[RFC] pinctrl: imx: use radix trees for groups and functions

[Gary Bisson]

This change is inspired from the pinctrl-single architecture.

The problem with current implementation is that it isn't possible
to add/remove functions and/or groups dynamically. The radix tree
offers an easy way to do so. The intent is to offer a follow-up
patch later that will enable the use of pinctrl nodes in dt-overlays.

Signed-off-by: Gary Bisson <gary.bisson@xxxxxxxxxxxxxxxxxxx>
---
Hi all,

This patch is marked as RFC since I'm not sure if it is the right approach.
The story behind it is that I've been experiencing with dt-overlays. While
pretty much everything went smoothly using the configfs patches from Pantelis,
the imx pinctrl doesn't allow to add/remove groups/functions.

To be honest I don't see much value in dt-overlays if a new pinmux group can't
be added. So I've looked at other implementation, pinctrl-single was the
primary source of inspiration.

Also, the idea behind this patch is to make it as small as possible, not
breaking the current implementation and keeping the same legacy with both
flat_funcs and old device trees supported.

Anyway, let me know your thoughts. If that's an acceptable approach, I'll
offer it as a patch plus a follow up that adds an of_notifier most likely.

Note that Pantelis suggested to do lazy allocation instead of the current
implementation but it requires a much larger change in the driver.

Regards,
Gary
---
 drivers/pinctrl/freescale/pinctrl-imx.c | 171 +++++++++++++++++++++++++++-----
 drivers/pinctrl/freescale/pinctrl-imx.h |   5 +-
 2 files changed, 148 insertions(+), 28 deletions(-)

diff --git a/drivers/pinctrl/freescale/pinctrl-imx.c b/drivers/pinctrl/freescale/pinctrl-imx.c
index 5ef7e87..460d268 100644
--- a/drivers/pinctrl/freescale/pinctrl-imx.c
+++ b/drivers/pinctrl/freescale/pinctrl-imx.c
@@ -53,10 +53,9 @@ static inline const struct imx_pin_group *imx_pinctrl_find_group_by_name(
 	int i;
 
 	for (i = 0; i < info->ngroups; i++) {
-		if (!strcmp(info->groups[i].name, name)) {
-			grp = &info->groups[i];
+		grp = radix_tree_lookup(info->pgtree, i);
+		if (grp && !strcmp(grp->name, name))
 			break;
-		}
 	}
 
 	return grp;
@@ -75,8 +74,13 @@ static const char *imx_get_group_name(struct pinctrl_dev *pctldev,
 {
 	struct imx_pinctrl *ipctl = pinctrl_dev_get_drvdata(pctldev);
 	const struct imx_pinctrl_soc_info *info = ipctl->info;
+	const struct imx_pin_group *grp = NULL;
 
-	return info->groups[selector].name;
+	grp = radix_tree_lookup(info->pgtree, selector);
+	if (!grp)
+		return NULL;
+
+	return grp->name;
 }
 
 static int imx_get_group_pins(struct pinctrl_dev *pctldev, unsigned selector,
@@ -85,12 +89,17 @@ static int imx_get_group_pins(struct pinctrl_dev *pctldev, unsigned selector,
 {
 	struct imx_pinctrl *ipctl = pinctrl_dev_get_drvdata(pctldev);
 	const struct imx_pinctrl_soc_info *info = ipctl->info;
+	const struct imx_pin_group *grp = NULL;
 
 	if (selector >= info->ngroups)
 		return -EINVAL;
 
-	*pins = info->groups[selector].pin_ids;
-	*npins = info->groups[selector].npins;
+	grp = radix_tree_lookup(info->pgtree, selector);
+	if (!grp)
+		return -EINVAL;
+
+	*pins = grp->pin_ids;
+	*npins = grp->npins;
 
 	return 0;
 }
@@ -190,17 +199,25 @@ static int imx_pmx_set(struct pinctrl_dev *pctldev, unsigned selector,
 	const struct imx_pin_reg *pin_reg;
 	unsigned int npins, pin_id;
 	int i;
-	struct imx_pin_group *grp;
+	struct imx_pin_group *grp = NULL;
+	struct imx_pmx_func *func = NULL;
 
 	/*
 	 * Configure the mux mode for each pin in the group for a specific
 	 * function.
 	 */
-	grp = &info->groups[group];
+	grp = radix_tree_lookup(info->pgtree, group);
+	if (!grp)
+		return -EINVAL;
+
+	func = radix_tree_lookup(info->ftree, selector);
+	if (!func)
+		return -EINVAL;
+
 	npins = grp->npins;
 
 	dev_dbg(ipctl->dev, "enable function %s group %s\n",
-		info->functions[selector].name, grp->name);
+		func->name, grp->name);
 
 	for (i = 0; i < npins; i++) {
 		struct imx_pin *pin = &grp->pins[i];
@@ -285,8 +302,13 @@ static const char *imx_pmx_get_func_name(struct pinctrl_dev *pctldev,
 {
 	struct imx_pinctrl *ipctl = pinctrl_dev_get_drvdata(pctldev);
 	const struct imx_pinctrl_soc_info *info = ipctl->info;
+	struct imx_pmx_func *func = NULL;
+
+	func = radix_tree_lookup(info->ftree, selector);
+	if (!func)
+		return NULL;
 
