Hello,
This series contains the remaining two outstanding patches adding i2c
support to the nct6775 hwmon driver.
Changes since v4 [0]:
- Added missing type $ref to nuvoton,tsi-channel-mask property in DT
binding [Krzysztof, Rob's bot]
- Added 'F:' line for nuvoton,nct6775.yaml DT binding file to
MAINTAINERS
The first patch adds a DT binding for the Nuvoton Super I/O chips
supported by the nct6775 driver; the second adds an i2c hwmon driver
wrapped around the new nct6775-core module.
(Since the preparatory work for this that comprised the bulk of the
previous iterations of the series is now in Guenter's hwmon-next tree
this is a somewhat abridged cover letter; see [0] for additional
background info if needed.)
[0] https://lore.kernel.org/linux-hwmon/[email protected]/
Zev Weiss (2):
dt-bindings: hwmon: Add nuvoton,nct6775
hwmon: (nct6775) Add i2c driver
.../bindings/hwmon/nuvoton,nct6775.yaml | 57 +++++
MAINTAINERS | 7 +
drivers/hwmon/Kconfig | 17 ++
drivers/hwmon/Makefile | 1 +
drivers/hwmon/nct6775-i2c.c | 195 ++++++++++++++++++
5 files changed, 277 insertions(+)
create mode 100644 Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
create mode 100644 drivers/hwmon/nct6775-i2c.c
--
2.36.0
These Super I/O chips have an i2c interface that some systems expose
to a BMC; the BMC's device tree can now describe that via this
binding.
Signed-off-by: Zev Weiss <[email protected]>
---
.../bindings/hwmon/nuvoton,nct6775.yaml | 57 +++++++++++++++++++
1 file changed, 57 insertions(+)
create mode 100644 Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
diff --git a/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml b/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
new file mode 100644
index 000000000000..358b262431fc
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+
+$id: http://devicetree.org/schemas/hwmon/nuvoton,nct6775.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Nuvoton NCT6775 and compatible Super I/O chips
+
+maintainers:
+ - Zev Weiss <[email protected]>
+
+properties:
+ compatible:
+ enum:
+ - nuvoton,nct6106
+ - nuvoton,nct6116
+ - nuvoton,nct6775
+ - nuvoton,nct6776
+ - nuvoton,nct6779
+ - nuvoton,nct6791
+ - nuvoton,nct6792
+ - nuvoton,nct6793
+ - nuvoton,nct6795
+ - nuvoton,nct6796
+ - nuvoton,nct6797
+ - nuvoton,nct6798
+
+ reg:
+ maxItems: 1
+
+ nuvoton,tsi-channel-mask:
+ description:
+ Bitmask indicating which TSI temperature sensor channels are
+ active. LSB is TSI0, bit 1 is TSI1, etc.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ maximum: 0xff
+ default: 0
+
+required:
+ - compatible
+ - reg
+
+additionalProperties: false
+
+examples:
+ - |
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ superio@4d {
+ compatible = "nuvoton,nct6779";
+ reg = <0x4d>;
+ nuvoton,tsi-channel-mask = <0x03>;
+ };
+ };
--
2.36.0
This driver provides an i2c I/O mechanism for the core nct6775 driver,
as might be used by a BMC. Because the Super I/O chip is shared with
the host CPU in such a scenario (and the host should ultimately be in
control of it), the i2c driver is strictly read-only to avoid
interfering with any usage by the host (aside from the bank-select
register, which seems to be replicated for the i2c interface).
