Re: [PATCH v3 2/9] mfd: cgbc: Add I2C platform data

[Lee Jones <lee@kernel.org>]

On Fri, 11 Sep 2026, Thomas Richard (congatec GmbH) wrote:

> Define I2C platform data for each I2C bus in the cgbc MFD driver. Platform
> data passes per-bus parameters to the I2C driver, rather than being defined
> inside the i2c-cgbc driver itself. This makes the i2c-cgbc driver more
> generic.
> 
> Signed-off-by: Thomas Richard (congatec GmbH) <thomas.richard@bootlin.com>
> ---
>  MAINTAINERS                            |  1 +
>  drivers/mfd/cgbc-core.c                | 39 ++++++++++++++++++++++++++--------
>  include/linux/platform_data/i2c-cgbc.h | 22 +++++++++++++++++++
>  3 files changed, 53 insertions(+), 9 deletions(-)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 6215fcb07770..561f102c2541 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6621,6 +6621,7 @@ F:	drivers/mfd/cgbc-core.c
>  F:	drivers/video/backlight/cgbc_bl.c
>  F:	drivers/watchdog/cgbc_wdt.c
>  F:	include/linux/mfd/cgbc.h
> +F:	include/linux/platform_data/i2c-cgbc.h
>  
>  CONSOLE SUBSYSTEM
>  M:	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> diff --git a/drivers/mfd/cgbc-core.c b/drivers/mfd/cgbc-core.c
> index 4a409234e66c..321fa3fff2ac 100644
> --- a/drivers/mfd/cgbc-core.c
> +++ b/drivers/mfd/cgbc-core.c
> @@ -16,6 +16,7 @@
>  #include <linux/mfd/cgbc.h>
>  #include <linux/mfd/core.h>
>  #include <linux/module.h>
> +#include <linux/platform_data/i2c-cgbc.h>
>  #include <linux/platform_device.h>
>  #include <linux/sysfs.h>
>  
> @@ -55,6 +56,35 @@
>  
>  static struct platform_device *cgbc_pdev;
>  
> +static const struct cgbc_i2c_platform_data cgbc_i2c_gp_pdata = {
> +	.name = "Congatec General Purpose I2C adapter",
> +	.cgbc_bus_id = 0,
> +};
> +
> +static const struct cgbc_i2c_platform_data cgbc_i2c_pm_pdata = {
> +	.name  = "Congatec Power Management I2C adapter",
> +	.cgbc_bus_id = 4,
> +};
> +
> +static const struct mfd_cell cgbc_devs[] = {
> +	{ .name = "cgbc-backlight" },

MFD_CELL_*

> +	{ .name = "cgbc-gpio" },
> +	{ .name = "cgbc-hwmon" },
> +	{
> +		.name = "cgbc-i2c",
> +		.id = 1,

Why does PLATFORM_DEVID_AUTO not work for you?

> +		.platform_data = &cgbc_i2c_gp_pdata,
> +		.pdata_size = sizeof(cgbc_i2c_gp_pdata),
> +	},
> +	{
> +		.name = "cgbc-i2c",
> +		.id = 2,
> +		.platform_data = &cgbc_i2c_pm_pdata,
> +		.pdata_size = sizeof(cgbc_i2c_pm_pdata),
> +	},
> +	{ .name = "cgbc-wdt" },
> +};
> +
>  /* Wait the Board Controller is ready to receive some session commands */
>  static int cgbc_wait_device(struct cgbc_device_data *cgbc)
>  {
> @@ -235,15 +265,6 @@ int cgbc_command(struct cgbc_device_data *cgbc, void *cmd, unsigned int cmd_size
>  }
>  EXPORT_SYMBOL_GPL(cgbc_command);
>  
> -static struct mfd_cell cgbc_devs[] = {
> -	{ .name = "cgbc-wdt"	},
> -	{ .name = "cgbc-gpio"	},
> -	{ .name = "cgbc-i2c", .id = 1 },
> -	{ .name = "cgbc-i2c", .id = 2 },
> -	{ .name = "cgbc-hwmon"	},
> -	{ .name = "cgbc-backlight" },
> -};
> -
>  static int cgbc_map(struct cgbc_device_data *cgbc)
>  {
>  	struct device *dev = cgbc->dev;
> diff --git a/include/linux/platform_data/i2c-cgbc.h b/include/linux/platform_data/i2c-cgbc.h
> new file mode 100644
> index 000000000000..4465e8a7b40e
> --- /dev/null
> +++ b/include/linux/platform_data/i2c-cgbc.h

I think this area is mainly used to share data with OF.

Did you consider include/linux/mfd?

> @@ -0,0 +1,22 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * i2c-cgbc interface to platform code
> + *
> + * Copyright (C) 2026 congatec GmbH
> + * Author: Thomas Richard <thomas.richard@bootlin.com>
> + */
> +
> +#ifndef _LINUX_I2C_CGBC_H
> +#define _LINUX_I2C_CGBC_H
> +
> +/**
> + * struct cgbc_platform_data - Platform data of the CGBC I2C driver
> + * @name:		I2C adapter name
> + * @cgbc_bus_id:	I2C bus ID (from Board Controller point of view)
> + */
> +struct cgbc_i2c_platform_data {
> +	const char *name;
> +	int cgbc_bus_id;
> +};
> +
> +#endif /* _LINUX_I2C_CGBC_H */
> 
> -- 
> 2.53.0
> 

-- 
Lee Jones