* [PATCH] w1-gpio: add external pull-up enable callback
@ 2009-05-05 12:43 Daniel Mack
2009-05-06 9:33 ` Ville Syrjälä
` (2 more replies)
0 siblings, 3 replies; 9+ messages in thread
From: Daniel Mack @ 2009-05-05 12:43 UTC (permalink / raw)
To: linux-kernel; +Cc: Daniel Mack, Ville Syrjala
On embedded devices, sleep mode conditions can be tricky to handle,
Especially when processors tend to pull-down the w1 bus during sleep.
Bus slaves (such as the ds2760) may interpret this as a reason for
power-down conditions and entirely switch off the device.
This patch adds a callback function pointer to let users switch on and
off the external pull-up resistor. This lets the outside world know
whether the processor is currently actively driving the bus or not.
When this callback is not provided, the code behaviour won't change.
Signed-off-by: Daniel Mack <daniel@caiaq.de>
Cc: Ville Syrjala <syrjala@sci.fi>
---
drivers/w1/masters/w1-gpio.c | 35 +++++++++++++++++++++++++++++++++++
include/linux/w1-gpio.h | 1 +
2 files changed, 36 insertions(+), 0 deletions(-)
diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c
index a411702..6f8866d 100644
--- a/drivers/w1/masters/w1-gpio.c
+++ b/drivers/w1/masters/w1-gpio.c
@@ -74,6 +74,9 @@ static int __init w1_gpio_probe(struct platform_device *pdev)
if (err)
goto free_gpio;
+ if (pdata->enable_external_pullup)
+ pdata->enable_external_pullup(1);
+
platform_set_drvdata(pdev, master);
return 0;
@@ -91,6 +94,9 @@ static int __exit w1_gpio_remove(struct platform_device *pdev)
struct w1_bus_master *master = platform_get_drvdata(pdev);
struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
+ if (pdata->enable_external_pullup)
+ pdata->enable_external_pullup(0);
+
w1_remove_master_device(master);
gpio_free(pdata->pin);
kfree(master);
@@ -98,12 +104,41 @@ static int __exit w1_gpio_remove(struct platform_device *pdev)
return 0;
}
+#ifdef CONFIG_PM
+
+static int w1_gpio_suspend(struct platform_device *pdev, pm_message_t state)
+{
+ struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
+
+ if (pdata->enable_external_pullup)
+ pdata->enable_external_pullup(0);
+
+ return 0;
+}
+
+static int w1_gpio_resume(struct platform_device *pdev)
+{
+ struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
+
+ if (pdata->enable_external_pullup)
+ pdata->enable_external_pullup(1);
+
+ return 0;
+}
+
+#else
+#define w1_gpio_suspend NULL
+#define w1_gpio_resume NULL
+#endif
+
static struct platform_driver w1_gpio_driver = {
.driver = {
.name = "w1-gpio",
.owner = THIS_MODULE,
},
.remove = __exit_p(w1_gpio_remove),
+ .suspend = w1_gpio_suspend,
+ .resume = w1_gpio_resume,
};
static int __init w1_gpio_init(void)
diff --git a/include/linux/w1-gpio.h b/include/linux/w1-gpio.h
index 9797fec..3adeff8 100644
--- a/include/linux/w1-gpio.h
+++ b/include/linux/w1-gpio.h
@@ -18,6 +18,7 @@
struct w1_gpio_platform_data {
unsigned int pin;
unsigned int is_open_drain:1;
+ void (*enable_external_pullup)(int enable);
};
#endif /* _LINUX_W1_GPIO_H */
--
1.6.2.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH] w1-gpio: add external pull-up enable callback
2009-05-05 12:43 [PATCH] w1-gpio: add external pull-up enable callback Daniel Mack
@ 2009-05-06 9:33 ` Ville Syrjälä
2009-05-06 9:34 ` Daniel Mack
2009-05-08 20:13 ` Daniel Mack
2009-05-12 13:56 ` Daniel Mack
2 siblings, 1 reply; 9+ messages in thread
From: Ville Syrjälä @ 2009-05-06 9:33 UTC (permalink / raw)
To: Daniel Mack; +Cc: linux-kernel
On Tue, May 05, 2009 at 02:43:33PM +0200, Daniel Mack wrote:
> On embedded devices, sleep mode conditions can be tricky to handle,
> Especially when processors tend to pull-down the w1 bus during sleep.
