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Re: [PATCH v4 2/5] mfd: lm3533: Support initialization from Device Tree

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  Re: [PATCH v4 2/5] mfd: lm3533: Support initialization from Device  Tree Lee Jones <lee.jones@linaro.org> - 2017-01-04 13:10 +0100
    Re: [PATCH v4 2/5] mfd: lm3533: Support initialization from Device  Tree Bjorn Andersson <bjorn.andersson@linaro.org> - 2017-01-04 20:30 +0100
      Re: [PATCH v4 2/5] mfd: lm3533: Support initialization from Device  Tree Lee Jones <lee.jones@linaro.org> - 2017-01-05 08:50 +0100
        Re: [PATCH v4 2/5] mfd: lm3533: Support initialization from Device  Tree Bjorn Andersson <bjorn.andersson@linaro.org> - 2017-01-05 17:40 +0100
          Re: [PATCH v4 2/5] mfd: lm3533: Support initialization from Device  Tree Lee Jones <lee.jones@linaro.org> - 2017-01-06 11:00 +0100
            Re: [PATCH v4 2/5] mfd: lm3533: Support initialization from Device  Tree Bjorn Andersson <bjorn.andersson@linaro.org> - 2017-01-06 20:00 +0100
              Re: [PATCH v4 2/5] mfd: lm3533: Support initialization from Device  Tree Lee Jones <lee.jones@linaro.org> - 2017-01-09 09:40 +0100
                Re: [PATCH v4 2/5] mfd: lm3533: Support initialization from Device  Tree Bjorn Andersson <bjorn.andersson@linaro.org> - 2017-01-11 21:00 +0100

#1550699 — Re: [PATCH v4 2/5] mfd: lm3533: Support initialization from Device Tree

On Mon, 26 Dec 2016, Bjorn Andersson wrote:

> From: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> 
> Implement support for initialization of the lm3533 driver core and
> probing child devices from Device Tree.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
> 
> Changes since v3:
> - Moved parsing of child of nodes into each child driver
> - Use of_platform_populate() to instanciate child devices
> 
>  drivers/mfd/lm3533-core.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 76 insertions(+)
> 
> diff --git a/drivers/mfd/lm3533-core.c b/drivers/mfd/lm3533-core.c
> index 5abcbb2e8849..f147677f05ff 100644
> --- a/drivers/mfd/lm3533-core.c
> +++ b/drivers/mfd/lm3533-core.c
> @@ -18,6 +18,8 @@
>  #include <linux/gpio.h>
>  #include <linux/i2c.h>
>  #include <linux/mfd/core.h>
> +#include <linux/of_gpio.h>
> +#include <linux/of_platform.h>
>  #include <linux/regmap.h>
>  #include <linux/seq_file.h>
>  #include <linux/slab.h>
> @@ -512,6 +514,11 @@ static int lm3533_device_init(struct lm3533 *lm3533)
>  	lm3533_device_bl_init(lm3533);
>  	lm3533_device_led_init(lm3533);
>  
> +	if (lm3533->dev->of_node) {
> +		of_platform_populate(lm3533->dev->of_node, NULL, NULL,
> +				     lm3533->dev);
> +	}

I think it's save to call of_platform_populate(), even if !of_node.
It will just fail and return an error code, which you are ignoring
anyway.

