* [PATCH v2 0/2] am335x: set pinmux registers from pins debug file
@ 2021-05-17 20:00 Dario Binacchi
2021-05-17 20:00 ` [PATCH v2 2/2] pinctrl: single: set pinmux " Dario Binacchi
2021-05-19 11:31 ` [PATCH v2 0/2] am335x: set pinmux registers " Andy Shevchenko
0 siblings, 2 replies; 6+ messages in thread
From: Dario Binacchi @ 2021-05-17 20:00 UTC (permalink / raw)
To: linux-kernel
Cc: Dario Binacchi, Haojian Zhuang, Linus Walleij, Tony Lindgren,
linux-arm-kernel, linux-gpio, linux-omap
The patch was born from the need to change the slew rate of the LCD pins
of a custom AM335x board during EMC tests. The AM335x, as described in a
note in section 9.1 of its reference manual [1], is unable to write
pinmux registers from user space. The series now makes it possible to
write these registers from the pins debug file.
[1] https://www.ti.com/lit/ug/spruh73q/spruh73q.pdf
Changes in v2:
- Remove CONFIG_SOC_AM33XX dependency.
Dario Binacchi (2):
pinctrl: core: configure pinmux from pins debug file
pinctrl: single: set pinmux from pins debug file
drivers/pinctrl/core.c | 56 ++++++++++++++++++++++++++++++--
drivers/pinctrl/pinctrl-single.c | 20 ++++++++++++
include/linux/pinctrl/pinctrl.h | 2 ++
3 files changed, 76 insertions(+), 2 deletions(-)
--
2.17.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v2 2/2] pinctrl: single: set pinmux from pins debug file
2021-05-17 20:00 [PATCH v2 0/2] am335x: set pinmux registers from pins debug file Dario Binacchi
@ 2021-05-17 20:00 ` Dario Binacchi
2021-05-18 6:05 ` Tony Lindgren
2021-05-19 11:31 ` [PATCH v2 0/2] am335x: set pinmux registers " Andy Shevchenko
1 sibling, 1 reply; 6+ messages in thread
From: Dario Binacchi @ 2021-05-17 20:00 UTC (permalink / raw)
To: linux-kernel
Cc: Dario Binacchi, Haojian Zhuang, Linus Walleij, Tony Lindgren,
linux-arm-kernel, linux-gpio, linux-omap
As described in section 9.1 of the TI reference manual for AM335x [1],
"For writing to the control module registers, the MPU will need to be in
privileged mode of operation and writes will not work from user mode".
By adding the pin_dbg_set helper to pcs_pinctrl_ops it will be possible
to write these registers from the pins debug:
cd /sys/kernel/debug/pinctrl/44e10800.pinmux-pinctrl-single/
echo <pin-number> <reg-value> >pins
[1] https://www.ti.com/lit/ug/spruh73q/spruh73q.pdf
Signed-off-by: Dario Binacchi <dariobin@libero.it>
---
Changes in v2:
- Remove CONFIG_SOC_AM33XX dependency.
drivers/pinctrl/pinctrl-single.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/drivers/pinctrl/pinctrl-single.c b/drivers/pinctrl/pinctrl-single.c
index 2c9c9835f375..8497414e3384 100644
--- a/drivers/pinctrl/pinctrl-single.c
+++ b/drivers/pinctrl/pinctrl-single.c
@@ -313,6 +313,23 @@ static void pcs_pin_dbg_show(struct pinctrl_dev *pctldev,
seq_printf(s, "%zx %08x %s ", pa, val, DRIVER_NAME);
}
+static int pcs_pin_dbg_set(struct pinctrl_dev *pctldev, unsigned int pin,
+ char *buf)
+{
+ struct pcs_device *pcs;
+ unsigned int val, mux_bytes;
+
+ buf = skip_spaces(buf);
+ if (kstrtouint(buf, 0, &val))
+ return -EINVAL;
+
+ pcs = pinctrl_dev_get_drvdata(pctldev);
+
+ mux_bytes = pcs->width / BITS_PER_BYTE;
+ pcs->write(val, pcs->base + pin * mux_bytes);
+ return 0;
+}
+
static void pcs_dt_free_map(struct pinctrl_dev *pctldev,
struct pinctrl_map *map, unsigned num_maps)
{
@@ -331,6 +348,9 @@ static const struct pinctrl_ops pcs_pinctrl_ops = {
.get_group_name = pinctrl_generic_get_group_name,
.get_group_pins = pinctrl_generic_get_group_pins,
.pin_dbg_show = pcs_pin_dbg_show,
+#if IS_ENABLED(CONFIG_DEVMEM)
+ .pin_dbg_set = pcs_pin_dbg_set,
+#endif
.dt_node_to_map = pcs_dt_node_to_map,
.dt_free_map = pcs_dt_free_map,
};
--
2.17.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v2 2/2] pinctrl: single: set pinmux from pins debug file
2021-05-17 20:00 ` [PATCH v2 2/2] pinctrl: single: set pinmux " Dario Binacchi
@ 2021-05-18 6:05 ` Tony Lindgren
2021-05-18 8:57 ` Dario Binacchi
0 siblings, 1 reply; 6+ messages in thread
From: Tony Lindgren @ 2021-05-18 6:05 UTC (permalink / raw)
To: Dario Binacchi
Cc: linux-kernel, Haojian Zhuang, Linus Walleij, linux-arm-kernel,
linux-gpio, linux-omap
Hi,
I noticed few more things I started to wonder about after
looking at this again.