Signed-off-by: Zev Weiss <[email protected]>
Tested-by: Renze Nicolai <[email protected]>
---
MAINTAINERS | 7 ++
drivers/hwmon/Kconfig | 17 ++++
drivers/hwmon/Makefile | 1 +
drivers/hwmon/nct6775-i2c.c | 195 ++++++++++++++++++++++++++++++++++++
4 files changed, 220 insertions(+)
create mode 100644 drivers/hwmon/nct6775-i2c.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 88fdb7cb3197..aac1a184a4c9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13538,6 +13538,13 @@ F: drivers/hwmon/nct6775-core.c
F: drivers/hwmon/nct6775-platform.c
F: drivers/hwmon/nct6775.h
+NCT6775 HARDWARE MONITOR DRIVER - I2C DRIVER
+M: Zev Weiss <[email protected]>
+L: [email protected]
+S: Maintained
+F: Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
+F: drivers/hwmon/nct6775-i2c.c
+
NETDEVSIM
M: Jakub Kicinski <[email protected]>
S: Maintained
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 85c22bba439b..a1dac1aa4e3a 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1489,6 +1489,23 @@ config SENSORS_NCT6775
This driver can also be built as a module. If so, the module
will be called nct6775.
+config SENSORS_NCT6775_I2C
+ tristate "I2C driver for Nuvoton NCT6775F and compatibles"
+ depends on I2C
+ select REGMAP_I2C
+ select SENSORS_NCT6775
+ help
+ If you say yes here you get support for the hardware monitoring
+ functionality of the Nuvoton NCT6106D, NCT6775F, NCT6776F, NCT6779D,
+ NCT6791D, NCT6792D, NCT6793D, NCT6795D, NCT6796D, and compatible
+ Super-I/O chips via their I2C interface.
+
+ If you're not building a kernel for a BMC, this is probably
+ not the driver you want (see CONFIG_SENSORS_NCT6775_PLATFORM).
+
+ This driver can also be built as a module. If so, the module
+ will be called nct6775-i2c.
+
config SENSORS_NCT7802
tristate "Nuvoton NCT7802Y"
depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 93f2b774cc5e..004ab87c9b80 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -157,6 +157,7 @@ obj-$(CONFIG_SENSORS_NCT6683) += nct6683.o
obj-$(CONFIG_SENSORS_NCT6775_CORE) += nct6775-core.o
nct6775-objs := nct6775-platform.o
obj-$(CONFIG_SENSORS_NCT6775) += nct6775.o
+obj-$(CONFIG_SENSORS_NCT6775_I2C) += nct6775-i2c.o
obj-$(CONFIG_SENSORS_NCT7802) += nct7802.o
obj-$(CONFIG_SENSORS_NCT7904) += nct7904.o
obj-$(CONFIG_SENSORS_NPCM7XX) += npcm750-pwm-fan.o
diff --git a/drivers/hwmon/nct6775-i2c.c b/drivers/hwmon/nct6775-i2c.c
new file mode 100644
index 000000000000..e1bcd1146191
--- /dev/null
+++ b/drivers/hwmon/nct6775-i2c.c
@@ -0,0 +1,195 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * nct6775-i2c - I2C driver for the hardware monitoring functionality of
+ * Nuvoton NCT677x Super-I/O chips
+ *
+ * Copyright (C) 2022 Zev Weiss <[email protected]>
+ *
+ * This driver interacts with the chip via it's "back door" i2c interface, as
+ * is often exposed to a BMC. Because the host may still be operating the
+ * chip via the ("front door") LPC interface, this driver cannot assume that
+ * it actually has full control of the chip, and in particular must avoid
+ * making any changes that could confuse the host's LPC usage of it. It thus
+ * operates in a strictly read-only fashion, with the only exception being the
+ * bank-select register (which seems, thankfully, to be replicated for the i2c
+ * interface so it doesn't affect the LPC interface).
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/err.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+#include "nct6775.h"
+
+static int nct6775_i2c_read(void *ctx, unsigned int reg, unsigned int *val)
+{
+ int ret;
+ u32 tmp;
+ u8 bank = reg >> 8;
+ struct nct6775_data *data = ctx;
+ struct i2c_client *client = data->driver_data;
+
+ if (bank != data->bank) {
+ ret = i2c_smbus_write_byte_data(client, NCT6775_REG_BANK, bank);
+ if (ret)
+ return ret;
+ data->bank = bank;
+ }
+
+ ret = i2c_smbus_read_byte_data(client, reg & 0xff);
+ if (ret < 0)
+ return ret;
+ tmp = ret;
+
+ if (nct6775_reg_is_word_sized(data, reg)) {
+ ret = i2c_smbus_read_byte_data(client, (reg & 0xff) + 1);
+ if (ret < 0)
+ return ret;
+ tmp = (tmp << 8) | ret;
+ }
+
+ *val = tmp;
+ return 0;
+}
+
+/*
+ * The write operation is a dummy so as not to disturb anything being done
+ * with the chip via LPC.
