[PATCH v2 2/6] mfd: add support for the Khadas System control Microcontroller

[Neil Armstrong <narmstrong@baylibre.com>]

This Microcontroller is present on the Khadas VIM1, VIM2, VIM3 and Edge
boards.

It has multiple boot control features like password check, power-on
options, power-off control and system FAN control on recent boards.

This implements a very basic MFD driver with the fan control and User
NVMEM cells.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
 drivers/mfd/Kconfig            |  14 ++++
 drivers/mfd/Makefile           |   1 +
 drivers/mfd/khadas-mcu.c       | 143 +++++++++++++++++++++++++++++++++
 include/linux/mfd/khadas-mcu.h |  91 +++++++++++++++++++++
 4 files changed, 249 insertions(+)
 create mode 100644 drivers/mfd/khadas-mcu.c
 create mode 100644 include/linux/mfd/khadas-mcu.h

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 0a59249198d3..b95091397052 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -2003,6 +2003,20 @@ config MFD_WCD934X
 	  This driver provides common support WCD934x audio codec and its
 	  associated Pin Controller, Soundwire Controller and Audio codec.
 
+config MFD_KHADAS_MCU
+	tristate "Support for Khadas System control Microcontroller"
+	depends on I2C
+	depends on OF || COMPILE_TEST
+	select MFD_CORE
+	select REGMAP_I2C
+	help
+	  Support for the Khadas System control Microcontroller interface present
+	  on their VIM and Edge boards.
+
+	  This driver provides common support for accessing the device,
+	  additional drivers must be enabled in order to use the functionality
+	  of the device.
+
 menu "Multimedia Capabilities Port drivers"
 	depends on ARCH_SA1100
 
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index f935d10cbf0f..0f1633b096bb 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -257,5 +257,6 @@ obj-$(CONFIG_MFD_ROHM_BD70528)	+= rohm-bd70528.o
 obj-$(CONFIG_MFD_ROHM_BD71828)	+= rohm-bd71828.o
 obj-$(CONFIG_MFD_ROHM_BD718XX)	+= rohm-bd718x7.o
 obj-$(CONFIG_MFD_STMFX) 	+= stmfx.o
+obj-$(CONFIG_MFD_KHADAS_MCU) 	+= khadas-mcu.o
 
