[U-Boot] [PATCH 1/2] dm: gpio: mxc: fix mxc_gpio_bank_get_value

[U-Boot] [PATCH 1/2] dm: gpio: mxc: fix mxc_gpio_bank_get_value

[Peng Fan]

When configured a gpio to output direction, directly reading PSR register
can not return the output value, since we did not set SION bit for gpio
iomux. So, we can use data register to reflect what value is outputed.

If not, "regulator status" always return disabled, even if already "regulator
enable":
"
=> regulator enable
=> regulator status
Regulator VSD_3V3 status:
 * enable:         0 (false)
 * value uV:       3300000
 * current uA:     No data available (err: -61)
 * mode id:        Function not implemented (err: -38)
"

Signed-off-by: Peng Fan <van.freenix@gmail.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
---
 drivers/gpio/mxc_gpio.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpio/mxc_gpio.c b/drivers/gpio/mxc_gpio.c
index 70fe5b6..b6ae3fc 100644
--- a/drivers/gpio/mxc_gpio.c
+++ b/drivers/gpio/mxc_gpio.c
@@ -201,6 +201,9 @@ static void mxc_gpio_bank_set_value(struct gpio_regs *regs, int offset,
 
 static int mxc_gpio_bank_get_value(struct gpio_regs *regs, int offset)
 {
+	if (mxc_gpio_is_output(regs, offset))
+		return (readl(&regs->gpio_dr) >> offset) & 0x01;
+
 	return (readl(&regs->gpio_psr) >> offset) & 0x01;
 }
 
-- 
2.6.2

[U-Boot] [PATCH 2/2] dm: gpio: mxc: implement xlate function

[Peng Fan]

To i.MX controller, we use such as "<&gpio1 3 GPIO_ACTIVE_LOW>" for
a device to refer a gpio pin in device tree. So need to implement
xlate function, to correctly handle gpio flags and offset.

Signed-off-by: Peng Fan <van.freenix@gmail.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
---
 drivers/gpio/mxc_gpio.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/gpio/mxc_gpio.c b/drivers/gpio/mxc_gpio.c
index b6ae3fc..15449d7 100644
--- a/drivers/gpio/mxc_gpio.c
+++ b/drivers/gpio/mxc_gpio.c
@@ -10,10 +10,12 @@
 #include <common.h>
 #include <errno.h>
 #include <dm.h>
+#include <fdtdec.h>
 #include <malloc.h>
 #include <asm/arch/imx-regs.h>
 #include <asm/gpio.h>
 #include <asm/io.h>
+#include <dt-bindings/gpio/gpio.h>
 
 enum mxc_gpio_direction {
 	MXC_GPIO_DIRECTION_IN,
@@ -263,12 +265,22 @@ static int mxc_gpio_get_function(struct udevice *dev, unsigned offset)
 		return GPIOF_INPUT;
 }
 
+static int mxc_gpio_xlate(struct udevice *dev, struct gpio_desc *desc,
+			  struct fdtdec_phandle_args *args)
+{
+	desc->offset = args->args[0];
+	desc->flags = args->args[1] & GPIO_ACTIVE_LOW ? GPIOD_ACTIVE_LOW : 0;
+
+	return 0;
+}
+
 static const struct dm_gpio_ops gpio_mxc_ops = {
 	.direction_input	= mxc_gpio_direction_input,
 	.direction_output	= mxc_gpio_direction_output,
 	.get_value		= mxc_gpio_get_value,
 	.set_value		= mxc_gpio_set_value,
 	.get_function		= mxc_gpio_get_function,
+	.xlate			= mxc_gpio_xlate,
 };
 
 static int mxc_gpio_probe(struct udevice *dev)
-- 
2.6.2

[U-Boot] [PATCH 2/2] dm: gpio: mxc: implement xlate function

[Simon Glass]

On 14 March 2016 at 23:48, Peng Fan <van.freenix@gmail.com> wrote:
> To i.MX controller, we use such as "<&gpio1 3 GPIO_ACTIVE_LOW>" for
> a device to refer a gpio pin in device tree. So need to implement
> xlate function, to correctly handle gpio flags and offset.
>
> Signed-off-by: Peng Fan <van.freenix@gmail.com>
> Cc: Simon Glass <sjg@chromium.org>
> Cc: Stefano Babic <sbabic@denx.de>
> Cc: Fabio Estevam <fabio.estevam@nxp.com>
> ---
>  drivers/gpio/mxc_gpio.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)

Reviewed-by: Simon Glass <sjg@chromium.org>

[U-Boot] [PATCH 2/2] dm: gpio: mxc: implement xlate function

[Peng Fan]

On Tue, Mar 15, 2016 at 09:32:51PM -0600, Simon Glass wrote:
>On 14 March 2016 at 23:48, Peng Fan <van.freenix@gmail.com> wrote:
>> To i.MX controller, we use such as "<&gpio1 3 GPIO_ACTIVE_LOW>" for
>> a device to refer a gpio pin in device tree. So need to implement
>> xlate function, to correctly handle gpio flags and offset.
>>
>> Signed-off-by: Peng Fan <van.freenix@gmail.com>
>> Cc: Simon Glass <sjg@chromium.org>
>> Cc: Stefano Babic <sbabic@denx.de>
>> Cc: Fabio Estevam <fabio.estevam@nxp.com>
>> ---
>>  drivers/gpio/mxc_gpio.c | 12 ++++++++++++
>>  1 file changed, 12 insertions(+)
>
>Reviewed-by: Simon Glass <sjg@chromium.org>

Will this patch be picked up? Or droped, since Eric is trying to add a
common way.

Thanks,
Peng.

[U-Boot] [PATCH 2/2] dm: gpio: mxc: implement xlate function

[Eric Nelson]

Hi Peng,

On 04/10/2016 10:28 PM, Peng Fan wrote:
> On Tue, Mar 15, 2016 at 09:32:51PM -0600, Simon Glass wrote:
>> On 14 March 2016 at 23:48, Peng Fan <van.freenix@gmail.com> wrote:
>>> To i.MX controller, we use such as "<&gpio1 3 GPIO_ACTIVE_LOW>" for
>>> a device to refer a gpio pin in device tree. So need to implement
>>> xlate function, to correctly handle gpio flags and offset.
>>>
>>> Signed-off-by: Peng Fan <van.freenix@gmail.com>
>>> Cc: Simon Glass <sjg@chromium.org>
>>> Cc: Stefano Babic <sbabic@denx.de>
>>> Cc: Fabio Estevam <fabio.estevam@nxp.com>
>>> ---
>>>  drivers/gpio/mxc_gpio.c | 12 ++++++++++++
>>>  1 file changed, 12 insertions(+)
>>
>> Reviewed-by: Simon Glass <sjg@chromium.org>
> 
> Will this patch be picked up? Or droped, since Eric is trying to add a
> common way.
> 

I think this patch should be dropped.

[U-Boot] [PATCH 1/2] dm: gpio: mxc: fix mxc_gpio_bank_get_value

[Fabio Estevam]

On Tue, Mar 15, 2016 at 2:48 AM, Peng Fan <van.freenix@gmail.com> wrote:
> When configured a gpio to output direction, directly reading PSR register
> can not return the output value, since we did not set SION bit for gpio
> iomux. So, we can use data register to reflect what value is outputed.

Then why not simply set the SION bit instead?

[U-Boot] [PATCH 1/2] dm: gpio: mxc: fix mxc_gpio_bank_get_value

[Peng Fan]

Hi Fabio,

On Tue, Mar 15, 2016 at 09:53:15AM -0300, Fabio Estevam wrote:
>On Tue, Mar 15, 2016 at 2:48 AM, Peng Fan <van.freenix@gmail.com> wrote:
>> When configured a gpio to output direction, directly reading PSR register
>> can not return the output value, since we did not set SION bit for gpio
>> iomux. So, we can use data register to reflect what value is outputed.
>
>Then why not simply set the SION bit instead?

If set the SION bit, we need to change the pinmux settings in device tree,
however device tree are introduced from linux kernel. I would not like
to change the pinmux setting value.

So I choose to use data register but not PSR register.

Regards,
Peng.

[U-Boot] [PATCH 1/2] dm: gpio: mxc: fix mxc_gpio_bank_get_value

[Fabio Estevam]

Hi Peng,

On Tue, Mar 15, 2016 at 10:27 PM, Peng Fan <van.freenix@gmail.com> wrote:

> If set the SION bit, we need to change the pinmux settings in device tree,
> however device tree are introduced from linux kernel. I would not like
> to change the pinmux setting value.
>
> So I choose to use data register but not PSR register.

Haven't checked the kernel driver, but just curious: how does the
kernel handle this?

[U-Boot] [PATCH 1/2] dm: gpio: mxc: fix mxc_gpio_bank_get_value

[Peng Fan]

On Wed, Mar 16, 2016 at 09:48:24AM -0300, Fabio Estevam wrote:
>Hi Peng,
>
>On Tue, Mar 15, 2016 at 10:27 PM, Peng Fan <van.freenix@gmail.com> wrote:
>
>> If set the SION bit, we need to change the pinmux settings in device tree,
>> however device tree are introduced from linux kernel. I would not like
>> to change the pinmux setting value.
>>
>> So I choose to use data register but not PSR register.
>
>Haven't checked the kernel driver, but just curious: how does the
>kernel handle this?

bgc->gc.get = bgpio_get;

The get method:
* @get: returns value for signal "offset"; for output signals this
*      returns either the value actually sensed, or zero

138 static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
139 {
140         struct bgpio_chip *bgc = to_bgpio_chip(gc);
141
142         return !!(bgc->read_reg(bgc->reg_dat) & bgc->pin2mask(bgc, gpio));
143 }

The gpio subsystem use reg_data. The reg_data is GPIO_PSR for gpio-mxc.c:

450         err = bgpio_init(&port->bgc, &pdev->dev, 4,
451                          port->base + GPIO_PSR,
452                          port->base + GPIO_DR, NULL,
453                          port->base + GPIO_GDIR, NULL, 0);

So we know that kernel gpio-mxc use GPIO_PSR for reading data, but
as the comments for get method "for output signals this returns
either the value actually sensed, or zero", if no SION bit set, reading
PSR will return 0 with direction output.

But in U-Boot, the regulator driver needs to get the value when direction is
configured as output, we can use data register here or configure SION in pinmux.
But I prefer using data register here.

Thanks,
Peng.

[U-Boot] [PATCH 1/2] dm: gpio: mxc: fix mxc_gpio_bank_get_value

[Stefano Babic]

Hi Peng,

On 17/03/2016 02:44, Peng Fan wrote:
> On Wed, Mar 16, 2016 at 09:48:24AM -0300, Fabio Estevam wrote:
>> Hi Peng,
>>
>> On Tue, Mar 15, 2016 at 10:27 PM, Peng Fan <van.freenix@gmail.com> wrote:
>>
>>> If set the SION bit, we need to change the pinmux settings in device tree,
>>> however device tree are introduced from linux kernel. I would not like
>>> to change the pinmux setting value.
>>>
>>> So I choose to use data register but not PSR register.
>>
>> Haven't checked the kernel driver, but just curious: how does the
>> kernel handle this?
> 
> bgc->gc.get = bgpio_get;
> 
> The get method:
> * @get: returns value for signal "offset"; for output signals this
> *      returns either the value actually sensed, or zero
> 
> 138 static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
> 139 {
> 140         struct bgpio_chip *bgc = to_bgpio_chip(gc);
> 141
> 142         return !!(bgc->read_reg(bgc->reg_dat) & bgc->pin2mask(bgc, gpio));
> 143 }
> 
> The gpio subsystem use reg_data. The reg_data is GPIO_PSR for gpio-mxc.c:
> 
> 450         err = bgpio_init(&port->bgc, &pdev->dev, 4,
> 451                          port->base + GPIO_PSR,
> 452                          port->base + GPIO_DR, NULL,
> 453                          port->base + GPIO_GDIR, NULL, 0);
> 
> So we know that kernel gpio-mxc use GPIO_PSR for reading data, but
> as the comments for get method "for output signals this returns
> either the value actually sensed, or zero", if no SION bit set, reading
> PSR will return 0 with direction output.
> 