-	return info->functions[selector].name;
+	return func->name;
 }
 
 static int imx_pmx_get_groups(struct pinctrl_dev *pctldev, unsigned selector,
@@ -295,9 +317,14 @@ static int imx_pmx_get_groups(struct pinctrl_dev *pctldev, unsigned selector,
 {
 	struct imx_pinctrl *ipctl = pinctrl_dev_get_drvdata(pctldev);
 	const struct imx_pinctrl_soc_info *info = ipctl->info;
+	struct imx_pmx_func *func = NULL;
 
-	*groups = info->functions[selector].groups;
-	*num_groups = info->functions[selector].num_groups;
+	func = radix_tree_lookup(info->ftree, selector);
+	if (!func)
+		return -EINVAL;
+
+	*groups = func->groups;
+	*num_groups = func->num_groups;
 
 	return 0;
 }
@@ -323,7 +350,9 @@ static int imx_pmx_gpio_request_enable(struct pinctrl_dev *pctldev,
 
 	/* Find the pinctrl config with GPIO mux mode for the requested pin */
 	for (group = 0; group < info->ngroups; group++) {
-		grp = &info->groups[group];
+		grp = radix_tree_lookup(info->pgtree, group);
+		if (!grp)
+			continue;
 		for (pin = 0; pin < grp->npins; pin++) {
 			imx_pin = &grp->pins[pin];
 			if (imx_pin->pin == offset && !imx_pin->mux_mode)
@@ -494,7 +523,10 @@ static void imx_pinconf_group_dbg_show(struct pinctrl_dev *pctldev,
 		return;
 
 	seq_printf(s, "\n");
-	grp = &info->groups[group];
+	grp = radix_tree_lookup(info->pgtree, group);
+	if (!grp)
+		return;
+
 	for (i = 0; i < grp->npins; i++) {
 		struct imx_pin *pin = &grp->pins[i];
 		name = pin_get_name(pctldev, pin->pin);
@@ -614,7 +646,9 @@ static int imx_pinctrl_parse_functions(struct device_node *np,
 
 	dev_dbg(info->dev, "parse function(%d): %s\n", index, np->name);
 
-	func = &info->functions[index];
+	func = radix_tree_lookup(info->ftree, index);
+	if (!func)
+		return -EINVAL;
 
 	/* Initialise function */
 	func->name = np->name;
@@ -628,7 +662,16 @@ static int imx_pinctrl_parse_functions(struct device_node *np,
 
 	for_each_child_of_node(np, child) {
 		func->groups[i] = child->name;
-		grp = &info->groups[info->group_index++];
+
+		grp = devm_kzalloc(info->dev, sizeof(struct imx_pin_group),
+				   GFP_KERNEL);
+		if (!grp)
+			return -ENOMEM;
+
+		mutex_lock(&info->mutex);
+		radix_tree_insert(info->pgtree, info->group_index++, grp);
+		mutex_unlock(&info->mutex);
+
 		imx_pinctrl_parse_groups(child, grp, info, i++);
 	}
 
@@ -681,11 +724,19 @@ static int imx_pinctrl_probe_dt(struct platform_device *pdev,
 		}
 	}
 
-	info->nfunctions = nfuncs;
-	info->functions = devm_kzalloc(&pdev->dev, nfuncs * sizeof(struct imx_pmx_func),
+	for (i = 0; i < nfuncs; i++) {
+		struct imx_pmx_func *function;
+
+		function = devm_kzalloc(&pdev->dev, sizeof(*function),
 					GFP_KERNEL);
-	if (!info->functions)
-		return -ENOMEM;
+		if (!function)
+			return -ENOMEM;
+
+		mutex_lock(&info->mutex);
+		radix_tree_insert(info->ftree, i, function);
+		mutex_unlock(&info->mutex);
+	}
+	info->nfunctions = nfuncs;
 
 	info->group_index = 0;
 	if (flat_funcs) {
@@ -695,14 +746,11 @@ static int imx_pinctrl_probe_dt(struct platform_device *pdev,
 		for_each_child_of_node(np, child)
 			info->ngroups += of_get_child_count(child);
 	}
-	info->groups = devm_kzalloc(&pdev->dev, info->ngroups * sizeof(struct imx_pin_group),
-					GFP_KERNEL);
-	if (!info->groups)
-		return -ENOMEM;
 
 	if (flat_funcs) {
 		imx_pinctrl_parse_functions(np, info, 0);
 	} else {
+		i = 0;
 		for_each_child_of_node(np, child)
 			imx_pinctrl_parse_functions(child, info, i++);
 	}
@@ -710,6 +758,59 @@ static int imx_pinctrl_probe_dt(struct platform_device *pdev,
 	return 0;
 }
 
