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From: Dario Binacchi <dariobin@libero.it>
To: linux-kernel@vger.kernel.org
Cc: Dario Binacchi <dariobin@libero.it>,
	Haojian Zhuang <haojian.zhuang@linaro.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Tony Lindgren <tony@atomide.com>,
	linux-arm-kernel@lists.infradead.org, linux-gpio@vger.kernel.org,
	linux-omap@vger.kernel.org
Subject: [PATCH v2 2/2] pinctrl: single: set pinmux from pins debug file
Date: Mon, 17 May 2021 22:00:02 +0200	[thread overview]
Message-ID: <20210517200002.6316-3-dariobin@libero.it> (raw)
In-Reply-To: <20210517200002.6316-1-dariobin@libero.it>

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


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  reply	other threads:[~2021-05-17 20:02 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
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 [this message]
2021-05-18  6:05   ` [PATCH v2 2/2] pinctrl: single: set pinmux " 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

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