->adapter.name, "w1-"); + strcat(data->adapter.name, sl->name); + data->adapter.dev.parent = &sl->dev; + data->adapter.quirks = &w1_f19_i2c_adapter_quirks; + + return i2c_add_adapter(&data->adapter); +} + +static void w1_f19_remove_slave(struct w1_slave *sl) +{ + struct w1_f19_data *family_data = sl->family_data; + + /* Delete I2C adapter. */ + i2c_del_adapter(&family_data->adapter); + + /* Free slave specific data. */ + devm_kfree(&sl->dev, family_data); + sl->family_data = NULL; +} + + +/* Declarations within the w1 subsystem. */ +static struct w1_family_ops w1_f19_fops = { + .add_slave = w1_f19_add_slave, + .remove_slave = w1_f19_remove_slave, + .groups = w1_f19_groups, +}; + +static struct w1_family w1_family_19 = { + .fid = W1_FAMILY_DS28E17, + .fops = &w1_f19_fops, +}; + + +/* Module init and remove functions. */ +static int __init w1_f19_init(void) +{ + return w1_register_family(&w1_family_19); +} + +static void __exit w1_f19_fini(void) +{ + w1_unregister_family(&w1_family_19); +} + +module_init(w1_f19_init); +module_exit(w1_f19_fini); + |