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Re: [PATCH v3 23/24] drm/rockchip: dw-mipi-dsi: add reset control

Started byChris Zhong <zyw@rock-chips.com>
First post2017-02-15 04:40 +0100
Last post2017-02-16 15:20 +0100
Articles 4 — 2 participants

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  Re: [PATCH v3 23/24] drm/rockchip: dw-mipi-dsi: add reset control Chris Zhong <zyw@rock-chips.com> - 2017-02-15 04:40 +0100
    Re: [PATCH v3 23/24] drm/rockchip: dw-mipi-dsi: add reset control John Keeping <john@metanate.com> - 2017-02-15 13:50 +0100
      Re: [PATCH v3 23/24] drm/rockchip: dw-mipi-dsi: add reset control Chris Zhong <zyw@rock-chips.com> - 2017-02-16 03:20 +0100
        Re: [PATCH v3 23/24] drm/rockchip: dw-mipi-dsi: add reset control John Keeping <john@metanate.com> - 2017-02-16 15:20 +0100

#1581036 — Re: [PATCH v3 23/24] drm/rockchip: dw-mipi-dsi: add reset control

FromChris Zhong <zyw@rock-chips.com>
Date2017-02-15 04:40 +0100
SubjectRe: [PATCH v3 23/24] drm/rockchip: dw-mipi-dsi: add reset control
Message-ID<taYBH-2o3-1@gated-at.bofh.it>
Hi John

On 01/29/2017 09:24 PM, John Keeping wrote:
> In order to fully reset the state of the MIPI controller we must assert
> this reset.
>
> This is slightly more complicated than it could be in order to maintain
> compatibility with device trees that do not specify the reset property.
>
> Signed-off-by: John Keeping <john@metanate.com>
> Reviewed-by: Chris Zhong <zyw@rock-chips.com>
> ---
> v3:
> - Add Chris' Reviewed-by
> Unchanged in v2
>
>   drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 30 ++++++++++++++++++++++++++++++
>   1 file changed, 30 insertions(+)
>
> diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> index 58cb8ace2fe8..cf3ca6b0cbdb 100644
> --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> @@ -13,6 +13,7 @@
>   #include <linux/module.h>
>   #include <linux/of_device.h>
>   #include <linux/regmap.h>
> +#include <linux/reset.h>
>   #include <linux/mfd/syscon.h>
>   #include <drm/drm_atomic_helper.h>
>   #include <drm/drm_crtc.h>
> @@ -1124,6 +1125,7 @@ static int dw_mipi_dsi_bind(struct device *dev, struct device *master,
>   			of_match_device(dw_mipi_dsi_dt_ids, dev);
>   	const struct dw_mipi_dsi_plat_data *pdata = of_id->data;
>   	struct platform_device *pdev = to_platform_device(dev);
> +	struct reset_control *apb_rst;
>   	struct drm_device *drm = data;
>   	struct dw_mipi_dsi *dsi;
>   	struct resource *res;
> @@ -1162,6 +1164,34 @@ static int dw_mipi_dsi_bind(struct device *dev, struct device *master,
>   		return ret;
>   	}
>   
> +	/*
> +	 * Note that the reset was not defined in the initial device tree, so
> +	 * we have to be prepared for it not being found.
> +	 */
> +	apb_rst = devm_reset_control_get(dev, "apb");
> +	if (IS_ERR(apb_rst)) {
> +		if (PTR_ERR(apb_rst) == -ENODEV) {
According to [0], I think it should be -ENOENT here.

[0]
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=3d81216fde465e76c5eae98f61d3666163634395

commit 3d81216fde465e76c5eae98f61d3666163634395
Author: Alban Bedel <albeu@free.fr>
Date:   Tue Sep 1 17:28:31 2015 +0200

     reset: Fix of_reset_control_get() for consistent return values

     When of_reset_control_get() is called without connection ID it returns
     -ENOENT when the 'resets' property doesn't exists or is an empty entry.
     However when a connection ID is given it returns -EINVAL when the 
'resets'
     property doesn't exists or the requested name can't be found. This is
     because the error code returned by of_property_match_string() is just
     passed down as an index to of_parse_phandle_with_args(), which then
     returns -EINVAL.

     To get a consistent return value with both code paths we must return
     -ENOENT when of_property_match_string() fails.

