pinctrl: aspeed: Split out pinmux from general pinctrl

ASPEED have completely rearranged the System Control Unit register
layout with the AST2600. The existing code took advantage of the fact
that the AST2400 and AST2500 had layouts that were similar enough to
have little impact on the pinmux infrastructure (though there is a wart
with read-modify-write vs write-1-clear semantics of the hardware
strapping registers between the two).

Given that any similarity has been thrown out with the AST2600, separate
out the function applying an expression state to be driver-specific.
With it, extract out the pinmux macro jungle to its own header and
implementation so the pieces can be composed without dependency cycles.

Cc: Johnny Huang <johnny_huang@aspeedtech.com>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Link: https://lore.kernel.org/r/20190628023838.15426-8-andrew@aj.id.auSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/aspeed/Makefile

 # Aspeed pinctrl support
 
 ccflags-y += $(call cc-option,-Woverride-init)
-obj-$(CONFIG_PINCTRL_ASPEED)	+= pinctrl-aspeed.o
+obj-$(CONFIG_PINCTRL_ASPEED)	+= pinctrl-aspeed.o pinmux-aspeed.o
 obj-$(CONFIG_PINCTRL_ASPEED_G4)	+= pinctrl-aspeed-g4.o
 obj-$(CONFIG_PINCTRL_ASPEED_G5)	+= pinctrl-aspeed-g5.o

drivers/pinctrl/aspeed/pinctrl-aspeed-g4.c

@@ -22,8 +22,34 @@
 
 #include "../core.h"
 #include "../pinctrl-utils.h"
+#include "pinmux-aspeed.h"
 #include "pinctrl-aspeed.h"
 
+/*
+ * The "Multi-function Pins Mapping and Control" table in the SoC datasheet
+ * references registers by the device/offset mnemonic. The register macros
+ * below are named the same way to ease transcription and verification (as
+ * opposed to naming them e.g. PINMUX_CTRL_[0-9]). Further, signal expressions
+ * reference registers beyond those dedicated to pinmux, such as the system
+ * reset control and MAC clock configuration registers.
+ */
+#define SCU2C           0x2C /* Misc. Control Register */
+#define SCU3C           0x3C /* System Reset Control/Status Register */
+#define SCU48           0x48 /* MAC Interface Clock Delay Setting */
+#define HW_STRAP1       0x70 /* AST2400 strapping is 33 bits, is split */
+#define HW_REVISION_ID  0x7C /* Silicon revision ID register */
+#define SCU80           0x80 /* Multi-function Pin Control #1 */
+#define SCU84           0x84 /* Multi-function Pin Control #2 */
+#define SCU88           0x88 /* Multi-function Pin Control #3 */
+#define SCU8C           0x8C /* Multi-function Pin Control #4 */
+#define SCU90           0x90 /* Multi-function Pin Control #5 */
+#define SCU94           0x94 /* Multi-function Pin Control #6 */
+#define SCUA0           0xA0 /* Multi-function Pin Control #7 */
+#define SCUA4           0xA4 /* Multi-function Pin Control #8 */
+#define SCUA8           0xA8 /* Multi-function Pin Control #9 */
+#define SCUAC           0xAC /* Multi-function Pin Control #10 */
+#define HW_STRAP2       0xD0 /* Strapping */
+
 /*
  * Uses undefined macros for symbol naming and references, eg GPIOA0, MAC1LINK,
  * TIMER3 etc.
@@ -2390,13 +2416,73 @@ static const struct aspeed_pin_config aspeed_g4_configs[] = {
 	{ PIN_CONFIG_INPUT_DEBOUNCE, { C14, B14 }, SCUA8, 27 },
 };
 
