v9:
- Fix 'then' not aligned with 'if' in dt-bindings
- Split enhanced mode configuration into separate patch
- Add MAX7357/MAX7358 register definitions
- Rename config register defines
- Update comments and explain non default config being applied on MAX7357
- Check for I2C_FUNC_SMBUS_WRITE_BYTE_DATA functionality
v8:
- Move allOf in dt-binding and use double negation
v7:
- Reworked the commit message, comments and renamed a struct
field. No functional change.
v6:
- Fix typo in dt-bindings
v5:
- Remove optional and make vdd-supply mandatory
v4:
- Add missing maxitems dt-bindings property
v3:
- Merge dt-bindings into i2c-mux-pca954x.yaml
v2:
- Move dt-bindings to separate file
- Added support for MAX736x as they are very similar
- Fixed an issue found by kernel test robot
- Dropped max735x property and custom IRQ check
- Added MAX7357 config register defines instead of magic values
- Renamed vcc-supply to vdd-supply
Patrick Rudolph (4):
dt-bindings: i2c: Add Maxim MAX735x/MAX736x variants
i2c: muxes: pca954x: Add MAX735x/MAX736x support
i2c: muxes: pca954x: Configure MAX7357 in enhanced mode
i2c: muxes: pca954x: Add regulator support
.../bindings/i2c/i2c-mux-pca954x.yaml | 39 ++++-
drivers/i2c/muxes/Kconfig | 6 +-
drivers/i2c/muxes/i2c-mux-pca954x.c | 140 +++++++++++++++++-
3 files changed, 170 insertions(+), 15 deletions(-)
--
2.37.3
The MAX7357 and MAX7358 have 6 additional registers called enhanced mode
in the following paragraphs. While the MAX7357 exposes those registers
without a special sequence, the MAX7358 requires an unlock sequence.
The enhanced mode allows to configure optional features which are nice to
have on an I2C mux, but are not mandatory for it's general operation.
As I don't have a MAX7358 for testing the special unlock sequence the
enhanced mode isn't used on the MAX7358, but it could be added later
if required.
The MAX7357 enhanced mode is used to configure the chip to
- Disable interrupts on bus locked up detection
- Enable bus locked-up clearing
- Disconnect only locked bus instead of all channels
This configuration protects the I2C tree from total failure and attempts
to unbrick the faulty bus. It's unclear why this isn't the default
configuration.
Tested using the MAX7357 and verified that the stalled bus is disconnected
while the other channels remain operational.
Signed-off-by: Patrick Rudolph <[email protected]>
---
drivers/i2c/muxes/i2c-mux-pca954x.c | 46 ++++++++++++++++++++++++++++-
1 file changed, 45 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
index 4b63b1eb669e..992976fa6798 100644
--- a/drivers/i2c/muxes/i2c-mux-pca954x.c
+++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
@@ -57,6 +57,37 @@
#define PCA954X_IRQ_OFFSET 4
+/*
+ * The MAX7357 and MAX7358 have 6 additional registers called enhanced mode
+ * in the following paragraphs. While the MAX7357 exposes those registers
+ * without a special sequence, the MAX7358 requires an unlock sequence.
+ *
+ * The first enhanced mode register called CONF allows to configure
+ * additional features.
+ */
+#define MAX7357_REG_SWITCH 0
+#define MAX7357_REG_CONF 1
+#define MAX7357_CONF_INT_ENABLE BIT(0)
+#define MAX7357_CONF_FLUSH_OUT BIT(1)
+#define MAX7357_CONF_RELEASE_INT BIT(2)
+#define MAX7357_CONF_LOCK_UP_CLEAR_ON_READ BIT(3)
+#define MAX7357_CONF_DISCON_SINGLE_CHAN BIT(4)
+#define MAX7357_CONF_BUS_LOCKUP_DETECTION_DISABLE BIT(5)
+#define MAX7357_CONF_ENABLE_BASIC_MODE BIT(6)
+#define MAX7357_CONF_PRECONNECT_TEST BIT(7)
+
+/*
+ * On boot the MAX735x behave like a regular MUX. Apply a fixed
+ * default configuration on MAX7357 that:
+ * - disables interrupts
+ * - sents automatically flush-out sequence on locked-up channels
+ when a lock-up condition is detected
+ * - isolates only the locked channel instead of all channels
+ * - doesn't disable bus lock-up detection.
