w1: Add support for DS28EA00 sequence to w1-therm (d9411e57) · Commits · e / devices / android_kernel_fairphone_FP4

Documentation/ABI/stable/sysfs-driver-w1_ds28ea00

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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	Original line	Diff line number	Diff line
	@@ -11,12 +11,14 @@ Author: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
	Description		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:		supported family codes:
	W1_THERM_DS18S20 0x10		W1_THERM_DS18S20 0x10
	W1_THERM_DS1822 0x22		W1_THERM_DS1822 0x22
	W1_THERM_DS18B20 0x28		W1_THERM_DS18B20 0x28
	W1_THERM_DS1825 0x3B		W1_THERM_DS1825 0x3B
			W1_THERM_DS28EA00 0x42

	Support is provided through the sysfs w1_slave file. Each open and		Support is provided through the sysfs w1_slave file. Each open and
	read sequence will initiate a temperature conversion then provide two		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		maximum current draw of 1.5mA and that a 5k pullup resistor is not
	sufficient. The strong pullup is designed to provide the additional		sufficient. The strong pullup is designed to provide the additional
	current required.		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	Original line	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,		static ssize_t w1_slave_show(struct device *device,
	struct device_attribute attr, char buf);		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_slave);
			static DEVICE_ATTR_RO(w1_seq);

	static struct attribute *w1_therm_attrs[] = {		static struct attribute *w1_therm_attrs[] = {
	&dev_attr_w1_slave.attr,		&dev_attr_w1_slave.attr,
	NULL,		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_therm);
			ATTRIBUTE_GROUPS(w1_ds28ea00);

	static struct w1_family_ops w1_therm_fops = {		static struct w1_family_ops w1_therm_fops = {
	.add_slave = w1_therm_add_slave,		.add_slave = w1_therm_add_slave,
	@@ -106,6 +117,12 @@ static struct w1_family_ops w1_therm_fops = {
	.groups = w1_therm_groups,		.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 = {		static struct w1_family w1_therm_family_DS18S20 = {
	.fid = W1_THERM_DS18S20,		.fid = W1_THERM_DS18S20,
	.fops = &w1_therm_fops,		.fops = &w1_therm_fops,
	@@ -123,7 +140,7 @@ static struct w1_family w1_therm_family_DS1822 = {

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

	static struct w1_family w1_therm_family_DS1825 = {		static struct w1_family w1_therm_family_DS1825 = {
	@@ -316,6 +333,89 @@ static ssize_t w1_slave_show(struct device *device,
	return ret;		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)		static int __init w1_therm_init(void)
	{		{
	int err, i;		int err, i;