Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 821 insertions, 0 deletions

diff --git a/drivers/pinctrl/aspeed/pinmux-aspeed.h b/drivers/pinctrl/aspeed/pinmux-aspeed.h
new file mode 100644
index 000000000..aaa78a613
--- /dev/null
+++ b/drivers/pinctrl/aspeed/pinmux-aspeed.h
@@ -0,0 +1,821 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Copyright (C) 2019 IBM Corp.  */
+
+#ifndef ASPEED_PINMUX_H
+#define ASPEED_PINMUX_H
+
+#include <linux/regmap.h>
+
+/*
+ * The ASPEED SoCs provide typically more than 200 pins for GPIO and other
+ * functions. The SoC function enabled on a pin is determined on a priority
+ * basis where a given pin can provide a number of different signal types.
+ *
+ * The signal active on a pin is described by both a priority level and
+ * compound logical expressions involving multiple operators, registers and
+ * bits. Some difficulty arises as the pin's function bit masks for each
+ * priority level are frequently not the same (i.e. cannot just flip a bit to
+ * change from a high to low priority signal), or even in the same register.
+ * Further, not all signals can be unmuxed, as some expressions depend on
+ * values in the hardware strapping register (which may be treated as
+ * read-only).
+ *
+ * SoC Multi-function Pin Expression Examples
+ * ------------------------------------------
+ *
+ * Here are some sample mux configurations from the AST2400 and AST2500
+ * datasheets to illustrate the corner cases, roughly in order of least to most
+ * corner. The signal priorities are in decending order from P0 (highest).
+ *
+ * D6 is a pin with a single function (beside GPIO); a high priority signal
+ * that participates in one function:
+ *
+ * Ball | Default | P0 Signal | P0 Expression               | P1 Signal | P1 Expression | Other
+ * -----+---------+-----------+-----------------------------+-----------+---------------+----------
+ *  D6    GPIOA0    MAC1LINK    SCU80[0]=1                                                GPIOA0
+ * -----+---------+-----------+-----------------------------+-----------+---------------+----------
+ *
+ * C5 is a multi-signal pin (high and low priority signals). Here we touch
+ * different registers for the different functions that enable each signal:
+ *
+ * -----+---------+-----------+-----------------------------+-----------+---------------+----------
+ *  C5    GPIOA4    SCL9        SCU90[22]=1                   TIMER5      SCU80[4]=1      GPIOA4
+ * -----+---------+-----------+-----------------------------+-----------+---------------+----------
+ *
+ * E19 is a single-signal pin with two functions that influence the active
+ * signal. In this case both bits have the same meaning - enable a dedicated
+ * LPC reset pin. However it's not always the case that the bits in the
+ * OR-relationship have the same meaning.
+ *
+ * -----+---------+-----------+-----------------------------+-----------+---------------+----------
+ *  E19   GPIOB4    LPCRST#     SCU80[12]=1 | Strap[14]=1                                 GPIOB4
+ * -----+---------+-----------+-----------------------------+-----------+---------------+----------
+ *
+ * For example, pin B19 has a low-priority signal that's enabled by two
+ * distinct SoC functions: A specific SIOPBI bit in register SCUA4, and an ACPI
+ * bit in the STRAP register. The ACPI bit configures signals on pins in
+ * addition to B19. Both of the low priority functions as well as the high
+ * priority function must be disabled for GPIOF1 to be used.
+ *
+ * Ball | Default | P0 Signal | P0 Expression                           | P1 Signal | P1 Expression                          | Other
+ * -----+---------+-----------+-----------------------------------------+-----------+----------------------------------------+----------
+ *  B19   GPIOF1    NDCD4       SCU80[25]=1                               SIOPBI#     SCUA4[12]=1 | Strap[19]=0                GPIOF1
+ * -----+---------+-----------+-----------------------------------------+-----------+----------------------------------------+----------
+ *
+ * For pin E18, the SoC ANDs the expected state of three bits to determine the
+ * pin's active signal:
+ *
+ * * SCU3C[3]: Enable external SOC reset function
+ * * SCU80[15]: Enable SPICS1# or EXTRST# function pin
+ * * SCU90[31]: Select SPI interface CS# output
+ *
+ * -----+---------+-----------+-----------------------------------------+-----------+----------------------------------------+----------
+ *  E18   GPIOB7    EXTRST#     SCU3C[3]=1 & SCU80[15]=1 & SCU90[31]=0    SPICS1#     SCU3C[3]=1 & SCU80[15]=1 & SCU90[31]=1   GPIOB7
+ * -----+---------+-----------+-----------------------------------------+-----------+----------------------------------------+----------
+ *
+ * (Bits SCU3C[3] and SCU80[15] appear to only be used in the expressions for
+ * selecting the signals on pin E18)
+ *
+ * Pin T5 is a multi-signal pin with a more complex configuration:
+ *
+ * Ball | Default | P0 Signal | P0 Expression                | P1 Signal | P1 Expression | Other
+ * -----+---------+-----------+------------------------------+-----------+---------------+----------
+ *  T5    GPIOL1    VPIDE       SCU90[5:4]!=0 & SCU84[17]=1    NDCD1       SCU84[17]=1     GPIOL1
+ * -----+---------+-----------+------------------------------+-----------+---------------+----------
+ *
+ * The high priority signal configuration is best thought of in terms of its
+ * exploded form, with reference to the SCU90[5:4] bits:
+ *
+ * * SCU90[5:4]=00: disable
+ * * SCU90[5:4]=01: 18 bits (R6/G6/B6) video mode.