+static int aspeed_g4_sig_expr_set(const struct aspeed_pinmux_data *ctx,
+				  const struct aspeed_sig_expr *expr,
+				  bool enable)
+{
+	int ret;
+	int i;
+
+	for (i = 0; i < expr->ndescs; i++) {
+		const struct aspeed_sig_desc *desc = &expr->descs[i];
+		u32 pattern = enable ? desc->enable : desc->disable;
+		u32 val = (pattern << __ffs(desc->mask));
+
+		if (!ctx->maps[desc->ip])
+			return -ENODEV;
+
+		/*
+		 * Strap registers are configured in hardware or by early-boot
+		 * firmware. Treat them as read-only despite that we can write
+		 * them. This may mean that certain functions cannot be
+		 * deconfigured and is the reason we re-evaluate after writing
+		 * all descriptor bits.
+		 *
+		 * Port D and port E GPIO loopback modes are the only exception
+		 * as those are commonly used with front-panel buttons to allow
+		 * normal operation of the host when the BMC is powered off or
+		 * fails to boot. Once the BMC has booted, the loopback mode
+		 * must be disabled for the BMC to control host power-on and
+		 * reset.
+		 */
+		if (desc->ip == ASPEED_IP_SCU && desc->reg == HW_STRAP1 &&
+		    !(desc->mask & (BIT(21) | BIT(22))))
+			continue;
+
+		if (desc->ip == ASPEED_IP_SCU && desc->reg == HW_STRAP2)
+			continue;
+
+		ret = regmap_update_bits(ctx->maps[desc->ip], desc->reg,
+					 desc->mask, val);
+
+		if (ret)
+			return ret;
+	}
+
+	ret = aspeed_sig_expr_eval(ctx, expr, enable);
+	if (ret < 0)
+		return ret;
+
+	if (!ret)
+		return -EPERM;
+
+	return 0;
+}
+
+static const struct aspeed_pinmux_ops aspeed_g4_ops = {
+	.set = aspeed_g4_sig_expr_set,
+};
+
 static struct aspeed_pinctrl_data aspeed_g4_pinctrl_data = {
 	.pins = aspeed_g4_pins,
 	.npins = ARRAY_SIZE(aspeed_g4_pins),
-	.groups = aspeed_g4_groups,
-	.ngroups = ARRAY_SIZE(aspeed_g4_groups),
-	.functions = aspeed_g4_functions,
-	.nfunctions = ARRAY_SIZE(aspeed_g4_functions),
+	.pinmux = {
+		.ops = &aspeed_g4_ops,
+		.groups = aspeed_g4_groups,
+		.ngroups = ARRAY_SIZE(aspeed_g4_groups),
+		.functions = aspeed_g4_functions,
+		.nfunctions = ARRAY_SIZE(aspeed_g4_functions),
+	},
 	.configs = aspeed_g4_configs,
 	.nconfigs = ARRAY_SIZE(aspeed_g4_configs),
 };

drivers/pinctrl/aspeed/pinctrl-aspeed-g5.c

@@ -25,6 +25,32 @@
 #include "../pinctrl-utils.h"
 #include "pinctrl-aspeed.h"
 
+/*
+ * The "Multi-function Pins Mapping and Control" table in the SoC datasheet
+ * references registers by the device/offset mnemonic. The register macros
+ * below are named the same way to ease transcription and verification (as
+ * opposed to naming them e.g. PINMUX_CTRL_[0-9]). Further, signal expressions
+ * reference registers beyond those dedicated to pinmux, such as the system
+ * reset control and MAC clock configuration registers. The AST2500 goes a step
+ * further and references registers in the graphics IP block.
+ */
+#define SCU2C           0x2C /* Misc. Control Register */
+#define SCU3C           0x3C /* System Reset Control/Status Register */
+#define SCU48           0x48 /* MAC Interface Clock Delay Setting */
+#define HW_STRAP1       0x70 /* AST2400 strapping is 33 bits, is split */
+#define HW_REVISION_ID  0x7C /* Silicon revision ID register */
+#define SCU80           0x80 /* Multi-function Pin Control #1 */
+#define SCU84           0x84 /* Multi-function Pin Control #2 */
+#define SCU88           0x88 /* Multi-function Pin Control #3 */
+#define SCU8C           0x8C /* Multi-function Pin Control #4 */
+#define SCU90           0x90 /* Multi-function Pin Control #5 */
+#define SCU94           0x94 /* Multi-function Pin Control #6 */
+#define SCUA0           0xA0 /* Multi-function Pin Control #7 */
+#define SCUA4           0xA4 /* Multi-function Pin Control #8 */
+#define SCUA8           0xA8 /* Multi-function Pin Control #9 */
+#define SCUAC           0xAC /* Multi-function Pin Control #10 */
+#define HW_STRAP2       0xD0 /* Strapping */
+
 #define ASPEED_G5_NR_PINS 236
 
