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tty: xuartps: Implement suspend/resume callbacks 

Implement suspend and resume callbacks in order to support system
suspend/hibernation.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Soren Brinkmann 2013-10-17 14:08:12 -07:00 committed by Greg Kroah-Hartman
parent c4b0510cc1
commit 4b47d9aa1e
1 changed files with 114 additions and 0 deletions
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114
drivers/tty/serial/xilinx_uartps.c
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@ -1198,6 +1198,119 @@ console_initcall(xuartps_console_init);
#endif /* CONFIG_SERIAL_XILINX_PS_UART_CONSOLE */
#ifdef CONFIG_PM_SLEEP
/**
* xuartps_suspend - suspend event
* @device: Pointer to the device structure
*
* Returns 0
*/
static int xuartps_suspend(struct device *device)
{
struct uart_port *port = dev_get_drvdata(device);
struct tty_struct *tty;
struct device *tty_dev;
int may_wake = 0;
/* Get the tty which could be NULL so don't assume it's valid */
tty = tty_port_tty_get(&port->state->port);
if (tty) {
tty_dev = tty->dev;
may_wake = device_may_wakeup(tty_dev);
tty_kref_put(tty);
}
/*
* Call the API provided in serial_core.c file which handles
* the suspend.
*/
uart_suspend_port(&xuartps_uart_driver, port);
if (console_suspend_enabled && !may_wake) {
struct xuartps *xuartps = port->private_data;
clk_disable(xuartps->refclk);
clk_disable(xuartps->aperclk);
} else {
unsigned long flags = 0;
spin_lock_irqsave(&port->lock, flags);
/* Empty the receive FIFO 1st before making changes */
while (!(xuartps_readl(XUARTPS_SR_OFFSET) & XUARTPS_SR_RXEMPTY))
xuartps_readl(XUARTPS_FIFO_OFFSET);
/* set RX trigger level to 1 */
xuartps_writel(1, XUARTPS_RXWM_OFFSET);
/* disable RX timeout interrups */
xuartps_writel(XUARTPS_IXR_TOUT, XUARTPS_IDR_OFFSET);
spin_unlock_irqrestore(&port->lock, flags);
}
return 0;
}
/**
* xuartps_resume - Resume after a previous suspend
* @device: Pointer to the device structure
*
* Returns 0
*/
static int xuartps_resume(struct device *device)
{
struct uart_port *port = dev_get_drvdata(device);
unsigned long flags = 0;
u32 ctrl_reg;
struct tty_struct *tty;
struct device *tty_dev;
int may_wake = 0;
/* Get the tty which could be NULL so don't assume it's valid */
tty = tty_port_tty_get(&port->state->port);
if (tty) {
tty_dev = tty->dev;
may_wake = device_may_wakeup(tty_dev);
tty_kref_put(tty);
}
if (console_suspend_enabled && !may_wake) {
struct xuartps *xuartps = port->private_data;
clk_enable(xuartps->aperclk);
clk_enable(xuartps->refclk);
spin_lock_irqsave(&port->lock, flags);
/* Set TX/RX Reset */
xuartps_writel(xuartps_readl(XUARTPS_CR_OFFSET) |
(XUARTPS_CR_TXRST | XUARTPS_CR_RXRST),
XUARTPS_CR_OFFSET);
while (xuartps_readl(XUARTPS_CR_OFFSET) &
(XUARTPS_CR_TXRST | XUARTPS_CR_RXRST))
cpu_relax();
/* restore rx timeout value */
xuartps_writel(rx_timeout, XUARTPS_RXTOUT_OFFSET);
/* Enable Tx/Rx */
ctrl_reg = xuartps_readl(XUARTPS_CR_OFFSET);
xuartps_writel(
(ctrl_reg & ~(XUARTPS_CR_TX_DIS | XUARTPS_CR_RX_DIS)) |
(XUARTPS_CR_TX_EN | XUARTPS_CR_RX_EN),
XUARTPS_CR_OFFSET);
spin_unlock_irqrestore(&port->lock, flags);
} else {
spin_lock_irqsave(&port->lock, flags);
/* restore original rx trigger level */
xuartps_writel(rx_trigger_level, XUARTPS_RXWM_OFFSET);
/* enable RX timeout interrupt */
xuartps_writel(XUARTPS_IXR_TOUT, XUARTPS_IER_OFFSET);
spin_unlock_irqrestore(&port->lock, flags);
}
return uart_resume_port(&xuartps_uart_driver, port);
}
#endif /* ! CONFIG_PM_SLEEP */
static SIMPLE_DEV_PM_OPS(xuartps_dev_pm_ops, xuartps_suspend, xuartps_resume);
/** Structure Definitions
*/
static struct uart_driver xuartps_uart_driver = {
@ -1348,6 +1461,7 @@ static struct platform_driver xuartps_platform_driver = {
.owner = THIS_MODULE,
.name = XUARTPS_NAME, /* Driver name */
.of_match_table = xuartps_of_match,
.pm = &xuartps_dev_pm_ops,
},
};