+ * * SCU90[5:4]=10: 24 bits (R8/G8/B8) video mode.
+ * * SCU90[5:4]=11: 30 bits (R10/G10/B10) video mode.
+ *
+ * Re-writing:
+ *
+ * -----+---------+-----------+------------------------------+-----------+---------------+----------
+ *  T5    GPIOL1    VPIDE      (SCU90[5:4]=1 & SCU84[17]=1)    NDCD1       SCU84[17]=1     GPIOL1
+ *                             | (SCU90[5:4]=2 & SCU84[17]=1)
+ *                             | (SCU90[5:4]=3 & SCU84[17]=1)
+ * -----+---------+-----------+------------------------------+-----------+---------------+----------
+ *
+ * For reference the SCU84[17] bit configure the "UART1 NDCD1 or Video VPIDE
+ * function pin", where the signal itself is determined by whether SCU94[5:4]
+ * is disabled or in one of the 18, 24 or 30bit video modes.
+ *
+ * Other video-input-related pins require an explicit state in SCU90[5:4], e.g.
+ * W1 and U5:
+ *
+ * -----+---------+-----------+------------------------------+-----------+---------------+----------
+ *  W1    GPIOL6    VPIB0       SCU90[5:4]=3 & SCU84[22]=1     TXD1        SCU84[22]=1     GPIOL6
+ *  U5    GPIOL7    VPIB1       SCU90[5:4]=3 & SCU84[23]=1     RXD1        SCU84[23]=1     GPIOL7
+ * -----+---------+-----------+------------------------------+-----------+---------------+----------
+ *
+ * The examples of T5 and W1 are particularly fertile, as they also demonstrate
+ * that despite operating as part of the video input bus each signal needs to
+ * be enabled individually via it's own SCU84 (in the cases of T5 and W1)
+ * register bit. This is a little crazy if the bus doesn't have optional
+ * signals, but is used to decent effect with some of the UARTs where not all
+ * signals are required. However, this isn't done consistently - UART1 is
+ * enabled on a per-pin basis, and by contrast, all signals for UART6 are
+ * enabled by a single bit.
+ *
+ * Further, the high and low priority signals listed in the table above share
+ * a configuration bit. The VPI signals should operate in concert in a single
+ * function, but the UART signals should retain the ability to be configured
+ * independently. This pushes the implementation down the path of tagging a
+ * signal's expressions with the function they participate in, rather than
+ * defining masks affecting multiple signals per function. The latter approach
+ * fails in this instance where applying the configuration for the UART pin of
+ * interest will stomp on the state of other UART signals when disabling the
+ * VPI functions on the current pin.
+ *
+ * Ball |  Default   | P0 Signal | P0 Expression             | P1 Signal | P1 Expression | Other
+ * -----+------------+-----------+---------------------------+-----------+---------------+------------
+ *  A12   RGMII1TXCK   GPIOT0      SCUA0[0]=1                  RMII1TXEN   Strap[6]=0      RGMII1TXCK
+ *  B12   RGMII1TXCTL  GPIOT1      SCUA0[1]=1                  –           Strap[6]=0      RGMII1TXCTL
+ * -----+------------+-----------+---------------------------+-----------+---------------+------------
+ *
+ * A12 demonstrates that the "Other" signal isn't always GPIO - in this case
+ * GPIOT0 is a high-priority signal and RGMII1TXCK is Other. Thus, GPIO
+ * should be treated like any other signal type with full function expression
+ * requirements, and not assumed to be the default case. Separately, GPIOT0 and
+ * GPIOT1's signal descriptor bits are distinct, therefore we must iterate all
+ * pins in the function's group to disable the higher-priority signals such
+ * that the signal for the function of interest is correctly enabled.
+ *
+ * Finally, three priority levels aren't always enough; the AST2500 brings with
+ * it 18 pins of five priority levels, however the 18 pins only use three of
+ * the five priority levels.
+ *
+ * Ultimately the requirement to control pins in the examples above drive the
+ * design:
+ *
+ * * Pins provide signals according to functions activated in the mux
+ *   configuration
+ *
+ * * Pins provide up to five signal types in a priority order
+ *
+ * * For priorities levels defined on a pin, each priority provides one signal
+ *
+ * * Enabling lower priority signals requires higher priority signals be
+ *   disabled
+ *
+ * * A function represents a set of signals; functions are distinct if they
+ *   do not share a subset of signals (and may be distinct if they are a
+ *   strict subset).
