--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2015-2017 Pengutronix, Uwe Kleine-König <kernel@pengutronix.de>
+ */
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+
+#include "siox.h"
+
+/*
+ * The lowest bit in the SIOX status word signals if the in-device watchdog is
+ * ok. If the bit is set, the device is functional.
+ *
+ * On writing the watchdog timer is reset when this bit toggles.
+ */
+#define SIOX_STATUS_WDG 0x01
+
+/*
+ * Bits 1 to 3 of the status word read as the bitwise negation of what was
+ * clocked in before. The value clocked in is changed in each cycle and so
+ * allows to detect transmit/receive problems.
+ */
+#define SIOX_STATUS_COUNTER 0x0e
+
+/*
+ * Each Siox-Device has a 4 bit type number that is neither 0 nor 15. This is
+ * available in the upper nibble of the read status.
+ *
+ * On write these bits are DC.
+ */
+#define SIOX_STATUS_TYPE 0xf0
+
+static bool siox_is_registered;
+
+static void siox_master_lock(struct siox_master *smaster)
+{
+ mutex_lock(&smaster->lock);
+}
+
+static void siox_master_unlock(struct siox_master *smaster)
+{
+ mutex_unlock(&smaster->lock);
+}
+
+static inline u8 siox_status_clean(u8 status_read, u8 status_written)
+{
+ /*
+ * bits 3:1 of status sample the respective bit in the status
+ * byte written in the previous cycle but inverted. So if you wrote the
+ * status word as 0xa before (counter = 0b101), it is expected to get
+ * back the counter bits as 0b010.
+ *
+ * So given the last status written this function toggles the there
+ * unset counter bits in the read value such that the counter bits in
+ * the return value are all zero iff the bits were read as expected to
+ * simplify error detection.
+ */
+
+ return status_read ^ (~status_written & 0xe);
+}
+
+static bool siox_device_counter_error(struct siox_device *sdevice,
+ u8 status_clean)
+{
+ return (status_clean & SIOX_STATUS_COUNTER) != 0;
+}
+
+static bool siox_device_type_error(struct siox_device *sdevice, u8 status_clean)
+{
+ u8 statustype = (status_clean & SIOX_STATUS_TYPE) >> 4;
+
+ /*
+ * If the device knows which value the type bits should have, check
+ * against this value otherwise just rule out the invalid values 0b0000
+ * and 0b1111.
+ */
+ if (sdevice->statustype) {
+ if (statustype != sdevice->statustype)
+ return true;
+ } else {
+ switch (statustype) {
+ case 0:
+ case 0xf:
+ return true;
+ }
+ }
+
+ return false;
+}
+
+static bool siox_device_wdg_error(struct siox_device *sdevice, u8 status_clean)
+{
+ return (status_clean & SIOX_STATUS_WDG) == 0;
+}
+
+/*
+ * If there is a type or counter error the device is called "unsynced".
+ */
+bool siox_device_synced(struct siox_device *sdevice)
+{
+ if (siox_device_type_error(sdevice, sdevice->status_read_clean))
+ return false;
+
+ return !siox_device_counter_error(sdevice, sdevice->status_read_clean);
+
+}
+EXPORT_SYMBOL_GPL(siox_device_synced);
+
+/*
+ * A device is called "connected" if it is synced and the watchdog is not
+ * asserted.
+ */
+bool siox_device_connected(struct siox_device *sdevice)
+{
+ if (!siox_device_synced(sdevice))
+ return false;
+
+ return !siox_device_wdg_error(sdevice, sdevice->status_read_clean);
+}
+EXPORT_SYMBOL_GPL(siox_device_connected);
+
+static void siox_poll(struct siox_master *smaster)
+{
+ struct siox_device *sdevice;
+ size_t i = smaster->setbuf_len;
+ int unsync_error = 0;
+
+ smaster->last_poll = jiffies;
+
+ /*
+ * The counter bits change in each second cycle, the watchdog bit
+ * toggles each time.
+ * The counter bits hold values from [0, 6]. 7 would be possible
+ * theoretically but the protocol designer considered that a bad idea
+ * for reasons unknown today. (Maybe that's because then the status read
+ * back has only zeros in the counter bits then which might be confused
+ * with a stuck-at-0 error. But for the same reason (with s/0/1/) 0
+ * could be skipped.)
