--- /dev/null
+/*
+ * w1_ds2405.c
+ *
+ * Copyright (c) 2017 Maciej S. Szmigiero <mail@maciej.szmigiero.name>
+ * Based on w1_therm.c copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the therms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/mutex.h>
+#include <linux/string.h>
+#include <linux/types.h>
+
+#include "../w1.h"
+#include "../w1_family.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Maciej S. Szmigiero <mail@maciej.szmigiero.name>");
+MODULE_DESCRIPTION("Driver for 1-wire Dallas DS2405 PIO.");
+MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2405));
+
+static int w1_ds2405_select(struct w1_slave *sl, bool only_active)
+{
+ struct w1_master *dev = sl->master;
+
+ u64 dev_addr = le64_to_cpu(*(u64 *)&sl->reg_num);
+ unsigned int bit_ctr;
+
+ if (w1_reset_bus(dev) != 0)
+ return 0;
+
+ /*
+ * We cannot use a normal Match ROM command
+ * since doing so would toggle PIO state
+ */
+ w1_write_8(dev, only_active ? W1_ALARM_SEARCH : W1_SEARCH);
+
+ for (bit_ctr = 0; bit_ctr < 64; bit_ctr++) {
+ int bit2send = !!(dev_addr & BIT(bit_ctr));
+ u8 ret;
+
+ ret = w1_triplet(dev, bit2send);
+
+ if ((ret & (BIT(0) | BIT(1))) ==
+ (BIT(0) | BIT(1))) /* no devices found */
+ return 0;
+
+ if (!!(ret & BIT(2)) != bit2send)
+ /* wrong direction taken - no such device */
+ return 0;
+ }
+
+ return 1;
+}
+
+static int w1_ds2405_read_pio(struct w1_slave *sl)
+{
+ if (w1_ds2405_select(sl, true))
+ return 0; /* "active" means PIO is low */
+
+ if (w1_ds2405_select(sl, false))
+ return 1;
+
+ return -ENODEV;
+}
+
+static ssize_t state_show(struct device *device,
+ struct device_attribute *attr, char *buf)
+{
+ struct w1_slave *sl = dev_to_w1_slave(device);
+ struct w1_master *dev = sl->master;
+
+ int ret;
+ ssize_t f_retval;
+ u8 state;
+
+ ret = mutex_lock_interruptible(&dev->bus_mutex);
+ if (ret)
+ return ret;
+
+ if (!w1_ds2405_select(sl, false)) {
+ f_retval = -ENODEV;
+ goto out_unlock;
+ }
+
+ state = w1_read_8(dev);
+ if (state != 0 &&
+ state != 0xff) {
+ dev_err(device, "non-consistent state %x\n", state);
+ f_retval = -EIO;
+ goto out_unlock;
+ }
+
+ *buf = state ? '1' : '0';
+ f_retval = 1;
+
+out_unlock:
+ w1_reset_bus(dev);
+ mutex_unlock(&dev->bus_mutex);
+
+ return f_retval;
+}
+
+static ssize_t output_show(struct device *device,
+ struct device_attribute *attr, char *buf)
+{
+ struct w1_slave *sl = dev_to_w1_slave(device);
+ struct w1_master *dev = sl->master;
+
+ int ret;
+ ssize_t f_retval;
+
+ ret = mutex_lock_interruptible(&dev->bus_mutex);
+ if (ret)
+ return ret;
+
+ ret = w1_ds2405_read_pio(sl);
+ if (ret < 0) {
+ f_retval = ret;
+ goto out_unlock;
+ }
+
+ *buf = ret ? '1' : '0';
+ f_retval = 1;
+
+out_unlock:
+ w1_reset_bus(dev);
+ mutex_unlock(&dev->bus_mutex);
+
+ return f_retval;
+}
+
+static ssize_t output_store(struct device *device,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct w1_slave *sl = dev_to_w1_slave(device);
+ struct w1_master *dev = sl->master;
+
+ int ret, current_pio;
+ unsigned int val;
+ ssize_t f_retval;
+
+ if (count < 1)
+ return -EINVAL;
+
+ if (sscanf(buf, " %u%n", &val, &ret) < 1)
+ return -EINVAL;
+
+ if (val != 0 && val != 1)
+ return -EINVAL;
+
+ f_retval = ret;
+
+ ret = mutex_lock_interruptible(&dev->bus_mutex);
+ if (ret)
+ return ret;
+
+ current_pio = w1_ds2405_read_pio(sl);
+ if (current_pio < 0) {
+ f_retval = current_pio;
+ goto out_unlock;
+ }
+
+ if (current_pio == val)
+ goto out_unlock;
+
+ if (w1_reset_bus(dev) != 0) {
+ f_retval = -ENODEV;
+ goto out_unlock;
+ }
+
+ /*
+ * can't use w1_reset_select_slave() here since it uses Skip ROM if
+ * there is only one device on bus
+ */
+ do {
+ u64 dev_addr = le64_to_cpu(*(u64 *)&sl->reg_num);
+ u8 cmd[9];
+
+ cmd[0] = W1_MATCH_ROM;
+ memcpy(&cmd[1], &dev_addr, sizeof(dev_addr));
+
+ w1_write_block(dev, cmd, sizeof(cmd));
+ } while (0);
+
+out_unlock:
+ w1_reset_bus(dev);
+ mutex_unlock(&dev->bus_mutex);
+
+ return f_retval;
+}
+
+static DEVICE_ATTR_RO(state);
+static DEVICE_ATTR_RW(output);
+
+static struct attribute *w1_ds2405_attrs[] = {
+ &dev_attr_state.attr,
+ &dev_attr_output.attr,
+ NULL
+};
+
+ATTRIBUTE_GROUPS(w1_ds2405);
+
+static struct w1_family_ops w1_ds2405_fops = {
+ .groups = w1_ds2405_groups
+};
+
+static struct w1_family w1_family_ds2405 = {
+ .fid = W1_FAMILY_DS2405,
+ .fops = &w1_ds2405_fops
+};
+
+static int __init w1_ds2405_init(void)
+{
+ return w1_register_family(&w1_family_ds2405);
+}
+
+static void __exit w1_ds2405_fini(void)
+{
+ w1_unregister_family(&w1_family_ds2405);
+}
+
+module_init(w1_ds2405_init);
+module_exit(w1_ds2405_fini);
projects / GitHub / LineageOS / android_kernel_motorola_exynos9610.git / commitdiff