[PATCH v15 3/4] i2c: muxes: pca954x: Add MAX735x/MAX736x support

[Patrick Rudolph <patrick.rudolph@9elements.com>]

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 | 64 ++++++++++++++++++++++++++++-
 2 files changed, 66 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..968111442625 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>
  *
  * 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 +103,45 @@ 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 },
+		/* No interrupt controller support.
+		   The interrupt provides information about stuck channels. */
+	},
+	[max_7358] = {
+		.nchans = 8,
+		.muxtype = pca954x_isswi,
+		.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
+		/* No interrupt controller support.
+		   The interrupt provides information about stuck channels. */
+	},
+	[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 +227,12 @@ 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 +250,12 @@ 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] },
-- 
2.41.0