     Signed-off-by: Alban Bedel <albeu@free.fr>
     Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>


> +			apb_rst = NULL;
> +		} else {
> +			dev_err(dev, "Unable to get reset control: %d\n", ret);
> +			return PTR_ERR(apb_rst);
> +		}
> +	}
> +
> +	if (apb_rst) {
> +		ret = clk_prepare_enable(dsi->pclk);
> +		if (ret) {
> +			dev_err(dev, "%s: Failed to enable pclk\n", __func__);
> +			return ret;
> +		}
> +
> +		reset_control_assert(apb_rst);
> +		usleep_range(10, 20);
> +		reset_control_deassert(apb_rst);
> +
> +		clk_disable_unprepare(dsi->pclk);
> +	}
> +
>   	ret = clk_prepare_enable(dsi->pllref_clk);
>   	if (ret) {
>   		dev_err(dev, "%s: Failed to enable pllref_clk\n", __func__);

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#1581286

FromJohn Keeping <john@metanate.com>
Date2017-02-15 13:50 +0100
Message-ID<tb7bX-8tC-3@gated-at.bofh.it>
In reply to#1581036
On Wed, 15 Feb 2017 11:38:45 +0800, Chris Zhong wrote:

> On 01/29/2017 09:24 PM, John Keeping wrote:
> > In order to fully reset the state of the MIPI controller we must assert
> > this reset.
> >
> > This is slightly more complicated than it could be in order to maintain
> > compatibility with device trees that do not specify the reset property.
> >
> > Signed-off-by: John Keeping <john@metanate.com>
> > Reviewed-by: Chris Zhong <zyw@rock-chips.com>
> > ---
> > v3:
> > - Add Chris' Reviewed-by
> > Unchanged in v2
> >
> >   drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 30 ++++++++++++++++++++++++++++++
> >   1 file changed, 30 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> > index 58cb8ace2fe8..cf3ca6b0cbdb 100644
> > --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> > +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> > @@ -13,6 +13,7 @@
> >   #include <linux/module.h>
> >   #include <linux/of_device.h>
> >   #include <linux/regmap.h>
> > +#include <linux/reset.h>
> >   #include <linux/mfd/syscon.h>
> >   #include <drm/drm_atomic_helper.h>
> >   #include <drm/drm_crtc.h>
> > @@ -1124,6 +1125,7 @@ static int dw_mipi_dsi_bind(struct device *dev, struct device *master,
> >   			of_match_device(dw_mipi_dsi_dt_ids, dev);
> >   	const struct dw_mipi_dsi_plat_data *pdata = of_id->data;
> >   	struct platform_device *pdev = to_platform_device(dev);
> > +	struct reset_control *apb_rst;
> >   	struct drm_device *drm = data;
> >   	struct dw_mipi_dsi *dsi;
> >   	struct resource *res;
> > @@ -1162,6 +1164,34 @@ static int dw_mipi_dsi_bind(struct device *dev, struct device *master,
> >   		return ret;
> >   	}
> >   
> > +	/*
> > +	 * Note that the reset was not defined in the initial device tree, so
> > +	 * we have to be prepared for it not being found.
> > +	 */
> > +	apb_rst = devm_reset_control_get(dev, "apb");
> > +	if (IS_ERR(apb_rst)) {
> > +		if (PTR_ERR(apb_rst) == -ENODEV) {  
> According to [0], I think it should be -ENOENT here.

Nice catch, I'll fix this.

> [0]
> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=3d81216fde465e76c5eae98f61d3666163634395
> 
> commit 3d81216fde465e76c5eae98f61d3666163634395
> Author: Alban Bedel <albeu@free.fr>
> Date:   Tue Sep 1 17:28:31 2015 +0200
> 
>      reset: Fix of_reset_control_get() for consistent return values
> 
>      When of_reset_control_get() is called without connection ID it returns
>      -ENOENT when the 'resets' property doesn't exists or is an empty entry.
>      However when a connection ID is given it returns -EINVAL when the 
> 'resets'
>      property doesn't exists or the requested name can't be found. This is
>      because the error code returned by of_property_match_string() is just
>      passed down as an index to of_parse_phandle_with_args(), which then
>      returns -EINVAL.
> 
>      To get a consistent return value with both code paths we must return
>      -ENOENT when of_property_match_string() fails.
> 
>      Signed-off-by: Alban Bedel <albeu@free.fr>
>      Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
> 
> 
> > +			apb_rst = NULL;
> > +		} else {
> > +			dev_err(dev, "Unable to get reset control: %d\n", ret);
> > +			return PTR_ERR(apb_rst);
> > +		}
> > +	}
> > +
> > +	if (apb_rst) {
> > +		ret = clk_prepare_enable(dsi->pclk);
> > +		if (ret) {
> > +			dev_err(dev, "%s: Failed to enable pclk\n", __func__);
> > +			return ret;
> > +		}
> > +
> > +		reset_control_assert(apb_rst);
> > +		usleep_range(10, 20);
> > +		reset_control_deassert(apb_rst);
> > +
> > +		clk_disable_unprepare(dsi->pclk);
> > +	}
> > +
> >   	ret = clk_prepare_enable(dsi->pllref_clk);
> >   	if (ret) {
> >   		dev_err(dev, "%s: Failed to enable pllref_clk\n", __func__);  
> 
>

