[S] [HostAddr] [Wr] A [DevAddr] A [DataLow] A [DataHigh] A [P]
This is implemented in the following way in the Linux kernel:
-* I2C bus drivers which support SMBus Host Notify should call
- i2c_setup_smbus_host_notify() to setup SMBus Host Notify support.
-* I2C drivers for devices which can trigger SMBus Host Notify should implement
- the optional alert() callback.
+* I2C bus drivers which support SMBus Host Notify should report
+ I2C_FUNC_SMBUS_HOST_NOTIFY.
+* I2C bus drivers trigger SMBus Host Notify by a call to
+ i2c_handle_smbus_host_notify().
+* I2C drivers for devices which can trigger SMBus Host Notify will have
+ client->irq assigned to a Host Notify IRQ if noone else specified an other.
+
+There is currently no way to retrieve the data parameter from the client.
Packet Error Checking (PEC)
config I2C
tristate "I2C support"
select RT_MUTEXES
+ select IRQ_DOMAIN
---help---
I2C (pronounce: I-squared-C) is a slow serial bus protocol used in
many micro controller applications and developed by Philips. SMBus,
*/
bool acpi_reserved;
struct mutex acpi_lock;
- struct smbus_host_notify *host_notify;
};
#define FEATURE_SMBUS_PEC BIT(0)
/*
* With the tested platforms, reading SMBNTFDDAT (22 + (p)->smba)
- * always returns 0 and is safe to read.
- * We just use 0 given we have no use of the data right now.
+ * always returns 0. Our current implementation doesn't provide
+ * data, so we just ignore it.
*/
- i2c_handle_smbus_host_notify(priv->host_notify, addr, 0);
+ i2c_handle_smbus_host_notify(&priv->adapter, addr);
/* clear Host Notify bit and return */
outb_p(SMBSLVSTS_HST_NTFY_STS, SMBSLVSTS(priv));
I2C_FUNC_SMBUS_HOST_NOTIFY : 0);
}
-static int i801_enable_host_notify(struct i2c_adapter *adapter)
+static void i801_enable_host_notify(struct i2c_adapter *adapter)
{
struct i801_priv *priv = i2c_get_adapdata(adapter);
if (!(priv->features & FEATURE_HOST_NOTIFY))
- return -ENOTSUPP;
-
- if (!priv->host_notify)
- priv->host_notify = i2c_setup_smbus_host_notify(adapter);
- if (!priv->host_notify)
- return -ENOMEM;
+ return;
priv->original_slvcmd = inb_p(SMBSLVCMD(priv));
/* clear Host Notify bit to allow a new notification */
outb_p(SMBSLVSTS_HST_NTFY_STS, SMBSLVSTS(priv));
-
- return 0;
}
static void i801_disable_host_notify(struct i801_priv *priv)
return err;
}
- /*
- * Enable Host Notify for chips that supports it.
- * It is done after i2c_add_adapter() so that we are sure the work queue
- * is not used if i2c_add_adapter() fails.
- */
- err = i801_enable_host_notify(&priv->adapter);
- if (err && err != -ENOTSUPP)
- dev_warn(&dev->dev, "Unable to enable SMBus Host Notify\n");
+ i801_enable_host_notify(&priv->adapter);
i801_probe_optional_slaves(priv);
/* We ignore errors - multiplexing is optional */
{
struct pci_dev *pci_dev = to_pci_dev(dev);
struct i801_priv *priv = pci_get_drvdata(pci_dev);
- int err;
- err = i801_enable_host_notify(&priv->adapter);
- if (err && err != -ENOTSUPP)
- dev_warn(dev, "Unable to enable SMBus Host Notify\n");
+ i801_enable_host_notify(&priv->adapter);
return 0;
}
#define I2C_ADDR_OFFSET_TEN_BIT 0xa000
#define I2C_ADDR_OFFSET_SLAVE 0x1000
+#define I2C_ADDR_7BITS_MAX 0x77
+#define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
+
/* core_lock protects i2c_adapter_idr, and guarantees
that device detection, deletion of detected devices, and attach_adapter
calls are serialized */
adap->bus_recovery_info = NULL;
}
+static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
+{
+ struct i2c_adapter *adap = client->adapter;
+ unsigned int irq;
+
+ if (!adap->host_notify_domain)
+ return -ENXIO;
+
+ if (client->flags & I2C_CLIENT_TEN)
+ return -EINVAL;
+
+ irq = irq_find_mapping(adap->host_notify_domain, client->addr);
+ if (!irq)
+ irq = irq_create_mapping(adap->host_notify_domain,
+ client->addr);
+
+ return irq > 0 ? irq : -ENXIO;
+}
+
static int i2c_device_probe(struct device *dev)
{
struct i2c_client *client = i2c_verify_client(dev);
}
if (irq == -EPROBE_DEFER)
return irq;
+ /*
+ * ACPI and OF did not find any useful IRQ, try to see
+ * if Host Notify can be used.