>  	ret = sysfs_create_group(&lm3533->dev->kobj, &lm3533_attribute_group);
>  	if (ret < 0) {
>  		dev_err(lm3533->dev, "failed to create sysfs attributes\n");
> @@ -588,10 +595,73 @@ static const struct regmap_config regmap_config = {
>  	.precious_reg	= lm3533_precious_register,
>  };
>  
> +static int lm3533_of_parse_enum(struct device *dev, const char *propname,
> +				const unsigned int *match, size_t num_matches)
> +{
> +	size_t i;
> +	int ret;
> +	u32 val;
> +
> +	ret = of_property_read_u32(dev->of_node, propname, &val);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to parse %s\n", propname);
> +		return ret;
> +	}
> +
> +	for (i = 0; i < num_matches; i++) {
> +		if (val == match[i])
> +			return i;
> +	}
> +
> +	dev_err(dev, "unsupported value of %s\n", propname);
> +	return -EINVAL;
> +}
> +
> +static int lm3533_pdata_from_of_node(struct device *dev)
> +{
> +	struct lm3533_platform_data *pdata;
> +	int ret;
> +	const unsigned int freqs[] = {
> +		[LM3533_BOOST_FREQ_500KHZ] = 500000,
> +		[LM3533_BOOST_FREQ_1000KHZ] = 1000000,
> +	};
> +	const unsigned int ovps[] = {
> +		[LM3533_BOOST_OVP_16V] = 16000,
> +		[LM3533_BOOST_OVP_24V] = 24000,
> +		[LM3533_BOOST_OVP_32V] = 32000,
> +		[LM3533_BOOST_OVP_40V] = 40000,
> +	};
> +
> +	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
> +	if (!pdata)
> +		return -ENOMEM;
> +
> +	pdata->gpio_hwen = of_get_named_gpio(dev->of_node, "hwen-gpios", 0);
> +	if (pdata->gpio_hwen < 0)
> +		return pdata->gpio_hwen;
> +
> +	ret = lm3533_of_parse_enum(dev, "ti,boost-freq-hz",
> +				   freqs, ARRAY_SIZE(freqs));
> +	if (ret < 0)
> +		return ret;
> +	pdata->boost_freq = ret;
> +
> +	ret = lm3533_of_parse_enum(dev, "ti,boost-ovp-mv",
> +				   ovps, ARRAY_SIZE(ovps));
> +	if (ret < 0)
> +		return ret;
> +	pdata->boost_ovp = ret;
> +
> +	dev->platform_data = pdata;
> +
> +	return 0;
> +}
> +
>  static int lm3533_i2c_probe(struct i2c_client *i2c,
>  					const struct i2c_device_id *id)
>  {
>  	struct lm3533 *lm3533;
> +	int ret;
>  
>  	dev_dbg(&i2c->dev, "%s\n", __func__);
>  
> @@ -608,6 +678,12 @@ static int lm3533_i2c_probe(struct i2c_client *i2c,
>  	lm3533->dev = &i2c->dev;
>  	lm3533->irq = i2c->irq;
>  
> +	if (i2c->dev.of_node) {

I'd prefer this check to be placed in lm3533_pdata_from_of_node().

Just return silently if !dev->of_node.

> +		ret = lm3533_pdata_from_of_node(lm3533->dev);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
>  	return lm3533_device_init(lm3533);
>  }
>  

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

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#1551129

On Wed 04 Jan 03:54 PST 2017, Lee Jones wrote:

> On Mon, 26 Dec 2016, Bjorn Andersson wrote:
> 
> > From: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> > 
> > Implement support for initialization of the lm3533 driver core and
> > probing child devices from Device Tree.
> > 

[..]

> > @@ -512,6 +514,11 @@ static int lm3533_device_init(struct lm3533 *lm3533)
> >  	lm3533_device_bl_init(lm3533);
> >  	lm3533_device_led_init(lm3533);
> >  
> > +	if (lm3533->dev->of_node) {
> > +		of_platform_populate(lm3533->dev->of_node, NULL, NULL,
> > +				     lm3533->dev);
> > +	}
> 
> I think it's save to call of_platform_populate(), even if !of_node.
> It will just fail and return an error code, which you are ignoring
> anyway.
> 

I thought so too, but that's apparently how you trigger probing children
of the root node. So we're stuck with a conditional.

[..]

> >  static int lm3533_i2c_probe(struct i2c_client *i2c,
> >  					const struct i2c_device_id *id)
> >  {

[..]

> >  
> > +	if (i2c->dev.of_node) {
> 
> I'd prefer this check to be placed in lm3533_pdata_from_of_node().
> 
> Just return silently if !dev->of_node.
> 

I agree, will update this.

> > +		ret = lm3533_pdata_from_of_node(lm3533->dev);
> > +		if (ret < 0)
> > +			return ret;
> > +	}
> > +
> >  	return lm3533_device_init(lm3533);
> >  }
> >  

Regards,
Bjorn

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#1551695

On Wed, 04 Jan 2017, Bjorn Andersson wrote:

> On Wed 04 Jan 03:54 PST 2017, Lee Jones wrote:
> 
> > On Mon, 26 Dec 2016, Bjorn Andersson wrote:
> > 
> > > From: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> > > 
> > > Implement support for initialization of the lm3533 driver core and
> > > probing child devices from Device Tree.
> > > 
> 
> [..]
> 
> > > @@ -512,6 +514,11 @@ static int lm3533_device_init(struct lm3533 *lm3533)
> > >  	lm3533_device_bl_init(lm3533);
> > >  	lm3533_device_led_init(lm3533);
> > >  
> > > +	if (lm3533->dev->of_node) {
> > > +		of_platform_populate(lm3533->dev->of_node, NULL, NULL,
> > > +				     lm3533->dev);
> > > +	}
> > 
> > I think it's save to call of_platform_populate(), even if !of_node.
> > It will just fail and return an error code, which you are ignoring
> > anyway.
> > 
> 
> I thought so too, but that's apparently how you trigger probing children
> of the root node. So we're stuck with a conditional.

