On Sun, Jul 01, 2018 at 01:43:33PM +0530, Manivannan Sadhasivam wrote:

Hi Andy,

On Sun, Jul 01, 2018 at 12:11:00AM +0300, Andy Shevchenko wrote:

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On Sat, Jun 30, 2018 at 4:33 PM, Manivannan Sadhasivam
[off-list ref] wrote:

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Add Actions Semiconductor Owl family S900 I2C driver.

Thanks for an update. Few left comments and it would LGTM.

Thanks :)

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+static int owl_i2c_reset(struct owl_i2c_dev *i2c_dev)
+{

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+       mdelay(1);

But now, since it's not used in atomic context, we may switch to
usleep_range() / msleep() instead.

okay, will use msleep()

Just realised, I have to use spinlock for the entire owl_i2c_master_xfer
function, so can't use sleep* for delay.

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+       owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL,
+                               OWL_I2C_CTL_EN, true);
+

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+       /* Wait 50ms for FIFO reset complete */
+       do {

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+               mdelay(1);

Especially in this case it's very important.

Okay.

Same here, but I'm not sure about the latency. What is your suggestion?

Thanks,
Mani

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+       } while (timeout++ < OWL_I2C_MAX_RETRIES);

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+}

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+       val = (i2c_dev->clk_rate + i2c_dev->bus_freq * 16 - 1) /
+                               (i2c_dev->bus_freq * 16);

This is effectively DIV_ROUND_UP(->clk_rate, ->bus_freq * 16).

Ack.

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+       /*
+        * By default, 0 will be returned if interrupt occurred but no
+        * read or write happened. Else if msg_ptr equals to message length,
+        * message count will be returned.
+        */

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+       if (i2c_dev->msg_ptr == msg->len)
+               ret = num;

I dunno if

ret = ->msg_ptr == len ? num : 0;

would be slightly more explicit (yes, I aware about ret == 0).

Up to you to choose.

As per Peter's comment, returning 0 will get changed to an error value.
Will use this pattern once we settle with a proper error value.

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+       /* We support only frequencies of 100k and 400k for now */
+       if (i2c_dev->bus_freq != OWL_I2C_DEF_SPEED_HZ &&
+                       i2c_dev->bus_freq > OWL_I2C_MAX_SPEED_HZ) {

I think it should be != in the second case as well.

yeah, agree. We don't support any other frequencies now.

Thanks,
Mani

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+               dev_err(dev, "invalid clock-frequency %d\n", i2c_dev->bus_freq);
+               return -EINVAL;
+       }

-- 
With Best Regards,
Andy Shevchenko