[PATCH v11 0/3] Add support for the Gateworks System Controller

[PATCH v11 0/3] Add support for the Gateworks System Controller

[Tim Harvey]

This series adds support for the Gateworks System Controller used on Gateworks
Laguna, Ventana, and Newport product families.

The GSC is an MSP430 I2C slave controller whose firmware embeds the following
features:
 - I/O expander (16 GPIO's emulating a PCA955x)
 - EEPROM (enumating AT24)
 - RTC (enumating DS1672)
 - HWMON
 - Interrupt controller with tamper detect, user pushbotton
 - Watchdog controller capable of full board power-cycle
 - Power Control capable of full board power-cycle

see http://trac.gateworks.com/wiki/gsc for more details

v11:
 - mfd: fix compile error

v10:
 - mfd: fix typo and gramatical errors in Kconfig and comment block
 - mfd: drop unused i2c device-id table
 - mfd: added Lee's ack in s-o-b

v9:
 - rebase against 5.7-rc2
 - dt-binding: remove allOf: see https://lkml.org/lkml/2020/4/15/1930
 - dt-binding: encorporate Lee's review comments for item descriptions
 - dt-binding: added Reviewed-by: Rob Herring <robh@kernel.org>
 - mfd: cleanup gsc_powerdown() by using BIT(), put_unaligned_le32(), and
   avoid unnecessary assignments
 - mfd: rename GSC_CTRL_1 SLEEP related defines to simplify
 - mfd: add better description and sub-module info to driver description
 - mfd: whitespace changes per review
 - mfd: remove unused irq_data pointer in ddata
 - mfd: remove unnecesary i2c_set_clientdata
 - mfd: use devm_i2c_new_dummy_device to avoid need of free's
 - mfd: change regsiter definitions to enum
 - mfd: export gsc_{read,write} instead of sharing them via ddata
 - hwmon: use exported gsc_{read,write}
 - hwmon: added Reviewed-by: Guenter Roeck <linux@roeck-us.net>

v8:
 - mfd: whitespace fixes
 - mfd: describe sub-devices in Kconfig
 - mfd: add error print for invalid command
 - mfd: update copyright
 - mfd: use devm_of_platform_populate
 - mfd: use probe_new
 - mfd: move hwmon's regmap init to hwmon
 - hwmon: move hwmon's regmap init to hwmon
 - dt-bindings: add register to fan-controller node name

v7:
 - dt-bindings: change divider from mili-ohms to ohms
 - dt-bindings: add constraints for voltage divider and offset
 - dt-bindings: remove unnecessary ref for offset
 - dt-bindings: renamed fan to fan-controller and changed base prop to reg
 - mfd:  remove irq from private data struct
 - hwmon: fix whitespace in Kconfig
 - hwmon: remove unnecessary device pointer in private data
 - hwmon: change divider from mili-ohms to ohms
 - hwmon: move fan base property to reg

v6:
 - hwmon: fix size of info field
 - hwmon: improve pwm output control documentation
 - hwmon: include unit suffix in divider and offset
 - hwmon: change subnode name to gsc-adc
 - hwmon: change to fan subnode
 - hwmon: fix voltage offset
 - dt-bindings: fix commit message typo
 - dt-bindings: drop invalid description from #interrupt-cells property
 - dt-bindings: fix adc pattern property
 - dt-bindings: add unit suffix
 - dt-bindings: replace hwmon/adc with adc/channel
 - dt-bindings: changed adc type to gw,mode
 - dt-bindings: add unit suffix and drop ref for voltage-divider
 - dt-bindings: add unit suffix for voltage-offset
 - dt-bindings: moved fan to its own subnode with base register

v5:
 - fix checkpatch issues
 - fix dt_binding_check issues
 - address feedback from v4

v4:
 - hwmon: move to using pwm<n>_auto_point<m>_{pwm,temp} for FAN PWM
 - hwmon: remove unncessary resolution/scaling properties for ADCs
 - bindings: update to yaml Documentation
 - removed watchdog driver