+ */
+ if (irq < 0) {
+ dev_dbg(dev, "Using Host Notify IRQ\n");
+ irq = i2c_smbus_host_notify_to_irq(client);
+ }
if (irq < 0)
irq = 0;
.unlock_bus = i2c_adapter_unlock_bus,
};
+static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
+{
+ struct irq_domain *domain = adap->host_notify_domain;
+ irq_hw_number_t hwirq;
+
+ if (!domain)
+ return;
+
+ for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
+ irq_dispose_mapping(irq_find_mapping(domain, hwirq));
+
+ irq_domain_remove(domain);
+ adap->host_notify_domain = NULL;
+}
+
+static int i2c_host_notify_irq_map(struct irq_domain *h,
+ unsigned int virq,
+ irq_hw_number_t hw_irq_num)
+{
+ irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
+
+ return 0;
+}
+
+static const struct irq_domain_ops i2c_host_notify_irq_ops = {
+ .map = i2c_host_notify_irq_map,
+};
+
+static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
+{
+ struct irq_domain *domain;
+
+ if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
+ return 0;
+
+ domain = irq_domain_create_linear(adap->dev.fwnode,
+ I2C_ADDR_7BITS_COUNT,
+ &i2c_host_notify_irq_ops, adap);
+ if (!domain)
+ return -ENOMEM;
+
+ adap->host_notify_domain = domain;
+
+ return 0;
+}
+
+/**
+ * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
+ * I2C client.
+ * @adap: the adapter
+ * @addr: the I2C address of the notifying device
+ * Context: can't sleep
+ *
+ * Helper function to be called from an I2C bus driver's interrupt
+ * handler. It will schedule the Host Notify IRQ.
+ */
+int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
+{
+ int irq;
+
+ if (!adap)
+ return -EINVAL;
+
+ irq = irq_find_mapping(adap->host_notify_domain, addr);
+ if (irq <= 0)
+ return -ENXIO;
+
+ generic_handle_irq(irq);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
+
static int i2c_register_adapter(struct i2c_adapter *adap)
{
int res = -EINVAL;
if (adap->timeout == 0)
adap->timeout = HZ;
+ /* register soft irqs for Host Notify */
+ res = i2c_setup_host_notify_irq_domain(adap);
+ if (res) {
+ pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
+ adap->name, res);
+ goto out_list;
+ }
+
dev_set_name(&adap->dev, "i2c-%d", adap->nr);
adap->dev.bus = &i2c_bus_type;
adap->dev.type = &i2c_adapter_type;
pm_runtime_disable(&adap->dev);
+ i2c_host_notify_irq_teardown(adap);
+
/* wait until all references to the device are gone
*
* FIXME: This is old code and should ideally be replaced by an
}
EXPORT_SYMBOL_GPL(i2c_handle_smbus_alert);
-static void smbus_host_notify_work(struct work_struct *work)
-{
- struct alert_data alert;
- struct i2c_adapter *adapter;
- unsigned long flags;
- u16 payload;
- u8 addr;
- struct smbus_host_notify *data;
-
- data = container_of(work, struct smbus_host_notify, work);
-
- spin_lock_irqsave(&data->lock, flags);
- payload = data->payload;
- addr = data->addr;
- adapter = data->adapter;
-
- /* clear the pending bit and release the spinlock */
- data->pending = false;
- spin_unlock_irqrestore(&data->lock, flags);
-
- if (!adapter || !addr)
- return;
-
- alert.type = I2C_PROTOCOL_SMBUS_HOST_NOTIFY;
- alert.addr = addr;
- alert.data = payload;
-
- device_for_each_child(&adapter->dev, &alert, smbus_do_alert);
-}
-
-/**
- * i2c_setup_smbus_host_notify - Allocate a new smbus_host_notify for the given
- * I2C adapter.
