linux-kernel - [PATCH 2/2] pinctrl: zynqmp: Support muxing individual pins

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Message-Id: <20240503162217.1999467-3-sean.anderson@linux.dev>
Date: Fri,  3 May 2024 12:22:17 -0400
From: Sean Anderson <sean.anderson@...ux.dev>
To: Linus Walleij <linus.walleij@...aro.org>,
	Michal Simek <michal.simek@....com>,
	linux-gpio@...r.kernel.org
Cc: Krishna Potthuri <sai.krishna.potthuri@....com>,
	linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	Sean Anderson <sean.anderson@...ux.dev>
Subject: [PATCH 2/2] pinctrl: zynqmp: Support muxing individual pins

While muxing groups of pins at once can be convenient for large
interfaces, it can also be rigid. This is because the group is set to
all pins which support a particular function, even though not all pins
may be used. For example, the sdhci0 function may be used with a 8-bit
eMMC, 4-bit SD card, or even a 1-bit SD card. In these cases, the extra
pins may be repurposed for other uses, but this is not currently
allowed.

Add a new group for each pin which can be muxed. These groups are part
of each function the pin can be muxed to. We treat group selectors
beyond the number of groups as "pin" groups. To set this up, we
initialize groups before functions, and then create a bitmap of used
pins for each function. These used pins are appended to the function's
list of groups.

Signed-off-by: Sean Anderson <sean.anderson@...ux.dev>
---

 drivers/pinctrl/pinctrl-zynqmp.c | 61 ++++++++++++++++++++++----------
 1 file changed, 43 insertions(+), 18 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-zynqmp.c b/drivers/pinctrl/pinctrl-zynqmp.c
index 5c46b7d7ebcb..4829150ab069 100644
--- a/drivers/pinctrl/pinctrl-zynqmp.c
+++ b/drivers/pinctrl/pinctrl-zynqmp.c
@@ -10,6 +10,7 @@
 
 #include <dt-bindings/pinctrl/pinctrl-zynqmp.h>
 
+#include <linux/bitmap.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
@@ -97,7 +98,7 @@ static int zynqmp_pctrl_get_groups_count(struct pinctrl_dev *pctldev)
 {
 	struct zynqmp_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
 
-	return pctrl->ngroups;
+	return pctrl->ngroups + zynqmp_desc.npins;
 }
 
 static const char *zynqmp_pctrl_get_group_name(struct pinctrl_dev *pctldev,
@@ -105,7 +106,10 @@ static const char *zynqmp_pctrl_get_group_name(struct pinctrl_dev *pctldev,
 {
 	struct zynqmp_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
 
-	return pctrl->groups[selector].name;
+	if (selector < pctrl->ngroups)
+		return pctrl->groups[selector].name;
+
+	return zynqmp_desc.pins[selector - pctrl->ngroups].name;
 }
 
 static int zynqmp_pctrl_get_group_pins(struct pinctrl_dev *pctldev,
@@ -115,8 +119,13 @@ static int zynqmp_pctrl_get_group_pins(struct pinctrl_dev *pctldev,
 {
 	struct zynqmp_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
 
-	*pins = pctrl->groups[selector].pins;
-	*npins = pctrl->groups[selector].npins;
+	if (selector < pctrl->ngroups) {
+		*pins = pctrl->groups[selector].pins;
+		*npins = pctrl->groups[selector].npins;
+	} else {
+		*pins = &zynqmp_desc.pins[selector - pctrl->ngroups].number;
+		*npins = 1;
+	}
 
 	return 0;
 }
@@ -560,10 +569,12 @@ static int zynqmp_pinctrl_prepare_func_groups(struct device *dev, u32 fid,
 {
 	u16 resp[NUM_GROUPS_PER_RESP] = {0};
 	const char **fgroups;
-	int ret, index, i;
+	int ret, index, i, pin;
+	unsigned int npins;
+	unsigned long *used_pins __free(bitmap) =
+		bitmap_zalloc(zynqmp_desc.npins, GFP_KERNEL);
 
-	fgroups = devm_kcalloc(dev, func->ngroups, sizeof(*fgroups), GFP_KERNEL);
-	if (!fgroups)
+	if (!used_pins)
 		return -ENOMEM;
 
 	for (index = 0; index < func->ngroups; index += NUM_GROUPS_PER_RESP) {
@@ -578,23 +589,37 @@ static int zynqmp_pinctrl_prepare_func_groups(struct device *dev, u32 fid,
 			if (resp[i] == RESERVED_GROUP)
 				continue;
 
-			fgroups[index + i] = devm_kasprintf(dev, GFP_KERNEL,
-							    "%s_%d_grp",
-							    func->name,
-							    index + i);
-			if (!fgroups[index + i])
-				return -ENOMEM;
-
 			groups[resp[i]].name = devm_kasprintf(dev, GFP_KERNEL,
 							      "%s_%d_grp",
 							      func->name,
 							      index + i);
 			if (!groups[resp[i]].name)
 				return -ENOMEM;
+
+			for (pin = 0; pin < groups[resp[i]].npins; pin++)
+				set_bit(groups[resp[i]].pins[pin], used_pins);
 		}
 	}
 done:
+	npins = bitmap_weight(used_pins, zynqmp_desc.npins);
+	fgroups = devm_kcalloc(dev, func->ngroups + npins, sizeof(*fgroups),
+			       GFP_KERNEL);
+	if (!fgroups)
+		return -ENOMEM;
+
+	for (i = 0; i < func->ngroups; i++) {
+		fgroups[i] = devm_kasprintf(dev, GFP_KERNEL, "%s_%d_grp",
+					    func->name, i);
+		if (!fgroups[i])
+			return -ENOMEM;
+	}
+
+	pin = 0;
+	for_each_set_bit(pin, used_pins, zynqmp_desc.npins)
+		fgroups[i++] = zynqmp_desc.pins[pin].name;
+
 	func->groups = fgroups;
+	func->ngroups += npins;
 
 	return 0;
 }
@@ -772,6 +797,10 @@ static int zynqmp_pinctrl_prepare_function_info(struct device *dev,
 	if (!groups)
 		return -ENOMEM;
 
+	ret = zynqmp_pinctrl_prepare_group_pins(dev, groups, pctrl->ngroups);
+	if (ret)
+		return ret;
+
 	for (i = 0; i < pctrl->nfuncs; i++) {
 		ret = zynqmp_pinctrl_prepare_func_groups(dev, i, &funcs[i],
 							 groups);
@@ -779,10 +808,6 @@ static int zynqmp_pinctrl_prepare_function_info(struct device *dev,
 			return ret;
 	}
 
-	ret = zynqmp_pinctrl_prepare_group_pins(dev, groups, pctrl->ngroups);
-	if (ret)
-		return ret;
-
 	pctrl->funcs = funcs;
 	pctrl->groups = groups;
 
-- 
2.35.1.1320.gc452695387.dirty