 #define COND1		{ ASPEED_IP_SCU, SCU90, BIT(6), 0, 0 }
@@ -2485,13 +2511,98 @@ static struct aspeed_pin_config aspeed_g5_configs[] = {
 	{ PIN_CONFIG_INPUT_DEBOUNCE, { A20, B19 }, SCUA8, 27 },
 };
 
+/**
+ * Configure a pin's signal by applying an expression's descriptor state for
+ * all descriptors in the expression.
+ *
+ * @ctx: The pinmux context
+ * @expr: The expression associated with the function whose signal is to be
+ *        configured
+ * @enable: true to enable an function's signal through a pin's signal
+ *          expression, false to disable the function's signal
+ *
+ * Return: 0 if the expression is configured as requested and a negative error
+ * code otherwise
+ */
+static int aspeed_g5_sig_expr_set(const struct aspeed_pinmux_data *ctx,
+				  const struct aspeed_sig_expr *expr,
+				  bool enable)
+{
+	int ret;
+	int i;
+
+	for (i = 0; i < expr->ndescs; i++) {
+		const struct aspeed_sig_desc *desc = &expr->descs[i];
+		u32 pattern = enable ? desc->enable : desc->disable;
+		u32 val = (pattern << __ffs(desc->mask));
+
+		if (!ctx->maps[desc->ip])
+			return -ENODEV;
+
+		/*
+		 * Strap registers are configured in hardware or by early-boot
+		 * firmware. Treat them as read-only despite that we can write
+		 * them. This may mean that certain functions cannot be
+		 * deconfigured and is the reason we re-evaluate after writing
+		 * all descriptor bits.
+		 *
+		 * Port D and port E GPIO loopback modes are the only exception
+		 * as those are commonly used with front-panel buttons to allow
+		 * normal operation of the host when the BMC is powered off or
+		 * fails to boot. Once the BMC has booted, the loopback mode
+		 * must be disabled for the BMC to control host power-on and
+		 * reset.
+		 */
+		if (desc->ip == ASPEED_IP_SCU && desc->reg == HW_STRAP1 &&
+		    !(desc->mask & (BIT(21) | BIT(22))))
+			continue;
+
+		if (desc->ip == ASPEED_IP_SCU && desc->reg == HW_STRAP2)
+			continue;
+
+		/* On AST2500, Set bits in SCU70 are cleared from SCU7C */
+		if (desc->ip == ASPEED_IP_SCU && desc->reg == HW_STRAP1) {
+			u32 value = ~val & desc->mask;
+
+			if (value) {
+				ret = regmap_write(ctx->maps[desc->ip],
+						   HW_REVISION_ID, value);
+				if (ret < 0)
+					return ret;
+			}
+		}
+
+		ret = regmap_update_bits(ctx->maps[desc->ip], desc->reg,
+					 desc->mask, val);
+
+		if (ret)
+			return ret;
+	}
+
+	ret = aspeed_sig_expr_eval(ctx, expr, enable);
+	if (ret < 0)
+		return ret;
+
+	if (!ret)
+		return -EPERM;
+
+	return 0;
+}
+
+static const struct aspeed_pinmux_ops aspeed_g5_ops = {
+	.set = aspeed_g5_sig_expr_set,
+};
+
 static struct aspeed_pinctrl_data aspeed_g5_pinctrl_data = {
 	.pins = aspeed_g5_pins,
 	.npins = ARRAY_SIZE(aspeed_g5_pins),
-	.groups = aspeed_g5_groups,
-	.ngroups = ARRAY_SIZE(aspeed_g5_groups),
-	.functions = aspeed_g5_functions,
-	.nfunctions = ARRAY_SIZE(aspeed_g5_functions),
+	.pinmux = {
+		.ops = &aspeed_g5_ops,
+		.groups = aspeed_g5_groups,
+		.ngroups = ARRAY_SIZE(aspeed_g5_groups),
+		.functions = aspeed_g5_functions,
+		.nfunctions = ARRAY_SIZE(aspeed_g5_functions),
+	},
 	.configs = aspeed_g5_configs,
 	.nconfigs = ARRAY_SIZE(aspeed_g5_configs),
 };
@@ -2547,7 +2658,7 @@ static int aspeed_g5_pinctrl_probe(struct platform_device *pdev)
 		dev_warn(&pdev->dev, "No GFX phandle found, some mux configurations may fail\n");
 		map = NULL;
 	}
-	aspeed_g5_pinctrl_data.maps[ASPEED_IP_GFX] = map;
+	aspeed_g5_pinctrl_data.pinmux.maps[ASPEED_IP_GFX] = map;
 