+ */
+ if (++smaster->status > 0x0d)
+ smaster->status = 0;
+
+ memset(smaster->buf, 0, smaster->setbuf_len);
+
+ /* prepare data pushed out to devices in buf[0..setbuf_len) */
+ list_for_each_entry(sdevice, &smaster->devices, node) {
+ struct siox_driver *sdriver =
+ to_siox_driver(sdevice->dev.driver);
+ sdevice->status_written = smaster->status;
+
+ i -= sdevice->inbytes;
+
+ /*
+ * If the device or a previous one is unsynced, don't pet the
+ * watchdog. This is done to ensure that the device is kept in
+ * reset when something is wrong.
+ */
+ if (!siox_device_synced(sdevice))
+ unsync_error = 1;
+
+ if (sdriver && !unsync_error)
+ sdriver->set_data(sdevice, sdevice->status_written,
+ &smaster->buf[i + 1]);
+ else
+ /*
+ * Don't trigger watchdog if there is no driver or a
+ * sync problem
+ */
+ sdevice->status_written &= ~SIOX_STATUS_WDG;
+
+ smaster->buf[i] = sdevice->status_written;
+ }
+
+ smaster->pushpull(smaster, smaster->setbuf_len, smaster->buf,
+ smaster->getbuf_len,
+ smaster->buf + smaster->setbuf_len);
+
+ unsync_error = 0;
+
+ /* interpret data pulled in from devices in buf[setbuf_len..] */
+ i = smaster->setbuf_len;
+ list_for_each_entry(sdevice, &smaster->devices, node) {
+ struct siox_driver *sdriver =
+ to_siox_driver(sdevice->dev.driver);
+ u8 status = smaster->buf[i + sdevice->outbytes - 1];
+ u8 status_clean;
+ u8 prev_status_clean = sdevice->status_read_clean;
+ bool synced = true;
+ bool connected = true;
+
+ if (!siox_device_synced(sdevice))
+ unsync_error = 1;
+
+ /*
+ * If the watchdog bit wasn't toggled in this cycle, report the
+ * watchdog as active to give a consistent view for drivers and
+ * sysfs consumers.
+ */
+ if (!sdriver || unsync_error)
+ status &= ~SIOX_STATUS_WDG;
+
+ status_clean =
+ siox_status_clean(status,
+ sdevice->status_written_lastcycle);
+
+ /* Check counter bits */
+ if (siox_device_counter_error(sdevice, status_clean)) {
+ bool prev_counter_error;
+
+ synced = false;
+
+ /* only report a new error if the last cycle was ok */
+ prev_counter_error =
+ siox_device_counter_error(sdevice,
+ prev_status_clean);
+ if (!prev_counter_error) {
+ sdevice->status_errors++;
+ sysfs_notify_dirent(sdevice->status_errors_kn);
+ }
+ }
+
+ /* Check type bits */
+ if (siox_device_type_error(sdevice, status_clean))
+ synced = false;
+
+ /* If the device is unsynced report the watchdog as active */
+ if (!synced) {
+ status &= ~SIOX_STATUS_WDG;
+ status_clean &= ~SIOX_STATUS_WDG;
+ }
+
+ if (siox_device_wdg_error(sdevice, status_clean))
+ connected = false;
+
+ /* The watchdog state changed just now */
+ if ((status_clean ^ prev_status_clean) & SIOX_STATUS_WDG) {
+ sysfs_notify_dirent(sdevice->watchdog_kn);
+
+ if (siox_device_wdg_error(sdevice, status_clean)) {
+ struct kernfs_node *wd_errs =
+ sdevice->watchdog_errors_kn;
+
+ sdevice->watchdog_errors++;
+ sysfs_notify_dirent(wd_errs);
+ }
+ }
+
+ if (connected != sdevice->connected)
+ sysfs_notify_dirent(sdevice->connected_kn);
+
+ sdevice->status_read_clean = status_clean;
+ sdevice->status_written_lastcycle = sdevice->status_written;
+ sdevice->connected = connected;
+
+ /* only give data read to driver if the device is connected */
+ if (sdriver && connected)
+ sdriver->get_data(sdevice, &smaster->buf[i]);
+
+ i += sdevice->outbytes;
+ }
+}
+
+static int siox_poll_thread(void *data)
+{
+ struct siox_master *smaster = data;
+ signed long timeout = 0;
+
+ get_device(&smaster->dev);
+
+ for (;;) {
+ if (kthread_should_stop()) {
+ put_device(&smaster->dev);
+ return 0;
+ }
+
+ siox_master_lock(smaster);
+
+ if (smaster->active) {
+ unsigned long next_poll =
+ smaster->last_poll + smaster->poll_interval;
+ if (time_is_before_eq_jiffies(next_poll))
+ siox_poll(smaster);
+
+ timeout = smaster->poll_interval -
+ (jiffies - smaster->last_poll);
+ } else {
+ timeout = MAX_SCHEDULE_TIMEOUT;
+ }
+
+ /*
+ * Set the task to idle while holding the lock. This makes sure
+ * that we don't sleep too long when the bus is reenabled before
+ * schedule_timeout is reached.
