[v13,3/4] i2c: muxes: pca954x: Add MAX735x/MAX736x support

Add support for the following Maxim chips using the existing PCA954x
driver:
- MAX7356
- MAX7357
- MAX7358
- MAX7367
- MAX7368
- MAX7369

All added Maxim chips behave like the PCA954x, where a single SMBUS byte
write selects up to 8 channels to be bridged to the primary bus.

While the MAX7357/MAX7358 have interrupt support, they don't act as
interrupt controller like the PCA9545 does. Thus don't enable IRQ support
and handle them like the PCA9548.

Tested using the MAX7357.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
---
 drivers/i2c/muxes/Kconfig           |  6 +--
 drivers/i2c/muxes/i2c-mux-pca954x.c | 60 ++++++++++++++++++++++++++++-
 2 files changed, 62 insertions(+), 4 deletions(-)

Hi Patrick,

On Tue, Apr 18, 2023 at 12:34:28PM +0200, Patrick Rudolph wrote:
> Add support for the following Maxim chips using the existing PCA954x
> driver:
> - MAX7356
> - MAX7357
> - MAX7358
> - MAX7367
> - MAX7368
> - MAX7369
> 
> All added Maxim chips behave like the PCA954x, where a single SMBUS byte
> write selects up to 8 channels to be bridged to the primary bus.
> 
> While the MAX7357/MAX7358 have interrupt support, they don't act as
> interrupt controller like the PCA9545 does. Thus don't enable IRQ support
> and handle them like the PCA9548.

Can you add this as a comment also in the chip_desc?

> Tested using the MAX7357.
> 
> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> ---
>  drivers/i2c/muxes/Kconfig           |  6 +--
>  drivers/i2c/muxes/i2c-mux-pca954x.c | 60 ++++++++++++++++++++++++++++-
>  2 files changed, 62 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
> index ea838dbae32e..db1b9057612a 100644
> --- a/drivers/i2c/muxes/Kconfig
> +++ b/drivers/i2c/muxes/Kconfig
> @@ -65,11 +65,11 @@ config I2C_MUX_PCA9541
>  	  will be called i2c-mux-pca9541.
>  
>  config I2C_MUX_PCA954x
> -	tristate "NXP PCA954x and PCA984x I2C Mux/switches"
> +	tristate "NXP PCA954x/PCA984x and Maxim MAX735x/MAX736x I2C Mux/switches"
>  	depends on GPIOLIB || COMPILE_TEST
>  	help
> -	  If you say yes here you get support for the NXP PCA954x
> -	  and PCA984x I2C mux/switch devices.
> +	  If you say yes here you get support for NXP PCA954x/PCA984x
> +	  and Maxim MAX735x/MAX736x I2C mux/switch devices.
>  
>  	  This driver can also be built as a module.  If so, the module
>  	  will be called i2c-mux-pca954x.
> diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
> index 0ccee2ae5720..a9195d1547f1 100644
> --- a/drivers/i2c/muxes/i2c-mux-pca954x.c
> +++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
> @@ -4,6 +4,7 @@
>   *
>   * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
>   * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
> + * Copyright (c) 2022 9elements GmbH <patrick.rudolph@9elements.com>

2023

Otherwise, looks good,

Reviewed-by: Andi Shyti <andi.shyti@kernel.org> 

Andi

>   *
>   * This module supports the PCA954x and PCA984x series of I2C multiplexer/switch
>   * chips made by NXP Semiconductors.
> @@ -11,6 +12,12 @@
>   *	 PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547,
>   *	 PCA9548, PCA9846, PCA9847, PCA9848 and PCA9849.
>   *
> + * It's also compatible to Maxims MAX735x I2C switch chips, which are controlled
> + * as the NXP PCA9548 and the MAX736x chips that act like the PCA9544.
> + *
> + * This includes the:
> + *	 MAX7356, MAX7357, MAX7358, MAX7367, MAX7368 and MAX7369
> + *
>   * These chips are all controlled via the I2C bus itself, and all have a
>   * single 8-bit register. The upstream "parent" bus fans out to two,
>   * four, or eight downstream busses or channels; which of these
> @@ -51,6 +58,12 @@
>  #define PCA954X_IRQ_OFFSET 4
>  
>  enum pca_type {
> +	max_7356,
> +	max_7357,
> +	max_7358,
> +	max_7367,
> +	max_7368,
> +	max_7369,
>  	pca_9540,
>  	pca_9542,
>  	pca_9543,
> @@ -90,8 +103,41 @@ struct pca954x {
>  	raw_spinlock_t lock;
>  };
>  
> -/* Provide specs for the PCA954x types we know about */
> +/* Provide specs for the MAX735x, PCA954x and PCA984x types we know about */
>  static const struct chip_desc chips[] = {
> +	[max_7356] = {
> +		.nchans = 8,
> +		.muxtype = pca954x_isswi,
> +		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
> +	},
> +	[max_7357] = {
> +		.nchans = 8,
> +		.muxtype = pca954x_isswi,
> +		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
> +	},
> +	[max_7358] = {
> +		.nchans = 8,
> +		.muxtype = pca954x_isswi,
> +		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
> +	},
> +	[max_7367] = {
> +		.nchans = 4,
> +		.muxtype = pca954x_isswi,
> +		.has_irq = 1,
> +		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
> +	},
> +	[max_7368] = {
> +		.nchans = 4,
> +		.muxtype = pca954x_isswi,
> +		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
> +	},
> +	[max_7369] = {
> +		.nchans = 4,
> +		.enable = 0x4,
> +		.muxtype = pca954x_ismux,
> +		.has_irq = 1,
> +		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
> +	},
>  	[pca_9540] = {
>  		.nchans = 2,
>  		.enable = 0x4,
> @@ -177,6 +223,12 @@ static const struct chip_desc chips[] = {
>  };
>  
>  static const struct i2c_device_id pca954x_id[] = {
> +	{ "max7356", max_7356 },
> +	{ "max7357", max_7357 },
> +	{ "max7358", max_7358 },
> +	{ "max7367", max_7367 },
> +	{ "max7368", max_7368 },
> +	{ "max7369", max_7369 },
>  	{ "pca9540", pca_9540 },
>  	{ "pca9542", pca_9542 },
>  	{ "pca9543", pca_9543 },
> @@ -194,6 +246,12 @@ static const struct i2c_device_id pca954x_id[] = {
>  MODULE_DEVICE_TABLE(i2c, pca954x_id);
>  
>  static const struct of_device_id pca954x_of_match[] = {
> +	{ .compatible = "maxim,max7356", .data = &chips[max_7356] },
> +	{ .compatible = "maxim,max7357", .data = &chips[max_7357] },
> +	{ .compatible = "maxim,max7358", .data = &chips[max_7358] },
> +	{ .compatible = "maxim,max7367", .data = &chips[max_7367] },
> +	{ .compatible = "maxim,max7368", .data = &chips[max_7368] },
> +	{ .compatible = "maxim,max7369", .data = &chips[max_7369] },
>  	{ .compatible = "nxp,pca9540", .data = &chips[pca_9540] },
>  	{ .compatible = "nxp,pca9542", .data = &chips[pca_9542] },
>  	{ .compatible = "nxp,pca9543", .data = &chips[pca_9543] },
> -- 
> 2.39.2
>