Ah, so this is to protect against the case where DT is present, but a
node for this device is not (or is disabled), so is left unprobed.
Then the bind is initiated via I2C?  Or something else?

> > >  static int lm3533_i2c_probe(struct i2c_client *i2c,
> > >  					const struct i2c_device_id *id)
> > >  {
> 
> [..]
> 
> > >  
> > > +	if (i2c->dev.of_node) {
> > 
> > I'd prefer this check to be placed in lm3533_pdata_from_of_node().
> > 
> > Just return silently if !dev->of_node.
> > 
> 
> I agree, will update this.
> 
> > > +		ret = lm3533_pdata_from_of_node(lm3533->dev);
> > > +		if (ret < 0)
> > > +			return ret;
> > > +	}
> > > +
> > >  	return lm3533_device_init(lm3533);
> > >  }
> > >  
> 
> Regards,
> Bjorn

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

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#1552100

On Wed 04 Jan 23:49 PST 2017, Lee Jones wrote:

> On Wed, 04 Jan 2017, Bjorn Andersson wrote:
> 
> > On Wed 04 Jan 03:54 PST 2017, Lee Jones wrote:
> > 
> > > On Mon, 26 Dec 2016, Bjorn Andersson wrote:
> > > 
> > > > From: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> > > > 
> > > > Implement support for initialization of the lm3533 driver core and
> > > > probing child devices from Device Tree.
> > > > 
> > 
> > [..]
> > 
> > > > @@ -512,6 +514,11 @@ static int lm3533_device_init(struct lm3533 *lm3533)
> > > >  	lm3533_device_bl_init(lm3533);
> > > >  	lm3533_device_led_init(lm3533);
> > > >  
> > > > +	if (lm3533->dev->of_node) {
> > > > +		of_platform_populate(lm3533->dev->of_node, NULL, NULL,
> > > > +				     lm3533->dev);
> > > > +	}
> > > 
> > > I think it's save to call of_platform_populate(), even if !of_node.
> > > It will just fail and return an error code, which you are ignoring
> > > anyway.
> > > 
> > 
> > I thought so too, but that's apparently how you trigger probing children
> > of the root node. So we're stuck with a conditional.
> 
> Ah, so this is to protect against the case where DT is present, but a
> node for this device is not (or is disabled), so is left unprobed.
> Then the bind is initiated via I2C?  Or something else?
> 

In the event that a new lm3533 is spawned from sysfs we would not have
platform_data when entering lm3533_device_init() and just bail early.

Therefor, this issue would be limited to the odd case of lm3533 being
initiated from code (e.g. a board file) on a DT enabled system. In which
case it will create and probe new devices from the root of the DT.

Regards,
Bjorn

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#1552656

On Thu, 05 Jan 2017, Bjorn Andersson wrote:

> On Wed 04 Jan 23:49 PST 2017, Lee Jones wrote:
> 
> > On Wed, 04 Jan 2017, Bjorn Andersson wrote:
> > 
> > > On Wed 04 Jan 03:54 PST 2017, Lee Jones wrote:
> > > 
> > > > On Mon, 26 Dec 2016, Bjorn Andersson wrote:
> > > > 
> > > > > From: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> > > > > 
> > > > > Implement support for initialization of the lm3533 driver core and
> > > > > probing child devices from Device Tree.
> > > > > 
> > > 
> > > [..]
> > > 
> > > > > @@ -512,6 +514,11 @@ static int lm3533_device_init(struct lm3533 *lm3533)
> > > > >  	lm3533_device_bl_init(lm3533);
> > > > >  	lm3533_device_led_init(lm3533);
> > > > >  
> > > > > +	if (lm3533->dev->of_node) {
> > > > > +		of_platform_populate(lm3533->dev->of_node, NULL, NULL,
> > > > > +				     lm3533->dev);
> > > > > +	}
> > > > 
> > > > I think it's save to call of_platform_populate(), even if !of_node.
> > > > It will just fail and return an error code, which you are ignoring
> > > > anyway.
> > > > 
> > > 
> > > I thought so too, but that's apparently how you trigger probing children
> > > of the root node. So we're stuck with a conditional.
> > 
> > Ah, so this is to protect against the case where DT is present, but a
> > node for this device is not (or is disabled), so is left unprobed.
> > Then the bind is initiated via I2C?  Or something else?
> > 
> 
> In the event that a new lm3533 is spawned from sysfs we would not have
> platform_data when entering lm3533_device_init() and just bail early.
> 
> Therefor, this issue would be limited to the odd case of lm3533 being
> initiated from code (e.g. a board file) on a DT enabled system. In which
> case it will create and probe new devices from the root of the DT.