There was already a debate in the past about this point. You can take a
look at the commit:

commit 5dafa4543c399d329c7b01df1afa98437861cac0
Author: Beno?t Th?baudeau <benoit.thebaudeau@advansee.com>
Date:   Mon Aug 20 10:55:41 2012 +0000

    mxc: Make gpio_get_value() use PSR


There were good reasons to switch to PSR (mxc-gpio used DR before) - we
cannot switch any time back to solve a single issue.

I would like to remain compliant with Linux - your change breaks also
boards that rely on this behavior.


> But in U-Boot, the regulator driver needs to get the value when direction is
> configured as output, we can use data register here or configure SION in pinmux.
> But I prefer using data register here.
> 

Best regards,
Stefano

-- 
=====================================================================
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de
=====================================================================

[U-Boot] [PATCH 1/2] dm: gpio: mxc: fix mxc_gpio_bank_get_value

[Peng Fan]

Hi Stefano,

On Sun, Apr 03, 2016 at 08:09:35PM +0200, Stefano Babic wrote:
>Hi Peng,
>
>On 17/03/2016 02:44, Peng Fan wrote:
>> On Wed, Mar 16, 2016 at 09:48:24AM -0300, Fabio Estevam wrote:
>>> Hi Peng,
>>>
>>> On Tue, Mar 15, 2016 at 10:27 PM, Peng Fan <van.freenix@gmail.com> wrote:
>>>
>>>> If set the SION bit, we need to change the pinmux settings in device tree,
>>>> however device tree are introduced from linux kernel. I would not like
>>>> to change the pinmux setting value.
>>>>
>>>> So I choose to use data register but not PSR register.
>>>
>>> Haven't checked the kernel driver, but just curious: how does the
>>> kernel handle this?
>> 
>> bgc->gc.get = bgpio_get;
>> 
>> The get method:
>> * @get: returns value for signal "offset"; for output signals this
>> *      returns either the value actually sensed, or zero
>> 
>> 138 static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
>> 139 {
>> 140         struct bgpio_chip *bgc = to_bgpio_chip(gc);
>> 141
>> 142         return !!(bgc->read_reg(bgc->reg_dat) & bgc->pin2mask(bgc, gpio));
>> 143 }
>> 
>> The gpio subsystem use reg_data. The reg_data is GPIO_PSR for gpio-mxc.c:
>> 
>> 450         err = bgpio_init(&port->bgc, &pdev->dev, 4,
>> 451                          port->base + GPIO_PSR,
>> 452                          port->base + GPIO_DR, NULL,
>> 453                          port->base + GPIO_GDIR, NULL, 0);
>> 
>> So we know that kernel gpio-mxc use GPIO_PSR for reading data, but
>> as the comments for get method "for output signals this returns
>> either the value actually sensed, or zero", if no SION bit set, reading
>> PSR will return 0 with direction output.
>> 
>
>There was already a debate in the past about this point. You can take a
>look at the commit:
>
>commit 5dafa4543c399d329c7b01df1afa98437861cac0
>Author: Beno?t Th?baudeau <benoit.thebaudeau@advansee.com>
>Date:   Mon Aug 20 10:55:41 2012 +0000
>
>    mxc: Make gpio_get_value() use PSR
>
>
>There were good reasons to switch to PSR (mxc-gpio used DR before) - we
>cannot switch any time back to solve a single issue.
>
>I would like to remain compliant with Linux - your change breaks also
>boards that rely on this behavior.

