--- /dev/null
+w1_ds2406 kernel driver
+=======================
+
+Supported chips:
+ * Maxim DS2406 (and other family 0x12) addressable switches
+
+Author: Scott Alfter <scott@alfter.us>
+
+Description
+-----------
+
+The w1_ds2406 driver allows connected devices to be switched on and off.
+These chips also provide 128 bytes of OTP EPROM, but reading/writing it is
+not supported. In TSOC-6 form, the DS2406 provides two switch outputs and
+can be provided with power on a dedicated input. In TO-92 form, it provides
+one output and uses parasitic power only.
+
+The driver provides two sysfs files. state is readable; it gives the
+current state of each switch, with PIO A in bit 0 and PIO B in bit 1. The
+driver ORs this state with 0x30, so shell scripts get an ASCII 0/1/2/3 to
+work with. output is writable; bits 0 and 1 control PIO A and B,
+respectively. Bits 2-7 are ignored, so it's safe to write ASCII data.
+
+CRCs are checked on read and write. Failed checks cause an I/O error to be
+returned. On a failed write, the switch status is not changed.
--- /dev/null
+/*
+ * w1_ds2406.c - w1 family 12 (DS2406) driver
+ * based on w1_ds2413.c by Mariusz Bialonczyk <manio@skyboo.net>
+ *
+ * Copyright (c) 2014 Scott Alfter <scott@alfter.us>
+ *
+ * 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/moduleparam.h>
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/crc16.h>
+
+#include "../w1.h"
+#include "../w1_int.h"
+#include "../w1_family.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Scott Alfter <scott@alfter.us>");
+MODULE_DESCRIPTION("w1 family 12 driver for DS2406 2 Pin IO");
+
+#define W1_F12_FUNC_READ_STATUS 0xAA
+#define W1_F12_FUNC_WRITE_STATUS 0x55
+
+static ssize_t w1_f12_read_state(
+ struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buf, loff_t off, size_t count)
+{
+ u8 w1_buf[6]={W1_F12_FUNC_READ_STATUS, 7, 0, 0, 0, 0};
+ struct w1_slave *sl = kobj_to_w1_slave(kobj);
+ u16 crc=0;
+ int i;
+ ssize_t rtnval=1;
+
+ if (off != 0)
+ return 0;
+ if (!buf)
+ return -EINVAL;
+
+ mutex_lock(&sl->master->bus_mutex);
+
+ if (w1_reset_select_slave(sl)) {
+ mutex_unlock(&sl->master->bus_mutex);
+ return -EIO;
+ }
+
+ w1_write_block(sl->master, w1_buf, 3);
+ w1_read_block(sl->master, w1_buf+3, 3);
+ for (i=0; i<6; i++)
+ crc=crc16_byte(crc, w1_buf[i]);
+ if (crc==0xb001) /* good read? */
+ *buf=((w1_buf[3]>>5)&3)|0x30;
+ else
+ rtnval=-EIO;
+
+ mutex_unlock(&sl->master->bus_mutex);
+
+ return rtnval;
+}
+
+static ssize_t w1_f12_write_output(
+ 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);
+ u8 w1_buf[6]={W1_F12_FUNC_WRITE_STATUS, 7, 0, 0, 0, 0};
+ u16 crc=0;
+ int i;
+ ssize_t rtnval=1;
+
+ if (count != 1 || off != 0)
+ return -EFAULT;
+
+ mutex_lock(&sl->master->bus_mutex);
+
+ if (w1_reset_select_slave(sl)) {
+ mutex_unlock(&sl->master->bus_mutex);
+ return -EIO;
+ }
+
+ w1_buf[3] = (((*buf)&3)<<5)|0x1F;
+ w1_write_block(sl->master, w1_buf, 4);
+ w1_read_block(sl->master, w1_buf+4, 2);
+ for (i=0; i<6; i++)
+ crc=crc16_byte(crc, w1_buf[i]);
+ if (crc==0xb001) /* good read? */
+ w1_write_8(sl->master, 0xFF);
+ else
+ rtnval=-EIO;
+
+ mutex_unlock(&sl->master->bus_mutex);
+ return rtnval;
+}
+
+#define NB_SYSFS_BIN_FILES 2
+static struct bin_attribute w1_f12_sysfs_bin_files[NB_SYSFS_BIN_FILES] = {
+ {
+ .attr = {
+ .name = "state",
+ .mode = S_IRUGO,
+ },
+ .size = 1,
+ .read = w1_f12_read_state,
+ },
+ {
+ .attr = {
+ .name = "output",
+ .mode = S_IRUGO | S_IWUSR | S_IWGRP,
+ },
+ .size = 1,
+ .write = w1_f12_write_output,
+ }
+};
+
+static int w1_f12_add_slave(struct w1_slave *sl)
+{
+ int err = 0;
+ int i;
+
+ for (i = 0; i < NB_SYSFS_BIN_FILES && !err; ++i)
+ err = sysfs_create_bin_file(
+ &sl->dev.kobj,
+ &(w1_f12_sysfs_bin_files[i]));
+ if (err)
+ while (--i >= 0)
+ sysfs_remove_bin_file(&sl->dev.kobj,
+ &(w1_f12_sysfs_bin_files[i]));
+ return err;
+}
+
+static void w1_f12_remove_slave(struct w1_slave *sl)
+{
+ int i;
+ for (i = NB_SYSFS_BIN_FILES - 1; i >= 0; --i)
+ sysfs_remove_bin_file(&sl->dev.kobj,
+ &(w1_f12_sysfs_bin_files[i]));
+}
+
+static struct w1_family_ops w1_f12_fops = {
+ .add_slave = w1_f12_add_slave,
+ .remove_slave = w1_f12_remove_slave,
+};
+
+static struct w1_family w1_family_12 = {
+ .fid = W1_FAMILY_DS2406,
+ .fops = &w1_f12_fops,
+};
+
+static int __init w1_f12_init(void)
+{
+ return w1_register_family(&w1_family_12);
+}
+
+static void __exit w1_f12_exit(void)
+{
+ w1_unregister_family(&w1_family_12);
+}
+
+module_init(w1_f12_init);
+module_exit(w1_f12_exit);
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff