0008-bone-pinmux-helper-Add-support-for-mode-device-tree-.patch

From 09fc2898db65eb52d0928440aa8dd20776227bef Mon Sep 17 00:00:00 2001
From: Charles Steinkuehler <charles@steinkuehler.net>
Date: Tue, 16 Sep 2014 20:42:56 +0000
Subject: [PATCH 08/19] bone-pinmux-helper: Add support for "mode" device-tree
 parameter

The new mode parameter is used to set the initial pinmux mode to
something other than "default" or NULL, which is what happens currently. This
allows enabling SoC hardware via device-tree which requires specific pinmux
settings to function on boot, but still leaves the pinmux register under
control of the bone-pinmux- helper driver meaning the pinmux setting can be
changed at run time via user-mode access to sysfs.

Signed-off-by: Charles Steinkuehler <charles@steinkuehler.net>
---
 drivers/misc/cape/beaglebone/bone-pinmux-helper.c | 58 ++++++++++++++++++-----
 1 file changed, 47 insertions(+), 11 deletions(-)

diff --git a/drivers/misc/cape/beaglebone/bone-pinmux-helper.c b/drivers/misc/cape/beaglebone/bone-pinmux-helper.c
index 5074365..d81363a 100644
--- a/drivers/misc/cape/beaglebone/bone-pinmux-helper.c
+++ b/drivers/misc/cape/beaglebone/bone-pinmux-helper.c
@@ -117,6 +117,8 @@ static int bone_pinmux_helper_probe(struct platform_device *pdev)
 	struct pinmux_helper_data *data;
 	struct pinctrl_state *state;
 	char *state_name;
+	const char *mode_name;
+	int mode_len;
 	int err;
 
 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
@@ -125,12 +127,13 @@ static int bone_pinmux_helper_probe(struct platform_device *pdev)
 		err = -ENOMEM;
 		goto err_no_mem;
 	}
+
 	state_name = kmalloc(strlen(PINCTRL_STATE_DEFAULT) + 1,
 			GFP_KERNEL);
 	if (state_name == NULL) {
 		dev_err(dev, "Failed to allocate state name\n");
 		err = -ENOMEM;
-		goto err_no_mem;
+		goto err_no_state_mem;
 	}
 	data->selected_state_name = state_name;
 	strcpy(data->selected_state_name, PINCTRL_STATE_DEFAULT);
@@ -144,17 +147,47 @@ static int bone_pinmux_helper_probe(struct platform_device *pdev)
 		goto err_no_pinctrl;
 	}
 
-	/* try to select default state at first (if it exists) */
-	state = pinctrl_lookup_state(data->pinctrl,
-			data->selected_state_name);
-	if (!IS_ERR(state)) {
-		err = pinctrl_select_state(data->pinctrl, state);
-		if (err != 0) {
-			dev_err(dev, "Failed to select default state\n");
-			goto err_no_state;
+	/* See if an initial mode is specified in the device tree */
+	mode_name = of_get_property(dev->of_node, "mode", &mode_len);
+
+	err = -1;
+	if (mode_name != NULL ) {
+		state_name = kmalloc(mode_len + 1, GFP_KERNEL);
+		if (state_name == NULL) {
+			dev_err(dev, "Failed to allocate state name\n");
+			err = -ENOMEM;
+			goto err_no_mode_mem;
+		}
+		strncpy(state_name, mode_name, mode_len);
+
+		/* try to select requested mode */
+		state = pinctrl_lookup_state(data->pinctrl, state_name);
+		if (!IS_ERR(state)) {
+			err = pinctrl_select_state(data->pinctrl, state);
+			if (err != 0) {
+				dev_warn(dev, "Unable to select requested mode %s\n", state_name);
+				kfree(state_name);
+			} else {
+				kfree(data->selected_state_name);
+				data->selected_state_name = state_name;
+				dev_notice(dev, "Set initial pinmux mode to %s\n", state_name);
+			}
+		}
+	}
+
+	/* try to select default state if mode_name failed */
+	if ( err != 0) {
+		state = pinctrl_lookup_state(data->pinctrl,
+				data->selected_state_name);
+		if (!IS_ERR(state)) {
+			err = pinctrl_select_state(data->pinctrl, state);
+			if (err != 0) {
+				dev_err(dev, "Failed to select default state\n");
+				goto err_no_state;
+			}
+		} else {
+			data->selected_state_name = '\0';
 		}
-	} else {
-		data->selected_state_name = '\0';
 	}
 
 	/* Register sysfs hooks */
@@ -168,8 +201,11 @@ static int bone_pinmux_helper_probe(struct platform_device *pdev)
 
 err_no_sysfs:
 err_no_state:
+err_no_mode_mem:
 	devm_pinctrl_put(data->pinctrl);
 err_no_pinctrl:
+	devm_kfree(dev, data->selected_state_name);
+err_no_state_mem:
 	devm_kfree(dev, data);
 err_no_mem:
 	return err;
-- 
2.10.1