v3:
 - removed unnecessary input driver
 - added wdt driver
 - bindings: encorporated feedback from mailng list
 - hwmon:
 - encoroprated feedback from mailng list
 - added support for raw ADC voltage input used in newer GSC firmware

v2:
 - change license comment block style
 - remove COMPILE_TEST
 - fixed whitespace issues
 - replaced a printk with dev_err
 - remove DEBUG
 - simplify regmap_bulk_read err check
 - remove break after returns in switch statement
 - fix fan setpoint buffer address
 - remove unnecessary parens
 - consistently use struct device *dev pointer
 - add validation for hwmon child node props
 - move parsing of of to own function
 - use strlcpy to ensure null termination
 - fix static array sizes and removed unnecessary initializers
 - dynamically allocate channels
 - fix fan input label
 - support platform data

Tim Harvey (3):
  dt-bindings: mfd: Add Gateworks System Controller bindings
  mfd: add Gateworks System Controller core driver
  hwmon: add Gateworks System Controller support

 .../devicetree/bindings/mfd/gateworks-gsc.yaml     | 196 +++++++++++
 Documentation/hwmon/gsc-hwmon.rst                  |  53 +++
 Documentation/hwmon/index.rst                      |   1 +
 MAINTAINERS                                        |  11 +
 drivers/hwmon/Kconfig                              |   9 +
 drivers/hwmon/Makefile                             |   1 +
 drivers/hwmon/gsc-hwmon.c                          | 390 +++++++++++++++++++++
 drivers/mfd/Kconfig                                |  15 +
 drivers/mfd/Makefile                               |   1 +
 drivers/mfd/gateworks-gsc.c                        | 277 +++++++++++++++
 include/linux/mfd/gsc.h                            |  76 ++++
 include/linux/platform_data/gsc_hwmon.h            |  44 +++
 12 files changed, 1074 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml
 create mode 100644 Documentation/hwmon/gsc-hwmon.rst
 create mode 100644 drivers/hwmon/gsc-hwmon.c
 create mode 100644 drivers/mfd/gateworks-gsc.c
 create mode 100644 include/linux/mfd/gsc.h
 create mode 100644 include/linux/platform_data/gsc_hwmon.h

-- 
2.7.4

[PATCH v11 1/3] dt-bindings: mfd: Add Gateworks System Controller bindings

[Tim Harvey]

This patch adds documentation of device-tree bindings for the
Gateworks System Controller (GSC).

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Rob Herring <robh@kernel.org>
---
v11:
 - no change

v10:
 - no change

v9:
 - added Reviewed-by: Rob Herring <robh@kernel.org>
 - remove allOf: see https://lkml.org/lkml/2020/4/15/1930
 - encorporate Lee's review comments for item descriptions

v8:
 - add register to fan-controller node name

v7:
 - change divider from mili-ohms to ohms
 - add constraints for voltage divider and offset
 - remove unnecessary ref for offset
 - renamed fan to fan-controller and changed base prop to reg

v6:
 - fix typo
 - drop invalid description from #interrupt-cells property
 - fix adc pattern property
 - add unit suffix
 - replace hwmon/adc with adc/channel
 - changed adc type to mode and enum int
 - add unit suffix and drop ref for voltage-divider
 - moved fan to its own subnode with base register

v5:
 - resolve dt_binding_check issues

v4:
 - move to using pwm<n>_auto_point<m>_{pwm,temp} for FAN PWM
 - remove unncessary resolution/scaling properties for ADCs
 - update to yaml
 - remove watchdog

v3:
 - replaced _ with -
 - remove input bindings
 - added full description of hwmon
 - fix unit address of hwmon child nodes
---
 .../devicetree/bindings/mfd/gateworks-gsc.yaml     | 196 +++++++++++++++++++++
 1 file changed, 196 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml

diff --git a/Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml b/Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml
new file mode 100644
index 00000000..487a844
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml
@@ -0,0 +1,196 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/gateworks-gsc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Gateworks System Controller
+
+description: |
+  The Gateworks System Controller (GSC) is a device present across various
+  Gateworks product families that provides a set of system related features
+  such as the following (refer to the board hardware user manuals to see what
+  features are present)
+   - Watchdog Timer
+   - GPIO
+   - Pushbutton controller
+   - Hardware monitor with ADC's for temperature and voltage rails and
+     fan controller
+
+maintainers:
+  - Tim Harvey <tharvey@gateworks.com>
+  - Robert Jones <rjones@gateworks.com>
+
+properties:
+  $nodename:
+    pattern: "gsc@[0-9a-f]{1,2}"
+  compatible:
+    const: gw,gsc
+
+  reg:
+    description: I2C device address
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  interrupt-controller: true
+
+  "#interrupt-cells":
+    const: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+  adc:
+    type: object
+    description: Optional hardware monitoring module
+
+    properties:
+      compatible:
+        const: gw,gsc-adc
+
+      "#address-cells":
+        const: 1
+
+      "#size-cells":
+        const: 0
+
+    patternProperties:
+      "^channel@[0-9]+$":
+        type: object
+        description: |
+          Properties for a single ADC which can report cooked values
+          (i.e. temperature sensor based on thermister), raw values
+          (i.e. voltage rail with a pre-scaling resistor divider).
+
+        properties:
+          reg:
+            description: Register of the ADC
+            maxItems: 1
+
+          label:
+            description: Name of the ADC input
+
+          gw,mode:
+            description: |
+              conversion mode:
+                0 - temperature, in C*10
+                1 - pre-scaled voltage value
+                2 - scaled voltage based on an optional resistor divider
+                    and optional offset
+            $ref: /schemas/types.yaml#/definitions/uint32
+            enum: [0, 1, 2]
+
+          gw,voltage-divider-ohms:
+            description: Values of resistors for divider on raw ADC input
+            maxItems: 2
+            items:
+             minimum: 1000
+             maximum: 1000000
+
+          gw,voltage-offset-microvolt:
+            description: |
+              A positive voltage offset to apply to a raw ADC
+              (i.e. to compensate for a diode drop).
+            minimum: 0
+            maximum: 1000000
+
+        required:
+          - gw,mode
+          - reg
+          - label
+
+    required:
+      - compatible
+      - "#address-cells"
+      - "#size-cells"
+
+patternProperties:
+  "^fan-controller@[0-9a-f]+$":
+    type: object
+    description: Optional fan controller
+
+    properties:
+      compatible:
+        const: gw,gsc-fan
+
+      "#address-cells":
+        const: 1
+
+      "#size-cells":
+        const: 0
+
+      reg:
+        description: The fan controller base address
+        maxItems: 1
+
+    required:
+      - compatible
+      - reg
+      - "#address-cells"
+      - "#size-cells"
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-controller
+  - "#interrupt-cells"
+  - "#address-cells"
+  - "#size-cells"
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        gsc@20 {
+            compatible = "gw,gsc";
+            reg = <0x20>;
+            interrupt-parent = <&gpio1>;
+            interrupts = <4 GPIO_ACTIVE_LOW>;
+            interrupt-controller;
+            #interrupt-cells = <1>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            adc {
+                compatible = "gw,gsc-adc";
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                channel@0 { /* A0: Board Temperature */
+                    reg = <0x00>;
+                    label = "temp";
+                    gw,mode = <0>;
+                };
+
+                channel@2 { /* A1: Input Voltage (raw ADC) */
+                    reg = <0x02>;
+                    label = "vdd_vin";
+                    gw,mode = <1>;
+                    gw,voltage-divider-ohms = <22100 1000>;
+                    gw,voltage-offset-microvolt = <800000>;
+                };
+
+                channel@b { /* A2: Battery voltage */
+                    reg = <0x0b>;
+                    label = "vdd_bat";
+                    gw,mode = <1>;
+                };
+            };
+
+            fan-controller@2c {
+                #address-cells = <1>;
+                #size-cells = <0>;
+                compatible = "gw,gsc-fan";
+                reg = <0x2c>;
+            };
+        };
+    };
-- 
2.7.4

