[PATCH 10/18] tty: serial: fsl_lpuart: support suspend/resume

Shawn Guo
2016-03-31T11:41:48Z

On Wed, Mar 09, 2016 at 06:16:51PM -0800, Stefan Agner wrote:
> In order to allow wake support in STOP sleep mode, clocks are
> needed. Use imx_clk_gate2_cgr to disable automatic clock gating
> in low power mode STOP. This allows to enable wake by UART using:
> echo enabled > /sys/class/tty/ttyLP0/power/wakeup
>
> However, if wake is not enabled, the driver should disable the
> clocks explicitly to save power.
>
> Signed-off-by: Stefan Agner <stefan@agner.ch>
> ---
> drivers/clk/imx/clk-vf610.c | 12 ++++++------

It should go to a separate patch.

Shawn

> drivers/tty/serial/fsl_lpuart.c | 16 ++++++++++++++--
> 2 files changed, 20 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/clk/imx/clk-vf610.c b/drivers/clk/imx/clk-vf610.c
> index e2e2c43..170a96c 100644
> --- a/drivers/clk/imx/clk-vf610.c
> +++ b/drivers/clk/imx/clk-vf610.c
> @@ -315,12 +315,12 @@ static void __init vf610_clocks_init(struct device_node *ccm_node)
>
> clk[VF610_CLK_PIT] = imx_clk_gate2("pit", "ipg_bus", CCM_CCGR1, CCM_CCGRx_CGn(7));
>
> - clk[VF610_CLK_UART0] = imx_clk_gate2("uart0", "ipg_bus", CCM_CCGR0, CCM_CCGRx_CGn(7));
> - clk[VF610_CLK_UART1] = imx_clk_gate2("uart1", "ipg_bus", CCM_CCGR0, CCM_CCGRx_CGn(8));
> - clk[VF610_CLK_UART2] = imx_clk_gate2("uart2", "ipg_bus", CCM_CCGR0, CCM_CCGRx_CGn(9));
> - clk[VF610_CLK_UART3] = imx_clk_gate2("uart3", "ipg_bus", CCM_CCGR0, CCM_CCGRx_CGn(10));
> - clk[VF610_CLK_UART4] = imx_clk_gate2("uart4", "ipg_bus", CCM_CCGR6, CCM_CCGRx_CGn(9));
> - clk[VF610_CLK_UART5] = imx_clk_gate2("uart5", "ipg_bus", CCM_CCGR6, CCM_CCGRx_CGn(10));
> + clk[VF610_CLK_UART0] = imx_clk_gate2_cgr("uart0", "ipg_bus", CCM_CCGR0, CCM_CCGRx_CGn(7), 0x2);
> + clk[VF610_CLK_UART1] = imx_clk_gate2_cgr("uart1", "ipg_bus", CCM_CCGR0, CCM_CCGRx_CGn(8), 0x2);
> + clk[VF610_CLK_UART2] = imx_clk_gate2_cgr("uart2", "ipg_bus", CCM_CCGR0, CCM_CCGRx_CGn(9), 0x2);
> + clk[VF610_CLK_UART3] = imx_clk_gate2_cgr("uart3", "ipg_bus", CCM_CCGR0, CCM_CCGRx_CGn(10), 0x2);
> + clk[VF610_CLK_UART4] = imx_clk_gate2_cgr("uart4", "ipg_bus", CCM_CCGR6, CCM_CCGRx_CGn(9), 0x2);
> + clk[VF610_CLK_UART5] = imx_clk_gate2_cgr("uart5", "ipg_bus", CCM_CCGR6, CCM_CCGRx_CGn(10), 0x2);
>
> clk[VF610_CLK_I2C0] = imx_clk_gate2("i2c0", "ipg_bus", CCM_CCGR4, CCM_CCGRx_CGn(6));
> clk[VF610_CLK_I2C1] = imx_clk_gate2("i2c1", "ipg_bus", CCM_CCGR4, CCM_CCGRx_CGn(7));
> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
> index 3d79003..94e29ba 100644
> --- a/drivers/tty/serial/fsl_lpuart.c
> +++ b/drivers/tty/serial/fsl_lpuart.c
> @@ -483,9 +483,8 @@ static void lpuart_dma_rx_complete(void *arg)
> spin_unlock_irqrestore(&sport->port.lock, flags);
> }
>
> -static void lpuart_timer_func(unsigned long data)
> +static void lpuart_dma_rx_terminate(struct lpuart_port *sport)
> {
> - struct lpuart_port *sport = (struct lpuart_port *)data;
> struct tty_port *port = &sport->port.state->port;
> struct dma_tx_state state;
> unsigned long flags;
> @@ -510,6 +509,11 @@ static void lpuart_timer_func(unsigned long data)
> spin_unlock_irqrestore(&sport->port.lock, flags);
> }
>
> +static void lpuart_timer_func(unsigned long data)
> +{
> + lpuart_dma_rx_terminate((struct lpuart_port *)data);
> +}
> +
> static inline void lpuart_prepare_rx(struct lpuart_port *sport)
> {
> unsigned long flags;
> @@ -1915,7 +1919,12 @@ static int lpuart_suspend(struct device *dev)
> writeb(temp, sport->port.membase + UARTCR2);
> }
>
> + if (sport->dma_rx_in_progress)
> + lpuart_dma_rx_terminate(sport);
> +
> uart_suspend_port(&lpuart_reg, &sport->port);
> + if (sport->port.suspended && !sport->port.irq_wake)
> + clk_disable_unprepare(sport->clk);
>
> return 0;
> }
> @@ -1925,6 +1934,9 @@ static int lpuart_resume(struct device *dev)
> struct lpuart_port *sport = dev_get_drvdata(dev);
> unsigned long temp;
>
> + if (sport->port.suspended && !sport->port.irq_wake)
> + clk_prepare_enable(sport->clk);
> +
> if (sport->lpuart32) {
> lpuart32_setup_watermark(sport);
> temp = lpuart32_read(sport->port.membase + UARTCTRL);
> --
> 2.7.2
>
>