From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Zhao Subject: Re: [PATCH 4/4] i2c: imx: disable clock when it's possible to save power. Date: Thu, 1 Oct 2009 15:56:29 +0800 Message-ID: <4e090d470910010056n56bff9f4l1fec703c2dde9edf@mail.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> <20091001073434.GY27039@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20091001073434.GY27039-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Sascha Hauer 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 1, 2009 at 3:34 PM, Sascha Hauer w= rote: > 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-i= mx.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 { >> =A0 =A0 =A0 wait_queue_head_t =A0 =A0 =A0 queue; >> =A0 =A0 =A0 unsigned long =A0 =A0 =A0 =A0 =A0 i2csr; >> =A0 =A0 =A0 unsigned int =A0 =A0 =A0 =A0 =A0 =A0disable_delay; >> + =A0 =A0 unsigned int =A0 =A0 =A0 =A0 =A0 =A0ifdr; /* IMX_I2C_IFDR = */ >> =A0}; >> >> =A0/** Functions for IMX I2C adapter driver ************************= *************** >> @@ -210,6 +211,8 @@ static int i2c_imx_start(struct imx_i2c_struct *= i2c_imx) >> >> =A0 =A0 =A0 dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); >> >> + =A0 =A0 clk_enable(i2c_imx->clk); >> + =A0 =A0 writeb(i2c_imx->ifdr, i2c_imx->base + IMX_I2C_IFDR); >> =A0 =A0 =A0 /* Enable I2C controller */ >> =A0 =A0 =A0 writeb(0, i2c_imx->base + IMX_I2C_I2SR); >> =A0 =A0 =A0 writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR); >> @@ -254,6 +257,7 @@ static void i2c_imx_stop(struct imx_i2c_struct *= i2c_imx) >> >> =A0 =A0 =A0 /* Disable I2C controller */ >> =A0 =A0 =A0 writeb(0, i2c_imx->base + IMX_I2C_I2CR); >> + =A0 =A0 clk_disable(i2c_imx->clk); >> =A0} >> >> =A0static 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_i2= c_struct *i2c_imx, >> =A0 =A0 =A0 else >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 for (i =3D 0; i2c_clk_div[i][0] < div; i= ++); >> >> - =A0 =A0 /* Write divider value to register */ >> - =A0 =A0 writeb(i2c_clk_div[i][1], i2c_imx->base + IMX_I2C_IFDR); >> + =A0 =A0 /* Store divider value */ >> + =A0 =A0 i2c_imx->ifdr =3D i2c_clk_div[i][1]; >> >> =A0 =A0 =A0 if (cpu_is_mx1()) { >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 /* >> @@ -555,7 +559,6 @@ static int __init i2c_imx_probe(struct platform_= device *pdev) >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 dev_err(&pdev->dev, "can't get I2C clock= \n"); >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 goto fail3; >> =A0 =A0 =A0 } >> - =A0 =A0 clk_enable(i2c_imx->clk); >> >> =A0 =A0 =A0 /* Request IRQ */ >> =A0 =A0 =A0 ret =3D 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) >> =A0fail5: >> =A0 =A0 =A0 free_irq(i2c_imx->irq, i2c_imx); >> =A0fail4: >> - =A0 =A0 clk_disable(i2c_imx->clk); >> =A0 =A0 =A0 clk_put(i2c_imx->clk); >> =A0fail3: >> =A0 =A0 =A0 release_mem_region(i2c_imx->res->start, resource_size(re= s)); >> @@ -641,8 +643,6 @@ static int __exit i2c_imx_remove(struct platform= _device *pdev) >> =A0 =A0 =A0 if (pdata && pdata->exit) >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 pdata->exit(&pdev->dev); >> >> - =A0 =A0 /* Disable I2C clock */ >> - =A0 =A0 clk_disable(i2c_imx->clk); >> =A0 =A0 =A0 clk_put(i2c_imx->clk); >> >> =A0 =A0 =A0 release_mem_region(i2c_imx->res->start, resource_size(i2= c_imx->res)); >> -- >> 1.6.0.4 >> >> > > -- > Pengutronix e.K. =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 = | =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | > Industrial Linux Solutions =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | http://w= ww.pengutronix.de/ =A0| > Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0= =A0 =A0| > Amtsgericht Hildesheim, HRA 2686 =A0 =A0 =A0 =A0 =A0 | Fax: =A0 +49-5= 121-206917-5555 | > I don't think we have any suspend/resume routine. And we won't need it = any more. Thanks Richard