[PATCH v4 2/2] add w1_ds28e17 driver for the DS28E17 Onewire to I2C master bridge

Jan Kandziora
2017-09-18T13:04:10Z

This subpatch adds a driver for the DS28E17 Onewire to I2C master bridge.

Signed-off-by: Jan Kandziora <jjj@gmx.de>
---
Changes in v4 against v3 in this subpatch:
- adapted to linux-4.12.0

Changes in v3 against v2 in this subpatch:
- fixed a bug in using the i2c_adapter_quirks structure

Changes in v2 against v1 in this subpatch:
- added error handling in w1_f19_error()
- added struct i2c_adapter_quirks
- removed unnecessary checks of I2C address and read count
- cleaned up error codes
+ EOPNOTSUPP for read/write count == 0
+ ETIMEDOUT for busy timeout
+ ENXIO for no reply of I2C slave
+ EAGAIN for I2C invalid start condition
+ EIO for all w1 errors
- devm_kzalloc() instead of kzalloc()
- i2c speed to be set as 100, 400, 900 instead of 0, 1, 2
- added driver parameter documentation
- added sysfs documentation
- Kconfig fixed

Documentation/ABI/testing/sysfs-driver-w1_ds28e17 | 21 +
Documentation/w1/slaves/00-INDEX | 2 +
Documentation/w1/slaves/w1_ds28e17 | 68 ++
drivers/w1/slaves/Kconfig | 15 +
drivers/w1/slaves/Makefile | 1 +
drivers/w1/slaves/w1_ds28e17.c | 772 ++++++++++++++++++++++
drivers/w1/w1_family.h | 1 +
7 files changed, 880 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-driver-w1_ds28e17
create mode 100644 Documentation/w1/slaves/w1_ds28e17
create mode 100644 drivers/w1/slaves/w1_ds28e17.c

diff --git a/Documentation/ABI/testing/sysfs-driver-w1_ds28e17 b/Documentation/ABI/testing/sysfs-driver-w1_ds28e17
new file mode 100644
index 0000000..b97b101
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-w1_ds28e17
@@ -0,0 +1,21 @@
+What: /sys/bus/w1/devices/19-<id>/speed
+Date: Jul 2016
+KernelVersion: 4.7
+Contact: Jan Kandziora <jjj@gmx.de>
+Description: When written, this file sets the I2C speed on the connected
+ DS28E17 chip. When read, it reads the current setting from
+ the DS28E17 chip.
+ Valid values: 100, 400, 900 [kBaud].
+ Default 100, can be set by w1_ds28e17.speed= module parameter.
+Users: w1_ds28e17 driver
+
+What: /sys/bus/w1/devices/19-<id>/stretch
+Date: Jul 2016
+KernelVersion: 4.7
+Contact: Jan Kandziora <jjj@gmx.de>
+Description: When written, this file sets the multiplier used to calculate
+ the busy timeout for I2C operations on the connected DS28E17
+ chip. When read, returns the current setting.
+ Valid values: 1 to 9.
+ Default 1, can be set by w1_ds28e17.stretch= module parameter.
+Users: w1_ds28e17 driver
diff --git a/Documentation/w1/slaves/00-INDEX b/Documentation/w1/slaves/00-INDEX
index 8d76718..68946f8 100644
--- a/Documentation/w1/slaves/00-INDEX
+++ b/Documentation/w1/slaves/00-INDEX
@@ -10,3 +10,5 @@ w1_ds2438
- The Maxim/Dallas Semiconductor ds2438 smart battery monitor.
w1_ds28e04
- The Maxim/Dallas Semiconductor ds28e04 eeprom.
+w1_ds28e17
+ - The Maxim/Dallas Semiconductor ds28e17 1-Wire-to-I2C Master Bridge.
diff --git a/Documentation/w1/slaves/w1_ds28e17 b/Documentation/w1/slaves/w1_ds28e17
new file mode 100644
index 0000000..e82e16e
--- /dev/null
+++ b/Documentation/w1/slaves/w1_ds28e17
@@ -0,0 +1,68 @@
+Kernel driver w1_ds28e17
+========================
+
+Supported chips:
+ * Maxim DS28E17 1-Wire-to-I2C Master Bridge
+
+supported family codes:
+ W1_FAMILY_DS28E17 0x19
+
+Author: Jan Kandziora <jjj@gmx.de>
+
+
+Description
+-----------
+The DS28E17 is a Onewire slave device which acts as an I2C bus master.
+
+This driver creates a new I2C bus for any DS28E17 device detected. I2C buses
+come and go as the DS28E17 devices come and go. I2C slave devices connected to
+a DS28E17 can be accessed by the kernel or userspace tools as if they were
+connected to a "native" I2C bus master.
+
+
+An udev rule like the following
+-------------------------------------------------------------------------------
+SUBSYSTEM=="i2c-dev", KERNEL=="i2c-[0-9]*", ATTRS{name}=="w1-19-*", \
+ SYMLINK+="i2c-$attr{name}"
+-------------------------------------------------------------------------------
+may be used to create stable /dev/i2c- entries based on the unique id of the
+DS28E17 chip.
+
+
+Driver parameters are:
+
+speed:
+ This sets up the default I2C speed a DS28E17 get configured for as soon
+ it is connected. The power-on default of the DS28E17 is 400kBaud, but
+ chips may come and go on the Onewire bus without being de-powered and
+ as soon the "w1_ds28e17" driver notices a freshly connected, or
+ reconnected DS28E17 device on the Onewire bus, it will re-apply this
+ setting.
+
+ Valid values are 100, 400, 900 [kBaud]. Any other value means to leave
+ alone the current DS28E17 setting on detect. The default value is 100.
+
+stretch:
+ This sets up the default stretch value used for freshly connected
+ DS28E17 devices. It is a multiplier used on the calculation of the busy
+ wait time for an I2C transfer. This is to account for I2C slave devices
+ which make heavy use of the I2C clock stretching feature and thus, the
+ needed timeout cannot be pre-calculated correctly. As the w1_ds28e17
+ driver checks the DS28E17's busy flag in a loop after the precalculated
+ wait time, it should be hardly needed to tweak this setting.
+
+ Leave it at 1 unless you get ETIMEDOUT errors and a "w1_slave_driver
+ 19-00000002dbd8: busy timeout" in the kernel log.
+
+ Valid values are 1 to 9. The default is 1.
+
+
+The driver creates sysfs files /sys/bus/w1/devices/19-<id>/speed and
+/sys/bus/w1/devices/19-<id>/stretch for each device, preloaded with the default
+settings from the driver parameters. They may be changed anytime. In addition a
+directory /sys/bus/w1/devices/19-<id>/i2c-<nnn> for the I2C bus master sysfs
+structure is created.
+
+
+See https://github.com/ianka/w1_ds28e17 for even more information.
+
diff --git a/drivers/w1/slaves/Kconfig b/drivers/w1/slaves/Kconfig
index fb68465..b94c55c 100644
--- a/drivers/w1/slaves/Kconfig
+++ b/drivers/w1/slaves/Kconfig
@@ -140,6 +140,21 @@ config W1_SLAVE_DS28E04