+ */
+ if (timeout > 0)
+ set_current_state(TASK_IDLE);
+
+ siox_master_unlock(smaster);
+
+ if (timeout > 0)
+ schedule_timeout(timeout);
+
+ /*
+ * I'm not clear if/why it is important to set the state to
+ * RUNNING again, but it fixes a "do not call blocking ops when
+ * !TASK_RUNNING;"-warning.
+ */
+ set_current_state(TASK_RUNNING);
+ }
+}
+
+static int __siox_start(struct siox_master *smaster)
+{
+ if (!(smaster->setbuf_len + smaster->getbuf_len))
+ return -ENODEV;
+
+ if (!smaster->buf)
+ return -ENOMEM;
+
+ if (smaster->active)
+ return 0;
+
+ smaster->active = 1;
+ wake_up_process(smaster->poll_thread);
+
+ return 1;
+}
+
+static int siox_start(struct siox_master *smaster)
+{
+ int ret;
+
+ siox_master_lock(smaster);
+ ret = __siox_start(smaster);
+ siox_master_unlock(smaster);
+
+ return ret;
+}
+
+static int __siox_stop(struct siox_master *smaster)
+{
+ if (smaster->active) {
+ struct siox_device *sdevice;
+
+ smaster->active = 0;
+
+ list_for_each_entry(sdevice, &smaster->devices, node) {
+ if (sdevice->connected)
+ sysfs_notify_dirent(sdevice->connected_kn);
+ sdevice->connected = false;
+ }
+
+ return 1;
+ }
+ return 0;
+}
+
+static int siox_stop(struct siox_master *smaster)
+{
+ int ret;
+
+ siox_master_lock(smaster);
+ ret = __siox_stop(smaster);
+ siox_master_unlock(smaster);
+
+ return ret;
+}
+
+static ssize_t type_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct siox_device *sdev = to_siox_device(dev);
+
+ return sprintf(buf, "%s\n", sdev->type);
+}
+
+static DEVICE_ATTR_RO(type);
+
+static ssize_t inbytes_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct siox_device *sdev = to_siox_device(dev);
+
+ return sprintf(buf, "%zu\n", sdev->inbytes);
+}
+
+static DEVICE_ATTR_RO(inbytes);
+
+static ssize_t outbytes_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct siox_device *sdev = to_siox_device(dev);
+
+ return sprintf(buf, "%zu\n", sdev->outbytes);
+}
+
+static DEVICE_ATTR_RO(outbytes);
+
+static ssize_t status_errors_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct siox_device *sdev = to_siox_device(dev);
+ unsigned int status_errors;
+
+ siox_master_lock(sdev->smaster);
+
+ status_errors = sdev->status_errors;
+
+ siox_master_unlock(sdev->smaster);
+
+ return sprintf(buf, "%u\n", status_errors);
+}
+
+static DEVICE_ATTR_RO(status_errors);
+
+static ssize_t connected_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct siox_device *sdev = to_siox_device(dev);
+ bool connected;
+
+ siox_master_lock(sdev->smaster);
+
+ connected = sdev->connected;
+
+ siox_master_unlock(sdev->smaster);
+
+ return sprintf(buf, "%u\n", connected);
+}
+
+static DEVICE_ATTR_RO(connected);
+
+static ssize_t watchdog_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct siox_device *sdev = to_siox_device(dev);
+ u8 status;
+
+ siox_master_lock(sdev->smaster);
+
+ status = sdev->status_read_clean;
+
+ siox_master_unlock(sdev->smaster);
+
+ return sprintf(buf, "%d\n", status & SIOX_STATUS_WDG);
+}
+
+static DEVICE_ATTR_RO(watchdog);
+
+static ssize_t watchdog_errors_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct siox_device *sdev = to_siox_device(dev);
+ unsigned int watchdog_errors;
+
+ siox_master_lock(sdev->smaster);
+
+ watchdog_errors = sdev->watchdog_errors;
+
+ siox_master_unlock(sdev->smaster);
+
+ return sprintf(buf, "%u\n", watchdog_errors);
+}
+
+static DEVICE_ATTR_RO(watchdog_errors);
+
