[PATCH 3/4] i2c: imx: add macros and printk to make debug easy
Richard Zhao
linuxzsc at gmail.com
Sun Oct 4 08:23:25 EDT 2009
On Thu, Oct 1, 2009 at 5:30 PM, Richard Zhao <linuxzsc at gmail.com> wrote:
> On Thu, Oct 1, 2009 at 4:26 PM, Sascha Hauer <s.hauer at pengutronix.de> wrote:
>> On Thu, Oct 01, 2009 at 04:01:50PM +0800, Richard Zhao wrote:
>>> On Thu, Oct 1, 2009 at 3:29 PM, Sascha Hauer <s.hauer at pengutronix.de> wrote:
>>> > On Thu, Oct 01, 2009 at 09:13:32AM +0800, Richard Zhao wrote:
>>> >> When CONFIG_I2C_DEBUG_BUS is enabled, it helps dump registers at operation
>>> >> fail condition, and print i2c_msg to xfer.
>>> >>
>>> >> Signed-off-by: Richard Zhao <linuxzsc at gmail.com>
>>> >
>>> > Honestly I don't think we need this. It makes the driver too verbose for
>>> > my taste.
>>> >
>>> > Sascha
>>> >
>>> >
>>> >>
>>> >> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
>>> >> index c1e541c..87faea4 100644
>>> >> --- a/drivers/i2c/busses/i2c-imx.c
>>> >> +++ b/drivers/i2c/busses/i2c-imx.c
>>> >> @@ -125,6 +125,20 @@ struct imx_i2c_struct {
>>> >> /** Functions for IMX I2C adapter driver ***************************************
>>> >> *******************************************************************************/
>>> >>
>>> >> +#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
>>> >> +
>>> >> static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy)
>>> >> {
>>> >> unsigned long orig_jiffies = jiffies;
>>> >> @@ -146,6 +160,7 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy)
>>> >> 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();
>>> >> @@ -164,9 +179,11 @@ 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__);
>>> >> @@ -178,6 +195,7 @@ 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 */
>>> >> }
>>> >>
>>> >> @@ -197,17 +215,20 @@ static int i2c_imx_start(struct imx_i2c_struct *i2c_imx)
>>> >> writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
>>> >>
>>> >> result = i2c_imx_bus_busy(i2c_imx, 0);
>>> >> - if (result)
>>> >> + 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)
>>> >> + 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;
>>> >> @@ -228,7 +249,8 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
>>> >> */
>>> >> udelay(i2c_imx->disable_delay);
>>> >>
>>> >> - i2c_imx_bus_busy(i2c_imx, 0);
>>> >> + if (i2c_imx_bus_busy(i2c_imx, 0))
>>> >> + reg_dump(i2c_imx);
>>> >>
>>> >> /* Disable I2C controller */
>>> >> writeb(0, i2c_imx->base + IMX_I2C_I2CR);
>>> >> @@ -389,7 +411,18 @@ 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
>>> >> /* Start I2C transfer */
>>> >> result = i2c_imx_start(i2c_imx);
>>> >> if (result)
>>> >> @@ -404,8 +437,10 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter,
>>> >> temp |= I2CR_RSTA;
>>> >> writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
>>> >> result = i2c_imx_bus_busy(i2c_imx, 1);
>>> >> - if (result)
>>> >> + if (result) {
>>> >> + reg_dump(i2c_imx);
>>> >> goto fail0;
>>> >> + }
>>> >> }
>>> >> dev_dbg(&i2c_imx->adapter.dev,
>>> >> "<%s> transfer message: %d\n", __func__, i);
>>> >> @@ -562,7 +597,7 @@ static int __init i2c_imx_probe(struct platform_device *pdev)
>>> >> res_size, i2c_imx->res->start);
>>> >> dev_dbg(&i2c_imx->adapter.dev, "adapter name: \"%s\"\n",
>>> >> i2c_imx->adapter.name);
>>> >> - dev_dbg(&i2c_imx->adapter.dev, "IMX I2C adapter registered\n");
>>> >> + dev_info(&i2c_imx->adapter.dev, "IMX I2C adapter registered\n");
>>> >>
>>> >> return 0; /* Return OK */
>>> >>
>>> >> --
>>> >> 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 |
>>> >
>>>
>>> 1. i2c is more important bus in embedded system than PC. Many PMICs
>>> are connected to cpu via i2c. Before system boot up, we depend much on
>>> printk message.
>>> 2. When we add a new i2c device, it's easy to have problems. Maybe
>>> it's hw issue, one device fails, all ones in the same bus fails. In
>>> such condition, debug message is very helpfull.
>>
>> The driver already consists to 15% of debug statements, there is
>> definitely no need to add even more. If anything, you could concentrate
>> on making the output more useful.
> The dump_reg are only added when operation fails. It's not used to
> track function call path or anything else.
> I'm not supposed to show detailed message when there's operation fail?
> The reason to add a switch to disable it is, when i2c tools scan the
> bus, it will cause operation fail.
>
> Richard
>>
>> 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 |
>>
>
Hi Sascha,
Follow your suggestion. I will remove the patch.
Thanks
Richard
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