> Bus slaves (such as the ds2760) may interpret this as a reason for
> power-down conditions and entirely switch off the device.
>
> This patch adds a callback function pointer to let users switch on and
> off the external pull-up resistor. This lets the outside world know
> whether the processor is currently actively driving the bus or not.
Looks simple enough but I wonder if you could just do this from the
platform code. I suppose the downside would be that you would enable the
pullup even if w1-gpio is not loaded.
--
Ville Syrjälä
syrjala@sci.fi
http://www.sci.fi/~syrjala/
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] w1-gpio: add external pull-up enable callback
2009-05-06 9:33 ` Ville Syrjälä
@ 2009-05-06 9:34 ` Daniel Mack
2009-05-06 20:28 ` Ville Syrjälä
0 siblings, 1 reply; 9+ messages in thread
From: Daniel Mack @ 2009-05-06 9:34 UTC (permalink / raw)
To: Ville Syrjälä, linux-kernel
On Wed, May 06, 2009 at 12:33:07PM +0300, Ville Syrjälä wrote:
> On Tue, May 05, 2009 at 02:43:33PM +0200, Daniel Mack wrote:
> > On embedded devices, sleep mode conditions can be tricky to handle,
> > Especially when processors tend to pull-down the w1 bus during sleep.
> > Bus slaves (such as the ds2760) may interpret this as a reason for
> > power-down conditions and entirely switch off the device.
> >
> > This patch adds a callback function pointer to let users switch on and
> > off the external pull-up resistor. This lets the outside world know
> > whether the processor is currently actively driving the bus or not.
>
> Looks simple enough but I wonder if you could just do this from the
> platform code. I suppose the downside would be that you would enable the
> pullup even if w1-gpio is not loaded.
That's right. Hence I put it where I believe it belongs to.
Thanks,
Daniel
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] w1-gpio: add external pull-up enable callback
2009-05-06 9:34 ` Daniel Mack
@ 2009-05-06 20:28 ` Ville Syrjälä
2009-05-07 1:30 ` Daniel Mack
0 siblings, 1 reply; 9+ messages in thread
From: Ville Syrjälä @ 2009-05-06 20:28 UTC (permalink / raw)
To: Daniel Mack; +Cc: linux-kernel
On Wed, May 06, 2009 at 11:34:45AM +0200, Daniel Mack wrote:
> On Wed, May 06, 2009 at 12:33:07PM +0300, Ville Syrjälä wrote:
> > On Tue, May 05, 2009 at 02:43:33PM +0200, Daniel Mack wrote:
> > > On embedded devices, sleep mode conditions can be tricky to handle,
> > > Especially when processors tend to pull-down the w1 bus during sleep.
> > > Bus slaves (such as the ds2760) may interpret this as a reason for
> > > power-down conditions and entirely switch off the device.
> > >
> > > This patch adds a callback function pointer to let users switch on and
> > > off the external pull-up resistor. This lets the outside world know
> > > whether the processor is currently actively driving the bus or not.
> >
> > Looks simple enough but I wonder if you could just do this from the
> > platform code. I suppose the downside would be that you would enable the
> > pullup even if w1-gpio is not loaded.
>
> That's right. Hence I put it where I believe it belongs to.
Well, if you think you need it who am I to argue :)
Acked-by: Ville Syrjälä <syrjala@sci.fi>
--
Ville Syrjälä
syrjala@sci.fi
http://www.sci.fi/~syrjala/
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] w1-gpio: add external pull-up enable callback
2009-05-06 20:28 ` Ville Syrjälä
@ 2009-05-07 1:30 ` Daniel Mack
2009-05-08 18:19 ` Ville Syrjälä
0 siblings, 1 reply; 9+ messages in thread
From: Daniel Mack @ 2009-05-07 1:30 UTC (permalink / raw)
To: Ville Syrjälä, linux-kernel
On Wed, May 06, 2009 at 11:28:18PM +0300, Ville Syrjälä wrote:
> > > > This patch adds a callback function pointer to let users switch on and
> > > > off the external pull-up resistor. This lets the outside world know
> > > > whether the processor is currently actively driving the bus or not.