+static struct attribute *siox_device_attrs[] = {
+ &dev_attr_type.attr,
+ &dev_attr_inbytes.attr,
+ &dev_attr_outbytes.attr,
+ &dev_attr_status_errors.attr,
+ &dev_attr_connected.attr,
+ &dev_attr_watchdog.attr,
+ &dev_attr_watchdog_errors.attr,
+ NULL
+};
+ATTRIBUTE_GROUPS(siox_device);
+
+static void siox_device_release(struct device *dev)
+{
+ struct siox_device *sdevice = to_siox_device(dev);
+
+ kfree(sdevice);
+}
+
+static struct device_type siox_device_type = {
+ .groups = siox_device_groups,
+ .release = siox_device_release,
+};
+
+static int siox_match(struct device *dev, struct device_driver *drv)
+{
+ if (dev->type != &siox_device_type)
+ return 0;
+
+ /* up to now there is only a single driver so keeping this simple */
+ return 1;
+}
+
+static struct bus_type siox_bus_type = {
+ .name = "siox",
+ .match = siox_match,
+};
+
+static int siox_driver_probe(struct device *dev)
+{
+ struct siox_driver *sdriver = to_siox_driver(dev->driver);
+ struct siox_device *sdevice = to_siox_device(dev);
+ int ret;
+
+ ret = sdriver->probe(sdevice);
+ return ret;
+}
+
+static int siox_driver_remove(struct device *dev)
+{
+ struct siox_driver *sdriver =
+ container_of(dev->driver, struct siox_driver, driver);
+ struct siox_device *sdevice = to_siox_device(dev);
+ int ret;
+
+ ret = sdriver->remove(sdevice);
+ return ret;
+}
+
+static void siox_driver_shutdown(struct device *dev)
+{
+ struct siox_driver *sdriver =
+ container_of(dev->driver, struct siox_driver, driver);
+ struct siox_device *sdevice = to_siox_device(dev);
+
+ sdriver->shutdown(sdevice);
+}
+
+static ssize_t active_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct siox_master *smaster = to_siox_master(dev);
+
+ return sprintf(buf, "%d\n", smaster->active);
+}
+
+static ssize_t active_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct siox_master *smaster = to_siox_master(dev);
+ int ret;
+ int active;
+
+ ret = kstrtoint(buf, 0, &active);
+ if (ret < 0)
+ return ret;
+
+ if (active)
+ ret = siox_start(smaster);
+ else
+ ret = siox_stop(smaster);
+
+ if (ret < 0)
+ return ret;
+
+ return count;
+}
+
+static DEVICE_ATTR_RW(active);
+
+static struct siox_device *siox_device_add(struct siox_master *smaster,
+ const char *type, size_t inbytes,
+ size_t outbytes, u8 statustype);
+
+static ssize_t device_add_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct siox_master *smaster = to_siox_master(dev);
+ int ret;
+ char type[20] = "";
+ size_t inbytes = 0, outbytes = 0;
+ u8 statustype = 0;
+
+ ret = sscanf(buf, "%20s %zu %zu %hhu", type, &inbytes,
+ &outbytes, &statustype);
+ if (ret != 3 && ret != 4)
+ return -EINVAL;
+
+ if (strcmp(type, "siox-12x8") || inbytes != 2 || outbytes != 4)
+ return -EINVAL;
+
+ siox_device_add(smaster, "siox-12x8", inbytes, outbytes, statustype);
+
+ return count;
+}
+
+static DEVICE_ATTR_WO(device_add);
+
+static void siox_device_remove(struct siox_master *smaster);
+
+static ssize_t device_remove_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct siox_master *smaster = to_siox_master(dev);
+
+ /* XXX? require to write <type> <inbytes> <outbytes> */
+ siox_device_remove(smaster);
+
+ return count;
+}
+
+static DEVICE_ATTR_WO(device_remove);
+
+static ssize_t poll_interval_ns_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct siox_master *smaster = to_siox_master(dev);
+
+ return sprintf(buf, "%lld\n", jiffies_to_nsecs(smaster->poll_interval));
