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From: Dongchun Zhu <dongchun.zhu@mediatek.com>
To: Tomasz Figa <tfiga@chromium.org>
Cc: <linus.walleij@linaro.org>, <bgolaszewski@baylibre.com>,
	<mchehab@kernel.org>, <andriy.shevchenko@linux.intel.com>,
	<robh+dt@kernel.org>, <mark.rutland@arm.com>,
	<sakari.ailus@linux.intel.com>, <drinkcat@chromium.org>,
	<matthias.bgg@gmail.com>, <bingbu.cao@intel.com>,
	<srv_heupstream@mediatek.com>,
	<linux-mediatek@lists.infradead.org>,
	<linux-arm-kernel@lists.infradead.org>, <sj.huang@mediatek.com>,
	<linux-media@vger.kernel.org>, <devicetree@vger.kernel.org>,
	<louis.kuo@mediatek.com>, <shengnan.wang@mediatek.com>,
	<dongchun.zhu@mediatek.com>
Subject: Re: [V7, 2/2] media: i2c: dw9768: Add DW9768 VCM driver
Date: Sat, 6 Jun 2020 14:42:58 +0800
Message-ID: <1591425778.8804.614.camel@mhfsdcap03> (raw)
In-Reply-To: <20200605134440.GA20379@chromium.org>

Hi Tomasz,

Thanks for the review.

On Fri, 2020-06-05 at 13:44 +0000, Tomasz Figa wrote:
> Hi Dongchun,
> 
> On Fri, Jun 05, 2020 at 06:54:12PM +0800, Dongchun Zhu wrote:
> > Add a V4L2 sub-device driver for DW9768 voice coil motor, providing
> > control to set the desired focus via IIC serial interface.
> > 
> > Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
> > ---
> >  MAINTAINERS                |   1 +
> >  drivers/media/i2c/Kconfig  |  13 ++
> >  drivers/media/i2c/Makefile |   1 +
> >  drivers/media/i2c/dw9768.c | 566 +++++++++++++++++++++++++++++++++++++++++++++
> >  4 files changed, 581 insertions(+)
> >  create mode 100644 drivers/media/i2c/dw9768.c
> > 
> 
> Thank you for the patch. Please see my comments inline.
> 
> [snip]
> > +/*
> > + * DW9768 requires waiting time (delay time) of t_OPR after power-up,
> > + * or in the case of PD reset taking place.
> > + */
> > +#define DW9768_T_OPR_US				1000
> > +#define DW9768_Tvib_MS_BASE10			(64 - 1)
> 
> Kernel macro names are uppercase only.
> 

Aha... This is caused by my carelessness.
Fixed in next release.

> [snip]
> > +	/* Set AAC Timing */
> > +	if (dw9768->aac_timing != DW9768_AAC_TIME_DEFAULT) {
> > +		ret = i2c_smbus_write_byte_data(client, DW9768_AAC_TIME_REG,
> > +						dw9768->aac_timing);
> > +		if (ret < 0)
> > +			return ret;
> > +	}
> > +
> > +	move_delay_us = dw9768_cal_move_delay(dw9768->aac_mode,
> > +					      dw9768->clock_presc,
> > +					      dw9768->aac_timing) / 100;
> 
> We could calculate this once in probe() and store the ready us value in
> the dw9768 struct.
> 

Great idea :-)
From the perspective of 'move_delay_us' itself, it defines VCM Operation
Time, which is indeed an intrinsic parameter that belongs to DW9768
private structure.

> > +
> > +	for (val = dw9768->focus->val % DW9768_MOVE_STEPS;
> > +	     val <= dw9768->focus->val;
> > +	     val += DW9768_MOVE_STEPS) {
> > +		ret = dw9768_set_dac(dw9768, val);
> > +		if (ret) {
> > +			dev_err(&client->dev, "%s I2C failure: %d",
> > +				__func__, ret);
> > +			return ret;
> > +		}
> > +		usleep_range(move_delay_us, move_delay_us + 1000);
> > +	}
> > +
> > +	return 0;
> > +}
> [snip]
> > +	pm_runtime_enable(dev);
> > +	if (!pm_runtime_enabled(dev)) {
> > +		ret = dw9768_runtime_resume(dev);
> > +		if (ret < 0) {
> > +			dev_err(dev, "failed to power on: %d\n", ret);
> > +			goto err_clean_entity;
> > +		}
> > +	}
> > +
> > +	ret = v4l2_async_register_subdev(&dw9768->sd);
> > +	if (ret < 0) {
> > +		dev_err(dev, "failed to register V4L2 subdev: %d", ret);
> > +		goto error_async_register;
> > +	}
> > +
> > +	return 0;
> > +
> > +error_async_register:
> 
> The recommendation is to name the labels after the clean-up task that needs
> to be done. Should this one be called error_power_off?
> 

Understood.
'error_async_register' would be replaced of 'err_power_off' in next
release.

> > +	if (!pm_runtime_enabled(dev))
> > +		dw9768_runtime_suspend(dev);
> 
> Shouldn't we also call pm_runtime_disable() here?
> 

Thanks for the reminder.
We would add pm_runtime_disable() in next release.
Just like:
err_power_off:
	pm_runtime_disable(dev);
	if (!pm_runtime_enabled(dev))
		dw9768_runtime_suspend(dev);

> > +err_clean_entity:
> > +	media_entity_cleanup(&dw9768->sd.entity);
> > +err_free_handler:
> > +	v4l2_ctrl_handler_free(&dw9768->ctrls);
> > +
> > +	return ret;
> > +}
> > +
> > +static int dw9768_remove(struct i2c_client *client)
> > +{
> > +	struct v4l2_subdev *sd = i2c_get_clientdata(client);
> > +	struct dw9768 *dw9768 = sd_to_dw9768(sd);
> > +
> > +	v4l2_async_unregister_subdev(&dw9768->sd);
> > +	v4l2_ctrl_handler_free(&dw9768->ctrls);
> > +	media_entity_cleanup(&dw9768->sd.entity);
> > +	pm_runtime_disable(&client->dev);
> > +	if (!pm_runtime_status_suspended(&client->dev))
> 
> pm_runtime_status_suspended() doesn't consider the runtime PM disable
> state. There is also pm_runtime_suspended() and that should be correct
> here.
> 

Fixed in next release.

> Best regards,
> Tomasz


      reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-05 10:54 [V7, 0/2] media: i2c: Add support for " Dongchun Zhu
2020-06-05 10:54 ` [V7, 1/2] media: dt-bindings: media: i2c: Document DW9768 bindings Dongchun Zhu
2020-06-09 19:47   ` Rob Herring
2020-06-05 10:54 ` [V7, 2/2] media: i2c: dw9768: Add DW9768 VCM driver Dongchun Zhu
2020-06-05 12:14   ` Sakari Ailus
2020-06-05 13:02     ` Tomasz Figa
2020-06-05 13:37       ` Sakari Ailus
2020-06-06  6:24     ` Dongchun Zhu
2020-06-05 12:46   ` Andy Shevchenko
2020-06-05 13:10     ` Tomasz Figa
2020-06-06  6:19     ` Dongchun Zhu
2020-06-08 13:27       ` Andy Shevchenko
2020-06-09  3:45         ` Dongchun Zhu
2020-06-09 11:14           ` Andy Shevchenko
2020-06-10 12:58             ` Sakari Ailus
2020-06-05 13:44   ` Tomasz Figa
2020-06-06  6:42     ` Dongchun Zhu [this message]

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