[PATCH v11 2/3] mfd: add Gateworks System Controller core driver

[Tim Harvey]

The Gateworks System Controller (GSC) is an I2C slave controller
implemented with an MSP430 micro-controller whose firmware embeds the
following features:
 - I/O expander (16 GPIO's) using PCA955x protocol
 - Real Time Clock using DS1672 protocol
 - User EEPROM using AT24 protocol
 - HWMON using custom protocol
 - Interrupt controller with tamper detect, user pushbotton
 - Watchdog controller capable of full board power-cycle
 - Power Control capable of full board power-cycle

see http://trac.gateworks.com/wiki/gsc for more details

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>
---
v11:
- fix compile error

v10:
- fix typo and gramatical errors in Kconfig and comment block
- drop unused i2c device-id table
- added Lee's ack in s-o-b

v9:
- rebase against 5.7-rc2
- cleanup gsc_powerdown() by using BIT(), put_unaligned_le32(), and avoid
  unnecessary assignments
- rename GSC_CTRL_1 SLEEP related defines to simplify
- add better description and sub-module info to driver description
- whitespace changes per review
- remove unused irq_data pointer in ddata
- remove unnecesary i2c_set_clientdata
- use devm_i2c_new_dummy_device to avoid need of free's
- change regsiter definitions to enum
- export gsc_{read,write} instead of sharing them via ddata

v8:
- whitespace fixes
- describe sub-devices in Kconfig
- add error print for invalid command
- update copyright
- use devm_of_platform_populate
- use probe_new
- move hwmon's regmap init to hwmon

v7:
- remove irq from private data struct

v6:
- remove duplicate signature and fix commit log

v5:
- simplify powerdown function

v4:
- remove hwmon max reg check/define
- fix powerdown function

v3:
- rename gsc->gateworks-gsc
- remove uncecessary include for linux/mfd/core.h
- upercase I2C in comments
- remove i2c debug
- remove uncecessary comments
- don't use KBUILD_MODNAME for name
- remove unnecessary v1/v2/v3 tracking
- unregister hwmon i2c adapter on remove

v2:
- change license comment block style
- remove COMPILE_TEST (Randy)
- fixed whitespace issues
- replaced a printk with dev_err
---
 MAINTAINERS                 |   8 ++
 drivers/mfd/Kconfig         |  15 +++
 drivers/mfd/Makefile        |   1 +
 drivers/mfd/gateworks-gsc.c | 277 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/mfd/gsc.h     |  76 ++++++++++++
 5 files changed, 377 insertions(+)
 create mode 100644 drivers/mfd/gateworks-gsc.c
 create mode 100644 include/linux/mfd/gsc.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 091ec22..c78a014 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7028,6 +7028,14 @@ F:	kernel/futex.c
 F:	tools/perf/bench/futex*
 F:	tools/testing/selftests/futex/
 
+GATEWORKS SYSTEM CONTROLLER (GSC) DRIVER
+M:	Tim Harvey <tharvey@gateworks.com>
+M:	Robert Jones <rjones@gateworks.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml
+F:	drivers/mfd/gateworks-gsc.c
+F:	include/linux/mfd/gsc.h
+
 GASKET DRIVER FRAMEWORK
 M:	Rob Springer <rspringer@google.com>
 M:	Todd Poynor <toddpoynor@google.com>
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 0a59249..05448e7 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -407,6 +407,21 @@ config MFD_EXYNOS_LPASS
 	  Select this option to enable support for Samsung Exynos Low Power
 	  Audio Subsystem.
 