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#1582238

FromChris Zhong <zyw@rock-chips.com>
Date2017-02-16 03:20 +0100
Message-ID<tbjPP-89f-15@gated-at.bofh.it>
In reply to#1581286
Hi John

On 02/15/2017 08:39 PM, John Keeping wrote:
> On Wed, 15 Feb 2017 11:38:45 +0800, Chris Zhong wrote:
>
>> On 01/29/2017 09:24 PM, John Keeping wrote:
>>> In order to fully reset the state of the MIPI controller we must assert
>>> this reset.
>>>
>>> This is slightly more complicated than it could be in order to maintain
>>> compatibility with device trees that do not specify the reset property.
>>>
>>> Signed-off-by: John Keeping <john@metanate.com>
>>> Reviewed-by: Chris Zhong <zyw@rock-chips.com>
>>> ---
>>> v3:
>>> - Add Chris' Reviewed-by
>>> Unchanged in v2
>>>
>>>    drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 30 ++++++++++++++++++++++++++++++
>>>    1 file changed, 30 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
>>> index 58cb8ace2fe8..cf3ca6b0cbdb 100644
>>> --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
>>> +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
>>> @@ -13,6 +13,7 @@
>>>    #include <linux/module.h>
>>>    #include <linux/of_device.h>
>>>    #include <linux/regmap.h>
>>> +#include <linux/reset.h>
>>>    #include <linux/mfd/syscon.h>
>>>    #include <drm/drm_atomic_helper.h>
>>>    #include <drm/drm_crtc.h>
>>> @@ -1124,6 +1125,7 @@ static int dw_mipi_dsi_bind(struct device *dev, struct device *master,
>>>    			of_match_device(dw_mipi_dsi_dt_ids, dev);
>>>    	const struct dw_mipi_dsi_plat_data *pdata = of_id->data;
>>>    	struct platform_device *pdev = to_platform_device(dev);
>>> +	struct reset_control *apb_rst;
>>>    	struct drm_device *drm = data;
>>>    	struct dw_mipi_dsi *dsi;
>>>    	struct resource *res;
>>> @@ -1162,6 +1164,34 @@ static int dw_mipi_dsi_bind(struct device *dev, struct device *master,
>>>    		return ret;
>>>    	}
>>>    
>>> +	/*
>>> +	 * Note that the reset was not defined in the initial device tree, so
>>> +	 * we have to be prepared for it not being found.
>>> +	 */
>>> +	apb_rst = devm_reset_control_get(dev, "apb");
>>> +	if (IS_ERR(apb_rst)) {
>>> +		if (PTR_ERR(apb_rst) == -ENODEV) {
>> According to [0], I think it should be -ENOENT here.
> Nice catch, I'll fix this.
>
>> [0]
>> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=3d81216fde465e76c5eae98f61d3666163634395
>>
>> commit 3d81216fde465e76c5eae98f61d3666163634395
>> Author: Alban Bedel <albeu@free.fr>
>> Date:   Tue Sep 1 17:28:31 2015 +0200
>>
>>       reset: Fix of_reset_control_get() for consistent return values
>>
>>       When of_reset_control_get() is called without connection ID it returns
>>       -ENOENT when the 'resets' property doesn't exists or is an empty entry.
>>       However when a connection ID is given it returns -EINVAL when the
>> 'resets'
>>       property doesn't exists or the requested name can't be found. This is
>>       because the error code returned by of_property_match_string() is just
>>       passed down as an index to of_parse_phandle_with_args(), which then
>>       returns -EINVAL.
>>
>>       To get a consistent return value with both code paths we must return
>>       -ENOENT when of_property_match_string() fails.
>>
>>       Signed-off-by: Alban Bedel <albeu@free.fr>
>>       Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
>>
>>
>>> +			apb_rst = NULL;
>>> +		} else {
>>> +			dev_err(dev, "Unable to get reset control: %d\n", ret);
Also, we can not get error number from "ret" here.