+ */
+static int nct6775_i2c_write(void *ctx, unsigned int reg, unsigned int value)
+{
+ struct nct6775_data *data = ctx;
+ struct i2c_client *client = data->driver_data;
+
+ dev_dbg(&client->dev, "skipping attempted write: %02x -> %03x\n", value, reg);
+
+ /*
+ * This is a lie, but writing anything but the bank-select register is
+ * something this driver shouldn't be doing.
+ */
+ return 0;
+}
+
+static const struct of_device_id __maybe_unused nct6775_i2c_of_match[] = {
+ { .compatible = "nuvoton,nct6106", .data = (void *)nct6106, },
+ { .compatible = "nuvoton,nct6116", .data = (void *)nct6116, },
+ { .compatible = "nuvoton,nct6775", .data = (void *)nct6775, },
+ { .compatible = "nuvoton,nct6776", .data = (void *)nct6776, },
+ { .compatible = "nuvoton,nct6779", .data = (void *)nct6779, },
+ { .compatible = "nuvoton,nct6791", .data = (void *)nct6791, },
+ { .compatible = "nuvoton,nct6792", .data = (void *)nct6792, },
+ { .compatible = "nuvoton,nct6793", .data = (void *)nct6793, },
+ { .compatible = "nuvoton,nct6795", .data = (void *)nct6795, },
+ { .compatible = "nuvoton,nct6796", .data = (void *)nct6796, },
+ { .compatible = "nuvoton,nct6797", .data = (void *)nct6797, },
+ { .compatible = "nuvoton,nct6798", .data = (void *)nct6798, },
+ { },
+};
+MODULE_DEVICE_TABLE(of, nct6775_i2c_of_match);
+
+static const struct i2c_device_id nct6775_i2c_id[] = {
+ { "nct6106", nct6106 },
+ { "nct6116", nct6116 },
+ { "nct6775", nct6775 },
+ { "nct6776", nct6776 },
+ { "nct6779", nct6779 },
+ { "nct6791", nct6791 },
+ { "nct6792", nct6792 },
+ { "nct6793", nct6793 },
+ { "nct6795", nct6795 },
+ { "nct6796", nct6796 },
+ { "nct6797", nct6797 },
+ { "nct6798", nct6798 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, nct6775_i2c_id);
+
+static int nct6775_i2c_probe_init(struct nct6775_data *data)
+{
+ u32 tsi_channel_mask;
+ struct i2c_client *client = data->driver_data;
+
+ /*
+ * The i2c interface doesn't provide access to the control registers
+ * needed to determine the presence of other fans, but fans 1 and 2
+ * are (in principle) always there.
+ *
+ * In practice this is perhaps a little silly, because the system
+ * using this driver is mostly likely a BMC, and hence probably has
+ * totally separate fan tachs & pwms of its own that are actually
+ * controlling/monitoring the fans -- these are thus unlikely to be
+ * doing anything actually useful.
+ */
+ data->has_fan = 0x03;
+ data->has_fan_min = 0x03;
+ data->has_pwm = 0x03;
+
+ /*
+ * Because on a BMC this driver may be bound very shortly after power
+ * is first applied to the device, the automatic TSI channel detection
+ * in nct6775_probe() (which has already been run at this point) may
+ * not find anything if a channel hasn't yet produced a temperature
+ * reading. Augment whatever was found via autodetection (if
+ * anything) with the channels DT says should be active.
+ */
+ if (!of_property_read_u32(client->dev.of_node, "nuvoton,tsi-channel-mask",
+ &tsi_channel_mask))
+ data->have_tsi_temp |= tsi_channel_mask & GENMASK(NUM_TSI_TEMP - 1, 0);
+
+ return 0;
+}
+
+static const struct regmap_config nct6775_i2c_regmap_config = {
+ .reg_bits = 16,
+ .val_bits = 16,
+ .reg_read = nct6775_i2c_read,
+ .reg_write = nct6775_i2c_write,
+};
+
+static int nct6775_i2c_probe(struct i2c_client *client)
+{
+ struct nct6775_data *data;
+ const struct of_device_id *of_id;
+ const struct i2c_device_id *i2c_id;
+ struct device *dev = &client->dev;
+
+ of_id = of_match_device(nct6775_i2c_of_match, dev);
+ i2c_id = i2c_match_id(nct6775_i2c_id, client);
+
+ if (of_id && (unsigned long)of_id->data != i2c_id->driver_data)
+ dev_notice(dev, "Device mismatch: %s in device tree, %s detected\n",
+ of_id->name, i2c_id->name);
+
+ data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->kind = i2c_id->driver_data;
+
+ data->read_only = true;
+ data->driver_data = client;
+ data->driver_init = nct6775_i2c_probe_init;
+
+ return nct6775_probe(dev, data, &nct6775_i2c_regmap_config);
+}
+
+static struct i2c_driver nct6775_i2c_driver = {
+ .class = I2C_CLASS_HWMON,
+ .driver = {
+ .name = "nct6775-i2c",
+ .of_match_table = of_match_ptr(nct6775_i2c_of_match),
+ },
+ .probe_new = nct6775_i2c_probe,
+ .id_table = nct6775_i2c_id,
+};
+
+module_i2c_driver(nct6775_i2c_driver);
+
+MODULE_AUTHOR("Zev Weiss <[email protected]>");
+MODULE_DESCRIPTION("I2C driver for NCT6775F and compatible chips");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(HWMON_NCT6775);
--
2.36.0
On Wed, 27 Apr 2022 18:27:06 -0700, Zev Weiss wrote:
> These Super I/O chips have an i2c interface that some systems expose
> to a BMC; the BMC's device tree can now describe that via this
> binding.
>
> Signed-off-by: Zev Weiss <[email protected]>
> ---
> .../bindings/hwmon/nuvoton,nct6775.yaml | 57 +++++++++++++++++++
> 1 file changed, 57 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
>
Reviewed-by: Rob Herring <[email protected]>
On Wed, Apr 27, 2022 at 06:27:07PM -0700, Zev Weiss wrote:
> This driver provides an i2c I/O mechanism for the core nct6775 driver,
> as might be used by a BMC. Because the Super I/O chip is shared with
> the host CPU in such a scenario (and the host should ultimately be in
> control of it), the i2c driver is strictly read-only to avoid
> interfering with any usage by the host (aside from the bank-select
> register, which seems to be replicated for the i2c interface).
>
> Signed-off-by: Zev Weiss <[email protected]>
> Tested-by: Renze Nicolai <[email protected]>
Applied.
Thanks,
Guenter
> ---
> MAINTAINERS | 7 ++
> drivers/hwmon/Kconfig | 17 ++++
> drivers/hwmon/Makefile | 1 +
> drivers/hwmon/nct6775-i2c.c | 195 ++++++++++++++++++++++++++++++++++++
> 4 files changed, 220 insertions(+)
> create mode 100644 drivers/hwmon/nct6775-i2c.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 88fdb7cb3197..aac1a184a4c9 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -13538,6 +13538,13 @@ F: drivers/hwmon/nct6775-core.c
> F: drivers/hwmon/nct6775-platform.c
> F: drivers/hwmon/nct6775.h
>
> +NCT6775 HARDWARE MONITOR DRIVER - I2C DRIVER
> +M: Zev Weiss <[email protected]>
> +L: [email protected]
> +S: Maintained
> +F: Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
> +F: drivers/hwmon/nct6775-i2c.c
> +
> NETDEVSIM
> M: Jakub Kicinski <[email protected]>
> S: Maintained
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 85c22bba439b..a1dac1aa4e3a 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1489,6 +1489,23 @@ config SENSORS_NCT6775
> This driver can also be built as a module. If so, the module
> will be called nct6775.
