This patch enables ACPI power domain on UART user devices. With this
patch, Linux can achieve open/close based ACPI power manageability for
UART tty ports.
Signed-off-by: Lv Zheng <lv.zheng@xxxxxxxxx>
---
drivers/acpi/acpi_uart.c | 40 ++++++++++++++++++++++++++++++++++++++
drivers/tty/serial/serial_core.c | 5 +++++
include/linux/tty.h | 4 ++++
3 files changed, 49 insertions(+)
diff --git a/drivers/acpi/acpi_uart.c b/drivers/acpi/acpi_uart.c
index c27fc7c..a6735b1 100644
--- a/drivers/acpi/acpi_uart.c
+++ b/drivers/acpi/acpi_uart.c
@@ -163,3 +163,43 @@ void acpi_uart_register_user_device(struct device *parent,
}
}
EXPORT_SYMBOL_GPL(acpi_uart_register_user_device);
+
+/**
+ * acpi_uart_user_change_pm - change pm for tty port
+ * @port: the tty port
+ * @power_on: whether or not power on the device
+ *
+ * Change PM for tty user device.
+ */
+void acpi_uart_user_change_pm(struct tty_port *port, bool power_on)
+{
+ acpi_handle handle;
+ struct acpi_device *adev;
+ struct acpi_device_physical_node *entry;
+ struct device *ldev;
+
+ BUG_ON(!port);
+ handle = ACPI_NODE_GET(port->acpi_node);
+ if (!handle)
+ return;
+ if (acpi_bus_get_device(handle, &adev))
+ return;
+ if (acpi_bus_get_status(adev) || !adev->status.present)
+ return;
+
+ list_for_each_entry(entry, &adev->physical_node_list, node) {
+ ldev = get_device(entry->dev);
+ if (!ldev)
+ continue;
+ if (ldev->class == tty_class) {
+ if (power_on)
+ acpi_dev_pm_attach(ldev, true);
+ else
+ acpi_dev_pm_detach(ldev, false);
+ put_device(ldev);
+ return;
+ }
+ put_device(ldev);
+ }
+}
+EXPORT_SYMBOL_GPL(acpi_uart_user_change_pm);
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index c10bb4c..6ca4a5c 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1901,10 +1901,15 @@ static void uart_change_pm(struct uart_state *state,
enum uart_pm_state pm_state)
{
struct uart_port *port = state->uart_port;
+ struct tty_port *tport = &state->port;
if (state->pm_state != pm_state) {
+ if (pm_state == UART_PM_STATE_ON)
+ acpi_uart_user_change_pm(tport, true);
if (port->ops->pm)
port->ops->pm(port, pm_state, state->pm_state);
+ if (pm_state == UART_PM_STATE_OFF)
+ acpi_uart_user_change_pm(tport, false);
state->pm_state = pm_state;
}
}
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 5f17ab5..fbf8def 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -687,11 +687,15 @@ void acpi_uart_register_user_device(struct device *parent,
struct device *dev,
struct tty_driver *driver,
unsigned int index);
+extern void acpi_uart_user_change_pm(struct tty_port *port,
+ bool power_on);
#else
static inline void acpi_uart_register_user_device(struct device *parent,
struct device *dev,
struct tty_driver *driver,
unsigned int index) {}
+static inline void acpi_uart_user_change_pm(struct tty_port *port,
+ bool power_on) {}
#endif
#endif
--
1.7.10
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