+config MFD_GATEWORKS_GSC
+	tristate "Gateworks System Controller"
+	depends on (I2C && OF)
+	select MFD_CORE
+	select REGMAP_I2C
+	select REGMAP_IRQ
+	help
+	  Enable support for the Gateworks System Controller (GSC) found
+	  on Gateworks Single Board Computers supporting system functions
+	  such as push-button monitor, multiple ADC's for voltage and
+	  temperature monitoring, fan controller and watchdog monitor.
+	  This driver provides common support for accessing the device.
+	  Additional drivers must be enabled in order to use the
+	  functionality of the device.
+
 config MFD_MC13XXX
 	tristate
 	depends on (SPI_MASTER || I2C)
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index f935d10..ed433ae 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_MFD_BCM590XX)	+= bcm590xx.o
 obj-$(CONFIG_MFD_BD9571MWV)	+= bd9571mwv.o
 obj-$(CONFIG_MFD_CROS_EC_DEV)	+= cros_ec_dev.o
 obj-$(CONFIG_MFD_EXYNOS_LPASS)	+= exynos-lpass.o
+obj-$(CONFIG_MFD_GATEWORKS_GSC)	+= gateworks-gsc.o
 
 obj-$(CONFIG_HTC_PASIC3)	+= htc-pasic3.o
 obj-$(CONFIG_HTC_I2CPLD)	+= htc-i2cpld.o
diff --git a/drivers/mfd/gateworks-gsc.c b/drivers/mfd/gateworks-gsc.c
new file mode 100644
index 00000000..576da62
--- /dev/null
+++ b/drivers/mfd/gateworks-gsc.c
@@ -0,0 +1,277 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * The Gateworks System Controller (GSC) is a multi-function
+ * device designed for use in Gateworks Single Board Computers.
+ * The control interface is I2C, with an interrupt. The device supports
+ * system functions such as push-button monitoring, multiple ADC's for
+ * voltage and temperature monitoring, fan controller and watchdog monitor.
+ *
+ * Copyright (C) 2020 Gateworks Corporation
+ */
+
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/gsc.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include <asm/unaligned.h>
+
+/*
+ * The GSC suffers from an errata where occasionally during
+ * ADC cycles the chip can NAK I2C transactions. To ensure we have reliable
+ * register access we place retries around register access.
+ */
+#define I2C_RETRIES	3
+
+int gsc_write(void *context, unsigned int reg, unsigned int val)
+{
+	struct i2c_client *client = context;
+	int retry, ret;
+
+	for (retry = 0; retry < I2C_RETRIES; retry++) {
+		ret = i2c_smbus_write_byte_data(client, reg, val);
+		/*
+		 * -EAGAIN returned when the i2c host controller is busy
+		 * -EIO returned when i2c device is busy
+		 */
+		if (ret != -EAGAIN && ret != -EIO)
+			break;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gsc_write);
+
+int gsc_read(void *context, unsigned int reg, unsigned int *val)
+{
+	struct i2c_client *client = context;
+	int retry, ret;
+
+	for (retry = 0; retry < I2C_RETRIES; retry++) {
+		ret = i2c_smbus_read_byte_data(client, reg);
+		/*
+		 * -EAGAIN returned when the i2c host controller is busy