>
> +config SENSORS_NCT6775_I2C
> + tristate "I2C driver for Nuvoton NCT6775F and compatibles"
> + depends on I2C
> + select REGMAP_I2C
> + select SENSORS_NCT6775
> + help
> + If you say yes here you get support for the hardware monitoring
> + functionality of the Nuvoton NCT6106D, NCT6775F, NCT6776F, NCT6779D,
> + NCT6791D, NCT6792D, NCT6793D, NCT6795D, NCT6796D, and compatible
> + Super-I/O chips via their I2C interface.
> +
> + If you're not building a kernel for a BMC, this is probably
> + not the driver you want (see CONFIG_SENSORS_NCT6775_PLATFORM).
> +
> + This driver can also be built as a module. If so, the module
> + will be called nct6775-i2c.
> +
> config SENSORS_NCT7802
> tristate "Nuvoton NCT7802Y"
> depends on I2C
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index 93f2b774cc5e..004ab87c9b80 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -157,6 +157,7 @@ obj-$(CONFIG_SENSORS_NCT6683) += nct6683.o
> obj-$(CONFIG_SENSORS_NCT6775_CORE) += nct6775-core.o
> nct6775-objs := nct6775-platform.o
> obj-$(CONFIG_SENSORS_NCT6775) += nct6775.o
> +obj-$(CONFIG_SENSORS_NCT6775_I2C) += nct6775-i2c.o
> obj-$(CONFIG_SENSORS_NCT7802) += nct7802.o
> obj-$(CONFIG_SENSORS_NCT7904) += nct7904.o
> obj-$(CONFIG_SENSORS_NPCM7XX) += npcm750-pwm-fan.o
> diff --git a/drivers/hwmon/nct6775-i2c.c b/drivers/hwmon/nct6775-i2c.c
> new file mode 100644
> index 000000000000..e1bcd1146191
> --- /dev/null
> +++ b/drivers/hwmon/nct6775-i2c.c
> @@ -0,0 +1,195 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * nct6775-i2c - I2C driver for the hardware monitoring functionality of
> + * Nuvoton NCT677x Super-I/O chips
> + *
> + * Copyright (C) 2022 Zev Weiss <[email protected]>
> + *
> + * This driver interacts with the chip via it's "back door" i2c interface, as
> + * is often exposed to a BMC. Because the host may still be operating the
> + * chip via the ("front door") LPC interface, this driver cannot assume that
> + * it actually has full control of the chip, and in particular must avoid
> + * making any changes that could confuse the host's LPC usage of it. It thus
> + * operates in a strictly read-only fashion, with the only exception being the
> + * bank-select register (which seems, thankfully, to be replicated for the i2c
> + * interface so it doesn't affect the LPC interface).
> + */
> +
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/i2c.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>
> +#include <linux/err.h>
> +#include <linux/of_device.h>
> +#include <linux/regmap.h>
> +#include "nct6775.h"
> +
> +static int nct6775_i2c_read(void *ctx, unsigned int reg, unsigned int *val)
> +{
> + int ret;
> + u32 tmp;
> + u8 bank = reg >> 8;
> + struct nct6775_data *data = ctx;
> + struct i2c_client *client = data->driver_data;
> +
> + if (bank != data->bank) {
> + ret = i2c_smbus_write_byte_data(client, NCT6775_REG_BANK, bank);
> + if (ret)
> + return ret;
> + data->bank = bank;
> + }
> +
> + ret = i2c_smbus_read_byte_data(client, reg & 0xff);
> + if (ret < 0)
> + return ret;
> + tmp = ret;
> +
> + if (nct6775_reg_is_word_sized(data, reg)) {
> + ret = i2c_smbus_read_byte_data(client, (reg & 0xff) + 1);
> + if (ret < 0)
> + return ret;
> + tmp = (tmp << 8) | ret;
> + }
> +
> + *val = tmp;
> + return 0;
> +}
> +
> +/*
> + * The write operation is a dummy so as not to disturb anything being done
> + * with the chip via LPC.