 	node = of_parse_phandle(pdev->dev.of_node, "aspeed,external-nodes", 1);
 	if (node) {
@@ -2561,7 +2672,7 @@ static int aspeed_g5_pinctrl_probe(struct platform_device *pdev)
 		map = NULL;
 	}
 	of_node_put(node);
-	aspeed_g5_pinctrl_data.maps[ASPEED_IP_LPC] = map;
+	aspeed_g5_pinctrl_data.pinmux.maps[ASPEED_IP_LPC] = map;
 
 	return aspeed_pinctrl_probe(pdev, &aspeed_g5_pinctrl_desc,
 			&aspeed_g5_pinctrl_data);

drivers/pinctrl/aspeed/pinctrl-aspeed.h

@@ -528,22 +528,6 @@ struct aspeed_pin_config {
 	u8 value;
 };
 
-struct aspeed_pinctrl_data {
-	struct regmap *maps[ASPEED_NR_PINMUX_IPS];
-
-	const struct pinctrl_pin_desc *pins;
-	const unsigned int npins;
-
-	const struct aspeed_pin_group *groups;
-	const unsigned int ngroups;
-
-	const struct aspeed_pin_function *functions;
-	const unsigned int nfunctions;
-
-	const struct aspeed_pin_config *configs;
-	const unsigned int nconfigs;
-};
-
 #define ASPEED_PINCTRL_PIN(name_) \
 	[name_] = { \
 		.number = name_, \
@@ -551,30 +535,19 @@ struct aspeed_pinctrl_data {
 		.drv_data = (void *) &(PIN_SYM(name_)) \
 	}
 
-struct aspeed_pin_group {
-	const char *name;
-	const unsigned int *pins;
+struct aspeed_pinctrl_data {
+	struct regmap *scu;
+
+	const struct pinctrl_pin_desc *pins;
 	const unsigned int npins;
-};
 
-#define ASPEED_PINCTRL_GROUP(name_) { \
-	.name = #name_, \
-	.pins = &(PIN_GROUP_SYM(name_))[0], \
-	.npins = ARRAY_SIZE(PIN_GROUP_SYM(name_)), \
-}
+	const struct aspeed_pin_config *configs;
+	const unsigned int nconfigs;
 
-struct aspeed_pin_function {
-	const char *name;
-	const char *const *groups;
-	unsigned int ngroups;
+	struct aspeed_pinmux_data pinmux;
 };
 