> > >
> > > Looks simple enough but I wonder if you could just do this from the
> > > platform code. I suppose the downside would be that you would enable the
> > > pullup even if w1-gpio is not loaded.
> >
> > That's right. Hence I put it where I believe it belongs to.
>
> Well, if you think you need it who am I to argue :)
>
> Acked-by: Ville Syrjälä <syrjala@sci.fi>
Thanks :)
Daniel
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] w1-gpio: add external pull-up enable callback
2009-05-07 1:30 ` Daniel Mack
@ 2009-05-08 18:19 ` Ville Syrjälä
0 siblings, 0 replies; 9+ messages in thread
From: Ville Syrjälä @ 2009-05-08 18:19 UTC (permalink / raw)
To: Daniel Mack; +Cc: linux-kernel
On Thu, May 07, 2009 at 03:30:32AM +0200, Daniel Mack wrote:
> On Wed, May 06, 2009 at 11:28:18PM +0300, Ville Syrjälä wrote:
> > > > > This patch adds a callback function pointer to let users switch on and
> > > > > off the external pull-up resistor. This lets the outside world know
> > > > > whether the processor is currently actively driving the bus or not.
> > > >
> > > > Looks simple enough but I wonder if you could just do this from the
> > > > platform code. I suppose the downside would be that you would enable the
> > > > pullup even if w1-gpio is not loaded.
> > >
> > > That's right. Hence I put it where I believe it belongs to.
> >
> > Well, if you think you need it who am I to argue :)
> >
> > Acked-by: Ville Syrjälä <syrjala@sci.fi>
>
> Thanks :)
BTW you should probably send this via Evgeniy Polyakov if you want it
included in the kernel at some point.
--
Ville Syrjälä
syrjala@sci.fi
http://www.sci.fi/~syrjala/
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] w1-gpio: add external pull-up enable callback
2009-05-05 12:43 [PATCH] w1-gpio: add external pull-up enable callback Daniel Mack
2009-05-06 9:33 ` Ville Syrjälä
@ 2009-05-08 20:13 ` Daniel Mack
2009-05-08 20:53 ` Evgeniy Polyakov
2009-05-12 13:56 ` Daniel Mack
2 siblings, 1 reply; 9+ messages in thread
From: Daniel Mack @ 2009-05-08 20:13 UTC (permalink / raw)
To: linux-kernel; +Cc: Ville Syrjala, Evgeniy Polyakov
(cc Evgeniy Polyakov)
Evgeniy, could you give some feedback on this? Ville Syrjala gave his
Acked-by already.
Thanks,
Daniel
On Tue, May 05, 2009 at 02:43:33PM +0200, Daniel Mack wrote:
> On embedded devices, sleep mode conditions can be tricky to handle,
> Especially when processors tend to pull-down the w1 bus during sleep.
> Bus slaves (such as the ds2760) may interpret this as a reason for
> power-down conditions and entirely switch off the device.
>
> This patch adds a callback function pointer to let users switch on and
> off the external pull-up resistor. This lets the outside world know
> whether the processor is currently actively driving the bus or not.
>
> When this callback is not provided, the code behaviour won't change.
