Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751911AbaJTCBZ (ORCPT ); Sun, 19 Oct 2014 22:01:25 -0400 Received: from nasmtp01.atmel.com ([192.199.1.245]:22633 "EHLO DVREDG01.corp.atmel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751187AbaJTCBX convert rfc822-to-8bit (ORCPT ); Sun, 19 Oct 2014 22:01:23 -0400 From: "Yang, Wenyou" To: Kevin Hilman CC: "broonie@kernel.org" , "linux-spi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "Ferre, Nicolas" , "linux-arm-kernel@lists.infradead.org" Subject: RE: [PATCH] spi/atmel: add support for runtime PM Thread-Topic: [PATCH] spi/atmel: add support for runtime PM Thread-Index: AQHP6OOz3LvTFspzlkWsWVFQ1Yxkwpw0Q30ogAP5RlA= Date: Mon, 20 Oct 2014 01:59:05 +0000 Message-ID: References: <1413424160-21180-1-git-send-email-wenyou.yang@atmel.com> <7hk33yhms4.fsf@deeprootsystems.com> In-Reply-To: <7hk33yhms4.fsf@deeprootsystems.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.168.5.13] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > -----Original Message----- > From: Kevin Hilman [mailto:khilman@kernel.org] > Sent: Friday, October 17, 2014 9:03 PM > To: Yang, Wenyou > Cc: broonie@kernel.org; linux-spi@vger.kernel.org; linux-kernel@vger.kernel.org; > Ferre, Nicolas; linux-arm-kernel@lists.infradead.org > Subject: Re: [PATCH] spi/atmel: add support for runtime PM > > Wenyou Yang writes: > > > Drivers should put the device into low power states proactively > > whenever the device is not in use. Thus implement support for runtime > > PM and use the autosuspend feature to make sure that we can still > > perform well in case we see lots of SPI traffic within short period of time. > > > > Signed-off-by: Wenyou Yang > > --- > > drivers/spi/spi-atmel.c | 62 > +++++++++++++++++++++++++++++++++++++++++------ > > 1 file changed, 55 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c index > > 649dcb5..aca285e 100644 > > --- a/drivers/spi/spi-atmel.c > > +++ b/drivers/spi/spi-atmel.c > > @@ -26,6 +26,7 @@ > > #include > > #include > > #include > > +#include > > > > /* SPI register offsets */ > > #define SPI_CR 0x0000 > > @@ -191,6 +192,8 @@ > > > > #define SPI_DMA_TIMEOUT (msecs_to_jiffies(1000)) > > > > +#define AUTOSUSPEND_TIMEOUT 2000 > > + > > struct atmel_spi_dma { > > struct dma_chan *chan_rx; > > struct dma_chan *chan_tx; > > @@ -1313,6 +1316,7 @@ static int atmel_spi_probe(struct platform_device > *pdev) > > master->setup = atmel_spi_setup; > > master->transfer_one_message = atmel_spi_transfer_one_message; > > master->cleanup = atmel_spi_cleanup; > > + master->auto_runtime_pm = true; > > platform_set_drvdata(pdev, master); > > > > as = spi_master_get_devdata(master); @@ -1385,6 +1389,11 @@ static > > int atmel_spi_probe(struct platform_device *pdev) > > dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n", > > (unsigned long)regs->start, irq); > > > > + pm_runtime_set_autosuspend_delay(&pdev->dev, > AUTOSUSPEND_TIMEOUT); > > + pm_runtime_use_autosuspend(&pdev->dev); > > + pm_runtime_set_active(&pdev->dev); > > + pm_runtime_enable(&pdev->dev); > > + > > ret = devm_spi_register_master(&pdev->dev, master); > > if (ret) > > goto out_free_dma; > > @@ -1392,6 +1401,9 @@ static int atmel_spi_probe(struct platform_device > *pdev) > > return 0; > > > > out_free_dma: > > + pm_runtime_disable(&pdev->dev); > > + pm_runtime_set_suspended(&pdev->dev); > > + > > if (as->use_dma) > > atmel_spi_release_dma(as); > > > > @@ -1413,6 +1425,8 @@ static int atmel_spi_remove(struct platform_device > *pdev) > > struct spi_master *master = platform_get_drvdata(pdev); > > struct atmel_spi *as = spi_master_get_devdata(master); > > > > + pm_runtime_get_sync(&pdev->dev); > > + > > /* reset the hardware and block queue progress */ > > spin_lock_irq(&as->lock); > > if (as->use_dma) { > > @@ -1430,9 +1444,13 @@ static int atmel_spi_remove(struct > > platform_device *pdev) > > > > clk_disable_unprepare(as->clk); > > > > + pm_runtime_put_noidle(&pdev->dev); > > Why the _noidle version? Because invoked from the _remove function, only decrement the device's usage counter, no further idle operation need. > > > + pm_runtime_disable(&pdev->dev); > > + > > return 0; > > } > > > > +#ifdef CONFIG_PM > > Why CONFIG_PM? CONFIG_PM_SLEEP causes CONFIG_PM=y, so this seems > redundant. Accepted, I will remove it. > > > #ifdef CONFIG_PM_SLEEP > > static int atmel_spi_suspend(struct device *dev) { @@ -1447,9 > > +1465,10 @@ static int atmel_spi_suspend(struct device *dev) > > return ret; > > } > > > > - clk_disable_unprepare(as->clk); > > - > > - pinctrl_pm_select_sleep_state(dev); > > + if (!pm_runtime_suspended(dev)) { > > + clk_disable_unprepare(as->clk); > > + pinctrl_pm_select_sleep_state(dev); > > + } > > a.k.a. pm_runtime_put_sync() since the ->runtime_suspend() callback does the > same thing. > > > return 0; > > } > > @@ -1460,9 +1479,10 @@ static int atmel_spi_resume(struct device *dev) > > struct atmel_spi *as = spi_master_get_devdata(master); > > int ret; > > > > - pinctrl_pm_select_default_state(dev); > > - > > - clk_prepare_enable(as->clk); > > + if (!pm_runtime_suspended(dev)) { > > + pinctrl_pm_select_default_state(dev); > > + clk_prepare_enable(as->clk); > > + } > > a.k.a. pm_runtime_get_sync() > > Kevin > > > /* Start the queue running */ > > ret = spi_master_resume(master); > > @@ -1471,9 +1491,37 @@ static int atmel_spi_resume(struct device *dev) > > > > return ret; > > } > > +#endif > > > > -static SIMPLE_DEV_PM_OPS(atmel_spi_pm_ops, atmel_spi_suspend, > > atmel_spi_resume); > > +#ifdef CONFIG_PM_RUNTIME > > +static int atmel_spi_runtime_suspend(struct device *dev) { > > + struct spi_master *master = dev_get_drvdata(dev); > > + struct atmel_spi *as = spi_master_get_devdata(master); > > > > + clk_disable_unprepare(as->clk); > > + pinctrl_pm_select_sleep_state(dev); > > + > > + return 0; > > +} > > + > > +static int atmel_spi_runtime_resume(struct device *dev) { > > + struct spi_master *master = dev_get_drvdata(dev); > > + struct atmel_spi *as = spi_master_get_devdata(master); > > + > > + pinctrl_pm_select_default_state(dev); > > + clk_prepare_enable(as->clk); > > + > > + return 0; > > +} > > +#endif > > + > > +static const struct dev_pm_ops atmel_spi_pm_ops = { > > + SET_SYSTEM_SLEEP_PM_OPS(atmel_spi_suspend, atmel_spi_resume) > > + SET_RUNTIME_PM_OPS(atmel_spi_runtime_suspend, > > + atmel_spi_runtime_resume, NULL) }; > > #define ATMEL_SPI_PM_OPS (&atmel_spi_pm_ops) > > #else > > #define ATMEL_SPI_PM_OPS NULL Best Regards, Wenyou Yang -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/