If you are unsure, say N.

+config W1_SLAVE_DS28E17
+ tristate "1-wire-to-I2C master bridge (DS28E17)"
+ select CRC16
+ depends on I2C
+ help
+ Say Y here if you want to use the DS28E17 1-wire-to-I2C master bridge.
+ For each DS28E17 detected, a new I2C adapter is created within the
+ kernel. I2C devices on that bus can be configured to be used by the
+ kernel and userspace tools as on any other "native" I2C bus.
+
+ This driver is also available as a module. If so, the module
+ will be called w1_ds28e17.
+
+ If you are unsure, say N.
+
config W1_SLAVE_BQ27000
tristate "BQ27000 slave support"
help
diff --git a/drivers/w1/slaves/Makefile b/drivers/w1/slaves/Makefile
index 54c63e4..5ec927b 100644
--- a/drivers/w1/slaves/Makefile
+++ b/drivers/w1/slaves/Makefile
@@ -17,3 +17,4 @@ obj-$(CONFIG_W1_SLAVE_DS2780) += w1_ds2780.o
obj-$(CONFIG_W1_SLAVE_DS2781) += w1_ds2781.o
obj-$(CONFIG_W1_SLAVE_BQ27000) += w1_bq27000.o
obj-$(CONFIG_W1_SLAVE_DS28E04) += w1_ds28e04.o
+obj-$(CONFIG_W1_SLAVE_DS28E17) += w1_ds28e17.o
diff --git a/drivers/w1/slaves/w1_ds28e17.c b/drivers/w1/slaves/w1_ds28e17.c
new file mode 100644
index 0000000..3e217e9
--- /dev/null
+++ b/drivers/w1/slaves/w1_ds28e17.c
@@ -0,0 +1,772 @@
+/*
+ * 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 "../w1.h"
+#include "../w1_int.h"
+#include "../w1_family.h"
+
+
+/* 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);
+
diff --git a/drivers/w1/w1_family.h b/drivers/w1/w1_family.h
index 869a3ff..f675638 100644
--- a/drivers/w1/w1_family.h
+++ b/drivers/w1/w1_family.h
@@ -25,6 +25,7 @@
#define W1_FAMILY_SMEM_81 0x81
#define W1_FAMILY_DS2405 0x05
#define W1_THERM_DS18S20 0x10
+#define W1_FAMILY_DS28E17 0x19
#define W1_FAMILY_DS28E04 0x1C
#define W1_COUNTER_DS2423 0x1D
#define W1_THERM_DS1822 0x22
--
2.13.3