* [PATCH 0/2] am335x: set pinmux registers from pins debug file
@ 2021-05-16 13:55 Dario Binacchi
2021-05-16 13:55 ` [PATCH 2/2] pinctrl: single: set pinmux " Dario Binacchi
0 siblings, 1 reply; 3+ messages in thread
From: Dario Binacchi @ 2021-05-16 13:55 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
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
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH 2/2] pinctrl: single: set pinmux from pins debug file
2021-05-16 13:55 [PATCH 0/2] am335x: set pinmux registers from pins debug file Dario Binacchi
@ 2021-05-16 13:55 ` Dario Binacchi
2021-05-17 5:57 ` Tony Lindgren
0 siblings, 1 reply; 3+ messages in thread
From: Dario Binacchi @ 2021-05-16 13:55 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>
---
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..cdbc2298360d 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) && IS_ENABLED(CONFIG_SOC_AM33XX)
+ .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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 2/2] pinctrl: single: set pinmux from pins debug file
2021-05-16 13:55 ` [PATCH 2/2] pinctrl: single: set pinmux " Dario Binacchi
@ 2021-05-17 5:57 ` Tony Lindgren
0 siblings, 0 replies; 3+ messages in thread
From: Tony Lindgren @ 2021-05-17 5:57 UTC (permalink / raw)
To: Dario Binacchi
Cc: linux-kernel, Haojian Zhuang, Linus Walleij, linux-arm-kernel,
linux-gpio, linux-omap
Hi,
* Dario Binacchi <dariobin@libero.it> [210516 13:55]:
> @@ -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) && IS_ENABLED(CONFIG_SOC_AM33XX)
> + .pin_dbg_set = pcs_pin_dbg_set,
> +#endif
> .dt_node_to_map = pcs_dt_node_to_map,
> .dt_free_map = pcs_dt_free_map,
> };
I don't think there should be any CONFIG_SOC_AM33XX dependency here?
Regards,
Tony
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-05-16 13:55 [PATCH 0/2] am335x: set pinmux registers from pins debug file Dario Binacchi
2021-05-16 13:55 ` [PATCH 2/2] pinctrl: single: set pinmux " Dario Binacchi
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