>>> +			return PTR_ERR(apb_rst);
>>> +		}
>>> +	}
>>> +
>>> +	if (apb_rst) {
>>> +		ret = clk_prepare_enable(dsi->pclk);
>>> +		if (ret) {
>>> +			dev_err(dev, "%s: Failed to enable pclk\n", __func__);
>>> +			return ret;
>>> +		}
>>> +
>>> +		reset_control_assert(apb_rst);
>>> +		usleep_range(10, 20);
>>> +		reset_control_deassert(apb_rst);
>>> +
>>> +		clk_disable_unprepare(dsi->pclk);
>>> +	}
>>> +
>>>    	ret = clk_prepare_enable(dsi->pllref_clk);
>>>    	if (ret) {
>>>    		dev_err(dev, "%s: Failed to enable pllref_clk\n", __func__);
>>
>
>

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#1582605

FromJohn Keeping <john@metanate.com>
Date2017-02-16 15:20 +0100
Message-ID<tbv4B-7ic-1@gated-at.bofh.it>
In reply to#1582238
On Thu, 16 Feb 2017 10:12:33 +0800, Chris Zhong wrote:

> On 02/15/2017 08:39 PM, John Keeping wrote:
> > On Wed, 15 Feb 2017 11:38:45 +0800, Chris Zhong wrote:
> >  
> >> On 01/29/2017 09:24 PM, John Keeping wrote:  
> >>> In order to fully reset the state of the MIPI controller we must assert
> >>> this reset.
> >>>
> >>> This is slightly more complicated than it could be in order to maintain
> >>> compatibility with device trees that do not specify the reset property.
> >>>
> >>> Signed-off-by: John Keeping <john@metanate.com>
> >>> Reviewed-by: Chris Zhong <zyw@rock-chips.com>
> >>> ---
> >>> v3:
> >>> - Add Chris' Reviewed-by
> >>> Unchanged in v2
> >>>
> >>>    drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 30 ++++++++++++++++++++++++++++++
> >>>    1 file changed, 30 insertions(+)
> >>>
> >>> diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> >>> index 58cb8ace2fe8..cf3ca6b0cbdb 100644
> >>> --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> >>> +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> >>> @@ -13,6 +13,7 @@
> >>>    #include <linux/module.h>
> >>>    #include <linux/of_device.h>
> >>>    #include <linux/regmap.h>
> >>> +#include <linux/reset.h>
> >>>    #include <linux/mfd/syscon.h>
> >>>    #include <drm/drm_atomic_helper.h>
> >>>    #include <drm/drm_crtc.h>
> >>> @@ -1124,6 +1125,7 @@ static int dw_mipi_dsi_bind(struct device *dev, struct device *master,
> >>>    			of_match_device(dw_mipi_dsi_dt_ids, dev);
> >>>    	const struct dw_mipi_dsi_plat_data *pdata = of_id->data;
> >>>    	struct platform_device *pdev = to_platform_device(dev);
> >>> +	struct reset_control *apb_rst;
> >>>    	struct drm_device *drm = data;
> >>>    	struct dw_mipi_dsi *dsi;
> >>>    	struct resource *res;
> >>> @@ -1162,6 +1164,34 @@ static int dw_mipi_dsi_bind(struct device *dev, struct device *master,
> >>>    		return ret;
> >>>    	}
> >>>    
> >>> +	/*
> >>> +	 * Note that the reset was not defined in the initial device tree, so
> >>> +	 * we have to be prepared for it not being found.
> >>> +	 */
> >>> +	apb_rst = devm_reset_control_get(dev, "apb");
> >>> +	if (IS_ERR(apb_rst)) {
> >>> +		if (PTR_ERR(apb_rst) == -ENODEV) {  
> >> According to [0], I think it should be -ENOENT here.  
> > Nice catch, I'll fix this.
> >  
> >> [0]
> >> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=3d81216fde465e76c5eae98f61d3666163634395
> >>
> >> commit 3d81216fde465e76c5eae98f61d3666163634395
> >> Author: Alban Bedel <albeu@free.fr>
> >> Date:   Tue Sep 1 17:28:31 2015 +0200
> >>
> >>       reset: Fix of_reset_control_get() for consistent return values
> >>
> >>       When of_reset_control_get() is called without connection ID it returns
> >>       -ENOENT when the 'resets' property doesn't exists or is an empty entry.
> >>       However when a connection ID is given it returns -EINVAL when the
> >> 'resets'
> >>       property doesn't exists or the requested name can't be found. This is
> >>       because the error code returned by of_property_match_string() is just
> >>       passed down as an index to of_parse_phandle_with_args(), which then
> >>       returns -EINVAL.
> >>
> >>       To get a consistent return value with both code paths we must return
> >>       -ENOENT when of_property_match_string() fails.
> >>
> >>       Signed-off-by: Alban Bedel <albeu@free.fr>
> >>       Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
> >>
> >>  
> >>> +			apb_rst = NULL;
> >>> +		} else {
> >>> +			dev_err(dev, "Unable to get reset control: %d\n", ret);  
> Also, we can not get error number from "ret" here.

Good point, I'll fix this.


John

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