+ *
+ * * Signals participate in one or more functions or groups
+ *
+ * * A function is described by an expression of one or more signal
+ *   descriptors, which compare bit values in a register
+ *
+ * * A signal expression is the smallest set of signal descriptors whose
+ *   comparisons must evaluate 'true' for a signal to be enabled on a pin.
+ *
+ * * A signal participating in a function is active on a pin if evaluating all
+ *   signal descriptors in the pin's signal expression for the function yields
+ *   a 'true' result
+ *
+ * * A signal at a given priority on a given pin is active if any of the
+ *   functions in which the signal participates are active, and no higher
+ *   priority signal on the pin is active
+ *
+ * * GPIO is configured per-pin
+ *
+ * And so:
+ *
+ * * To disable a signal, any function(s) activating the signal must be
+ *   disabled
+ *
+ * * Each pin must know the signal expressions of functions in which it
+ *   participates, for the purpose of enabling the Other function. This is done
+ *   by deactivating all functions that activate higher priority signals on the
+ *   pin.
+ *
+ * As a concrete example:
+ *
+ * * T5 provides three signals types: VPIDE, NDCD1 and GPIO
+ *
+ * * The VPIDE signal participates in 3 functions: VPI18, VPI24 and VPI30
+ *
+ * * The NDCD1 signal participates in just its own NDCD1 function
+ *
+ * * VPIDE is high priority, NDCD1 is low priority, and GPIOL1 is the least
+ *   prioritised
+ *
+ * * The prerequisit for activating the NDCD1 signal is that the VPI18, VPI24
+ *   and VPI30 functions all be disabled
+ *
+ * * Similarly, all of VPI18, VPI24, VPI30 and NDCD1 functions must be disabled
+ *   to provide GPIOL6
+ *
+ * Considerations
+ * --------------
+ *
+ * If pinctrl allows us to allocate a pin we can configure a function without
+ * concern for the function of already allocated pins, if pin groups are
+ * created with respect to the SoC functions in which they participate. This is
+ * intuitive, but it did not feel obvious from the bit/pin relationships.
+ *
+ * Conversely, failing to allocate all pins in a group indicates some bits (as
+ * well as pins) required for the group's configuration will already be in use,
+ * likely in a way that's inconsistent with the requirements of the failed
+ * group.
+ *
+ * Implementation
+ * --------------
+ *
+ * Beyond the documentation below the various structures and helper macros that
+ * allow the implementation to hang together are defined. The macros are fairly
+ * dense, so below we walk through some raw examples of the configuration
+ * tables in an effort to clarify the concepts.
+ *
+ * The complexity of configuring the mux combined with the scale of the pins
+ * and functions was a concern, so the table design along with the macro jungle
+ * is an attempt to address it. The rough principles of the approach are:
+ *
+ * 1. Use a data-driven solution rather than embedding state into code
+ * 2. Minimise editing to the specifics of the given mux configuration
+ * 3. Detect as many errors as possible at compile time
+ *
+ * Addressing point 3 leads to naming of symbols in terms of the four
+ * properties associated with a given mux configuration: The pin, the signal,
+ * the group and the function. In this way copy/paste errors cause duplicate
+ * symbols to be defined, which prevents successful compilation. Failing to
+ * properly parent the tables leads to unused symbol warnings, and use of
+ * designated initialisers and additional warnings ensures that there are
+ * no override errors in the pin, group and function arrays.
+ *
+ * Addressing point 2 drives the development of the macro jungle, as it
+ * centralises the definition noise at the cost of taking some time to
+ * understand.
