Kind PING. > -----Original Message----- > From: linux-arm-kernel [mailto:linux-arm-kernel-bounces@xxxxxxxxxxxxxxxxxxx] On > Behalf Of Shenwei Wang > Sent: 2015年7月17日 15:30 > To: gregkh@xxxxxxxxxxxxxxxxxxx > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-serial@xxxxxxxxxxxxxxx > Subject: [PATCH 1/1] Serial: imx: add dev_pm_ops to support suspend to ram/disk > > When system goes into low power states like SUSPEND_MEM and HIBERNATION, > the hardware IP block may be powered off to reduce the power consumption. > This power down may cause problems on some imx platforms, because the > hardware settings are reset to its power on default values which may differ from > the ones when it power off. This patch added the dev_pm_ops and implemented > two callbacks: suspend_noirq and resume_noirq, which will save the necessory > hardware parameters right before power down and recover them before system > uses the hardware. > > Signed-off-by: Shenwei Wang <shenwei.wang@xxxxxxxxxxxxx> > --- > drivers/tty/serial/imx.c | 54 > ++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 54 insertions(+) > > diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index > c8cfa06..acaaa68 100644 > --- a/drivers/tty/serial/imx.c > +++ b/drivers/tty/serial/imx.c > @@ -216,6 +216,7 @@ struct imx_port { > unsigned int tx_bytes; > unsigned int dma_tx_nents; > wait_queue_head_t dma_wait; > + unsigned int saved_reg[10]; > }; > > struct imx_port_ucrs { > @@ -1986,6 +1987,58 @@ static int serial_imx_remove(struct platform_device > *pdev) > return uart_remove_one_port(&imx_reg, &sport->port); } > > +static int imx_serial_port_suspend_noirq(struct device *dev) { > + struct platform_device *pdev = to_platform_device(dev); > + struct imx_port *sport = platform_get_drvdata(pdev); > + > + /* Save necessary regs */ > + clk_enable(sport->clk_ipg); > + sport->saved_reg[0] = readl(sport->port.membase + UCR1); > + sport->saved_reg[1] = readl(sport->port.membase + UCR2); > + sport->saved_reg[2] = readl(sport->port.membase + UCR3); > + sport->saved_reg[3] = readl(sport->port.membase + UCR4); > + sport->saved_reg[4] = readl(sport->port.membase + UFCR); > + sport->saved_reg[5] = readl(sport->port.membase + UESC); > + sport->saved_reg[6] = readl(sport->port.membase + UTIM); > + sport->saved_reg[7] = readl(sport->port.membase + UBIR); > + sport->saved_reg[8] = readl(sport->port.membase + UBMR); > + sport->saved_reg[9] = readl(sport->port.membase + IMX21_UTS); > + clk_disable(sport->clk_ipg); > + > + pr_debug("0x%p (%d)\r\n", sport->port.membase, sport->port.line); > + > + return 0; > +} > + > +static int imx_serial_port_resume_noirq(struct device *dev) { > + struct platform_device *pdev = to_platform_device(dev); > + struct imx_port *sport = platform_get_drvdata(pdev); > + > + clk_enable(sport->clk_ipg); > + writel(sport->saved_reg[4], sport->port.membase + UFCR); > + writel(sport->saved_reg[5], sport->port.membase + UESC); > + writel(sport->saved_reg[6], sport->port.membase + UTIM); > + writel(sport->saved_reg[7], sport->port.membase + UBIR); > + writel(sport->saved_reg[8], sport->port.membase + UBMR); > + writel(sport->saved_reg[9], sport->port.membase + IMX21_UTS); > + writel(sport->saved_reg[0], sport->port.membase + UCR1); > + writel(sport->saved_reg[1] | 0x1, sport->port.membase + UCR2); > + writel(sport->saved_reg[2], sport->port.membase + UCR3); > + writel(sport->saved_reg[3], sport->port.membase + UCR4); > + clk_disable(sport->clk_ipg); > + > + pr_debug("0x%p (%d)\r\n", sport->port.membase, sport->port.line); > + > + return 0; > +} > + > +static const struct dev_pm_ops imx_serial_port_pm_ops = { > + .suspend_noirq = imx_serial_port_suspend_noirq, > + .resume_noirq = imx_serial_port_resume_noirq, }; > + > static struct platform_driver serial_imx_driver = { > .probe = serial_imx_probe, > .remove = serial_imx_remove, > @@ -1996,6 +2049,7 @@ static struct platform_driver serial_imx_driver = { > .driver = { > .name = "imx-uart", > .of_match_table = imx_uart_dt_ids, > + .pm = &imx_serial_port_pm_ops, > }, > }; > > -- > 2.5.0.rc2 > > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel ?韬{.n?????%??檩??w?{.n???{炳谦??{ay????j?f＂??????_璁(????"??m???G??⒏??璀?ｘ??