+}
+
+static ssize_t poll_interval_ns_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct siox_master *smaster = to_siox_master(dev);
+ int ret;
+ u64 val;
+
+ ret = kstrtou64(buf, 0, &val);
+ if (ret < 0)
+ return ret;
+
+ siox_master_lock(smaster);
+
+ smaster->poll_interval = nsecs_to_jiffies(val);
+
+ siox_master_unlock(smaster);
+
+ return count;
+}
+
+static DEVICE_ATTR_RW(poll_interval_ns);
+
+static struct attribute *siox_master_attrs[] = {
+ &dev_attr_active.attr,
+ &dev_attr_device_add.attr,
+ &dev_attr_device_remove.attr,
+ &dev_attr_poll_interval_ns.attr,
+ NULL
+};
+ATTRIBUTE_GROUPS(siox_master);
+
+static void siox_master_release(struct device *dev)
+{
+ struct siox_master *smaster = to_siox_master(dev);
+
+ kfree(smaster);
+}
+
+static struct device_type siox_master_type = {
+ .groups = siox_master_groups,
+ .release = siox_master_release,
+};
+
+struct siox_master *siox_master_alloc(struct device *dev,
+ size_t size)
+{
+ struct siox_master *smaster;
+
+ if (!dev)
+ return NULL;
+
+ smaster = kzalloc(sizeof(*smaster) + size, GFP_KERNEL);
+ if (!smaster)
+ return NULL;
+
+ device_initialize(&smaster->dev);
+
+ smaster->busno = -1;
+ smaster->dev.bus = &siox_bus_type;
+ smaster->dev.type = &siox_master_type;
+ smaster->dev.parent = dev;
+ smaster->poll_interval = DIV_ROUND_UP(HZ, 40);
+
+ dev_set_drvdata(&smaster->dev, &smaster[1]);
+
+ return smaster;
+}
+EXPORT_SYMBOL_GPL(siox_master_alloc);
+
+int siox_master_register(struct siox_master *smaster)
+{
+ int ret;
+
+ if (!siox_is_registered)
+ return -EPROBE_DEFER;
+
+ if (!smaster->pushpull)
+ return -EINVAL;
+
+ dev_set_name(&smaster->dev, "siox-%d", smaster->busno);
+
+ smaster->last_poll = jiffies;
+ smaster->poll_thread = kthread_create(siox_poll_thread, smaster,
+ "siox-%d", smaster->busno);
+ if (IS_ERR(smaster->poll_thread)) {
+ smaster->active = 0;
+ return PTR_ERR(smaster->poll_thread);
+ }
+
+ mutex_init(&smaster->lock);
+ INIT_LIST_HEAD(&smaster->devices);
+
+ ret = device_add(&smaster->dev);
+ if (ret)
+ kthread_stop(smaster->poll_thread);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(siox_master_register);
+
+void siox_master_unregister(struct siox_master *smaster)
+{
+ /* remove device */
+ device_del(&smaster->dev);
+
+ siox_master_lock(smaster);
+
+ __siox_stop(smaster);
+
+ while (smaster->num_devices) {
+ struct siox_device *sdevice;
+
+ sdevice = container_of(smaster->devices.prev,
+ struct siox_device, node);
+ list_del(&sdevice->node);
+ smaster->num_devices--;
+
+ siox_master_unlock(smaster);
+
+ device_unregister(&sdevice->dev);
+
+ siox_master_lock(smaster);
+ }
+
+ siox_master_unlock(smaster);
+
+ put_device(&smaster->dev);
+}
+EXPORT_SYMBOL_GPL(siox_master_unregister);
+
+static struct siox_device *siox_device_add(struct siox_master *smaster,
+ const char *type, size_t inbytes,
+ size_t outbytes, u8 statustype)
+{
+ struct siox_device *sdevice;
+ int ret;
+ size_t buf_len;
+
+ sdevice = kzalloc(sizeof(*sdevice), GFP_KERNEL);
+ if (!sdevice)
+ return ERR_PTR(-ENOMEM);
+
+ sdevice->type = type;
+ sdevice->inbytes = inbytes;
+ sdevice->outbytes = outbytes;
+ sdevice->statustype = statustype;
+
+ sdevice->smaster = smaster;
+ sdevice->dev.parent = &smaster->dev;
+ sdevice->dev.bus = &siox_bus_type;
+ sdevice->dev.type = &siox_device_type;
+
+ siox_master_lock(smaster);
+
+ dev_set_name(&sdevice->dev, "siox-%d-%d",
+ smaster->busno, smaster->num_devices);
