From mboxrd@z Thu Jan 1 00:00:00 1970 From: s.hauer@pengutronix.de (Sascha Hauer) Date: Thu, 1 Oct 2009 10:00:53 +0200 Subject: [PATCH 4/4] i2c: imx: disable clock when it's possible to save power. In-Reply-To: <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> <4e090d470910010056n56bff9f4l1fec703c2dde9edf@mail.gmail.com> Message-ID: <20091001080053.GA27039@pengutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Oct 01, 2009 at 03:56:29PM +0800, Richard Zhao wrote: > On Thu, Oct 1, 2009 at 3:34 PM, Sascha Hauer wrote: > > 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 | > > > > I don't think we have any suspend/resume routine. And we won't need it any more. Ups, my bad. I have it in my local tree and didn't realize it isn't upstream. Sascha -- 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 |