+ */
+#define MAX7357_CONF_DEFAULTS (MAX7357_CONF_FLUSH_OUT | \
+ MAX7357_CONF_DISCON_SINGLE_CHAN)
+
enum pca_type {
max_7367,
max_7368,
@@ -82,6 +113,7 @@ struct chip_desc {
u8 nchans;
u8 enable; /* used for muxes only */
u8 has_irq;
+ u8 maxim_enhanced_mode;
enum muxtype {
pca954x_ismux = 0,
pca954x_isswi
@@ -113,6 +145,7 @@ static const struct chip_desc chips[] = {
[max_7357] = {
.nchans = 8,
.muxtype = pca954x_isswi,
+ .maxim_enhanced_mode = 1,
.id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
},
[max_7358] = {
@@ -452,6 +485,7 @@ static void pca954x_cleanup(struct i2c_mux_core *muxc)
static int pca954x_init(struct i2c_client *client, struct pca954x *data)
{
+ struct i2c_adapter *adap = client->adapter;
int ret;
if (data->idle_state >= 0)
@@ -459,7 +493,17 @@ static int pca954x_init(struct i2c_client *client, struct pca954x *data)
else
data->last_chan = 0; /* Disconnect multiplexer */
- ret = i2c_smbus_write_byte(client, data->last_chan);
+ if (data->chip->maxim_enhanced_mode) {
+ if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
+ ret = i2c_smbus_write_byte_data(client, data->last_chan,
+ MAX7357_CONF_DEFAULTS);
+ } else {
+ dev_warn(&client->dev, "Didn't configure enhanced defaults\n");
+ ret = i2c_smbus_write_byte(client, data->last_chan);
+ }
+ } else {
+ ret = i2c_smbus_write_byte(client, data->last_chan);
+ }
if (ret < 0)
data->last_chan = 0;
--
2.37.3
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 and verified that the stalled bus is disconnected
while the other channels remain operational.
Signed-off-by: Patrick Rudolph <[email protected]>
---
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 a5f458b635df..4b63b1eb669e 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 <[email protected]>
* Copyright (c) 2008-2009 Eurotech S.p.A. <[email protected]>
+ * Copyright (c) 2022 9elements GmbH <[email protected]>
*
* 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_7367,
+ max_7368,
+ max_7369,
+ max_7356,
+ max_7357,
+ max_7358,
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] },
--
2.37.3
On Fri, Oct 07, 2022 at 09:53:52AM +0200, Patrick Rudolph wrote:
> The MAX7357 and MAX7358 have 6 additional registers called enhanced mode
> in the following paragraphs. While the MAX7357 exposes those registers
> without a special sequence, the MAX7358 requires an unlock sequence.
> The enhanced mode allows to configure optional features which are nice to
> have on an I2C mux, but are not mandatory for it's general operation.
>
> As I don't have a MAX7358 for testing the special unlock sequence the
> enhanced mode isn't used on the MAX7358, but it could be added later
> if required.
Not that hard to do. Just place four I2C_SMBUS_QUICK messages in a
single transfer:
S Addr Wr [A] Sr Addr Rd [A] Sr Addr Wr [A] Sr Addr Rd [A] P
it can be easily done by means of the i2c_transfer() method called
with four i2c_msg instances (Wr/Rd/Wr/Rd with zero length) passed.
See the way the quicks smbus-messages are implemented in
i2c_smbus_xfer_emulated((). Just place four if them in single array
and pass to the i2c_transfer() method.
Note some drivers may unsupport the I2C-level transfers. Also note
some adapters may unsupport the zero-length I2C-transfers. AFAIR we
had such problem with the Synopsys DW I2C controller.
>
> The MAX7357 enhanced mode is used to configure the chip to
> - Disable interrupts on bus locked up detection
> - Enable bus locked-up clearing
> - Disconnect only locked bus instead of all channels
>
> This configuration protects the I2C tree from total failure and attempts
> to unbrick the faulty bus. It's unclear why this isn't the default
> configuration.
>
> Tested using the MAX7357 and verified that the stalled bus is disconnected
> while the other channels remain operational.
>
> Signed-off-by: Patrick Rudolph <[email protected]>
> ---
> drivers/i2c/muxes/i2c-mux-pca954x.c | 46 ++++++++++++++++++++++++++++-
> 1 file changed, 45 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
> index 4b63b1eb669e..992976fa6798 100644
> --- a/drivers/i2c/muxes/i2c-mux-pca954x.c
> +++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
> @@ -57,6 +57,37 @@
>
> #define PCA954X_IRQ_OFFSET 4
>
> +/*
> + * The MAX7357 and MAX7358 have 6 additional registers called enhanced mode
> + * in the following paragraphs. While the MAX7357 exposes those registers
> + * without a special sequence, the MAX7358 requires an unlock sequence.
> + *
> + * The first enhanced mode register called CONF allows to configure
> + * additional features.