+
+ buf_len = smaster->setbuf_len + inbytes +
+ smaster->getbuf_len + outbytes;
+ if (smaster->buf_len < buf_len) {
+ u8 *buf = krealloc(smaster->buf, buf_len, GFP_KERNEL);
+
+ if (!buf) {
+ dev_err(&smaster->dev,
+ "failed to realloc buffer to %zu\n", buf_len);
+ ret = -ENOMEM;
+ goto err_buf_alloc;
+ }
+
+ smaster->buf_len = buf_len;
+ smaster->buf = buf;
+ }
+
+ ret = device_register(&sdevice->dev);
+ if (ret) {
+ dev_err(&smaster->dev, "failed to register device: %d\n", ret);
+
+ goto err_device_register;
+ }
+
+ smaster->num_devices++;
+ list_add_tail(&sdevice->node, &smaster->devices);
+
+ smaster->setbuf_len += sdevice->inbytes;
+ smaster->getbuf_len += sdevice->outbytes;
+
+ sdevice->status_errors_kn = sysfs_get_dirent(sdevice->dev.kobj.sd,
+ "status_errors");
+ sdevice->watchdog_kn = sysfs_get_dirent(sdevice->dev.kobj.sd,
+ "watchdog");
+ sdevice->watchdog_errors_kn = sysfs_get_dirent(sdevice->dev.kobj.sd,
+ "watchdog_errors");
+ sdevice->connected_kn = sysfs_get_dirent(sdevice->dev.kobj.sd,
+ "connected");
+
+ siox_master_unlock(smaster);
+
+ return sdevice;
+
+err_device_register:
+ /* don't care to make the buffer smaller again */
+
+err_buf_alloc:
+ siox_master_unlock(smaster);
+
+ kfree(sdevice);
+
+ return ERR_PTR(ret);
+}
+
+static void siox_device_remove(struct siox_master *smaster)
+{
+ struct siox_device *sdevice;
+
+ siox_master_lock(smaster);
+
+ if (!smaster->num_devices) {
+ siox_master_unlock(smaster);
+ return;
+ }
+
+ sdevice = container_of(smaster->devices.prev, struct siox_device, node);
+ list_del(&sdevice->node);
+ smaster->num_devices--;
+
+ smaster->setbuf_len -= sdevice->inbytes;
+ smaster->getbuf_len -= sdevice->outbytes;
+
+ if (!smaster->num_devices)
+ __siox_stop(smaster);
+
+ siox_master_unlock(smaster);
+
+ /*
+ * This must be done without holding the master lock because we're
+ * called from device_remove_store which also holds a sysfs mutex.
+ * device_unregister tries to aquire the same lock.
+ */
+ device_unregister(&sdevice->dev);
+}
+
+int __siox_driver_register(struct siox_driver *sdriver, struct module *owner)
+{
+ int ret;
+
+ if (unlikely(!siox_is_registered))
+ return -EPROBE_DEFER;
+
+ if (!sdriver->set_data && !sdriver->get_data) {
+ pr_err("Driver %s doesn't provide needed callbacks\n",
+ sdriver->driver.name);
+ return -EINVAL;
+ }
+
+ sdriver->driver.owner = owner;
+ sdriver->driver.bus = &siox_bus_type;
+
+ if (sdriver->probe)
+ sdriver->driver.probe = siox_driver_probe;
+ if (sdriver->remove)
+ sdriver->driver.remove = siox_driver_remove;
+ if (sdriver->shutdown)
+ sdriver->driver.shutdown = siox_driver_shutdown;
+
+ ret = driver_register(&sdriver->driver);
+ if (ret)
+ pr_err("Failed to register siox driver %s (%d)\n",
+ sdriver->driver.name, ret);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(__siox_driver_register);
+
+static int __init siox_init(void)
+{
+ int ret;
+
+ ret = bus_register(&siox_bus_type);
+ if (ret) {
+ pr_err("Registration of SIOX bus type failed: %d\n", ret);
+ return ret;
+ }
+
+ siox_is_registered = true;
+
+ return 0;
+}
+subsys_initcall(siox_init);
+
+static void __exit siox_exit(void)
+{
+ bus_unregister(&siox_bus_type);
+}
+module_exit(siox_exit);
+
+MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
+MODULE_DESCRIPTION("Eckelmann SIOX driver core");
+MODULE_LICENSE("GPL v2");
projects / platform / kernel / linux-starfive.git / commitdiff