 obj-$(CONFIG_SGI_MFD_IOC3)	+= ioc3.o
diff --git a/drivers/mfd/khadas-mcu.c b/drivers/mfd/khadas-mcu.c
new file mode 100644
index 000000000000..6d08fa2e373a
--- /dev/null
+++ b/drivers/mfd/khadas-mcu.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for Khadas System control Microcontroller
+ *
+ * Copyright (C) 2020 BayLibre SAS
+ * Author(s): Neil Armstrong <narmstrong@baylibre.com>
+ */
+#include <linux/bitfield.h>
+#include <linux/i2c.h>
+#include <linux/mfd/khadas-mcu.h>
+#include <linux/regmap.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+
+static bool khadas_mcu_reg_volatile(struct device *dev, unsigned int reg)
+{
+	if (reg >= KHADAS_MCU_USER_DATA_0_REG &&
+	    reg < KHADAS_MCU_PWR_OFF_CMD_REG)
+		return true;
+
+	switch (reg) {
+	case KHADAS_MCU_PWR_OFF_CMD_REG:
+	case KHADAS_MCU_PASSWD_START_REG:
+	case KHADAS_MCU_CHECK_VEN_PASSWD_REG:
+	case KHADAS_MCU_CHECK_USER_PASSWD_REG:
+	case KHADAS_MCU_WOL_INIT_START_REG:
+	case KHADAS_MCU_CMD_FAN_STATUS_CTRL_REG:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool khadas_mcu_reg_writeable(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case KHADAS_MCU_PASSWD_VEN_0_REG:
+	case KHADAS_MCU_PASSWD_VEN_1_REG:
+	case KHADAS_MCU_PASSWD_VEN_2_REG:
+	case KHADAS_MCU_PASSWD_VEN_3_REG:
+	case KHADAS_MCU_PASSWD_VEN_4_REG:
+	case KHADAS_MCU_PASSWD_VEN_5_REG:
+	case KHADAS_MCU_MAC_0_REG:
+	case KHADAS_MCU_MAC_1_REG:
+	case KHADAS_MCU_MAC_2_REG:
+	case KHADAS_MCU_MAC_3_REG:
+	case KHADAS_MCU_MAC_4_REG:
+	case KHADAS_MCU_MAC_5_REG:
+	case KHADAS_MCU_USID_0_REG:
+	case KHADAS_MCU_USID_1_REG:
+	case KHADAS_MCU_USID_2_REG:
+	case KHADAS_MCU_USID_3_REG:
+	case KHADAS_MCU_USID_4_REG:
+	case KHADAS_MCU_USID_5_REG:
+	case KHADAS_MCU_VERSION_0_REG:
+	case KHADAS_MCU_VERSION_1_REG:
+	case KHADAS_MCU_DEVICE_NO_0_REG:
+	case KHADAS_MCU_DEVICE_NO_1_REG:
+	case KHADAS_MCU_FACTORY_TEST_REG:
+	case KHADAS_MCU_SHUTDOWN_NORMAL_STATUS_REG:
+		return false;
+	default:
+		return true;
+	}
+}
+
+static const struct regmap_config khadas_mcu_regmap_config = {
+	.reg_bits	= 8,
+	.reg_stride	= 1,
+	.val_bits	= 8,
+	.max_register	= KHADAS_MCU_CMD_FAN_STATUS_CTRL_REG,
+	.volatile_reg	= khadas_mcu_reg_volatile,
+	.writeable_reg	= khadas_mcu_reg_writeable,
+	.cache_type	= REGCACHE_RBTREE,
+};
+
+static struct mfd_cell khadas_mcu_fan_cells[] = {
+	/* Feature supported only on VIM1/2 Rev13+ and VIM3 */
+	{ .name = "khadas-mcu-fan-ctrl", },
+};
+
+static struct mfd_cell khadas_mcu_cells[] = {
+	/* Features supported on all board revisions */
+	{ .name = "khadas-mcu-user-mem", },
+};
+
+static int khadas_mcu_probe(struct i2c_client *client,
+		       const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct khadas_mcu *khadas_mcu;
+	int ret;
+
+	khadas_mcu = devm_kzalloc(dev, sizeof(*khadas_mcu), GFP_KERNEL);
+	if (!khadas_mcu)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, khadas_mcu);
+
+	khadas_mcu->dev = dev;
+
+	khadas_mcu->map = devm_regmap_init_i2c(client,
+					       &khadas_mcu_regmap_config);
+	if (IS_ERR(khadas_mcu->map)) {
+		ret = PTR_ERR(khadas_mcu->map);
+		dev_err(dev, "Failed to allocate register map: %d\n", ret);
+		return ret;
+	}
+
+	ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
+				   khadas_mcu_cells,
+				   ARRAY_SIZE(khadas_mcu_cells),
+				   NULL, 0, NULL);
+	if (ret)
+		return ret;
+
+	if (of_find_property(dev->of_node, "#cooling-cells", NULL))
+		return devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
+					    khadas_mcu_fan_cells,
+					    ARRAY_SIZE(khadas_mcu_fan_cells),
+					    NULL, 0, NULL);
+
+	return 0;
+}
+
+static const struct of_device_id khadas_mcu_of_match[] = {
+	{ .compatible = "khadas,mcu", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, khadas_mcu_of_match);
+
+static struct i2c_driver khadas_mcu_driver = {
+	.driver = {
+		.name = "khadas-mcu-core",
+		.of_match_table = of_match_ptr(khadas_mcu_of_match),
+	},
+	.probe = khadas_mcu_probe,
+};