+/*
+ * imx_free_funcs() - free memory used by functions
+ * @info: info driver instance
+ */
+static void imx_free_funcs(const struct imx_pinctrl_soc_info *info)
+{
+	int i;
+
+	mutex_lock((struct mutex*)&info->mutex);
+	for (i = 0; i < info->nfunctions; i++) {
+		struct imx_pmx_func *func;
+
+		func = radix_tree_lookup(info->ftree, i);
+		if (!func)
+			continue;
+		radix_tree_delete(info->ftree, i);
+	}
+	mutex_unlock((struct mutex*)&info->mutex);
+}
+
+/*
+ * imx_free_pingroups() - free memory used by pingroups
+ * @info: info driver instance
+ */
+static void imx_free_pingroups(const struct imx_pinctrl_soc_info *info)
+{
+	int i;
+
+	mutex_lock((struct mutex*)&info->mutex);
+	for (i = 0; i < info->ngroups; i++) {
+		struct imx_pin_group *pingroup;
+
+		pingroup = radix_tree_lookup(info->pgtree, i);
+		if (!pingroup)
+			continue;
+		radix_tree_delete(info->pgtree, i);
+	}
+	mutex_unlock((struct mutex*)&info->mutex);
+}
+
+/*
+ * imx_free_resources() - free memory used by this driver
+ * @info: info driver instance
+ */
+static void imx_free_resources(const struct imx_pinctrl *ipctl)
+{
+	if (ipctl->pctl)
+		pinctrl_unregister(ipctl->pctl);
+
+	imx_free_funcs(ipctl->info);
+	imx_free_pingroups(ipctl->info);
+}
+
 int imx_pinctrl_probe(struct platform_device *pdev,
 		      struct imx_pinctrl_soc_info *info)
 {
@@ -783,10 +884,22 @@ int imx_pinctrl_probe(struct platform_device *pdev,
 	imx_pinctrl_desc->confops = &imx_pinconf_ops;
 	imx_pinctrl_desc->owner = THIS_MODULE;
 
+	mutex_init(&info->mutex);
+
+	info->ftree = devm_kzalloc(&pdev->dev, sizeof(struct radix_tree_root),
+				   GFP_KERNEL);
+	info->pgtree = devm_kzalloc(&pdev->dev, sizeof(struct radix_tree_root),
+				    GFP_KERNEL);
+	if (!info->ftree || !info->pgtree)
+		return -ENOMEM;
+
+	INIT_RADIX_TREE(info->pgtree, GFP_KERNEL);
+	INIT_RADIX_TREE(info->ftree, GFP_KERNEL);
+
 	ret = imx_pinctrl_probe_dt(pdev, info);
 	if (ret) {
 		dev_err(&pdev->dev, "fail to probe dt properties\n");
-		return ret;
+		goto free;
 	}
 
 	ipctl->info = info;
@@ -796,10 +909,16 @@ int imx_pinctrl_probe(struct platform_device *pdev,
 					    imx_pinctrl_desc, ipctl);
 	if (IS_ERR(ipctl->pctl)) {
 		dev_err(&pdev->dev, "could not register IMX pinctrl driver\n");
-		return PTR_ERR(ipctl->pctl);
+		ret = PTR_ERR(ipctl->pctl);
+		goto free;
 	}
 
 	dev_info(&pdev->dev, "initialized IMX pinctrl driver\n");
 
 	return 0;
+
+free:
+	imx_free_resources(ipctl);
+
+	return ret;
 }
diff --git a/drivers/pinctrl/freescale/pinctrl-imx.h b/drivers/pinctrl/freescale/pinctrl-imx.h
index 8af8aa2..34ad2d7 100644
--- a/drivers/pinctrl/freescale/pinctrl-imx.h
+++ b/drivers/pinctrl/freescale/pinctrl-imx.h
@@ -76,13 +76,14 @@ struct imx_pinctrl_soc_info {
 	const struct pinctrl_pin_desc *pins;
 	unsigned int npins;
 	struct imx_pin_reg *pin_regs;
-	struct imx_pin_group *groups;
 	unsigned int ngroups;
 	unsigned int group_index;
-	struct imx_pmx_func *functions;
 	unsigned int nfunctions;
 	unsigned int flags;
 	const char *gpr_compatible;
+	struct radix_tree_root *ftree;
+	struct radix_tree_root *pgtree;
+	struct mutex mutex;
 };
 
 #define SHARE_MUX_CONF_REG	0x1
-- 
2.9.3