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

[Neil Armstrong <narmstrong@baylibre.com>]

On 20/05/2020 11:01, Lee Jones wrote:
> On Tue, 12 May 2020, Neil Armstrong wrote:
> 
>> 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.
> 
> It would be good to describe the device here.

Ok

> 
>>  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
> 
> Nit: '\n' here please.

Ok

> 
>> + * 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>
> 
> Alphabetical.


Ok


> 
>> +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 */
> 
> Doesn't read great.
> 
> Consider reversing or make the sentence more succinct.
> 
> "VIM1/2 Rev13+ and VIM3 only"

Ok

> 
>> +	{ .name = "khadas-mcu-fan-ctrl", },
>> +};
>> +
>> +static struct mfd_cell khadas_mcu_cells[] = {
>> +	/* Features supported on all board revisions */
> 
> I think we can omit this.

Ok

> 
>> +	{ .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;
> 
> Prefer a rename to 'ddata'.

Ok

> 
>> +	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);
>

Ok

> Prefer a rename to 'regmap'.
> 
>> +	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
> 
> Nit: '\n'

Ok

> 
>> + * 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 */
> 
> Nit: Can you pad these please?

Ok

> 
>> +#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 */
> 
> I think the names make this superfluous.

Ok

> 
>> +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
> 
> Doesn't match the struct name>
> Prefer you drop the 'MFD' part.

Ok

> 
>> + * @device:		device reference used for logs
>> + * @map:		register map
>> + */
>> +struct khadas_mcu {
>> +	struct device *dev;
>> +	struct regmap *map;
>> +};
>> +
>> +#endif /* MFD_KHADAS_MCU_H */
> 

Thanks for the review.

Neil