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path: root/drivers/i2c/i2c-core.c
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Diffstat (limited to 'drivers/i2c/i2c-core.c')
-rw-r--r--drivers/i2c/i2c-core.c246
1 files changed, 204 insertions, 42 deletions
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 991d38daa87d..6b63cc7eb71e 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -27,7 +27,9 @@
#include <linux/module.h>
#include <linux/kernel.h>
+#include <linux/delay.h>
#include <linux/errno.h>
+#include <linux/gpio.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/init.h>
@@ -47,7 +49,7 @@
/* core_lock protects i2c_adapter_idr, and guarantees
that device detection, deletion of detected devices, and attach_adapter
- and detach_adapter calls are serialized */
+ calls are serialized */
static DEFINE_MUTEX(core_lock);
static DEFINE_IDR(i2c_adapter_idr);
@@ -91,7 +93,6 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv)
return 0;
}
-#ifdef CONFIG_HOTPLUG
/* uevent helps with hotplug: modprobe -q $(MODALIAS) */
static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
@@ -105,9 +106,129 @@ static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
return 0;
}
-#else
-#define i2c_device_uevent NULL
-#endif /* CONFIG_HOTPLUG */
+/* i2c bus recovery routines */
+static int get_scl_gpio_value(struct i2c_adapter *adap)
+{
+ return gpio_get_value(adap->bus_recovery_info->scl_gpio);
+}
+
+static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
+{
+ gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
+}
+
+static int get_sda_gpio_value(struct i2c_adapter *adap)
+{
+ return gpio_get_value(adap->bus_recovery_info->sda_gpio);
+}
+
+static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
+{
+ struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
+ struct device *dev = &adap->dev;
+ int ret = 0;
+
+ ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN |
+ GPIOF_OUT_INIT_HIGH, "i2c-scl");
+ if (ret) {
+ dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio);
+ return ret;
+ }
+
+ if (bri->get_sda) {
+ if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) {
+ /* work without SDA polling */
+ dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n",
+ bri->sda_gpio);
+ bri->get_sda = NULL;
+ }
+ }
+
+ return ret;
+}
+
+static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
+{
+ struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
+
+ if (bri->get_sda)
+ gpio_free(bri->sda_gpio);
+
+ gpio_free(bri->scl_gpio);
+}
+
+/*
+ * We are generating clock pulses. ndelay() determines durating of clk pulses.
+ * We will generate clock with rate 100 KHz and so duration of both clock levels
+ * is: delay in ns = (10^6 / 100) / 2
+ */
+#define RECOVERY_NDELAY 5000
+#define RECOVERY_CLK_CNT 9
+
+static int i2c_generic_recovery(struct i2c_adapter *adap)
+{
+ struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
+ int i = 0, val = 1, ret = 0;
+
+ if (bri->prepare_recovery)
+ bri->prepare_recovery(bri);
+
+ /*
+ * By this time SCL is high, as we need to give 9 falling-rising edges
+ */
+ while (i++ < RECOVERY_CLK_CNT * 2) {
+ if (val) {
+ /* Break if SDA is high */
+ if (bri->get_sda && bri->get_sda(adap))
+ break;
+ /* SCL shouldn't be low here */
+ if (!bri->get_scl(adap)) {