+module_i2c_driver(khadas_mcu_driver);
+
+MODULE_DESCRIPTION("Khadas MCU core driver");
+MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/mfd/khadas-mcu.h b/include/linux/mfd/khadas-mcu.h
new file mode 100644
index 000000000000..2e68af21735c
--- /dev/null
+++ b/include/linux/mfd/khadas-mcu.h
@@ -0,0 +1,91 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Khadas System control Microcontroller Register map
+ *
+ * Copyright (C) 2020 BayLibre SAS
+ * Author(s): Neil Armstrong <narmstrong@baylibre.com>
+ */
+
+#ifndef MFD_KHADAS_MCU_H
+#define MFD_KHADAS_MCU_H
+
+#define KHADAS_MCU_PASSWD_VEN_0_REG		0x0 /* RO */
+#define KHADAS_MCU_PASSWD_VEN_1_REG		0x1 /* RO */
+#define KHADAS_MCU_PASSWD_VEN_2_REG		0x2 /* RO */
+#define KHADAS_MCU_PASSWD_VEN_3_REG		0x3 /* RO */
+#define KHADAS_MCU_PASSWD_VEN_4_REG		0x4 /* RO */
+#define KHADAS_MCU_PASSWD_VEN_5_REG		0x5 /* RO */
+#define KHADAS_MCU_MAC_0_REG			0x6 /* RO */
+#define KHADAS_MCU_MAC_1_REG			0x7 /* RO */
+#define KHADAS_MCU_MAC_2_REG			0x8 /* RO */
+#define KHADAS_MCU_MAC_3_REG			0x9 /* RO */
+#define KHADAS_MCU_MAC_4_REG			0xa /* RO */
+#define KHADAS_MCU_MAC_5_REG			0xb /* RO */
+#define KHADAS_MCU_USID_0_REG			0xc /* RO */
+#define KHADAS_MCU_USID_1_REG			0xd /* RO */
+#define KHADAS_MCU_USID_2_REG			0xe /* RO */
+#define KHADAS_MCU_USID_3_REG			0xf /* RO */
+#define KHADAS_MCU_USID_4_REG			0x10 /* RO */
+#define KHADAS_MCU_USID_5_REG			0x11 /* RO */
+#define KHADAS_MCU_VERSION_0_REG		0x12 /* RO */
+#define KHADAS_MCU_VERSION_1_REG		0x13 /* RO */
+#define KHADAS_MCU_DEVICE_NO_0_REG		0x14 /* RO */
+#define KHADAS_MCU_DEVICE_NO_1_REG		0x15 /* RO */
+#define KHADAS_MCU_FACTORY_TEST_REG		0x16 /* R */
+#define KHADAS_MCU_BOOT_MODE_REG		0x20 /* RW */
+#define KHADAS_MCU_BOOT_EN_WOL_REG		0x21 /* RW */
+#define KHADAS_MCU_BOOT_EN_RTC_REG		0x22 /* RW */
+#define KHADAS_MCU_BOOT_EN_EXP_REG		0x23 /* RW */
+#define KHADAS_MCU_BOOT_EN_IR_REG		0x24 /* RW */
+#define KHADAS_MCU_BOOT_EN_DCIN_REG		0x25 /* RW */
+#define KHADAS_MCU_BOOT_EN_KEY_REG		0x26 /* RW */
+#define KHADAS_MCU_KEY_MODE_REG			0x27 /* RW */
+#define KHADAS_MCU_LED_MODE_ON_REG		0x28 /* RW */
+#define KHADAS_MCU_LED_MODE_OFF_REG		0x29 /* RW */
+#define KHADAS_MCU_SHUTDOWN_NORMAL_REG		0x2c /* RW */
+#define KHADAS_MCU_MAC_SWITCH_REG		0x2d /* RW */
+#define KHADAS_MCU_MCU_SLEEP_MODE_REG		0x2e /* RW */
+#define KHADAS_MCU_IR_CODE1_0_REG		0x2f /* RW */
+#define KHADAS_MCU_IR_CODE1_1_REG		0x30 /* RW */
+#define KHADAS_MCU_IR_CODE1_2_REG		0x31 /* RW */
+#define KHADAS_MCU_IR_CODE1_3_REG		0x32 /* RW */
+#define KHADAS_MCU_USB_PCIE_SWITCH_REG		0x33 /* RW */
+#define KHADAS_MCU_IR_CODE2_0_REG		0x34 /* RW */
+#define KHADAS_MCU_IR_CODE2_1_REG		0x35 /* RW */
+#define KHADAS_MCU_IR_CODE2_2_REG		0x36 /* RW */
+#define KHADAS_MCU_IR_CODE2_3_REG		0x37 /* RW */
+#define KHADAS_MCU_PASSWD_USER_0_REG		0x40 /* RW */
+#define KHADAS_MCU_PASSWD_USER_1_REG		0x41 /* RW */
+#define KHADAS_MCU_PASSWD_USER_2_REG		0x42 /* RW */
+#define KHADAS_MCU_PASSWD_USER_3_REG		0x43 /* RW */
+#define KHADAS_MCU_PASSWD_USER_4_REG		0x44 /* RW */
+#define KHADAS_MCU_PASSWD_USER_5_REG		0x45 /* RW */
+#define KHADAS_MCU_USER_DATA_0_REG		0x46 /* RW 56 bytes */
+#define KHADAS_MCU_PWR_OFF_CMD_REG		0x80 /* WO */
+#define KHADAS_MCU_PASSWD_START_REG		0x81 /* WO */
+#define KHADAS_MCU_CHECK_VEN_PASSWD_REG		0x82 /* WO */
+#define KHADAS_MCU_CHECK_USER_PASSWD_REG	0x83 /* WO */
+#define KHADAS_MCU_SHUTDOWN_NORMAL_STATUS_REG	0x86 /* RO */
+#define KHADAS_MCU_WOL_INIT_START_REG		0x87 /* WO */
+#define KHADAS_MCU_CMD_FAN_STATUS_CTRL_REG	0x88 /* WO */
+
+/* Boards */
+enum {
+	KHADAS_BOARD_VIM1 = 0x1,
+	KHADAS_BOARD_VIM2,
+	KHADAS_BOARD_VIM3,
+	KHADAS_BOARD_EDGE = 0x11,
+	KHADAS_BOARD_EDGE_V,
+};
+
+/**
+ * struct khadas_mcu_data - Khadas MCU MFD structure
+ * @device:		device reference used for logs
+ * @map:		register map
+ */
+struct khadas_mcu {
+	struct device *dev;
+	struct regmap *map;
+};
+
+#endif /* MFD_KHADAS_MCU_H */
-- 
2.22.0