+		 * -EIO returned when i2c device is busy
+		 */
+		if (ret != -EAGAIN && ret != -EIO)
+			break;
+	}
+	*val = ret & 0xff;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gsc_read);
+
+/*
+ * gsc_powerdown - API to use GSC to power down board for a specific time
+ *
+ * secs - number of seconds to remain powered off
+ */
+static int gsc_powerdown(struct gsc_dev *gsc, unsigned long secs)
+{
+	int ret;
+	unsigned char regs[4];
+
+	dev_info(&gsc->i2c->dev, "GSC powerdown for %ld seconds\n",
+		 secs);
+
+	put_unaligned_le32(secs, regs);
+	ret = regmap_bulk_write(gsc->regmap, GSC_TIME_ADD, regs, 4);
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(gsc->regmap, GSC_CTRL_1,
+				 BIT(GSC_CTRL_1_SLEEP_ADD),
+				 BIT(GSC_CTRL_1_SLEEP_ADD));
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(gsc->regmap, GSC_CTRL_1,
+				 BIT(GSC_CTRL_1_SLEEP_ACTIVATE) |
+				 BIT(GSC_CTRL_1_SLEEP_ENABLE),
+				 BIT(GSC_CTRL_1_SLEEP_ACTIVATE) |
+				 BIT(GSC_CTRL_1_SLEEP_ENABLE));
+
+
+	return ret;
+}
+
+static ssize_t gsc_show(struct device *dev, struct device_attribute *attr,
+			char *buf)
+{
+	struct gsc_dev *gsc = dev_get_drvdata(dev);
+	const char *name = attr->attr.name;
+	int rz = 0;
+
+	if (strcasecmp(name, "fw_version") == 0)
+		rz = sprintf(buf, "%d\n", gsc->fwver);
+	else if (strcasecmp(name, "fw_crc") == 0)
+		rz = sprintf(buf, "0x%04x\n", gsc->fwcrc);
+	else
+		dev_err(dev, "invalid command: '%s'\n", name);
+
+	return rz;
+}
+
+static ssize_t gsc_store(struct device *dev, struct device_attribute *attr,
+			 const char *buf, size_t count)
+{
+	struct gsc_dev *gsc = dev_get_drvdata(dev);
+	const char *name = attr->attr.name;
+	long value;
+
+	if (strcasecmp(name, "powerdown") == 0) {
+		if (kstrtol(buf, 0, &value) == 0)
+			gsc_powerdown(gsc, value);
+	} else {
+		dev_err(dev, "invalid command: '%s\n", name);
+	}
+
+	return count;
+}
+
+static struct device_attribute attr_fwver =
+	__ATTR(fw_version, 0440, gsc_show, NULL);
+static struct device_attribute attr_fwcrc =
+	__ATTR(fw_crc, 0440, gsc_show, NULL);
+static struct device_attribute attr_pwrdown =
+	__ATTR(powerdown, 0220, NULL, gsc_store);
+
+static struct attribute *gsc_attrs[] = {
+	&attr_fwver.attr,
+	&attr_fwcrc.attr,
+	&attr_pwrdown.attr,
+	NULL,
+};
+
+static struct attribute_group attr_group = {
+	.attrs = gsc_attrs,
+};
+
+static const struct of_device_id gsc_of_match[] = {
+	{ .compatible = "gw,gsc", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, gsc_of_match);
+
+static struct regmap_bus gsc_regmap_bus = {
+	.reg_read = gsc_read,
+	.reg_write = gsc_write,
+};
+
+static const struct regmap_config gsc_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.cache_type = REGCACHE_NONE,
+	.max_register = GSC_WP,
+};
+
+static const struct regmap_irq gsc_irqs[] = {
+	REGMAP_IRQ_REG(GSC_IRQ_PB, 0, BIT(GSC_IRQ_PB)),