-#define ASPEED_PINCTRL_FUNC(name_, ...) { \
-	.name = #name_, \
-	.groups = &FUNC_GROUP_SYM(name_)[0], \
-	.ngroups = ARRAY_SIZE(FUNC_GROUP_SYM(name_)), \
-}
-
+/* Aspeed pinctrl helpers */
 int aspeed_pinctrl_get_groups_count(struct pinctrl_dev *pctldev);
 const char *aspeed_pinctrl_get_group_name(struct pinctrl_dev *pctldev,
 		unsigned int group);

drivers/pinctrl/aspeed/pinmux-aspeed.c

+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Copyright (C) 2019 IBM Corp. */
+
+/* Pieces to enable drivers to implement the .set callback */
+
+#include "pinmux-aspeed.h"
+
+const char *const aspeed_pinmux_ips[] = {
+	[ASPEED_IP_SCU] = "SCU",
+	[ASPEED_IP_GFX] = "GFX",
+	[ASPEED_IP_LPC] = "LPC",
+};
+
+static inline void aspeed_sig_desc_print_val(
+		const struct aspeed_sig_desc *desc, bool enable, u32 rv)
+{
+	pr_debug("Want %s%X[0x%08X]=0x%X, got 0x%X from 0x%08X\n",
+			aspeed_pinmux_ips[desc->ip], desc->reg,
+			desc->mask, enable ? desc->enable : desc->disable,
+			(rv & desc->mask) >> __ffs(desc->mask), rv);
+}
+
+/**
+ * Query the enabled or disabled state of a signal descriptor
+ *
+ * @desc: The signal descriptor of interest
+ * @enabled: True to query the enabled state, false to query disabled state
+ * @map: The IP block's regmap instance
+ *
+ * Return: 1 if the descriptor's bitfield is configured to the state
+ * selected by @enabled, 0 if not, and less than zero if an unrecoverable
+ * failure occurred
+ *
+ * Evaluation of descriptor state is non-trivial in that it is not a binary
+ * outcome: The bitfields can be greater than one bit in size and thus can take
+ * a value that is neither the enabled nor disabled state recorded in the
+ * descriptor (typically this means a different function to the one of interest
+ * is enabled). Thus we must explicitly test for either condition as required.
+ */
+int aspeed_sig_desc_eval(const struct aspeed_sig_desc *desc,
+			 bool enabled, struct regmap *map)
+{
+	int ret;
+	unsigned int raw;
+	u32 want;
+
+	if (!map)
+		return -ENODEV;
+
+	ret = regmap_read(map, desc->reg, &raw);
+	if (ret)
+		return ret;
+
+	aspeed_sig_desc_print_val(desc, enabled, raw);
+	want = enabled ? desc->enable : desc->disable;
+
+	return ((raw & desc->mask) >> __ffs(desc->mask)) == want;
+}
+
+/**
+ * Query the enabled or disabled state for a mux function's signal on a pin
+ *
+ * @ctx: The driver context for the pinctrl IP
+ * @expr: An expression controlling the signal for a mux function on a pin
+ * @enabled: True to query the enabled state, false to query disabled state
+ *
+ * Return: 1 if the expression composed by @enabled evaluates true, 0 if not,
+ * and less than zero if an unrecoverable failure occurred.
+ *
+ * A mux function is enabled or disabled if the function's signal expression
+ * for each pin in the function's pin group evaluates true for the desired
+ * state. An signal expression evaluates true if all of its associated signal
+ * descriptors evaluate true for the desired state.
+ *
+ * If an expression's state is described by more than one bit, either through
+ * multi-bit bitfields in a single signal descriptor or through multiple signal
+ * descriptors of a single bit then it is possible for the expression to be in
+ * neither the enabled nor disabled state. Thus we must explicitly test for
+ * either condition as required.
+ */
+int aspeed_sig_expr_eval(const struct aspeed_pinmux_data *ctx,
+			 const struct aspeed_sig_expr *expr, bool enabled)
+{
+	int i;
+	int ret;
+
+	for (i = 0; i < expr->ndescs; i++) {
+		const struct aspeed_sig_desc *desc = &expr->descs[i];
+
+		ret = aspeed_sig_desc_eval(desc, enabled, ctx->maps[desc->ip]);
+		if (ret <= 0)
+			return ret;
+	}
+
+	return 1;
+}