[PATCH v11 3/6] mfd: khadas-mcu: Add support for VIM4 MCU variant
linux-kernel-dev at aliel.fr
linux-kernel-dev at aliel.fr
Wed Sep 16 06:01:42 PDT 2026
On 9/10/26 4:21 PM, Lee Jones wrote:
> On Wed, 02 Sep 2026, Ronald Claveau via B4 Relay wrote:
>
>> From: Ronald Claveau <linux-kernel-dev at aliel.fr>
>>
>> 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.
>>
>> Introduce struct khadas_mcu_fan_pdata to pass the fan
>> control register and duty-cycle levels per variant.
>> VIM4 uses a different register and level set (0-100)
>> declared as a list (0, 30, 40, 55, 75, 100) compared
>> to previous boards (0-3).
>>
>> Add a new compatible string "khadas,vim4-mcu".
>>
>> Reviewed-by: Neil Armstrong <neil.armstrong at linaro.org>
>> Signed-off-by: Ronald Claveau <linux-kernel-dev at aliel.fr>
>
> Generally fine.
>
>> ---
>> drivers/mfd/khadas-mcu.c | 120 +++++++++++++++++++++++++++++++++++++++++------
>> 1 file changed, 106 insertions(+), 14 deletions(-)
>>
>> diff --git a/drivers/mfd/khadas-mcu.c b/drivers/mfd/khadas-mcu.c
>> index 0e74efe14f367..4cb305ac915e1 100644
>> --- a/drivers/mfd/khadas-mcu.c
>> +++ b/drivers/mfd/khadas-mcu.c
>> @@ -75,47 +75,138 @@ static const struct regmap_config khadas_mcu_regmap_config = {
>> .cache_type = REGCACHE_MAPLE,
>> };
>>
>> +static const unsigned int khadas_mcu_fan_levels[] = {
>> + 0, 1, 2, 3,
>> +};
>> +
>> +static const struct khadas_mcu_fan_pdata khadas_mcu_fan_pdata = {
>> + .fan_reg = KHADAS_MCU_CMD_FAN_STATUS_CTRL_REG,
>> + .levels = khadas_mcu_fan_levels,
>> + .nlevels = ARRAY_SIZE(khadas_mcu_fan_levels),
>> +};
>
> I still don't think these belong in here.
>
I will move it to the fan driver.
>> static const struct mfd_cell khadas_mcu_fan_cells[] = {
>> /* VIM1/2 Rev13+ and VIM3 only */
>> - MFD_CELL_NAME("khadas-mcu-fan-ctrl"),
>> + MFD_CELL_BASIC("khadas-mcu-fan-ctrl", NULL, &khadas_mcu_fan_pdata,
>> + sizeof(khadas_mcu_fan_pdata), 0),
>> };
>>
>> 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 unsigned int khadas_mcu_vim4_fan_levels[] = {
>> + 0, 30, 40, 55, 75, 100,
>> +};
>> +
>> +static const struct khadas_mcu_fan_pdata khadas_mcu_vim4_fan_pdata = {
>> + .fan_reg = KHADAS_MCU_VIM4_FAN_CTRL_REG,
>> + .levels = khadas_mcu_vim4_fan_levels,
>> + .nlevels = ARRAY_SIZE(khadas_mcu_vim4_fan_levels),
>> +};
>> +
>> +static const struct mfd_cell khadas_mcu_vim4_fan_cells[] = {
>> + MFD_CELL_BASIC("khadas-mcu-fan-ctrl", NULL, &khadas_mcu_vim4_fan_pdata,
>> + sizeof(khadas_mcu_vim4_fan_pdata), 0),
>> +};
>> +
>> 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 *match;
>>
>> ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
>> if (!ddata)
>> return -ENOMEM;
>>
>> + match = i2c_get_match_data(client);
>
> The nomenclature can be improved here.
>
> What are these? Device ID? Chip ID? Revision?
>
I will change this to 'mcu_variant'
>> + if (!match)
>> + return -ENODEV;
>> +
>> + switch ((uintptr_t)match) {
>> + 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 +214,8 @@ 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);
>>
>> --
>> 2.49.0
>>
>>
>
--
Best regards,
Ronald
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