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Commit 394e8351 authored by Miquel Raynal's avatar Miquel Raynal Committed by Greg Kroah-Hartman
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serial: mvebu-uart: add suspend/resume support 



Add suspend and resume hooks to save/restore the registers content
during S2RAM operation.

Also save/restore the oversampling rate register (OSAMP) as earlier
stages already tuned that register to get a precise UART clock.

Suggested-by: default avatarAllen Yan <yanwei@marvell.com>
Signed-off-by: default avatarMiquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7a91e382

drivers/tty/serial/mvebu-uart.c

+64 −0
Original line number Diff line number Diff line
@@ -71,6 +71,8 @@ 
#define UART_BRDV		0x10

#define  BRDV_BAUD_MASK         0x3FF



#define UART_OSAMP		0x14



#define MVEBU_NR_UARTS		2



#define MVEBU_UART_TYPE		"mvebu-uart"
@@ -108,6 +110,17 @@ struct mvebu_uart_driver_data { 
	struct uart_flags flags;

};



/* Saved registers during suspend */

struct mvebu_uart_pm_regs {

	unsigned int rbr;

	unsigned int tsh;

	unsigned int ctrl;

	unsigned int intr;

	unsigned int stat;

	unsigned int brdv;

	unsigned int osamp;

};



/* MVEBU UART driver structure */

struct mvebu_uart {

	struct uart_port *port;
@@ -115,6 +128,9 @@ struct mvebu_uart { 
	int irq[UART_IRQ_COUNT];

	unsigned char __iomem *nb;

	struct mvebu_uart_driver_data *data;

#if defined(CONFIG_PM)

	struct mvebu_uart_pm_regs pm_regs;

#endif /* CONFIG_PM */

};



static struct mvebu_uart *to_mvuart(struct uart_port *port)
@@ -719,6 +735,51 @@ static struct uart_driver mvebu_uart_driver = { 
#endif

};



#if defined(CONFIG_PM)

static int mvebu_uart_suspend(struct device *dev)

{

	struct mvebu_uart *mvuart = dev_get_drvdata(dev);

	struct uart_port *port = mvuart->port;



	uart_suspend_port(&mvebu_uart_driver, port);



	mvuart->pm_regs.rbr = readl(port->membase + UART_RBR(port));

	mvuart->pm_regs.tsh = readl(port->membase + UART_TSH(port));

	mvuart->pm_regs.ctrl = readl(port->membase + UART_CTRL(port));

	mvuart->pm_regs.intr = readl(port->membase + UART_INTR(port));

	mvuart->pm_regs.stat = readl(port->membase + UART_STAT);

	mvuart->pm_regs.brdv = readl(port->membase + UART_BRDV);

	mvuart->pm_regs.osamp = readl(port->membase + UART_OSAMP);



	device_set_wakeup_enable(dev, true);



	return 0;

}



static int mvebu_uart_resume(struct device *dev)

{

	struct mvebu_uart *mvuart = dev_get_drvdata(dev);

	struct uart_port *port = mvuart->port;



	writel(mvuart->pm_regs.rbr, port->membase + UART_RBR(port));

	writel(mvuart->pm_regs.tsh, port->membase + UART_TSH(port));

	writel(mvuart->pm_regs.ctrl, port->membase + UART_CTRL(port));

	writel(mvuart->pm_regs.intr, port->membase + UART_INTR(port));

	writel(mvuart->pm_regs.stat, port->membase + UART_STAT);

	writel(mvuart->pm_regs.brdv, port->membase + UART_BRDV);

	writel(mvuart->pm_regs.osamp, port->membase + UART_OSAMP);



	uart_resume_port(&mvebu_uart_driver, port);



	return 0;

}



static const struct dev_pm_ops mvebu_uart_pm_ops = {

	.suspend        = mvebu_uart_suspend,

	.resume         = mvebu_uart_resume,

};

#endif /* CONFIG_PM */



static const struct of_device_id mvebu_uart_of_match[];



/* Counter to keep track of each UART port id when not using CONFIG_OF */
@@ -892,6 +953,9 @@ static struct platform_driver mvebu_uart_platform_driver = { 
		.name  = "mvebu-uart",

		.of_match_table = of_match_ptr(mvebu_uart_of_match),

		.suppress_bind_attrs = true,

#if defined(CONFIG_PM)

		.pm	= &mvebu_uart_pm_ops,

#endif /* CONFIG_PM */

	},

};