+ dev_err(&adap->dev,
+ "SCL is stuck low, exit recovery\n");
+ ret = -EBUSY;
+ break;
+ }
+ }
+
+ val = !val;
+ bri->set_scl(adap, val);
+ ndelay(RECOVERY_NDELAY);
+ }
+
+ if (bri->unprepare_recovery)
+ bri->unprepare_recovery(bri);
+
+ return ret;
+}
+
+int i2c_generic_scl_recovery(struct i2c_adapter *adap)
+{
+ adap->bus_recovery_info->set_scl(adap, 1);
+ return i2c_generic_recovery(adap);
+}
+
+int i2c_generic_gpio_recovery(struct i2c_adapter *adap)
+{
+ int ret;
+
+ ret = i2c_get_gpios_for_recovery(adap);
+ if (ret)
+ return ret;
+
+ ret = i2c_generic_recovery(adap);
+ i2c_put_gpios_for_recovery(adap);
+
+ return ret;
+}
+
+int i2c_recover_bus(struct i2c_adapter *adap)
+{
+ if (!adap->bus_recovery_info)
+ return -EOPNOTSUPP;
+
+ dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
+ return adap->bus_recovery_info->recover_bus(adap);
+}
static int i2c_device_probe(struct device *dev)
{
@@ -902,6 +1023,39 @@ static int i2c_register_adapter(struct i2c_adapter *adap)
"Failed to create compatibility class link\n");
#endif
+ /* bus recovery specific initialization */
+ if (adap->bus_recovery_info) {
+ struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
+
+ if (!bri->recover_bus) {
+ dev_err(&adap->dev, "No recover_bus() found, not using recovery\n");
+ adap->bus_recovery_info = NULL;
+ goto exit_recovery;
+ }
+
+ /* Generic GPIO recovery */
+ if (bri->recover_bus == i2c_generic_gpio_recovery) {
+ if (!gpio_is_valid(bri->scl_gpio)) {
+ dev_err(&adap->dev, "Invalid SCL gpio, not using recovery\n");
+ adap->bus_recovery_info = NULL;
+ goto exit_recovery;
+ }
+
+ if (gpio_is_valid(bri->sda_gpio))
+ bri->get_sda = get_sda_gpio_value;
+ else
+ bri->get_sda = NULL;
+
+ bri->get_scl = get_scl_gpio_value;
+ bri->set_scl = set_scl_gpio_value;
+ } else if (!bri->set_scl || !bri->get_scl) {
+ /* Generic SCL recovery */
+ dev_err(&adap->dev, "No {get|set}_gpio() found, not using recovery\n");
+ adap->bus_recovery_info = NULL;
+ }
+ }
+
+exit_recovery:
/* create pre-declared device nodes */
if (adap->nr < __i2c_first_dynamic_bus_num)
i2c_scan_static_board_info(adap);
@@ -921,13 +1075,35 @@ out_list:
}
/**
+ * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
+ * @adap: the adapter to register (with adap->nr initialized)
+ * Context: can sleep
+ *
+ * See i2c_add_numbered_adapter() for details.
+ */
+static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
+{
+ int id;
+
+ mutex_lock(&core_lock);
+ id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1,
+ GFP_KERNEL);
+ mutex_unlock(&core_lock);
+ if (id < 0)
+ return id == -ENOSPC ? -EBUSY : id;
+
+ return i2c_register_adapter(adap);
+}
+
+/**
* i2c_add_adapter - declare i2c adapter, use dynamic bus number
* @adapter: the adapter to add
* Context: can sleep
*
* This routine is used to declare an I2C adapter when its bus number
- * doesn't matter. Examples: for I2C adapters dynamically added by
- * USB links or PCI plugin cards.
+ * doesn't matter or when its bus number is specified by an dt alias.
+ * Examples of bases when the bus number doesn't matter: I2C adapters
+ * dynamically added by USB links or PCI plugin cards.
*
* When this returns zero, a new bus number was allocated and stored
* in adap->nr, and the specified adapter became available for clients.