+ *
+ * Here's a complete, concrete "pre-processed" example of the table structures
+ * used to describe the D6 ball from the examples above:
+ *
+ * ```
+ * static const struct aspeed_sig_desc sig_descs_MAC1LINK_MAC1LINK[] = {
+ *     {
+ *         .ip = ASPEED_IP_SCU,
+ *         .reg = 0x80,
+ *         .mask = BIT(0),
+ *         .enable = 1,
+ *         .disable = 0
+ *     },
+ * };
+ *
+ * static const struct aspeed_sig_expr sig_expr_MAC1LINK_MAC1LINK = {
+ *     .signal = "MAC1LINK",
+ *     .function = "MAC1LINK",
+ *     .ndescs = ARRAY_SIZE(sig_descs_MAC1LINK_MAC1LINK),
+ *     .descs = &(sig_descs_MAC1LINK_MAC1LINK)[0],
+ * };
+ *
+ * static const struct aspeed_sig_expr *sig_exprs_MAC1LINK_MAC1LINK[] = {
+ *     &sig_expr_MAC1LINK_MAC1LINK,
+ *     NULL,
+ * };
+ *
+ * static const struct aspeed_sig_desc sig_descs_GPIOA0_GPIOA0[] = { };
+ *
+ * static const struct aspeed_sig_expr sig_expr_GPIOA0_GPIOA0 = {
+ *     .signal = "GPIOA0",
+ *     .function = "GPIOA0",
+ *     .ndescs = ARRAY_SIZE(sig_descs_GPIOA0_GPIOA0),
+ *     .descs = &(sig_descs_GPIOA0_GPIOA0)[0],
+ * };
+ *
+ * static const struct aspeed_sig_expr *sig_exprs_GPIOA0_GPIOA0[] = {
+ *     &sig_expr_GPIOA0_GPIOA0,
+ *     NULL
+ * };
+ *
+ * static const struct aspeed_sig_expr **pin_exprs_0[] = {
+ *     sig_exprs_MAC1LINK_MAC1LINK,
+ *     sig_exprs_GPIOA0_GPIOA0,
+ *     NULL
+ * };
+ *
+ * static const struct aspeed_pin_desc pin_0 = { "0", (&pin_exprs_0[0]) };
+ * static const int group_pins_MAC1LINK[] = { 0 };
+ * static const char *func_groups_MAC1LINK[] = { "MAC1LINK" };
+ *
+ * static struct pinctrl_pin_desc aspeed_g4_pins[] = {
+ *     [0] = { .number = 0, .name = "D6", .drv_data = &pin_0 },
+ * };
+ *
+ * static const struct aspeed_pin_group aspeed_g4_groups[] = {
+ *     {
+ *         .name = "MAC1LINK",
+ *         .pins = &(group_pins_MAC1LINK)[0],
+ *         .npins = ARRAY_SIZE(group_pins_MAC1LINK),
+ *     },
+ * };
+ *
+ * static const struct aspeed_pin_function aspeed_g4_functions[] = {
+ *     {
+ *         .name = "MAC1LINK",
+ *         .groups = &func_groups_MAC1LINK[0],
+ *         .ngroups = ARRAY_SIZE(func_groups_MAC1LINK),
+ *     },
+ * };
+ * ```
+ *
+ * At the end of the day much of the above code is compressed into the
+ * following two lines:
+ *
+ * ```
+ * #define D6 0
+ * SSSF_PIN_DECL(D6, GPIOA0, MAC1LINK, SIG_DESC_SET(SCU80, 0));
+ * ```
+ *
+ * The two examples below show just the differences from the example above.
+ *
+ * Ball E18 demonstrates a function, EXTRST, that requires multiple descriptors
+ * be set for it to be muxed:
+ *
+ * ```
+ * static const struct aspeed_sig_desc sig_descs_EXTRST_EXTRST[] = {
+ *     {
+ *         .ip = ASPEED_IP_SCU,
+ *         .reg = 0x3C,
+ *         .mask = BIT(3),
+ *         .enable = 1,
+ *         .disable = 0
+ *     },
+ *     {
+ *         .ip = ASPEED_IP_SCU,
+ *         .reg = 0x80,
+ *         .mask = BIT(15),
+ *         .enable = 1,
+ *         .disable = 0
+ *     },
+ *     {
+ *         .ip = ASPEED_IP_SCU,
+ *         .reg = 0x90,
+ *         .mask = BIT(31),
+ *         .enable = 0,
+ *         .disable = 1
+ *     },
+ * };
+ *
+ * static const struct aspeed_sig_expr sig_expr_EXTRST_EXTRST = {
+ *     .signal = "EXTRST",
+ *     .function = "EXTRST",
+ *     .ndescs = ARRAY_SIZE(sig_descs_EXTRST_EXTRST),
+ *     .descs = &(sig_descs_EXTRST_EXTRST)[0],
+ * };
+ * ...
+ * ```
+ *
+ * For ball E19, we have multiple functions enabling a single signal, LPCRST#.
+ * The data structures look like:
+ *
+ * static const struct aspeed_sig_desc sig_descs_LPCRST_LPCRST[] = {
+ *     {
+ *         .ip = ASPEED_IP_SCU,
+ *         .reg = 0x80,
+ *         .mask = BIT(12),
+ *         .enable = 1,
+ *         .disable = 0
+ *     },
+ * };
+ *
+ * static const struct aspeed_sig_expr sig_expr_LPCRST_LPCRST = {
+ *     .signal = "LPCRST",
+ *     .function = "LPCRST",
+ *     .ndescs = ARRAY_SIZE(sig_descs_LPCRST_LPCRST),
+ *     .descs = &(sig_descs_LPCRST_LPCRST)[0],
+ * };
+ *
+ * static const struct aspeed_sig_desc sig_descs_LPCRST_LPCRSTS[] = {
+ *     {
+ *         .ip = ASPEED_IP_SCU,
+ *         .reg = 0x70,
+ *         .mask = BIT(14),
+ *         .enable = 1,
+ *         .disable = 0
+ *     },
+ * };
+ *
+ * static const struct aspeed_sig_expr sig_expr_LPCRST_LPCRSTS = {
+ *     .signal = "LPCRST",
+ *     .function = "LPCRSTS",
+ *     .ndescs = ARRAY_SIZE(sig_descs_LPCRST_LPCRSTS),
+ *     .descs = &(sig_descs_LPCRST_LPCRSTS)[0],
+ * };
+ *
+ * static const struct aspeed_sig_expr *sig_exprs_LPCRST_LPCRST[] = {
+ *     &sig_expr_LPCRST_LPCRST,
+ *     &sig_expr_LPCRST_LPCRSTS,
+ *     NULL,
+ * };
+ * ...