>
> Signed-off-by: Daniel Mack <daniel@caiaq.de>
> Cc: Ville Syrjala <syrjala@sci.fi>
> ---
> drivers/w1/masters/w1-gpio.c | 35 +++++++++++++++++++++++++++++++++++
> include/linux/w1-gpio.h | 1 +
> 2 files changed, 36 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c
> index a411702..6f8866d 100644
> --- a/drivers/w1/masters/w1-gpio.c
> +++ b/drivers/w1/masters/w1-gpio.c
> @@ -74,6 +74,9 @@ static int __init w1_gpio_probe(struct platform_device *pdev)
> if (err)
> goto free_gpio;
>
> + if (pdata->enable_external_pullup)
> + pdata->enable_external_pullup(1);
> +
> platform_set_drvdata(pdev, master);
>
> return 0;
> @@ -91,6 +94,9 @@ static int __exit w1_gpio_remove(struct platform_device *pdev)
> struct w1_bus_master *master = platform_get_drvdata(pdev);
> struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
>
> + if (pdata->enable_external_pullup)
> + pdata->enable_external_pullup(0);
> +
> w1_remove_master_device(master);
> gpio_free(pdata->pin);
> kfree(master);
> @@ -98,12 +104,41 @@ static int __exit w1_gpio_remove(struct platform_device *pdev)
> return 0;
> }
>
> +#ifdef CONFIG_PM
> +
> +static int w1_gpio_suspend(struct platform_device *pdev, pm_message_t state)
> +{
> + struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
> +
> + if (pdata->enable_external_pullup)
> + pdata->enable_external_pullup(0);
> +
> + return 0;
> +}
> +
> +static int w1_gpio_resume(struct platform_device *pdev)
> +{
> + struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
> +
> + if (pdata->enable_external_pullup)
> + pdata->enable_external_pullup(1);
> +
> + return 0;
> +}
> +
> +#else
> +#define w1_gpio_suspend NULL
> +#define w1_gpio_resume NULL
> +#endif
> +
> static struct platform_driver w1_gpio_driver = {
> .driver = {
> .name = "w1-gpio",
> .owner = THIS_MODULE,
> },
> .remove = __exit_p(w1_gpio_remove),
> + .suspend = w1_gpio_suspend,
> + .resume = w1_gpio_resume,
> };
>
> static int __init w1_gpio_init(void)
> diff --git a/include/linux/w1-gpio.h b/include/linux/w1-gpio.h
> index 9797fec..3adeff8 100644
> --- a/include/linux/w1-gpio.h
> +++ b/include/linux/w1-gpio.h
> @@ -18,6 +18,7 @@
> struct w1_gpio_platform_data {
> unsigned int pin;
> unsigned int is_open_drain:1;
> + void (*enable_external_pullup)(int enable);
> };
>
> #endif /* _LINUX_W1_GPIO_H */
> --
> 1.6.2.1
>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] w1-gpio: add external pull-up enable callback
2009-05-08 20:13 ` Daniel Mack
@ 2009-05-08 20:53 ` Evgeniy Polyakov
0 siblings, 0 replies; 9+ messages in thread
From: Evgeniy Polyakov @ 2009-05-08 20:53 UTC (permalink / raw)
To: Daniel Mack; +Cc: linux-kernel, Ville Syrjala
Hi Daniel.
On Fri, May 08, 2009 at 10:13:02PM +0200, Daniel Mack (daniel@caiaq.de) wrote:
> (cc Evgeniy Polyakov)
>
> Evgeniy, could you give some feedback on this? Ville Syrjala gave his
> Acked-by already.
Looks good! Feel free to add mine too and submit through Andrew Morton
or via other path.
--
Evgeniy Polyakov
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] w1-gpio: add external pull-up enable callback
2009-05-05 12:43 [PATCH] w1-gpio: add external pull-up enable callback Daniel Mack
2009-05-06 9:33 ` Ville Syrjälä
2009-05-08 20:13 ` Daniel Mack
@ 2009-05-12 13:56 ` Daniel Mack
2 siblings, 0 replies; 9+ messages in thread
From: Daniel Mack @ 2009-05-12 13:56 UTC (permalink / raw)
To: linux-kernel; +Cc: Ville Syrjala, Evgeniy Polyakov, Andrew Morton
(cc Andrew Morton)
Andrew,
could you add this to your patch queue? It's been acked by Ville Syrjala
and Evgeniy Polyakov.
