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@xxxxxxxxx> --- Changes in v3: - Remove CONFIG_DEV_MEM dependency. - Change pcs_pin_dbg_set() interface (char *buf -> unsigned int val). Changes in v2: - Remove CONFIG_SOC_AM33XX dependency. drivers/pinctrl/pinctrl-single.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/pinctrl/pinctrl-single.c b/drivers/pinctrl/pinctrl-single.c index 2c9c9835f375..1b75236563cf 100644 --- a/drivers/pinctrl/pinctrl-single.c +++ b/drivers/pinctrl/pinctrl-single.c @@ -313,6 +313,18 @@ 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, + unsigned int val) +{ + struct pcs_device *pcs; + unsigned int mux_bytes; + + 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 +343,7 @@ 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, + .pin_dbg_set = pcs_pin_dbg_set, .dt_node_to_map = pcs_dt_node_to_map, .dt_free_map = pcs_dt_free_map, }; -- 2.17.1