+ * ```
+ *
+ * Both expressions listed in the sig_exprs_LPCRST_LPCRST array need to be set
+ * to disabled for the associated GPIO to be muxed.
+ *
+ */
+
+#define ASPEED_IP_SCU		0
+#define ASPEED_IP_GFX		1
+#define ASPEED_IP_LPC		2
+#define ASPEED_NR_PINMUX_IPS	3
+
+ /**
+  * A signal descriptor, which describes the register, bits and the
+  * enable/disable values that should be compared or written.
+  *
+  * @ip: The IP block identifier, used as an index into the regmap array in
+  *      struct aspeed_pinctrl_data
+  * @reg: The register offset with respect to the base address of the IP block
+  * @mask: The mask to apply to the register. The lowest set bit of the mask is
+  *        used to derive the shift value.
+  * @enable: The value that enables the function. Value should be in the LSBs,
+  *          not at the position of the mask.
+  * @disable: The value that disables the function. Value should be in the
+  *           LSBs, not at the position of the mask.
+  */
+struct aspeed_sig_desc {
+	unsigned int ip;
+	unsigned int reg;
+	u32 mask;
+	u32 enable;
+	u32 disable;
+};
+
+/**
+ * Describes a signal expression. The expression is evaluated by ANDing the
+ * evaluation of the descriptors.
+ *
+ * @signal: The signal name for the priority level on the pin. If the signal
+ *          type is GPIO, then the signal name must begin with the
+ *          prefix "GPI", e.g. GPIOA0, GPIT0 etc.
+ * @function: The name of the function the signal participates in for the
+ *            associated expression. For pin-specific GPIO, the function
+ *            name must match the signal name.
+ * @ndescs: The number of signal descriptors in the expression
+ * @descs: Pointer to an array of signal descriptors that comprise the
+ *         function expression
+ */
+struct aspeed_sig_expr {
+	const char *signal;
+	const char *function;
+	int ndescs;
+	const struct aspeed_sig_desc *descs;
+};
+
+/**
+ * A struct capturing the list of expressions enabling signals at each priority
+ * for a given pin. The signal configuration for a priority level is evaluated
+ * by ORing the evaluation of the signal expressions in the respective
+ * priority's list.
+ *
+ * @name: A name for the pin
+ * @prios: A pointer to an array of expression list pointers
+ *
+ */
+struct aspeed_pin_desc {
+	const char *name;
+	const struct aspeed_sig_expr ***prios;
+};
+
+/* Macro hell */
+
+#define SIG_DESC_IP_BIT(ip, reg, idx, val) \
+	{ ip, reg, BIT_MASK(idx), val, (((val) + 1) & 1) }
+
+/**
+ * Short-hand macro for describing an SCU descriptor enabled by the state of
+ * one bit. The disable value is derived.
+ *
+ * @reg: The signal's associated register, offset from base
+ * @idx: The signal's bit index in the register
+ * @val: The value (0 or 1) that enables the function
+ */
+#define SIG_DESC_BIT(reg, idx, val) \
+	SIG_DESC_IP_BIT(ASPEED_IP_SCU, reg, idx, val)
+
+#define SIG_DESC_IP_SET(ip, reg, idx) SIG_DESC_IP_BIT(ip, reg, idx, 1)
+
+/**
+ * A further short-hand macro expanding to an SCU descriptor enabled by a set
+ * bit.
+ *
+ * @reg: The register, offset from base
+ * @idx: The bit index in the register
+ */
+#define SIG_DESC_SET(reg, idx) SIG_DESC_IP_BIT(ASPEED_IP_SCU, reg, idx, 1)
+#define SIG_DESC_CLEAR(reg, idx) { ASPEED_IP_SCU, reg, BIT_MASK(idx), 0, 0 }
+
+#define SIG_DESC_LIST_SYM(sig, group) sig_descs_ ## sig ## _ ## group
+#define SIG_DESC_LIST_DECL(sig, group, ...) \
+	static const struct aspeed_sig_desc SIG_DESC_LIST_SYM(sig, group)[] = \
+		{ __VA_ARGS__ }
+
+#define SIG_EXPR_SYM(sig, group) sig_expr_ ## sig ## _ ## group
+#define SIG_EXPR_DECL_(sig, group, func) \
+	static const struct aspeed_sig_expr SIG_EXPR_SYM(sig, group) = \
+	{ \
+		.signal = #sig, \
+		.function = #func, \
+		.ndescs = ARRAY_SIZE(SIG_DESC_LIST_SYM(sig, group)), \
+		.descs = &(SIG_DESC_LIST_SYM(sig, group))[0], \
+	}
+
+/**
+ * Declare a signal expression.
