w1: Add support for DS28EA00 sequence to w1-therm (d9411e57) · Commits · e / devices / android_kernel_oneplus_sm7250

Documentation/ABI/stable/sysfs-driver-w1_ds28ea00

0 → 100644

+6 −0

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		What: /sys/bus/w1/devices/.../w1_seq
		Date: Apr 2015
		Contact: Matt Campbell <mattrcampbell@gmail.com>
		Description: Support for the DS28EA00 chain sequence function
		see Documentation/w1/slaves/w1_therm for detailed information
		Users: any user space application which wants to communicate with DS28EA00

Documentation/w1/slaves/w1_therm

+10 −1

Original line number	Diff line number	Diff line
		@@ -11,12 +11,14 @@ Author: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
		Description
		-----------

		w1_therm provides basic temperature conversion for ds18*20 devices.
		w1_therm provides basic temperature conversion for ds18*20 devices, and the
		ds28ea00 device.
		supported family codes:
		W1_THERM_DS18S20 0x10
		W1_THERM_DS1822 0x22
		W1_THERM_DS18B20 0x28
		W1_THERM_DS1825 0x3B
		W1_THERM_DS28EA00 0x42

		Support is provided through the sysfs w1_slave file. Each open and
		read sequence will initiate a temperature conversion then provide two
		@@ -48,3 +50,10 @@ resistor). The DS18b20 temperature sensor specification lists a
		maximum current draw of 1.5mA and that a 5k pullup resistor is not
		sufficient. The strong pullup is designed to provide the additional
		current required.

		The DS28EA00 provides an additional two pins for implementing a sequence
		detection algorithm. This feature allows you to determine the physical
		location of the chip in the 1-wire bus without needing pre-existing
		knowledge of the bus ordering. Support is provided through the sysfs
		w1_seq file. The file will contain a single line with an integer value
		representing the device index in the bus starting at 0.

drivers/w1/slaves/w1_therm.c

+101 −1

Original line number	Diff line number	Diff line
		@@ -92,13 +92,24 @@ static void w1_therm_remove_slave(struct w1_slave *sl)
		static ssize_t w1_slave_show(struct device *device,
		struct device_attribute attr, char buf);

		static ssize_t w1_seq_show(struct device *device,
		struct device_attribute attr, char buf);

		static DEVICE_ATTR_RO(w1_slave);
		static DEVICE_ATTR_RO(w1_seq);

		static struct attribute *w1_therm_attrs[] = {
		&dev_attr_w1_slave.attr,
		NULL,
		};

		static struct attribute *w1_ds28ea00_attrs[] = {
		&dev_attr_w1_slave.attr,
		&dev_attr_w1_seq.attr,
		NULL,
		};
		ATTRIBUTE_GROUPS(w1_therm);
		ATTRIBUTE_GROUPS(w1_ds28ea00);

		static struct w1_family_ops w1_therm_fops = {
		.add_slave = w1_therm_add_slave,
		@@ -106,6 +117,12 @@ static struct w1_family_ops w1_therm_fops = {
		.groups = w1_therm_groups,
		};

		static struct w1_family_ops w1_ds28ea00_fops = {
		.add_slave = w1_therm_add_slave,
		.remove_slave = w1_therm_remove_slave,
		.groups = w1_ds28ea00_groups,
		};

		static struct w1_family w1_therm_family_DS18S20 = {
		.fid = W1_THERM_DS18S20,
		.fops = &w1_therm_fops,
		@@ -123,7 +140,7 @@ static struct w1_family w1_therm_family_DS1822 = {

		static struct w1_family w1_therm_family_DS28EA00 = {
		.fid = W1_THERM_DS28EA00,
		.fops = &w1_therm_fops,
		.fops = &w1_ds28ea00_fops,
		};

		static struct w1_family w1_therm_family_DS1825 = {
		@@ -316,6 +333,89 @@ static ssize_t w1_slave_show(struct device *device,
		return ret;
		}

		#define W1_42_CHAIN 0x99
		#define W1_42_CHAIN_OFF 0x3C
		#define W1_42_CHAIN_OFF_INV 0xC3
		#define W1_42_CHAIN_ON 0x5A
		#define W1_42_CHAIN_ON_INV 0xA5
		#define W1_42_CHAIN_DONE 0x96
		#define W1_42_CHAIN_DONE_INV 0x69
		#define W1_42_COND_READ 0x0F
		#define W1_42_SUCCESS_CONFIRM_BYTE 0xAA
		#define W1_42_FINISHED_BYTE 0xFF
		static ssize_t w1_seq_show(struct device *device,
		struct device_attribute attr, char buf)
		{
		struct w1_slave *sl = dev_to_w1_slave(device);
		ssize_t c = PAGE_SIZE;
		int rv;
		int i;
		u8 ack;
		u64 rn;
		struct w1_reg_num *reg_num;
		int seq = 0;

		mutex_lock(&sl->master->mutex);
		/* Place all devices in CHAIN state */
		if (w1_reset_bus(sl->master))
		goto error;
		w1_write_8(sl->master, W1_SKIP_ROM);
		w1_write_8(sl->master, W1_42_CHAIN);
		w1_write_8(sl->master, W1_42_CHAIN_ON);
		w1_write_8(sl->master, W1_42_CHAIN_ON_INV);
		msleep(sl->master->pullup_duration);

		/* check for acknowledgment */
		ack = w1_read_8(sl->master);
		if (ack != W1_42_SUCCESS_CONFIRM_BYTE)
		goto error;

		/* In case the bus fails to send 0xFF, limit*/
		for (i = 0; i <= 64; i++) {
		if (w1_reset_bus(sl->master))
		goto error;

		w1_write_8(sl->master, W1_42_COND_READ);
		rv = w1_read_block(sl->master, (u8 *)&rn, 8);
		reg_num = (struct w1_reg_num *) &rn;
		if ((char)reg_num->family == W1_42_FINISHED_BYTE)
		break;
		if (sl->reg_num.id == reg_num->id)
		seq = i;

		w1_write_8(sl->master, W1_42_CHAIN);
		w1_write_8(sl->master, W1_42_CHAIN_DONE);
		w1_write_8(sl->master, W1_42_CHAIN_DONE_INV);
		w1_read_block(sl->master, &ack, sizeof(ack));

		/* check for acknowledgment */
		ack = w1_read_8(sl->master);
		if (ack != W1_42_SUCCESS_CONFIRM_BYTE)
		goto error;

		}

		/* Exit from CHAIN state */
		if (w1_reset_bus(sl->master))
		goto error;
		w1_write_8(sl->master, W1_SKIP_ROM);
		w1_write_8(sl->master, W1_42_CHAIN);
		w1_write_8(sl->master, W1_42_CHAIN_OFF);
		w1_write_8(sl->master, W1_42_CHAIN_OFF_INV);

		/* check for acknowledgment */
		ack = w1_read_8(sl->master);
		if (ack != W1_42_SUCCESS_CONFIRM_BYTE)
		goto error;
		mutex_unlock(&sl->master->mutex);

		c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", seq);
		return PAGE_SIZE - c;
		error:
		mutex_unlock(&sl->master->bus_mutex);
		return -EIO;
		}

		static int __init w1_therm_init(void)
		{
		int err, i;