Thanks,
Daniel
>From 6a99f9453d9b0ad2dd705c012014063977781bf3 Mon Sep 17 00:00:00 2001
From: Daniel Mack <daniel@caiaq.de>
Date: Tue, 5 May 2009 14:35:04 +0200
Subject: [PATCH] w1-gpio: add external pull-up enable callback
On embedded devices, sleep mode conditions can be tricky to handle,
Especially when processors tend to pull-down the w1 bus during sleep.
Bus slaves (such as the ds2760) may interpret this as a reason for
power-down conditions and entirely switch off the device.
This patch adds a callback function pointer to let users switch on and
off the external pull-up resistor. This lets the outside world know
whether the processor is currently actively driving the bus or not.
When this callback is not provided, the code behaviour won't change.
Signed-off-by: Daniel Mack <daniel@caiaq.de>
Acked-by: Ville Syrjala <syrjala@sci.fi>
Acked-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
---
drivers/w1/masters/w1-gpio.c | 35 +++++++++++++++++++++++++++++++++++
include/linux/w1-gpio.h | 1 +
2 files changed, 36 insertions(+), 0 deletions(-)
diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c
index a411702..6f8866d 100644
--- a/drivers/w1/masters/w1-gpio.c
+++ b/drivers/w1/masters/w1-gpio.c
@@ -74,6 +74,9 @@ static int __init w1_gpio_probe(struct platform_device *pdev)
if (err)
goto free_gpio;
+ if (pdata->enable_external_pullup)
+ pdata->enable_external_pullup(1);
+
platform_set_drvdata(pdev, master);
return 0;
@@ -91,6 +94,9 @@ static int __exit w1_gpio_remove(struct platform_device *pdev)
struct w1_bus_master *master = platform_get_drvdata(pdev);
struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
+ if (pdata->enable_external_pullup)
+ pdata->enable_external_pullup(0);
+
w1_remove_master_device(master);
gpio_free(pdata->pin);
kfree(master);
@@ -98,12 +104,41 @@ static int __exit w1_gpio_remove(struct platform_device *pdev)
return 0;
}
+#ifdef CONFIG_PM
+
+static int w1_gpio_suspend(struct platform_device *pdev, pm_message_t state)
+{
+ struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
+
+ if (pdata->enable_external_pullup)
+ pdata->enable_external_pullup(0);
+
+ return 0;
+}
+
+static int w1_gpio_resume(struct platform_device *pdev)
+{
+ struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
+
+ if (pdata->enable_external_pullup)
+ pdata->enable_external_pullup(1);
+
+ return 0;
+}
+
+#else
+#define w1_gpio_suspend NULL
+#define w1_gpio_resume NULL
+#endif
+
static struct platform_driver w1_gpio_driver = {
.driver = {
.name = "w1-gpio",
.owner = THIS_MODULE,
},
.remove = __exit_p(w1_gpio_remove),
+ .suspend = w1_gpio_suspend,
+ .resume = w1_gpio_resume,
};
static int __init w1_gpio_init(void)
diff --git a/include/linux/w1-gpio.h b/include/linux/w1-gpio.h
index 9797fec..3adeff8 100644
--- a/include/linux/w1-gpio.h
+++ b/include/linux/w1-gpio.h
@@ -18,6 +18,7 @@
struct w1_gpio_platform_data {
unsigned int pin;
unsigned int is_open_drain:1;
+ void (*enable_external_pullup)(int enable);
};
#endif /* _LINUX_W1_GPIO_H */
--
1.6.2.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
end of thread, other threads:[~2009-05-12 13:57 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2009-05-05 12:43 [PATCH] w1-gpio: add external pull-up enable callback Daniel Mack
2009-05-06 9:33 ` Ville Syrjälä
2009-05-06 9:34 ` Daniel Mack
2009-05-06 20:28 ` Ville Syrjälä
2009-05-07 1:30 ` Daniel Mack
2009-05-08 18:19 ` Ville Syrjälä
2009-05-08 20:13 ` Daniel Mack
2009-05-08 20:53 ` Evgeniy Polyakov
2009-05-12 13:56 ` Daniel Mack
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).