+ *
+ * @sig: A macro symbol name for the signal (is subjected to stringification
+ *        and token pasting)
+ * @func: The function in which the signal is participating
+ * @...: Signal descriptors that define the signal expression
+ *
+ * For example, the following declares the ROMD8 signal for the ROM16 function:
+ *
+ *     SIG_EXPR_DECL(ROMD8, ROM16, ROM16, SIG_DESC_SET(SCU90, 6));
+ *
+ * And with multiple signal descriptors:
+ *
+ *     SIG_EXPR_DECL(ROMD8, ROM16S, ROM16S, SIG_DESC_SET(HW_STRAP1, 4),
+ *              { HW_STRAP1, GENMASK(1, 0), 0, 0 });
+ */
+#define SIG_EXPR_DECL(sig, group, func, ...) \
+	SIG_DESC_LIST_DECL(sig, group, __VA_ARGS__); \
+	SIG_EXPR_DECL_(sig, group, func)
+
+/**
+ * Declare a pointer to a signal expression
+ *
+ * @sig: The macro symbol name for the signal (subjected to token pasting)
+ * @func: The macro symbol name for the function (subjected to token pasting)
+ */
+#define SIG_EXPR_PTR(sig, group) (&SIG_EXPR_SYM(sig, group))
+
+#define SIG_EXPR_LIST_SYM(sig, group) sig_exprs_ ## sig ## _ ## group
+
+/**
+ * Declare a signal expression list for reference in a struct aspeed_pin_prio.
+ *
+ * @sig: A macro symbol name for the signal (is subjected to token pasting)
+ * @...: Signal expression structure pointers (use SIG_EXPR_PTR())
+ *
+ * For example, the 16-bit ROM bus can be enabled by one of two possible signal
+ * expressions:
+ *
+ *     SIG_EXPR_DECL(ROMD8, ROM16, ROM16, SIG_DESC_SET(SCU90, 6));
+ *     SIG_EXPR_DECL(ROMD8, ROM16S, ROM16S, SIG_DESC_SET(HW_STRAP1, 4),
+ *              { HW_STRAP1, GENMASK(1, 0), 0, 0 });
+ *     SIG_EXPR_LIST_DECL(ROMD8, SIG_EXPR_PTR(ROMD8, ROM16),
+ *              SIG_EXPR_PTR(ROMD8, ROM16S));
+ */
+#define SIG_EXPR_LIST_DECL(sig, group, ...) \
+	static const struct aspeed_sig_expr *SIG_EXPR_LIST_SYM(sig, group)[] =\
+		{ __VA_ARGS__, NULL }
+
+#define stringify(x) #x
+#define istringify(x) stringify(x)
+
+/**
+ * Create an expression symbol alias from (signal, group) to (pin, signal).
+ *
+ * @pin: The pin number
+ * @sig: The signal name
+ * @group: The name of the group of which the pin is a member that is
+ *         associated with the function's signal
+ *
+ * Using an alias in this way enables detection of copy/paste errors (defining
+ * the signal for a group multiple times) whilst enabling multiple pin groups
+ * to exist for a signal without intrusive side-effects on defining the list of
+ * signals available on a pin.
+ */
+#define SIG_EXPR_LIST_ALIAS(pin, sig, group) \
+	static const struct aspeed_sig_expr *\
+		SIG_EXPR_LIST_SYM(pin, sig)[ARRAY_SIZE(SIG_EXPR_LIST_SYM(sig, group))] \
+		__attribute__((alias(istringify(SIG_EXPR_LIST_SYM(sig, group)))))
+
+/**
+ * A short-hand macro for declaring a function expression and an expression
+ * list with a single expression (SE) and a single group (SG) of pins.
+ *
+ * @pin: The pin the signal will be routed to
+ * @sig: The signal that will be routed to the pin for the function
+ * @func: A macro symbol name for the function
+ * @...: Function descriptors that define the function expression
+ *
+ * For example, signal NCTS6 participates in its own function with one group:
+ *
+ *     SIG_EXPR_LIST_DECL_SINGLE(A18, NCTS6, NCTS6, SIG_DESC_SET(SCU90, 7));
+ */
+#define SIG_EXPR_LIST_DECL_SESG(pin, sig, func, ...) \
+	SIG_DESC_LIST_DECL(sig, func, __VA_ARGS__); \
+	SIG_EXPR_DECL_(sig, func, func); \
+	SIG_EXPR_LIST_DECL(sig, func, SIG_EXPR_PTR(sig, func)); \
+	SIG_EXPR_LIST_ALIAS(pin, sig, func)
+
+/**
+ * Similar to the above, but for pins with a single expression (SE) and
+ * multiple groups (MG) of pins.