* Dario Binacchi <dariobin@libero.it> [210517 20:00]:
> +static int pcs_pin_dbg_set(struct pinctrl_dev *pctldev, unsigned int pin,
> + char *buf)
> +{
> + struct pcs_device *pcs;
> + unsigned int val, mux_bytes;
> +
> + buf = skip_spaces(buf);
> + if (kstrtouint(buf, 0, &val))
> + return -EINVAL;
> +
> + pcs = pinctrl_dev_get_drvdata(pctldev);
> +
> + mux_bytes = pcs->width / BITS_PER_BYTE;
> + pcs->write(val, pcs->base + pin * mux_bytes);
> + return 0;
> +}
Since you're adding a new interface, how about pass unsigned
int val instead of char *buf?
> static void pcs_dt_free_map(struct pinctrl_dev *pctldev,
> struct pinctrl_map *map, unsigned num_maps)
> {
> @@ -331,6 +348,9 @@ static const struct pinctrl_ops pcs_pinctrl_ops = {
> .get_group_name = pinctrl_generic_get_group_name,
> .get_group_pins = pinctrl_generic_get_group_pins,
> .pin_dbg_show = pcs_pin_dbg_show,
> +#if IS_ENABLED(CONFIG_DEVMEM)
> + .pin_dbg_set = pcs_pin_dbg_set,
> +#endif
> .dt_node_to_map = pcs_dt_node_to_map,
> .dt_free_map = pcs_dt_free_map,
> };
It might be better to always have the .pin_dbg_set around to
avoid the IS_ENABLED(CONFIG_DEVMEM).
Does the new interface need something under Documentation too?
Regards,
Tony
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2 2/2] pinctrl: single: set pinmux from pins debug file
2021-05-18 6:05 ` Tony Lindgren
@ 2021-05-18 8:57 ` Dario Binacchi
2021-05-21 9:25 ` Tony Lindgren
0 siblings, 1 reply; 6+ messages in thread
From: Dario Binacchi @ 2021-05-18 8:57 UTC (permalink / raw)
To: Tony Lindgren
Cc: linux-kernel, Haojian Zhuang, Linus Walleij, linux-arm-kernel,
linux-gpio, linux-omap
Hi Tony,
> Il 18/05/2021 08:05 Tony Lindgren <tony@atomide.com> ha scritto:
>
>
> Hi,
>
> I noticed few more things I started to wonder about after
> looking at this again.
>
> * Dario Binacchi <dariobin@libero.it> [210517 20:00]:
> > +static int pcs_pin_dbg_set(struct pinctrl_dev *pctldev, unsigned int pin,
> > + char *buf)
> > +{
> > + struct pcs_device *pcs;
> > + unsigned int val, mux_bytes;
> > +
> > + buf = skip_spaces(buf);
> > + if (kstrtouint(buf, 0, &val))
> > + return -EINVAL;
> > +
> > + pcs = pinctrl_dev_get_drvdata(pctldev);
> > +
> > + mux_bytes = pcs->width / BITS_PER_BYTE;
> > + pcs->write(val, pcs->base + pin * mux_bytes);
> > + return 0;
> > +}
>
> Since you're adding a new interface, how about pass unsigned
> int val instead of char *buf?