Thanks for this. I'll look at whether I can have some new way.

Regards,
Peng.
>
>
>> But in U-Boot, the regulator driver needs to get the value when direction is
>> configured as output, we can use data register here or configure SION in pinmux.
>> But I prefer using data register here.
>> 
>
>Best regards,
>Stefano
>
>-- 
>=====================================================================
>DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
>HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
>Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de
>=====================================================================

[U-Boot] [PATCH 1/2] dm: gpio: mxc: fix mxc_gpio_bank_get_value

[Simon Glass]

Hi Peng,

On 4 April 2016 at 23:04, Peng Fan <van.freenix@gmail.com> wrote:
> Hi Stefano,
>
> On Sun, Apr 03, 2016 at 08:09:35PM +0200, Stefano Babic wrote:
>>Hi Peng,
>>
>>On 17/03/2016 02:44, Peng Fan wrote:
>>> On Wed, Mar 16, 2016 at 09:48:24AM -0300, Fabio Estevam wrote:
>>>> Hi Peng,
>>>>
>>>> On Tue, Mar 15, 2016 at 10:27 PM, Peng Fan <van.freenix@gmail.com> wrote:
>>>>
>>>>> If set the SION bit, we need to change the pinmux settings in device tree,
>>>>> however device tree are introduced from linux kernel. I would not like
>>>>> to change the pinmux setting value.
>>>>>
>>>>> So I choose to use data register but not PSR register.
>>>>
>>>> Haven't checked the kernel driver, but just curious: how does the
>>>> kernel handle this?
>>>
>>> bgc->gc.get = bgpio_get;
>>>
>>> The get method:
>>> * @get: returns value for signal "offset"; for output signals this
>>> *      returns either the value actually sensed, or zero
>>>
>>> 138 static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
>>> 139 {
>>> 140         struct bgpio_chip *bgc = to_bgpio_chip(gc);
>>> 141
>>> 142         return !!(bgc->read_reg(bgc->reg_dat) & bgc->pin2mask(bgc, gpio));
>>> 143 }
>>>
>>> The gpio subsystem use reg_data. The reg_data is GPIO_PSR for gpio-mxc.c:
>>>
>>> 450         err = bgpio_init(&port->bgc, &pdev->dev, 4,
>>> 451                          port->base + GPIO_PSR,
>>> 452                          port->base + GPIO_DR, NULL,
>>> 453                          port->base + GPIO_GDIR, NULL, 0);
>>>
>>> So we know that kernel gpio-mxc use GPIO_PSR for reading data, but
>>> as the comments for get method "for output signals this returns
>>> either the value actually sensed, or zero", if no SION bit set, reading
>>> PSR will return 0 with direction output.
>>>
>>
>>There was already a debate in the past about this point. You can take a
>>look at the commit:
>>
>>commit 5dafa4543c399d329c7b01df1afa98437861cac0
>>Author: Beno?t Th?baudeau <benoit.thebaudeau@advansee.com>
>>Date:   Mon Aug 20 10:55:41 2012 +0000
>>
>>    mxc: Make gpio_get_value() use PSR
>>
>>
>>There were good reasons to switch to PSR (mxc-gpio used DR before) - we
>>cannot switch any time back to solve a single issue.
>>
>>I would like to remain compliant with Linux - your change breaks also
>>boards that rely on this behavior.
>
> Thanks for this. I'll look at whether I can have some new way.

Two possible ideas:

1. Cache the output state in the driver so you can return it
2. Add a new get_output_value() method to the uclass (although maybe I
misunderstand the problem here)

>
> Regards,
> Peng.
>>
>>
>>> But in U-Boot, the regulator driver needs to get the value when direction is
>>> configured as output, we can use data register here or configure SION in pinmux.
>>> But I prefer using data register here.
>>>
>>
>>Best regards,
>>Stefano
>>
>>--
>>=====================================================================
>>DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
>>HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
>>Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de
>>=====================================================================

Regards,
Simon