@@ -935,8 +1111,17 @@ out_list:
*/
int i2c_add_adapter(struct i2c_adapter *adapter)
{
+ struct device *dev = &adapter->dev;
int id;
+ if (dev->of_node) {
+ id = of_alias_get_id(dev->of_node, "i2c");
+ if (id >= 0) {
+ adapter->nr = id;
+ return __i2c_add_numbered_adapter(adapter);
+ }
+ }
+
mutex_lock(&core_lock);
id = idr_alloc(&i2c_adapter_idr, adapter,
__i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
@@ -975,26 +1160,17 @@ EXPORT_SYMBOL(i2c_add_adapter);
*/
int i2c_add_numbered_adapter(struct i2c_adapter *adap)
{
- int id;
-
if (adap->nr == -1) /* -1 means dynamically assign bus id */
return i2c_add_adapter(adap);
- mutex_lock(&core_lock);
- id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1,
- GFP_KERNEL);
- mutex_unlock(&core_lock);
- if (id < 0)
- return id == -ENOSPC ? -EBUSY : id;
- return i2c_register_adapter(adap);
+ return __i2c_add_numbered_adapter(adap);
}
EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
-static int i2c_do_del_adapter(struct i2c_driver *driver,
+static void i2c_do_del_adapter(struct i2c_driver *driver,
struct i2c_adapter *adapter)
{
struct i2c_client *client, *_n;
- int res;
/* Remove the devices we created ourselves as the result of hardware
* probing (using a driver's detect method) */
@@ -1006,16 +1182,6 @@ static int i2c_do_del_adapter(struct i2c_driver *driver,
i2c_unregister_device(client);
}
}
-
- if (!driver->detach_adapter)
- return 0;
- dev_warn(&adapter->dev, "%s: detach_adapter method is deprecated\n",
- driver->driver.name);
- res = driver->detach_adapter(adapter);
- if (res)
- dev_err(&adapter->dev, "detach_adapter failed (%d) "
- "for driver [%s]\n", res, driver->driver.name);
- return res;
}
static int __unregister_client(struct device *dev, void *dummy)
@@ -1036,7 +1202,8 @@ static int __unregister_dummy(struct device *dev, void *dummy)
static int __process_removed_adapter(struct device_driver *d, void *data)
{
- return i2c_do_del_adapter(to_i2c_driver(d), data);
+ i2c_do_del_adapter(to_i2c_driver(d), data);
+ return 0;
}
/**
@@ -1047,9 +1214,8 @@ static int __process_removed_adapter(struct device_driver *d, void *data)
* This unregisters an I2C adapter which was previously registered
* by @i2c_add_adapter or @i2c_add_numbered_adapter.
*/
-int i2c_del_adapter(struct i2c_adapter *adap)
+void i2c_del_adapter(struct i2c_adapter *adap)
{
- int res = 0;
struct i2c_adapter *found;
struct i2c_client *client, *next;
@@ -1060,16 +1226,14 @@ int i2c_del_adapter(struct i2c_adapter *adap)
if (found != adap) {
pr_debug("i2c-core: attempting to delete unregistered "
"adapter [%s]\n", adap->name);
- return -EINVAL;
+ return;
}
/* Tell drivers about this removal */
mutex_lock(&core_lock);
- res = bus_for_each_drv(&i2c_bus_type, NULL, adap,
+ bus_for_each_drv(&i2c_bus_type, NULL, adap,
__process_removed_adapter);
mutex_unlock(&core_lock);
- if (res)
- return res;
/* Remove devices instantiated from sysfs */
mutex_lock_nested(&adap->userspace_clients_lock,
@@ -1088,8 +1252,8 @@ int i2c_del_adapter(struct i2c_adapter *adap)
* we can't remove the dummy devices during the first pass: they
* could have been instantiated by real devices wishing to clean
* them up properly, so we give them a chance to do that first. */
- res = device_for_each_child(&adap->dev, NULL, __unregister_client);
- res = device_for_each_child(&adap->dev, NULL, __unregister_dummy);
+ device_for_each_child(&adap->dev, NULL, __unregister_client);
+ device_for_each_child(&adap->dev, NULL, __unregister_dummy);
#ifdef CONFIG_I2C_COMPAT
class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
@@ -1114,8 +1278,6 @@ int i2c_del_adapter(struct i2c_adapter *adap)
/* Clear the device structure in case this adapter is ever going to be
added again */
memset(&adap->dev, 0, sizeof(adap->dev));
-
- return 0;
}
EXPORT_SYMBOL(i2c_del_adapter);
@@ -1185,9 +1347,9 @@ EXPORT_SYMBOL(i2c_register_driver);
static int __process_removed_driver(struct device *dev, void *data)
{
- if (dev->type != &i2c_adapter_type)
- return 0;
- return i2c_do_del_adapter(data, to_i2c_adapter(dev));
+ if (dev->type == &i2c_adapter_type)
+ i2c_do_del_adapter(data, to_i2c_adapter(dev));
+ return 0;
}
/**