> + */
> +static int nct6775_i2c_write(void *ctx, unsigned int reg, unsigned int value)
> +{
> + struct nct6775_data *data = ctx;
> + struct i2c_client *client = data->driver_data;
> +
> + dev_dbg(&client->dev, "skipping attempted write: %02x -> %03x\n", value, reg);
> +
> + /*
> + * This is a lie, but writing anything but the bank-select register is
> + * something this driver shouldn't be doing.
> + */
> + return 0;
> +}
> +
> +static const struct of_device_id __maybe_unused nct6775_i2c_of_match[] = {
> + { .compatible = "nuvoton,nct6106", .data = (void *)nct6106, },
> + { .compatible = "nuvoton,nct6116", .data = (void *)nct6116, },
> + { .compatible = "nuvoton,nct6775", .data = (void *)nct6775, },
> + { .compatible = "nuvoton,nct6776", .data = (void *)nct6776, },
> + { .compatible = "nuvoton,nct6779", .data = (void *)nct6779, },
> + { .compatible = "nuvoton,nct6791", .data = (void *)nct6791, },
> + { .compatible = "nuvoton,nct6792", .data = (void *)nct6792, },
> + { .compatible = "nuvoton,nct6793", .data = (void *)nct6793, },
> + { .compatible = "nuvoton,nct6795", .data = (void *)nct6795, },
> + { .compatible = "nuvoton,nct6796", .data = (void *)nct6796, },
> + { .compatible = "nuvoton,nct6797", .data = (void *)nct6797, },
> + { .compatible = "nuvoton,nct6798", .data = (void *)nct6798, },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, nct6775_i2c_of_match);
> +
> +static const struct i2c_device_id nct6775_i2c_id[] = {
> + { "nct6106", nct6106 },
> + { "nct6116", nct6116 },
> + { "nct6775", nct6775 },
> + { "nct6776", nct6776 },
> + { "nct6779", nct6779 },
> + { "nct6791", nct6791 },
> + { "nct6792", nct6792 },
> + { "nct6793", nct6793 },
> + { "nct6795", nct6795 },
> + { "nct6796", nct6796 },
> + { "nct6797", nct6797 },
> + { "nct6798", nct6798 },
> + { }
> +};
> +MODULE_DEVICE_TABLE(i2c, nct6775_i2c_id);
> +
> +static int nct6775_i2c_probe_init(struct nct6775_data *data)
> +{
> + u32 tsi_channel_mask;
> + struct i2c_client *client = data->driver_data;
> +
> + /*
> + * The i2c interface doesn't provide access to the control registers
> + * needed to determine the presence of other fans, but fans 1 and 2
> + * are (in principle) always there.
> + *
> + * In practice this is perhaps a little silly, because the system
> + * using this driver is mostly likely a BMC, and hence probably has
> + * totally separate fan tachs & pwms of its own that are actually
> + * controlling/monitoring the fans -- these are thus unlikely to be
> + * doing anything actually useful.
> + */
> + data->has_fan = 0x03;
> + data->has_fan_min = 0x03;
> + data->has_pwm = 0x03;
> +
> + /*
> + * Because on a BMC this driver may be bound very shortly after power
> + * is first applied to the device, the automatic TSI channel detection
> + * in nct6775_probe() (which has already been run at this point) may
> + * not find anything if a channel hasn't yet produced a temperature
> + * reading. Augment whatever was found via autodetection (if
> + * anything) with the channels DT says should be active.