I thought about passing char *buf because it seemed more generic
to me. As the output of pin_dbg_show() depends on the platform
driver, perhaps pin_dbg_set() may need driver-dependent data.
Is it possible that only the value to be set in the register
(unsigned int) is required?
>
> > static void pcs_dt_free_map(struct pinctrl_dev *pctldev,
> > struct pinctrl_map *map, unsigned num_maps)
> > {
> > @@ -331,6 +348,9 @@ static const struct pinctrl_ops pcs_pinctrl_ops = {
> > .get_group_name = pinctrl_generic_get_group_name,
> > .get_group_pins = pinctrl_generic_get_group_pins,
> > .pin_dbg_show = pcs_pin_dbg_show,
> > +#if IS_ENABLED(CONFIG_DEVMEM)
> > + .pin_dbg_set = pcs_pin_dbg_set,
> > +#endif
> > .dt_node_to_map = pcs_dt_node_to_map,
> > .dt_free_map = pcs_dt_free_map,
> > };
>
> It might be better to always have the .pin_dbg_set around to
> avoid the IS_ENABLED(CONFIG_DEVMEM).
Ok, I'll remove the CONFIG_DEVMEM dependency
>
> Does the new interface need something under Documentation too?
Yes, the description of `pins` in Documentation/driver-api/pin-control.rst
needs to be updated. I'll add another patch to the series.
Thanks and regards,
Dario
>
> Regards,
>
> Tony
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2 0/2] am335x: set pinmux registers from pins debug file
2021-05-17 20:00 [PATCH v2 0/2] am335x: set pinmux registers from pins debug file Dario Binacchi
2021-05-17 20:00 ` [PATCH v2 2/2] pinctrl: single: set pinmux " Dario Binacchi
@ 2021-05-19 11:31 ` Andy Shevchenko
1 sibling, 0 replies; 6+ messages in thread
From: Andy Shevchenko @ 2021-05-19 11:31 UTC (permalink / raw)
To: Dario Binacchi
Cc: Linux Kernel Mailing List, Haojian Zhuang, Linus Walleij,
Tony Lindgren, linux-arm Mailing List, open list:GPIO SUBSYSTEM,
Linux OMAP Mailing List
On Wed, May 19, 2021 at 3:58 AM Dario Binacchi <dariobin@libero.it> wrote:
>
>
> The patch was born from the need to change the slew rate of the LCD pins
> of a custom AM335x board during EMC tests. The AM335x, as described in a
> note in section 9.1 of its reference manual [1], is unable to write
> pinmux registers from user space. The series now makes it possible to
> write these registers from the pins debug file.
Even for debugfs it would be nice to have a piece of documentation.
Because pin control is a quite sensitive area and if something goes
wrong, it may damage the hardware.
> [1] https://www.ti.com/lit/ug/spruh73q/spruh73q.pdf
--
With Best Regards,
Andy Shevchenko
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2 2/2] pinctrl: single: set pinmux from pins debug file
2021-05-18 8:57 ` Dario Binacchi
@ 2021-05-21 9:25 ` Tony Lindgren
0 siblings, 0 replies; 6+ messages in thread
From: Tony Lindgren @ 2021-05-21 9:25 UTC (permalink / raw)
To: Dario Binacchi
Cc: linux-kernel, Haojian Zhuang, Linus Walleij, linux-arm-kernel,
linux-gpio, linux-omap
* Dario Binacchi <dariobin@libero.it> [210518 08:57]:
> I thought about passing char *buf because it seemed more generic
> to me. As the output of pin_dbg_show() depends on the platform
> driver, perhaps pin_dbg_set() may need driver-dependent data.
> Is it possible that only the value to be set in the register
> (unsigned int) is required?
Maybe Linus W can answer this one.
Regards,
Tony
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-05-21 9:27 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-05-17 20:00 [PATCH v2 0/2] am335x: set pinmux registers from pins debug file Dario Binacchi
2021-05-17 20:00 ` [PATCH v2 2/2] pinctrl: single: set pinmux " Dario Binacchi
2021-05-18 6:05 ` Tony Lindgren
2021-05-18 8:57 ` Dario Binacchi
2021-05-21 9:25 ` Tony Lindgren
2021-05-19 11:31 ` [PATCH v2 0/2] am335x: set pinmux registers " Andy Shevchenko
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).