+	REGMAP_IRQ_REG(GSC_IRQ_KEY_ERASED, 0, BIT(GSC_IRQ_KEY_ERASED)),
+	REGMAP_IRQ_REG(GSC_IRQ_EEPROM_WP, 0, BIT(GSC_IRQ_EEPROM_WP)),
+	REGMAP_IRQ_REG(GSC_IRQ_RESV, 0, BIT(GSC_IRQ_RESV)),
+	REGMAP_IRQ_REG(GSC_IRQ_GPIO, 0, BIT(GSC_IRQ_GPIO)),
+	REGMAP_IRQ_REG(GSC_IRQ_TAMPER, 0, BIT(GSC_IRQ_TAMPER)),
+	REGMAP_IRQ_REG(GSC_IRQ_WDT_TIMEOUT, 0, BIT(GSC_IRQ_WDT_TIMEOUT)),
+	REGMAP_IRQ_REG(GSC_IRQ_SWITCH_HOLD, 0, BIT(GSC_IRQ_SWITCH_HOLD)),
+};
+
+static const struct regmap_irq_chip gsc_irq_chip = {
+	.name = "gateworks-gsc",
+	.irqs = gsc_irqs,
+	.num_irqs = ARRAY_SIZE(gsc_irqs),
+	.num_regs = 1,
+	.status_base = GSC_IRQ_STATUS,
+	.mask_base = GSC_IRQ_ENABLE,
+	.mask_invert = true,
+	.ack_base = GSC_IRQ_STATUS,
+	.ack_invert = true,
+};
+
+static int gsc_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct gsc_dev *gsc;
+	struct regmap_irq_chip_data *irq_data;
+	int ret;
+	unsigned int reg;
+
+	gsc = devm_kzalloc(dev, sizeof(*gsc), GFP_KERNEL);
+	if (!gsc)
+		return -ENOMEM;
+
+	gsc->dev = &client->dev;
+	gsc->i2c = client;
+	i2c_set_clientdata(client, gsc);
+
+	gsc->regmap = devm_regmap_init(dev, &gsc_regmap_bus, client,
+				       &gsc_regmap_config);
+	if (IS_ERR(gsc->regmap))
+		return PTR_ERR(gsc->regmap);
+
+	if (regmap_read(gsc->regmap, GSC_FW_VER, &reg))
+		return -EIO;
+	gsc->fwver = reg;
+
+	regmap_read(gsc->regmap, GSC_FW_CRC, &reg);
+	gsc->fwcrc = reg;
+	regmap_read(gsc->regmap, GSC_FW_CRC + 1, &reg);
+	gsc->fwcrc |= reg << 8;
+
+	gsc->i2c_hwmon = devm_i2c_new_dummy_device(dev, client->adapter,
+						   GSC_HWMON);
+	if (IS_ERR(gsc->i2c_hwmon)) {
+		dev_err(dev, "Failed to allocate I2C device for HWMON\n");
+		return PTR_ERR(gsc->i2c_hwmon);
+	}
+
+	ret = devm_regmap_add_irq_chip(dev, gsc->regmap, client->irq,
+				       IRQF_ONESHOT | IRQF_SHARED |
+				       IRQF_TRIGGER_FALLING, 0,
+				       &gsc_irq_chip, &irq_data);
+	if (ret)
+		return ret;
+
+	dev_info(dev, "Gateworks System Controller v%d: fw 0x%04x\n",
+		 gsc->fwver, gsc->fwcrc);
+
+	ret = sysfs_create_group(&dev->kobj, &attr_group);
+	if (ret)
+		dev_err(dev, "failed to create sysfs attrs\n");
+
+	ret = devm_of_platform_populate(dev);
+	if (ret) {
+		sysfs_remove_group(&dev->kobj, &attr_group);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int gsc_remove(struct i2c_client *client)
+{
+	sysfs_remove_group(&client->dev.kobj, &attr_group);
+
+	return 0;
+}
+
+static struct i2c_driver gsc_driver = {
+	.driver = {
+		.name	= "gateworks-gsc",
+		.of_match_table = gsc_of_match,
+	},
+	.probe_new	= gsc_probe,
+	.remove		= gsc_remove,
+};
+module_i2c_driver(gsc_driver);
+
+MODULE_AUTHOR("Tim Harvey <tharvey@gateworks.com>");
+MODULE_DESCRIPTION("I2C Core interface for GSC");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/mfd/gsc.h b/include/linux/mfd/gsc.h
new file mode 100644
index 00000000..6bd639c
--- /dev/null
+++ b/include/linux/mfd/gsc.h