> + */
> + if (!of_property_read_u32(client->dev.of_node, "nuvoton,tsi-channel-mask",
> + &tsi_channel_mask))
> + data->have_tsi_temp |= tsi_channel_mask & GENMASK(NUM_TSI_TEMP - 1, 0);
> +
> + return 0;
> +}
> +
> +static const struct regmap_config nct6775_i2c_regmap_config = {
> + .reg_bits = 16,
> + .val_bits = 16,
> + .reg_read = nct6775_i2c_read,
> + .reg_write = nct6775_i2c_write,
> +};
> +
> +static int nct6775_i2c_probe(struct i2c_client *client)
> +{
> + struct nct6775_data *data;
> + const struct of_device_id *of_id;
> + const struct i2c_device_id *i2c_id;
> + struct device *dev = &client->dev;
> +
> + of_id = of_match_device(nct6775_i2c_of_match, dev);
> + i2c_id = i2c_match_id(nct6775_i2c_id, client);
> +
> + if (of_id && (unsigned long)of_id->data != i2c_id->driver_data)
> + dev_notice(dev, "Device mismatch: %s in device tree, %s detected\n",
> + of_id->name, i2c_id->name);
> +
> + data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
> +
> + data->kind = i2c_id->driver_data;
> +
> + data->read_only = true;
> + data->driver_data = client;
> + data->driver_init = nct6775_i2c_probe_init;
> +
> + return nct6775_probe(dev, data, &nct6775_i2c_regmap_config);
> +}
> +
> +static struct i2c_driver nct6775_i2c_driver = {
> + .class = I2C_CLASS_HWMON,
> + .driver = {
> + .name = "nct6775-i2c",
> + .of_match_table = of_match_ptr(nct6775_i2c_of_match),
> + },
> + .probe_new = nct6775_i2c_probe,
> + .id_table = nct6775_i2c_id,
> +};
> +
> +module_i2c_driver(nct6775_i2c_driver);
> +
> +MODULE_AUTHOR("Zev Weiss <[email protected]>");
> +MODULE_DESCRIPTION("I2C driver for NCT6775F and compatible chips");
> +MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(HWMON_NCT6775);
On Wed, Apr 27, 2022 at 06:27:06PM -0700, Zev Weiss wrote:
> These Super I/O chips have an i2c interface that some systems expose
> to a BMC; the BMC's device tree can now describe that via this
> binding.
>
> Signed-off-by: Zev Weiss <[email protected]>
> Reviewed-by: Rob Herring <[email protected]>
Applied.
Thanks,
Guenter
> ---
> .../bindings/hwmon/nuvoton,nct6775.yaml | 57 +++++++++++++++++++
> 1 file changed, 57 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
>
> diff --git a/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml b/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
> new file mode 100644
> index 000000000000..358b262431fc
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/nuvoton,nct6775.yaml
> @@ -0,0 +1,57 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +
> +$id: http://devicetree.org/schemas/hwmon/nuvoton,nct6775.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Nuvoton NCT6775 and compatible Super I/O chips
> +
> +maintainers:
> + - Zev Weiss <[email protected]>
> +
> +properties:
> + compatible:
> + enum:
> + - nuvoton,nct6106
> + - nuvoton,nct6116
> + - nuvoton,nct6775
> + - nuvoton,nct6776
> + - nuvoton,nct6779
> + - nuvoton,nct6791
> + - nuvoton,nct6792
> + - nuvoton,nct6793
> + - nuvoton,nct6795
> + - nuvoton,nct6796
> + - nuvoton,nct6797
> + - nuvoton,nct6798
> +
> + reg:
> + maxItems: 1
> +
> + nuvoton,tsi-channel-mask:
> + description:
> + Bitmask indicating which TSI temperature sensor channels are
> + active. LSB is TSI0, bit 1 is TSI1, etc.
> + $ref: /schemas/types.yaml#/definitions/uint32
> + maximum: 0xff
> + default: 0
> +
> +required:
> + - compatible
> + - reg
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + i2c {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + superio@4d {
> + compatible = "nuvoton,nct6779";
> + reg = <0x4d>;
> + nuvoton,tsi-channel-mask = <0x03>;
> + };
> + };