Hi Miquel,
On sam., avril 21 2018, Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote:
> 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: Allen Yan <yanwei@xxxxxxxxxxx>
> Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
It looks OK
Reviwed-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxx>
Thanks,
Gregory
> ---
> drivers/tty/serial/mvebu-uart.c | 64 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 64 insertions(+)
>
> diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c
> index 750e5645dc85..013b86a1044f 100644
> --- a/drivers/tty/serial/mvebu-uart.c
> +++ b/drivers/tty/serial/mvebu-uart.c
> @@ -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 */
> },
> };
>
> --
> 2.14.1
>
--
Gregory Clement, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
http://bootlin.com
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