mfd: khadas-mcu: Add support for VIM4 MCU variant

Refactor probe() to use per-variant values
instead of hardcoded globals.

Add dedicated regmap configuration for the VIM4 MCU,
with its own volatile/writeable registers.

Add a new compatible string "khadas,vim4-mcu".

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Ronald Claveau <linux-kernel-dev@aliel.fr>
Link: https://patch.msgid.link/20260917-add-mcu-fan-khadas-vim4-v12-3-497cd543a148@aliel.fr
Signed-off-by: Lee Jones <lee@kernel.org>

1 files changed, 83 insertions, 13 deletions

diff --git a/drivers/mfd/khadas-mcu.c b/drivers/mfd/khadas-mcu.c
index 0e74efe14f36..4b37e74e2b04 100644
--- a/drivers/mfd/khadas-mcu.c
+++ b/drivers/mfd/khadas-mcu.c
@@ -84,38 +84,107 @@ static const struct mfd_cell khadas_mcu_cells[] = {
 	MFD_CELL_NAME("khadas-mcu-user-mem"),
 };
 
+static bool khadas_mcu_vim4_reg_volatile(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case KHADAS_MCU_PWR_OFF_CMD_REG:
+	case KHADAS_MCU_VIM4_REST_CONF_REG:
+	case KHADAS_MCU_WOL_INIT_START_REG:
+	case KHADAS_MCU_VIM4_LED_ON_RAM_REG:
+	case KHADAS_MCU_VIM4_FAN_CTRL_REG:
+	case KHADAS_MCU_VIM4_WDT_EN_REG:
+	case KHADAS_MCU_VIM4_SYS_RST_REG:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool khadas_mcu_vim4_reg_writeable(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case KHADAS_MCU_VERSION_0_REG:
+	case KHADAS_MCU_VERSION_1_REG:
+	case KHADAS_MCU_SHUTDOWN_NORMAL_STATUS_REG:
+		return false;
+	default:
+		return true;
+	}
+}
+
+static const struct regmap_config khadas_mcu_vim4_regmap_config = {
+	.reg_bits	= 8,
+	.reg_stride	= 1,
+	.val_bits	= 8,
+	.max_register	= KHADAS_MCU_VIM4_SYS_RST_REG,
+	.volatile_reg	= khadas_mcu_vim4_reg_volatile,
+	.writeable_reg	= khadas_mcu_vim4_reg_writeable,
+	.cache_type	= REGCACHE_MAPLE,
+};
+
+static const struct mfd_cell khadas_mcu_vim4_fan_cells[] = {
+	MFD_CELL_NAME("khadas-mcu-vim4-fan"),
+};
+
 static int khadas_mcu_probe(struct i2c_client *client)
 {
+	const struct mfd_cell *cells, *fan_cells;
+	const struct regmap_config *regmap_cfg;
 	struct device *dev = &client->dev;
+	int ncells, nfan_cells, ret;
 	struct khadas_mcu *ddata;
-	int ret;
+	const void *mcu_variant;
 
 	ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
 	if (!ddata)
 		return -ENOMEM;
 
+	mcu_variant = i2c_get_match_data(client);
+	if (!mcu_variant)
+		return -ENODEV;
+
+	switch ((uintptr_t)mcu_variant) {
+	case KHADAS_MCU_GENERIC:
+		regmap_cfg	= &khadas_mcu_regmap_config;
+		cells		= khadas_mcu_cells;
+		ncells		= ARRAY_SIZE(khadas_mcu_cells);
+		fan_cells	= khadas_mcu_fan_cells;
+		nfan_cells	= ARRAY_SIZE(khadas_mcu_fan_cells);
+		break;
+	case KHADAS_MCU_VIM4:
+		regmap_cfg	= &khadas_mcu_vim4_regmap_config;
+		cells		= NULL;
+		ncells		= 0;
+		fan_cells	= khadas_mcu_vim4_fan_cells;
+		nfan_cells	= ARRAY_SIZE(khadas_mcu_vim4_fan_cells);
+		break;
+	default:
+		return -ENODEV;
+	}
+
 	i2c_set_clientdata(client, ddata);
 
 	ddata->dev = dev;
 
-	ddata->regmap = devm_regmap_init_i2c(client, &khadas_mcu_regmap_config);
+	ddata->regmap = devm_regmap_init_i2c(client, regmap_cfg);
 	if (IS_ERR(ddata->regmap)) {
 		ret = PTR_ERR(ddata->regmap);
-		dev_err(dev, "Failed to allocate register map: %d\n", ret);
-		return ret;
+		return dev_err_probe(dev, ret, "Failed to allocate register map\n");
 	}
 
-	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 (cells && ncells) {
+		ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
+					   cells,
+					   ncells,
+					   NULL, 0, NULL);
+		if (ret)
+			return ret;
+	}
 
 	if (of_property_present(dev->of_node, "#cooling-cells"))
 		return devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
-					    khadas_mcu_fan_cells,
-					    ARRAY_SIZE(khadas_mcu_fan_cells),
+					    fan_cells,
+					    nfan_cells,
 					    NULL, 0, NULL);
 
 	return 0;
@@ -123,7 +192,8 @@ static int khadas_mcu_probe(struct i2c_client *client)
 
 #ifdef CONFIG_OF
 static const struct of_device_id khadas_mcu_of_match[] = {
-	{ .compatible = "khadas,mcu", },
+	{ .compatible = "khadas,mcu", .data = (void *)KHADAS_MCU_GENERIC },
+	{ .compatible = "khadas,vim4-mcu", .data = (void *)KHADAS_MCU_VIM4 },
 	{},
 };
 MODULE_DEVICE_TABLE(of, khadas_mcu_of_match);