Hi Richard,
On Tue, Sep 29, 2009 at 07:41:44PM +0800, Richard Zhao wrote: > After START, wait busy bit to be set and > after STOP, wait busy bit to be clear. > > Disable clock when it's possible to save power. > > Signed-off-by: Richard Zhao <[email protected]> > --- > drivers/i2c/busses/i2c-imx.c | 116 > ++++++++++++++++++++++++++++++++---------- > 1 files changed, 88 insertions(+), 28 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c > index 4afba3e..59cde70 100644 > --- a/drivers/i2c/busses/i2c-imx.c > +++ b/drivers/i2c/busses/i2c-imx.c > @@ -120,19 +120,40 @@ 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 > *************************************** > > *******************************************************************************/ > > -static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx) > +#ifdef CONFIG_I2C_DEBUG_BUS > +#define reg_dump(i2c_imx) \ > +{ \ > + printk(KERN_DEBUG "fun %s:%d ", __func__, __LINE__); \ > + printk(KERN_DEBUG "IADR %02x IFDR %02x I2CR %02x I2SR %02x\n", \ > + readb(i2c_imx->base + IMX_I2C_IADR), \ > + readb(i2c_imx->base + IMX_I2C_IFDR), \ > + readb(i2c_imx->base + IMX_I2C_I2CR), \ > + readb(i2c_imx->base + IMX_I2C_I2SR)); \ > +} > +#else > +#define reg_dump(i2c_imx) > +#endif > + Can you please remove this reg_dump? If we really need this it should be in an extra patch and not clutter this one. > +static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy) > { > unsigned long orig_jiffies = jiffies; > + unsigned int temp; > > dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); > > /* wait for bus not busy */ This comment seems wrong now. This function waits for busy or not busy depending on for_busy. > - while (readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_IBB) { > + temp = readb(i2c_imx->base + IMX_I2C_I2SR); > + while (1) { > + if (for_busy && (temp & I2SR_IBB)) > + break; > + if (!for_busy && !(temp & I2SR_IBB)) > + break; > if (signal_pending(current)) { > dev_dbg(&i2c_imx->adapter.dev, > "<%s> I2C Interrupted\n", __func__); > @@ -141,9 +162,11 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct > *i2c_imx) > if (time_after(jiffies, orig_jiffies + HZ / 1000)) { > dev_dbg(&i2c_imx->adapter.dev, > "<%s> I2C bus is busy\n", __func__); > + reg_dump(i2c_imx); > return -EIO; > } > schedule(); > + temp = readb(i2c_imx->base + IMX_I2C_I2SR); > } > > return 0; > @@ -158,9 +181,11 @@ static int i2c_imx_trx_complete(struct > imx_i2c_struct *i2c_imx) > > if (unlikely(result < 0)) { > dev_dbg(&i2c_imx->adapter.dev, "<%s> result < 0\n", __func__); > + reg_dump(i2c_imx); > return result; > } else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) { > dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__); > + reg_dump(i2c_imx); > return -ETIMEDOUT; > } > dev_dbg(&i2c_imx->adapter.dev, "<%s> TRX complete\n", __func__); > @@ -172,6 +197,7 @@ static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx) > { > if (readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_RXAK) { > dev_dbg(&i2c_imx->adapter.dev, "<%s> No ACK\n", __func__); > + reg_dump(i2c_imx); > return -EIO; /* No ACK */ > } > > @@ -179,20 +205,37 @@ static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx) > return 0; > } > > -static void i2c_imx_start(struct imx_i2c_struct *i2c_imx) > +static int i2c_imx_start(struct imx_i2c_struct *i2c_imx) > { > unsigned int temp = 0; > + int result; > > 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); > + > + result = i2c_imx_bus_busy(i2c_imx, 0); > + if (result) { > + reg_dump(i2c_imx); > + return result; > + } > + > /* Start I2C transaction */ > temp = readb(i2c_imx->base + IMX_I2C_I2CR); > temp |= I2CR_MSTA; > writeb(temp, i2c_imx->base + IMX_I2C_I2CR); > + result = i2c_imx_bus_busy(i2c_imx, 1); > + if (result) { > + reg_dump(i2c_imx); > + return result; > + } > temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK; > writeb(temp, i2c_imx->base + IMX_I2C_I2CR); > + return result; > } > > static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx) > @@ -202,18 +245,21 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx) > /* Stop I2C transaction */ > dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); > temp = readb(i2c_imx->base + IMX_I2C_I2CR); > - temp &= ~I2CR_MSTA; > + temp &= ~(I2CR_MSTA | I2CR_MTX); This change seems unrelated. Is it necessary? > writeb(temp, i2c_imx->base + IMX_I2C_I2CR); > - /* setup chip registers to defaults */ > - writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR); > - writeb(0, i2c_imx->base + IMX_I2C_I2SR); > /* > * This delay caused by an i.MXL hardware bug. > * If no (or too short) delay, no "STOP" bit will be generated. > */ > udelay(i2c_imx->disable_delay); > + > + double blank line > + if (i2c_imx_bus_busy(i2c_imx, 0)) > + reg_dump(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, > @@ -233,17 +279,19 @@ 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); Why can't we write this value directly anymore... > - > - /* > - * There dummy delay is calculated. > - * It should be about one I2C clock period long. > - * This delay is used in I2C bus disable function > - * to fix chip hardware bug. > - */ > - i2c_imx->disable_delay = (500000U * i2c_clk_div[i][0] > - + (i2c_clk_rate / 2) - 1) / (i2c_clk_rate / 2); > + /* Store divider value */ > + i2c_imx->ifdr = i2c_clk_div[i][1]; ...but have to store it in a variable instead? > + > + if (cpu_is_mx1()) { > + /* > + * There dummy delay is calculated. > + * It should be about one I2C clock period long. > + * This delay is used in I2C bus disable function > + * to fix chip hardware bug. > + */ > + i2c_imx->disable_delay = (500000U * i2c_clk_div[i][0] > + + (i2c_clk_rate / 2) - 1) / (i2c_clk_rate / 2); > + } > > /* dev_dbg() can't be used, because adapter is not yet registered */ > #ifdef CONFIG_I2C_DEBUG_BUS > @@ -344,7 +392,7 @@ static int i2c_imx_read(struct imx_i2c_struct > *i2c_imx, struct i2c_msg *msgs) > dev_dbg(&i2c_imx->adapter.dev, > "<%s> clear MSTA\n", __func__); > temp = readb(i2c_imx->base + IMX_I2C_I2CR); > - temp &= ~I2CR_MSTA; > + temp &= ~(I2CR_MSTA | I2CR_MTX); > writeb(temp, i2c_imx->base + IMX_I2C_I2CR); > } else if (i == (msgs->len - 2)) { > dev_dbg(&i2c_imx->adapter.dev, > @@ -369,14 +417,24 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter, > struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter); > > dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); > - > +#ifdef CONFIG_I2C_DEBUG_BUS > + for (i = 0; i < num; i++) { > + printk(KERN_DEBUG "msg%d addr %02x RD %d cnt %d d:", i, > + msgs[i].addr, msgs[i].flags & I2C_M_RD, msgs[i].len); > + if (!(msgs[i].flags & I2C_M_RD)) { > + int j; > + for (j = 0; j < msgs[i].len; j++) > + printk("%02x ", msgs[i].buf[j]); > + } > + printk("\n"); > + } > +#endif > /* Check if i2c bus is not busy */ > - result = i2c_imx_bus_busy(i2c_imx); > - if (result) > - goto fail0; When removing the code you should also remove the comment. > > /* Start I2C transfer */ > - i2c_imx_start(i2c_imx); > + result = i2c_imx_start(i2c_imx); > + if (result) > + goto fail0; > > /* read/write data */ > for (i = 0; i < num; i++) { > @@ -386,6 +444,11 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter, > temp = readb(i2c_imx->base + IMX_I2C_I2CR); > temp |= I2CR_RSTA; > writeb(temp, i2c_imx->base + IMX_I2C_I2CR); > + result = i2c_imx_bus_busy(i2c_imx, 1); > + if (result) { > + reg_dump(i2c_imx); > + goto fail0; > + } > } > dev_dbg(&i2c_imx->adapter.dev, > "<%s> transfer message: %d\n", __func__, i); > @@ -442,7 +505,7 @@ static int __init i2c_imx_probe(struct > platform_device *pdev) > int irq; > int ret; > > - dev_dbg(&pdev->dev, "<%s>\n", __func__); > + dev_info(&pdev->dev, "<%s>\n", __func__); no > > res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > if (!res) { > @@ -500,7 +563,6 @@ 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); I think it's generally a good idea to start/stop the clocks when needed as you do here. It should be an extra patch though. > > /* Request IRQ */ > ret = request_irq(i2c_imx->irq, i2c_imx_isr, 0, pdev->name, i2c_imx); > @@ -549,7 +611,6 @@ 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)); > @@ -587,7 +648,6 @@ static int __exit i2c_imx_remove(struct > platform_device *pdev) > 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 | -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
