[PATCH v2] pinmux: allow exlusive pin allocation among GPIO and peripheral funtions via flag strict in struct pinctrl_desc

[Sonic Zhang <sonic.adi@xxxxxxxxx>]

From: Sonic Zhang <sonic.zhang@xxxxxxxxxx>

The blackfin pinmux and gpio controller doesn't allow user to set up 1 pin
for both GPIO and peripheral function. So, add flag strict in struct pinctrl
to check both gpio_owner and mux_owner before approving the pin request.

v2-changes:
- if strict flag is set, check gpio_owner and mux_onwer in if and else clause

Signed-off-by: Sonic Zhang <sonic.zhang@xxxxxxxxxx>
---
 drivers/pinctrl/pinctrl-adi2.c  |    1 +
 drivers/pinctrl/pinmux.c        |   13 +++++++++++++
 include/linux/pinctrl/pinctrl.h |    1 +
 3 files changed, 15 insertions(+)

diff --git a/drivers/pinctrl/pinctrl-adi2.c b/drivers/pinctrl/pinctrl-adi2.c
index 8434439..fbd4926 100644
--- a/drivers/pinctrl/pinctrl-adi2.c
+++ b/drivers/pinctrl/pinctrl-adi2.c
@@ -710,6 +710,7 @@ static struct pinctrl_desc adi_pinmux_desc = {
 	.name = DRIVER_NAME,
 	.pctlops = &adi_pctrl_ops,
 	.pmxops = &adi_pinmux_ops,
+	.strict = true,
 	.owner = THIS_MODULE,
 };
 
diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c
index b874458..2546fa7 100644
--- a/drivers/pinctrl/pinmux.c
+++ b/drivers/pinctrl/pinmux.c
@@ -107,6 +107,13 @@ static int pin_request(struct pinctrl_dev *pctldev,
 				desc->name, desc->gpio_owner, owner);
 			goto out;
 		}
+		if (pctldev->desc->strict && desc->mux_usecount &&
+		    strcmp(desc->mux_owner, owner)) {
+			dev_err(pctldev->dev,
+				"pin %s already requested by %s; cannot claim for %s\n",
+				desc->name, desc->mux_owner, owner);
+			goto out;
+		}
 
 		desc->gpio_owner = owner;
 	} else {
@@ -116,6 +123,12 @@ static int pin_request(struct pinctrl_dev *pctldev,
 				desc->name, desc->mux_owner, owner);
 			goto out;
 		}
+		if (pctldev->desc->strict && desc->gpio_owner) {
+			dev_err(pctldev->dev,
+				"pin %s already requested by %s; cannot claim for %s\n",
+				desc->name, desc->gpio_owner, owner);
+			goto out;
+		}
 
 		desc->mux_usecount++;
 		if (desc->mux_usecount > 1)
diff --git a/include/linux/pinctrl/pinctrl.h b/include/linux/pinctrl/pinctrl.h
index 66e4697..ca6c99c0 100644
--- a/include/linux/pinctrl/pinctrl.h
+++ b/include/linux/pinctrl/pinctrl.h
@@ -132,6 +132,7 @@ struct pinctrl_desc {
 	const struct pinctrl_ops *pctlops;
 	const struct pinmux_ops *pmxops;
 	const struct pinconf_ops *confops;
+	bool strict;
 	struct module *owner;
 #ifdef CONFIG_GENERIC_PINCONF
 	unsigned int num_custom_params;
-- 
1.7.9.5

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