- * @adapter: the adapter we want to associate a Host Notify function
- *
- * Returns a struct smbus_host_notify pointer on success, and NULL on failure.
- * The resulting smbus_host_notify must not be freed afterwards, it is a
- * managed resource already.
- */
-struct smbus_host_notify *i2c_setup_smbus_host_notify(struct i2c_adapter *adap)
-{
- struct smbus_host_notify *host_notify;
-
- host_notify = devm_kzalloc(&adap->dev, sizeof(struct smbus_host_notify),
- GFP_KERNEL);
- if (!host_notify)
- return NULL;
-
- host_notify->adapter = adap;
-
- spin_lock_init(&host_notify->lock);
- INIT_WORK(&host_notify->work, smbus_host_notify_work);
-
- return host_notify;
-}
-EXPORT_SYMBOL_GPL(i2c_setup_smbus_host_notify);
-
-/**
- * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
- * I2C client.
- * @host_notify: the struct host_notify attached to the relevant adapter
- * @addr: the I2C address of the notifying device
- * @data: the payload of the notification
- * Context: can't sleep
- *
- * Helper function to be called from an I2C bus driver's interrupt
- * handler. It will schedule the Host Notify work, in turn calling the
- * corresponding I2C device driver's alert function.
- *
- * host_notify should be a valid pointer previously returned by
- * i2c_setup_smbus_host_notify().
- */
-int i2c_handle_smbus_host_notify(struct smbus_host_notify *host_notify,
- unsigned short addr, unsigned int data)
-{
- unsigned long flags;
- struct i2c_adapter *adapter;
-
- if (!host_notify || !host_notify->adapter)
- return -EINVAL;
-
- adapter = host_notify->adapter;
-
- spin_lock_irqsave(&host_notify->lock, flags);
-
- if (host_notify->pending) {
- spin_unlock_irqrestore(&host_notify->lock, flags);
- dev_warn(&adapter->dev, "Host Notify already scheduled.\n");
- return -EBUSY;
- }
-
- host_notify->payload = data;
- host_notify->addr = addr;
-
- /* Mark that there is a pending notification and release the lock */
- host_notify->pending = true;
- spin_unlock_irqrestore(&host_notify->lock, flags);
-
- return schedule_work(&host_notify->work);
-}
-EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
-
module_i2c_driver(smbalert_driver);
MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
struct i2c_smbus_alert_setup *setup);
int i2c_handle_smbus_alert(struct i2c_client *ara);
-/**
- * smbus_host_notify - internal structure used by the Host Notify mechanism.
- * @adapter: the I2C adapter associated with this struct
- * @work: worker used to schedule the IRQ in the slave device
- * @lock: spinlock to check if a notification is already pending
- * @pending: flag set when a notification is pending (any new notification will
- * be rejected if pending is true)
- * @payload: the actual payload of the Host Notify event
- * @addr: the address of the slave device which raised the notification
- *
- * This struct needs to be allocated by i2c_setup_smbus_host_notify() and does
- * not need to be freed. Internally, i2c_setup_smbus_host_notify() uses a
- * managed resource to clean this up when the adapter get released.
- */
-struct smbus_host_notify {
- struct i2c_adapter *adapter;
- struct work_struct work;
- spinlock_t lock;
- bool pending;
- u16 payload;
- u8 addr;
-};
-
-struct smbus_host_notify *i2c_setup_smbus_host_notify(struct i2c_adapter *adap);
-int i2c_handle_smbus_host_notify(struct smbus_host_notify *host_notify,
- unsigned short addr, unsigned int data);
-
#endif /* _LINUX_I2C_SMBUS_H */
#include <linux/device.h> /* for struct device */
#include <linux/sched.h> /* for completion */
#include <linux/mutex.h>
+#include <linux/irqdomain.h> /* for Host Notify IRQ */
#include <linux/of.h> /* for struct device_node */
#include <linux/swab.h> /* for swab16 */
#include <uapi/linux/i2c.h>
struct i2c_bus_recovery_info *bus_recovery_info;
const struct i2c_adapter_quirks *quirks;
+
+ struct irq_domain *host_notify_domain;
};
#define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
return (msg->addr << 1) | (msg->flags & I2C_M_RD ? 1 : 0);
}
+int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr);
/**
* module_i2c_driver() - Helper macro for registering a modular I2C driver
* @__i2c_driver: i2c_driver struct
projects / platform / kernel / linux-starfive.git / commitdiff