+ *
+ * @pin: The pin the signal will be routed to
+ * @sig: The signal that will be routed to the pin for the function
+ * @group: The name of the function's pin group in which the pin participates
+ * @func: A macro symbol name for the function
+ * @...: Function descriptors that define the function expression
+ */
+#define SIG_EXPR_LIST_DECL_SEMG(pin, sig, group, func, ...) \
+	SIG_DESC_LIST_DECL(sig, group, __VA_ARGS__); \
+	SIG_EXPR_DECL_(sig, group, func); \
+	SIG_EXPR_LIST_DECL(sig, group, SIG_EXPR_PTR(sig, group)); \
+	SIG_EXPR_LIST_ALIAS(pin, sig, group)
+
+/**
+ * Similar to the above, but for pins with a dual expressions (DE)
+ * and a single group (SG) of pins.
+ *
+ * @pin: The pin the signal will be routed to
+ * @sig: The signal that will be routed to the pin for the function
+ * @group: The name of the function's pin group in which the pin participates
+ * @func: A macro symbol name for the function
+ * @...: Function descriptors that define the function expression
+ */
+#define SIG_EXPR_LIST_DECL_DESG(pin, sig, f0, f1) \
+	SIG_EXPR_LIST_DECL(sig, f0, \
+			   SIG_EXPR_PTR(sig, f0), \
+			   SIG_EXPR_PTR(sig, f1)); \
+	SIG_EXPR_LIST_ALIAS(pin, sig, f0)
+
+#define SIG_EXPR_LIST_PTR(sig, group) SIG_EXPR_LIST_SYM(sig, group)
+
+#define PIN_EXPRS_SYM(pin) pin_exprs_ ## pin
+#define PIN_EXPRS_PTR(pin) (&PIN_EXPRS_SYM(pin)[0])
+#define PIN_SYM(pin) pin_ ## pin
+
+#define PIN_DECL_(pin, ...) \
+	static const struct aspeed_sig_expr **PIN_EXPRS_SYM(pin)[] = \
+		{ __VA_ARGS__, NULL }; \
+	static const struct aspeed_pin_desc PIN_SYM(pin) = \
+		{ #pin, PIN_EXPRS_PTR(pin) }
+
+/**
+ * Declare a single signal pin
+ *
+ * @pin: The pin number
+ * @other: Macro name for "other" functionality (subjected to stringification)
+ * @sig: Macro name for the signal (subjected to stringification)
+ *
+ * For example:
+ *
+ *     #define E3 80
+ *     SIG_EXPR_LIST_DECL_SINGLE(SCL5, I2C5, I2C5_DESC);
+ *     PIN_DECL_1(E3, GPIOK0, SCL5);
+ */
+#define PIN_DECL_1(pin, other, sig) \
+	SIG_EXPR_LIST_DECL_SESG(pin, other, other); \
+	PIN_DECL_(pin, SIG_EXPR_LIST_PTR(pin, sig), \
+		  SIG_EXPR_LIST_PTR(pin, other))
+
+/**
+ * Single signal, single function pin declaration
+ *
+ * @pin: The pin number
+ * @other: Macro name for "other" functionality (subjected to stringification)
+ * @sig: Macro name for the signal (subjected to stringification)
+ * @...: Signal descriptors that define the function expression
+ *
+ * For example:
+ *
+ *    SSSF_PIN_DECL(A4, GPIOA2, TIMER3, SIG_DESC_SET(SCU80, 2));
+ */
+#define SSSF_PIN_DECL(pin, other, sig, ...) \
+	SIG_EXPR_LIST_DECL_SESG(pin, sig, sig, __VA_ARGS__); \
+	SIG_EXPR_LIST_DECL_SESG(pin, other, other); \
+	PIN_DECL_(pin, SIG_EXPR_LIST_PTR(pin, sig), \
+		  SIG_EXPR_LIST_PTR(pin, other)); \
+	FUNC_GROUP_DECL(sig, pin)
+/**
+ * Declare a two-signal pin
+ *
+ * @pin: The pin number
+ * @other: Macro name for "other" functionality (subjected to stringification)
+ * @high: Macro name for the highest priority signal functions
+ * @low: Macro name for the low signal functions
+ *
+ * For example:
+ *
+ *     #define A8 56
+ *     SIG_EXPR_DECL(ROMD8, ROM16, SIG_DESC_SET(SCU90, 6));
+ *     SIG_EXPR_DECL(ROMD8, ROM16S, SIG_DESC_SET(HW_STRAP1, 4),
+ *              { HW_STRAP1, GENMASK(1, 0), 0, 0 });
+ *     SIG_EXPR_LIST_DECL(ROMD8, SIG_EXPR_PTR(ROMD8, ROM16),
+ *              SIG_EXPR_PTR(ROMD8, ROM16S));
+ *     SIG_EXPR_LIST_DECL_SINGLE(NCTS6, NCTS6, SIG_DESC_SET(SCU90, 7));
+ *     PIN_DECL_2(A8, GPIOH0, ROMD8, NCTS6);
+ */
+#define PIN_DECL_2(pin, other, high, low) \
+	SIG_EXPR_LIST_DECL_SESG(pin, other, other); \
+	PIN_DECL_(pin, \
+			SIG_EXPR_LIST_PTR(pin, high), \
+			SIG_EXPR_LIST_PTR(pin, low), \
+			SIG_EXPR_LIST_PTR(pin, other))
+
+#define PIN_DECL_3(pin, other, high, medium, low) \
+	SIG_EXPR_LIST_DECL_SESG(pin, other, other); \
+	PIN_DECL_(pin, \
+			SIG_EXPR_LIST_PTR(pin, high), \
+			SIG_EXPR_LIST_PTR(pin, medium), \
+			SIG_EXPR_LIST_PTR(pin, low), \
+			SIG_EXPR_LIST_PTR(pin, other))
+
+#define PIN_DECL_4(pin, other, prio1, prio2, prio3, prio4) \
+	SIG_EXPR_LIST_DECL_SESG(pin, other, other); \
+	PIN_DECL_(pin, \
+			SIG_EXPR_LIST_PTR(pin, prio1), \
+			SIG_EXPR_LIST_PTR(pin, prio2), \
+			SIG_EXPR_LIST_PTR(pin, prio3), \
+			SIG_EXPR_LIST_PTR(pin, prio4), \
+			SIG_EXPR_LIST_PTR(pin, other))
+
+#define GROUP_SYM(group) group_pins_ ## group
+#define GROUP_DECL(group, ...) \
+	static const int GROUP_SYM(group)[] = { __VA_ARGS__ }
+
+#define FUNC_SYM(func) func_groups_ ## func
+#define FUNC_DECL_(func, ...) \
+	static const char *FUNC_SYM(func)[] = { __VA_ARGS__ }
+
+#define FUNC_DECL_1(func, group) FUNC_DECL_(func, #group)
+#define FUNC_DECL_2(func, one, two) FUNC_DECL_(func, #one, #two)
+#define FUNC_DECL_3(func, one, two, three) FUNC_DECL_(func, #one, #two, #three)
+
+#define FUNC_GROUP_DECL(func, ...) \
+	GROUP_DECL(func, __VA_ARGS__); \
+	FUNC_DECL_(func, #func)
+
+
+#define GPIO_PIN_DECL(pin, gpio) \
+	SIG_EXPR_LIST_DECL_SESG(pin, gpio, gpio); \
+	PIN_DECL_(pin, SIG_EXPR_LIST_PTR(pin, gpio))
+
+struct aspeed_pin_group {
+	const char *name;
+	const unsigned int *pins;
+	const unsigned int npins;
+};
+
+#define ASPEED_PINCTRL_GROUP(name_) { \
+	.name = #name_, \
+	.pins = &(GROUP_SYM(name_))[0], \
+	.npins = ARRAY_SIZE(GROUP_SYM(name_)), \
+}
+
+struct aspeed_pin_function {
+	const char *name;
+	const char *const *groups;
+	unsigned int ngroups;
+};
+
+#define ASPEED_PINCTRL_FUNC(name_, ...) { \
+	.name = #name_, \
+	.groups = &FUNC_SYM(name_)[0], \
+	.ngroups = ARRAY_SIZE(FUNC_SYM(name_)), \
+}
+
+struct aspeed_pinmux_data;
+
+struct aspeed_pinmux_ops {
+	int (*eval)(struct aspeed_pinmux_data *ctx,
+		    const struct aspeed_sig_expr *expr, bool enabled);
+	int (*set)(struct aspeed_pinmux_data *ctx,
+		   const struct aspeed_sig_expr *expr, bool enabled);
+};
+
+struct aspeed_pinmux_data {
+	struct device *dev;
+	struct regmap *maps[ASPEED_NR_PINMUX_IPS];
+
+	const struct aspeed_pinmux_ops *ops;
+
+	const struct aspeed_pin_group *groups;
+	const unsigned int ngroups;
+
+	const struct aspeed_pin_function *functions;
+	const unsigned int nfunctions;
+};
+
+int aspeed_sig_desc_eval(const struct aspeed_sig_desc *desc, bool enabled,
+			 struct regmap *map);
+
+int aspeed_sig_expr_eval(struct aspeed_pinmux_data *ctx,
+			 const struct aspeed_sig_expr *expr, bool enabled);
+
+static inline int aspeed_sig_expr_set(struct aspeed_pinmux_data *ctx,
+				      const struct aspeed_sig_expr *expr,
+				      bool enabled)
+{
+	return ctx->ops->set(ctx, expr, enabled);
+}
+
+#endif /* ASPEED_PINMUX_H */