> + */
> +#define MAX7357_REG_SWITCH 0
> +#define MAX7357_REG_CONF 1
> +#define MAX7357_CONF_INT_ENABLE BIT(0)
> +#define MAX7357_CONF_FLUSH_OUT BIT(1)
> +#define MAX7357_CONF_RELEASE_INT BIT(2)
> +#define MAX7357_CONF_LOCK_UP_CLEAR_ON_READ BIT(3)
> +#define MAX7357_CONF_DISCON_SINGLE_CHAN BIT(4)
> +#define MAX7357_CONF_BUS_LOCKUP_DETECTION_DISABLE BIT(5)
> +#define MAX7357_CONF_ENABLE_BASIC_MODE BIT(6)
> +#define MAX7357_CONF_PRECONNECT_TEST BIT(7)
> +
> +/*
> + * On boot the MAX735x behave like a regular MUX. Apply a fixed
> + * default configuration on MAX7357 that:
> + * - disables interrupts
> + * - sents automatically flush-out sequence on locked-up channels
> + when a lock-up condition is detected
> + * - isolates only the locked channel instead of all channels
> + * - doesn't disable bus lock-up detection.
> + */
> +#define MAX7357_CONF_DEFAULTS (MAX7357_CONF_FLUSH_OUT | \
> + MAX7357_CONF_DISCON_SINGLE_CHAN)
Moving the macro definition fully to the new line might look a bit
nicer:
+#define MAX7357_CONF_DEFAULTS \
(MAX7357_CONF_FLUSH_OUT | MAX7357_CONF_DISCON_SINGLE_CHAN)
> +
> enum pca_type {
> max_7367,
> max_7368,
> @@ -82,6 +113,7 @@ struct chip_desc {
> u8 nchans;
> u8 enable; /* used for muxes only */
> u8 has_irq;
> + u8 maxim_enhanced_mode;
So long name.( What about a shorter version, i.e. max(im)?_enh ?
BTW how to differentiate the devices with the enhanced mode
enabled/disabled by default?
-Sergey
> enum muxtype {
> pca954x_ismux = 0,
> pca954x_isswi
> @@ -113,6 +145,7 @@ static const struct chip_desc chips[] = {
> [max_7357] = {
> .nchans = 8,
> .muxtype = pca954x_isswi,
> + .maxim_enhanced_mode = 1,
> .id = { .manufacturer_id = I2C_DEVICE_ID_NONE },
> },
> [max_7358] = {
> @@ -452,6 +485,7 @@ static void pca954x_cleanup(struct i2c_mux_core *muxc)
>
> static int pca954x_init(struct i2c_client *client, struct pca954x *data)
> {
> + struct i2c_adapter *adap = client->adapter;
> int ret;
>
> if (data->idle_state >= 0)
> @@ -459,7 +493,17 @@ static int pca954x_init(struct i2c_client *client, struct pca954x *data)
> else
> data->last_chan = 0; /* Disconnect multiplexer */
>
> - ret = i2c_smbus_write_byte(client, data->last_chan);
> + if (data->chip->maxim_enhanced_mode) {
> + if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) {
> + ret = i2c_smbus_write_byte_data(client, data->last_chan,
> + MAX7357_CONF_DEFAULTS);
> + } else {
> + dev_warn(&client->dev, "Didn't configure enhanced defaults\n");
> + ret = i2c_smbus_write_byte(client, data->last_chan);
> + }
> + } else {
> + ret = i2c_smbus_write_byte(client, data->last_chan);
> + }
> if (ret < 0)
> data->last_chan = 0;
>
> --
> 2.37.3
>
2022-10-08 at 14:54, Serge Semin wrote:
> On Fri, Oct 07, 2022 at 09:53:52AM +0200, Patrick Rudolph wrote:
>> + u8 maxim_enhanced_mode;
>
> So long name.( What about a shorter version, i.e. max(im)?_enh ?
No thank you, please keep the long name as is. This is a corner
case and the name is not repeated that many times. Spelling it
out makes the code more readable.
Cheers,
Peter
On Sun, Oct 09, 2022 at 06:36:52PM +0200, Peter Rosin wrote:
> 2022-10-08 at 14:54, Serge Semin wrote:
> > On Fri, Oct 07, 2022 at 09:53:52AM +0200, Patrick Rudolph wrote:
> >> + u8 maxim_enhanced_mode;
> >
> > So long name.( What about a shorter version, i.e. max(im)?_enh ?
>
> No thank you, please keep the long name as is. This is a corner
> case and the name is not repeated that many times. Spelling it
> out makes the code more readable.
I don't insist. It was just a suggestion.
Anyway seeing there are going to be two variables with the flag
semantic (has_irq and maxim_enhanced_mode) it would be better to
convert them to a single quirk field. Moreover it will be useful
taking into account that a single maxim_enhanced_mode flag can't be
used to distinguish the Maxim I2C-muxes with the enhanced mode
disabled by default. Thus another flag will be needed for such
devices.
One more thing. Using u8 type for the flag variables isn't that
descriptive. It should be of the boolean type.
-Sergey
>
> Cheers,
> Peter