Eewww, do we really want to support that?

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

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#1553039

On Fri 06 Jan 01:53 PST 2017, Lee Jones wrote:

> On Thu, 05 Jan 2017, Bjorn Andersson wrote:
> 
> > On Wed 04 Jan 23:49 PST 2017, Lee Jones wrote:
> > 
> > > On Wed, 04 Jan 2017, Bjorn Andersson wrote:
> > > 
> > > > On Wed 04 Jan 03:54 PST 2017, Lee Jones wrote:
> > > > 
> > > > > On Mon, 26 Dec 2016, Bjorn Andersson wrote:
> > > > > 
> > > > > > From: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> > > > > > 
> > > > > > Implement support for initialization of the lm3533 driver core and
> > > > > > probing child devices from Device Tree.
> > > > > > 
> > > > 
> > > > [..]
> > > > 
> > > > > > @@ -512,6 +514,11 @@ static int lm3533_device_init(struct lm3533 *lm3533)
> > > > > >  	lm3533_device_bl_init(lm3533);
> > > > > >  	lm3533_device_led_init(lm3533);
> > > > > >  
> > > > > > +	if (lm3533->dev->of_node) {
> > > > > > +		of_platform_populate(lm3533->dev->of_node, NULL, NULL,
> > > > > > +				     lm3533->dev);
> > > > > > +	}
> > > > > 
> > > > > I think it's save to call of_platform_populate(), even if !of_node.
> > > > > It will just fail and return an error code, which you are ignoring
> > > > > anyway.
> > > > > 
> > > > 
> > > > I thought so too, but that's apparently how you trigger probing children
> > > > of the root node. So we're stuck with a conditional.
> > > 
> > > Ah, so this is to protect against the case where DT is present, but a
> > > node for this device is not (or is disabled), so is left unprobed.
> > > Then the bind is initiated via I2C?  Or something else?
> > > 
> > 
> > In the event that a new lm3533 is spawned from sysfs we would not have
> > platform_data when entering lm3533_device_init() and just bail early.
> > 
> > Therefor, this issue would be limited to the odd case of lm3533 being
> > initiated from code (e.g. a board file) on a DT enabled system. In which
> > case it will create and probe new devices from the root of the DT.
> 
> Eewww, do we really want to support that?
> 

As long as we support non-DT probing of the driver this is a possible
scenario. And with modern ARM being DT-centric I think that if anyone
uses this driver with a modern version of the Linux kernel it's likely
that they would have this kind of hybrid solution.

So, although ugly, I think we should keep this conditional and hope that
anyone using the driver will transition to use the DT binding.

Regards,
Bjorn

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#1554147

On Fri, 06 Jan 2017, Bjorn Andersson wrote:

> On Fri 06 Jan 01:53 PST 2017, Lee Jones wrote:
> 
> > On Thu, 05 Jan 2017, Bjorn Andersson wrote:
> > 
> > > On Wed 04 Jan 23:49 PST 2017, Lee Jones wrote:
> > > 
> > > > On Wed, 04 Jan 2017, Bjorn Andersson wrote:
> > > > 
> > > > > On Wed 04 Jan 03:54 PST 2017, Lee Jones wrote:
> > > > > 
> > > > > > On Mon, 26 Dec 2016, Bjorn Andersson wrote:
> > > > > > 
> > > > > > > From: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> > > > > > > 
> > > > > > > Implement support for initialization of the lm3533 driver core and
> > > > > > > probing child devices from Device Tree.
> > > > > > > 
> > > > > 
> > > > > [..]
> > > > > 
> > > > > > > @@ -512,6 +514,11 @@ static int lm3533_device_init(struct lm3533 *lm3533)
> > > > > > >  	lm3533_device_bl_init(lm3533);
> > > > > > >  	lm3533_device_led_init(lm3533);
> > > > > > >  
> > > > > > > +	if (lm3533->dev->of_node) {
> > > > > > > +		of_platform_populate(lm3533->dev->of_node, NULL, NULL,
> > > > > > > +				     lm3533->dev);
> > > > > > > +	}
> > > > > > 
> > > > > > I think it's save to call of_platform_populate(), even if !of_node.
> > > > > > It will just fail and return an error code, which you are ignoring
> > > > > > anyway.
> > > > > > 
> > > > > 
> > > > > I thought so too, but that's apparently how you trigger probing children
> > > > > of the root node. So we're stuck with a conditional.
> > > > 
> > > > Ah, so this is to protect against the case where DT is present, but a
> > > > node for this device is not (or is disabled), so is left unprobed.
> > > > Then the bind is initiated via I2C?  Or something else?
> > > > 
> > > 
> > > In the event that a new lm3533 is spawned from sysfs we would not have
> > > platform_data when entering lm3533_device_init() and just bail early.
> > > 
> > > Therefor, this issue would be limited to the odd case of lm3533 being
> > > initiated from code (e.g. a board file) on a DT enabled system. In which
> > > case it will create and probe new devices from the root of the DT.
> > 
> > Eewww, do we really want to support that?
> > 
> 
> As long as we support non-DT probing of the driver this is a possible
> scenario. And with modern ARM being DT-centric I think that if anyone
> uses this driver with a modern version of the Linux kernel it's likely
> that they would have this kind of hybrid solution.
> 
> So, although ugly, I think we should keep this conditional and hope that
> anyone using the driver will transition to use the DT binding.

