From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sascha Hauer Subject: Re: [PATCH 4/4] i2c: imx: disable clock when it's possible to save power. Date: Thu, 1 Oct 2009 09:34:34 +0200 Message-ID: <20091001073434.GY27039@pengutronix.de> References: <1254359613-21210-1-git-send-email-linuxzsc@gmail.com> <1254359613-21210-2-git-send-email-linuxzsc@gmail.com> <1254359613-21210-3-git-send-email-linuxzsc@gmail.com> <1254359613-21210-4-git-send-email-linuxzsc@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1254359613-21210-4-git-send-email-linuxzsc-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Richard Zhao Cc: kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org List-Id: linux-i2c@vger.kernel.org On Thu, Oct 01, 2009 at 09:13:33AM +0800, Richard Zhao wrote: > Enable clock before START, disable it after STOP. The clk_diable/enable calls in suspend/resume should be removed also. Sascha > > Signed-off-by: Richard Zhao > > diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c > index 87faea4..72ddea3 100644 > --- a/drivers/i2c/busses/i2c-imx.c > +++ b/drivers/i2c/busses/i2c-imx.c > @@ -120,6 +120,7 @@ struct imx_i2c_struct { > wait_queue_head_t queue; > unsigned long i2csr; > unsigned int disable_delay; > + unsigned int ifdr; /* IMX_I2C_IFDR */ > }; > > /** Functions for IMX I2C adapter driver *************************************** > @@ -210,6 +211,8 @@ static int i2c_imx_start(struct imx_i2c_struct *i2c_imx) > > dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); > > + clk_enable(i2c_imx->clk); > + writeb(i2c_imx->ifdr, i2c_imx->base + IMX_I2C_IFDR); > /* Enable I2C controller */ > writeb(0, i2c_imx->base + IMX_I2C_I2SR); > writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR); > @@ -254,6 +257,7 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx) > > /* Disable I2C controller */ > writeb(0, i2c_imx->base + IMX_I2C_I2CR); > + clk_disable(i2c_imx->clk); > } > > static void __init i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx, > @@ -273,8 +277,8 @@ static void __init i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx, > else > for (i = 0; i2c_clk_div[i][0] < div; i++); > > - /* Write divider value to register */ > - writeb(i2c_clk_div[i][1], i2c_imx->base + IMX_I2C_IFDR); > + /* Store divider value */ > + i2c_imx->ifdr = i2c_clk_div[i][1]; > > if (cpu_is_mx1()) { > /* > @@ -555,7 +559,6 @@ static int __init i2c_imx_probe(struct platform_device *pdev) > dev_err(&pdev->dev, "can't get I2C clock\n"); > goto fail3; > } > - clk_enable(i2c_imx->clk); > > /* Request IRQ */ > ret = request_irq(i2c_imx->irq, i2c_imx_isr, 0, pdev->name, i2c_imx); > @@ -604,7 +607,6 @@ static int __init i2c_imx_probe(struct platform_device *pdev) > fail5: > free_irq(i2c_imx->irq, i2c_imx); > fail4: > - clk_disable(i2c_imx->clk); > clk_put(i2c_imx->clk); > fail3: > release_mem_region(i2c_imx->res->start, resource_size(res)); > @@ -641,8 +643,6 @@ static int __exit i2c_imx_remove(struct platform_device *pdev) > if (pdata && pdata->exit) > pdata->exit(&pdev->dev); > > - /* Disable I2C clock */ > - clk_disable(i2c_imx->clk); > clk_put(i2c_imx->clk); > > release_mem_region(i2c_imx->res->start, resource_size(i2c_imx->res)); > -- > 1.6.0.4 > > -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | From mboxrd@z Thu Jan 1 00:00:00 1970 From: s.hauer@pengutronix.de (Sascha Hauer) Date: Thu, 1 Oct 2009 09:34:34 +0200 Subject: [PATCH 4/4] i2c: imx: disable clock when it's possible to save power. In-Reply-To: <1254359613-21210-4-git-send-email-linuxzsc@gmail.com> References: <1254359613-21210-1-git-send-email-linuxzsc@gmail.com> <1254359613-21210-2-git-send-email-linuxzsc@gmail.com> <1254359613-21210-3-git-send-email-linuxzsc@gmail.com> <1254359613-21210-4-git-send-email-linuxzsc@gmail.com> Message-ID: <20091001073434.GY27039@pengutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Oct 01, 2009 at 09:13:33AM +0800, Richard Zhao wrote: > Enable clock before START, disable it after STOP. The clk_diable/enable calls in suspend/resume should be removed also. Sascha > > Signed-off-by: Richard Zhao > > diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c > index 87faea4..72ddea3 100644 > --- a/drivers/i2c/busses/i2c-imx.c > +++ b/drivers/i2c/busses/i2c-imx.c > @@ -120,6 +120,7 @@ struct imx_i2c_struct { > wait_queue_head_t queue; > unsigned long i2csr; > unsigned int disable_delay; > + unsigned int ifdr; /* IMX_I2C_IFDR */ > }; > > /** Functions for IMX I2C adapter driver *************************************** > @@ -210,6 +211,8 @@ static int i2c_imx_start(struct imx_i2c_struct *i2c_imx) > > dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); > > + clk_enable(i2c_imx->clk); > + writeb(i2c_imx->ifdr, i2c_imx->base + IMX_I2C_IFDR); > /* Enable I2C controller */ > writeb(0, i2c_imx->base + IMX_I2C_I2SR); > writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR); > @@ -254,6 +257,7 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx) > > /* Disable I2C controller */ > writeb(0, i2c_imx->base + IMX_I2C_I2CR); > + clk_disable(i2c_imx->clk); > } > > static void __init i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx, > @@ -273,8 +277,8 @@ static void __init i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx, > else > for (i = 0; i2c_clk_div[i][0] < div; i++); > > - /* Write divider value to register */ > - writeb(i2c_clk_div[i][1], i2c_imx->base + IMX_I2C_IFDR); > + /* Store divider value */ > + i2c_imx->ifdr = i2c_clk_div[i][1]; > > if (cpu_is_mx1()) { > /* > @@ -555,7 +559,6 @@ static int __init i2c_imx_probe(struct platform_device *pdev) > dev_err(&pdev->dev, "can't get I2C clock\n"); > goto fail3; > } > - clk_enable(i2c_imx->clk); > > /* Request IRQ */ > ret = request_irq(i2c_imx->irq, i2c_imx_isr, 0, pdev->name, i2c_imx); > @@ -604,7 +607,6 @@ static int __init i2c_imx_probe(struct platform_device *pdev) > fail5: > free_irq(i2c_imx->irq, i2c_imx); > fail4: > - clk_disable(i2c_imx->clk); > clk_put(i2c_imx->clk); > fail3: > release_mem_region(i2c_imx->res->start, resource_size(res)); > @@ -641,8 +643,6 @@ static int __exit i2c_imx_remove(struct platform_device *pdev) > if (pdata && pdata->exit) > pdata->exit(&pdev->dev); > > - /* Disable I2C clock */ > - clk_disable(i2c_imx->clk); > clk_put(i2c_imx->clk); > > release_mem_region(i2c_imx->res->start, resource_size(i2c_imx->res)); > -- > 1.6.0.4 > > -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |