arch/risc-v/eic7700x: Add the CLMM pad multiplexer.

arch/risc-v/src/eic7700x/Kconfig

@@ -47,4 +47,21 @@ config EIC7700X_CPU_FREQ_MHZ
 		cores at 1400, so the default changes nothing and merely says
 		so in the log.
 
-endif 
+endif 
+
+config EIC7700X_PINCTRL
+	bool "CLMM pad multiplexing"
+	default y
+	select PINCTRL
+	---help---
+		Describe the pads of the Chip Level Mode Mux (CLMM) to the NuttX
+		pinctrl framework.  Initialisation writes nothing to the hardware:
+		a pad only moves when a driver asks it to.
+
+		Every pad on the SoC shares its ball with something else, so the
+		UARTs beyond the console, the GPIO block and the peripheral buses
+		all need a pad configured here before they reach a pin.
+
+		The board reports the pad count and how many differ from their
+		reset defaults once, at startup.  With DEBUG_PINCTRL_INFO the
+		driver also logs each pad as it is configured.

arch/risc-v/src/eic7700x/Make.defs

@@ -39,3 +39,7 @@ endif
 ifeq ($(CONFIG_EIC7700X_CPUCLK),y)
 CHIP_CSRCS += eic7700x_cpuclk.c
 endif
+
+ifeq ($(CONFIG_EIC7700X_PINCTRL),y)
+CHIP_CSRCS += eic7700x_pinctrl.c eic7700x_pinctrl_ops.c
+endif

arch/risc-v/src/eic7700x/eic7700x_pinctrl.h

@@ -0,0 +1,250 @@
+/****************************************************************************
+ * arch/risc-v/src/eic7700x/eic7700x_pinctrl.h
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __ARCH_RISCV_SRC_EIC7700X_EIC7700X_PINCTRL_H
+#define __ARCH_RISCV_SRC_EIC7700X_EIC7700X_PINCTRL_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+
+#include <nuttx/pinctrl/pinctrl.h>
+
+#include <arch/chip/eic7700x_pinctrl.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Whether anything wants a pad's name in text.  The names cost about nine
+ * kilobytes, so they are only compiled when something will print them.
+ * GPIO_PROCFS is a consumer to come: the GPIO driver's procfs entry names
+ * the pad behind each line.
+ */
+
+#if defined(CONFIG_PINCTRL_PROCFS) || defined(CONFIG_GPIO_PROCFS)
+#  define HAVE_PINCTRL_TEXT 1
+#endif
+
+/* How many distinct reset values the 166 pads have between them.  The
+ * manual gives a reset value per field; reassembled into words they
+ * collapse to this many, so the table stores an index instead of a word.
+ */
+
+#define EIC7700X_PAD_NDEFAULTS     (15)
+
+/* How many GPIO lines the SoC has.  Two of them, 5 and 11, are balls in
+ * part 1 table 2-4 that the register detail description gives no pad
+ * register for, so the reverse map below has holes there.
+ */
+
+#define EIC7700X_PAD_NGPIOS        (112)
+#define EIC7700X_PAD_NOPAD         (0xff)
+
+/* A pad's gpiofunc when the pad offers no GPIO function at all. */
+
+#define EIC7700X_PAD_NOGPIO        (0xff)
+
+/* Pad flags */
+
+#define EIC7700X_PAD_LOCKED        (1 << 0)  /* Refuses to be written */
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+/* Which of the four field layouts a pad uses.  See the layout notes in
+ * hardware/eic7700x_pinctrl.h: the same bit means different things, or
+ * nothing, depending on this.
+ */
+
+enum eic7700x_padshape_e
+{
+  EIC7700X_PADSHAPE_GENERAL = 0,  /* Function select, pull, drive, input  */
+  EIC7700X_PADSHAPE_RGMII,        /* Voltage mode instead of function     */
+  EIC7700X_PADSHAPE_OSC,          /* Drive, damping and feedback only     */
+  EIC7700X_PADSHAPE_MODESEL       /* Group voltage select, carries no pin */
+};
+
+/* One pad register.
+ *
+ * wmask comes straight from the access column of the manual's register
+ * detail description, one bit per writable register bit.  It is the only
+ * thing standing between a caller and a write the hardware will ignore,
+ * and five pads have it zero: the hardware reports their state and nothing
+ * more.
+ */
+
+struct eic7700x_pad_s
+{
+  uint32_t wmask;        /* Bits the hardware will let software drive     */
+  uint8_t  shape;        /* enum eic7700x_padshape_e                      */
+  uint8_t  dflt;         /* Index into g_eic7700x_pad_defaults[]          */
+  uint8_t  funcmask;     /* Bit n set: function select n is documented    */
+  uint8_t  gpiofunc;     /* Function select giving GPIO, or NOGPIO        */
+  uint8_t  flags;        /* EIC7700X_PAD_* flags                          */
+};
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+EXTERN const struct eic7700x_pad_s
+             g_eic7700x_pads[EIC7700X_PAD_NPADS];
+EXTERN const uint32_t
+             g_eic7700x_pad_defaults[EIC7700X_PAD_NDEFAULTS];
+EXTERN const uint8_t
+             g_eic7700x_pad_bygpio[EIC7700X_PAD_NGPIOS];
+EXTERN const struct pinctrl_ops_s g_eic7700x_pinctrl_ops;
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: eic7700x_pinctrl_initialize
+ *
+ * Description:
+ *   Bring up the pad multiplexing block.  This writes nothing to the
+ *   hardware: a pad only moves when a driver asks it to.
+ *
+ * Returned Value:
+ *   OK on success, or a negated errno on failure.
+ *
+ ****************************************************************************/
+
+int eic7700x_pinctrl_initialize(void);
+
+/****************************************************************************
+ * Name: eic7700x_pinctrl_count
+ *
+ * Description:
+ *   How many pads the block has, and through changed how many currently
+ *   differ from their reset defaults.
+ *
+ * Input Parameters:
+ *   changed - Receives the changed-pad count; may be NULL.
+ *
+ * Returned Value:
+ *   The number of pads.
+ *
+ ****************************************************************************/
+
+unsigned int eic7700x_pinctrl_count(FAR unsigned int *changed);
+
+/****************************************************************************
+ * Name: eic7700x_pad_name
+ *
+ * Description:
+ *   The manual's name for a pad.
+ *
+ * Input Parameters:
+ *   pad - The pad id, an enum eic7700x_pad_e value
+ *
+ * Returned Value:
+ *   The name, or NULL if the pad id is out of range or the name tables
+ *   are not built.
+ *
+ ****************************************************************************/
+
+FAR const char *eic7700x_pad_name(unsigned int pad);
+
+/****************************************************************************
+ * Name: eic7700x_pad_funcname
+ *
+ * Description:
+ *   The name of one of a pad's function selects.
+ *
+ * Input Parameters:
+ *   pad  - The pad id, an enum eic7700x_pad_e value
+ *   func - The function select
+ *
+ * Returned Value:
+ *   The name, or NULL if the manual does not document that select or the
+ *   name tables are not built.
+ *
+ ****************************************************************************/
+
+FAR const char *eic7700x_pad_funcname(unsigned int pad, unsigned int func);
+
+/****************************************************************************
+ * Name: eic7700x_pad_lookup
+ *
+ * Description:
+ *   Bound a pad id and return the row describing it.  Nothing else in this
+ *   driver may index the pad table directly: this is the single place an
+ *   out of range id is caught.
+ *
+ * Input Parameters:
+ *   pad - The pad id, an enum eic7700x_pad_e value
+ *
+ * Returned Value:
+ *   The pad description, or NULL if the id names no pad.
+ *
+ ****************************************************************************/
+
+FAR const struct eic7700x_pad_s *eic7700x_pad_lookup(unsigned int pad);
+
+/****************************************************************************
+ * Name: eic7700x_pad_config
+ *
+ * Description:
+ *   Configure one pad.  The value is a whole pad register, built from the
+ *   PINCTRL_* field macros for the layout the pad uses, and every field
+ *   lands in a single write so that a pad is never briefly half
+ *   configured.  Bits the hardware will not let software drive keep the
+ *   value they already had.
+ *
+ * Input Parameters:
+ *   pad - The pad id, an enum eic7700x_pad_e value
+ *   cfg - The register value to install
+ *
+ * Returned Value:
+ *   OK on success, or a negated errno:
+ *
+ *     -EINVAL  the id names no pad, or the value selects a function the
+ *              manual does not document for this pad
+ *     -EROFS   the value tries to drive a bit that reports state only
+ *     -EPERM   the pad is one this driver refuses to move
+ *
+ ****************************************************************************/
+
+int eic7700x_pad_config(unsigned int pad, uint32_t cfg);
+
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __ARCH_RISCV_SRC_EIC7700X_EIC7700X_PINCTRL_H */