Very well, but can you add a comment describing the reason for its
existence with a view to removing it further down the line?

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

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#1556872

On Mon 09 Jan 00:36 PST 2017, Lee Jones wrote:

> On Fri, 06 Jan 2017, Bjorn Andersson wrote:
> 
> > On Fri 06 Jan 01:53 PST 2017, Lee Jones wrote:
> > 
> > > On Thu, 05 Jan 2017, Bjorn Andersson wrote:
> > > 
> > > > On Wed 04 Jan 23:49 PST 2017, Lee Jones wrote:
> > > > 
> > > > > On Wed, 04 Jan 2017, Bjorn Andersson wrote:
> > > > > 
> > > > > > On Wed 04 Jan 03:54 PST 2017, Lee Jones wrote:
> > > > > > 
> > > > > > > On Mon, 26 Dec 2016, Bjorn Andersson wrote:
> > > > > > > 
> > > > > > > > From: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> > > > > > > > 
> > > > > > > > Implement support for initialization of the lm3533 driver core and
> > > > > > > > probing child devices from Device Tree.
> > > > > > > > 
> > > > > > 
> > > > > > [..]
> > > > > > 
> > > > > > > > @@ -512,6 +514,11 @@ static int lm3533_device_init(struct lm3533 *lm3533)
> > > > > > > >  	lm3533_device_bl_init(lm3533);
> > > > > > > >  	lm3533_device_led_init(lm3533);
> > > > > > > >  
> > > > > > > > +	if (lm3533->dev->of_node) {
> > > > > > > > +		of_platform_populate(lm3533->dev->of_node, NULL, NULL,
> > > > > > > > +				     lm3533->dev);
> > > > > > > > +	}
> > > > > > > 
> > > > > > > I think it's save to call of_platform_populate(), even if !of_node.
> > > > > > > It will just fail and return an error code, which you are ignoring
> > > > > > > anyway.
> > > > > > > 
> > > > > > 
> > > > > > I thought so too, but that's apparently how you trigger probing children
> > > > > > of the root node. So we're stuck with a conditional.
> > > > > 
> > > > > Ah, so this is to protect against the case where DT is present, but a
> > > > > node for this device is not (or is disabled), so is left unprobed.
> > > > > Then the bind is initiated via I2C?  Or something else?
> > > > > 
> > > > 
> > > > In the event that a new lm3533 is spawned from sysfs we would not have
> > > > platform_data when entering lm3533_device_init() and just bail early.
> > > > 
> > > > Therefor, this issue would be limited to the odd case of lm3533 being
> > > > initiated from code (e.g. a board file) on a DT enabled system. In which
> > > > case it will create and probe new devices from the root of the DT.
> > > 
> > > Eewww, do we really want to support that?
> > > 
> > 
> > As long as we support non-DT probing of the driver this is a possible
> > scenario. And with modern ARM being DT-centric I think that if anyone
> > uses this driver with a modern version of the Linux kernel it's likely
> > that they would have this kind of hybrid solution.
> > 
> > So, although ugly, I think we should keep this conditional and hope that
> > anyone using the driver will transition to use the DT binding.
> 
> Very well, but can you add a comment describing the reason for its
> existence with a view to removing it further down the line?
> 

Sounds reasonable, I will prepare an updated patch with this.

Regards,
Bjorn

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