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright (C) 2020 Gateworks Corporation
+ */
+#ifndef __LINUX_MFD_GSC_H_
+#define __LINUX_MFD_GSC_H_
+
+#include <linux/regmap.h>
+
+/* Device Addresses */
+#define GSC_MISC	0x20
+#define GSC_UPDATE	0x21
+#define GSC_GPIO	0x23
+#define GSC_HWMON	0x29
+#define GSC_EEPROM0	0x50
+#define GSC_EEPROM1	0x51
+#define GSC_EEPROM2	0x52
+#define GSC_EEPROM3	0x53
+#define GSC_RTC		0x68
+
+/* Register offsets */
+enum {
+	GSC_CTRL_0	= 0x00,
+	GSC_CTRL_1	= 0x01,
+	GSC_TIME	= 0x02,
+	GSC_TIME_ADD	= 0x06,
+	GSC_IRQ_STATUS	= 0x0A,
+	GSC_IRQ_ENABLE	= 0x0B,
+	GSC_FW_CRC	= 0x0C,
+	GSC_FW_VER	= 0x0E,
+	GSC_WP		= 0x0F,
+};
+
+/* Bit definitions */
+#define GSC_CTRL_0_PB_HARD_RESET	0
+#define GSC_CTRL_0_PB_CLEAR_SECURE_KEY	1
+#define GSC_CTRL_0_PB_SOFT_POWER_DOWN	2
+#define GSC_CTRL_0_PB_BOOT_ALTERNATE	3
+#define GSC_CTRL_0_PERFORM_CRC		4
+#define GSC_CTRL_0_TAMPER_DETECT	5
+#define GSC_CTRL_0_SWITCH_HOLD		6
+
+#define GSC_CTRL_1_SLEEP_ENABLE		0
+#define GSC_CTRL_1_SLEEP_ACTIVATE	1
+#define GSC_CTRL_1_SLEEP_ADD		2
+#define GSC_CTRL_1_SLEEP_NOWAKEPB	3
+#define GSC_CTRL_1_WDT_TIME		4
+#define GSC_CTRL_1_WDT_ENABLE		5
+#define GSC_CTRL_1_SWITCH_BOOT_ENABLE	6
+#define GSC_CTRL_1_SWITCH_BOOT_CLEAR	7
+
+#define GSC_IRQ_PB			0
+#define GSC_IRQ_KEY_ERASED		1
+#define GSC_IRQ_EEPROM_WP		2
+#define GSC_IRQ_RESV			3
+#define GSC_IRQ_GPIO			4
+#define GSC_IRQ_TAMPER			5
+#define GSC_IRQ_WDT_TIMEOUT		6
+#define GSC_IRQ_SWITCH_HOLD		7
+
+int gsc_read(void *context, unsigned int reg, unsigned int *val);
+int gsc_write(void *context, unsigned int reg, unsigned int val);
+
+struct gsc_dev {
+	struct device *dev;
+
+	struct i2c_client *i2c;		/* 0x20: interrupt controller, WDT */
+	struct i2c_client *i2c_hwmon;	/* 0x29: hwmon, fan controller */
+
+	struct regmap *regmap;
+
+	unsigned int fwver;
+	unsigned short fwcrc;
+};
+
+#endif /* __LINUX_MFD_GSC_H_ */
-- 
2.7.4

[PATCH 3/3] hwmon: add Gateworks System Controller support

[Tim Harvey]

The Gateworks System Controller has a hwmon sub-component that exposes
up to 16 ADC's, some of which are temperature sensors, others which are
voltage inputs. The ADC configuration (register mapping and name) is
configured via device-tree and varies board to board.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
---
v11:
- no change

v10:
- no change

v9:
- use exported gsc_{read,write}
- added Reviewed-by: Guenter Roeck <linux@roeck-us.net>

v8:
- move regmap init to hwmon

v7:
- fix whitespace in Kconfig
- remove unnecessary device pointer in private data
- change divider from mili-ohms to ohms
- move fan base property to reg

v6:
- fix size of info field
- improve pwm output control documentation
- include unit suffix in divider and offset
- change subnode name to gsc-adc
- change to fan subnode
- fix voltage offset

v5:
- fix various checkpatch issues
- correct gsc-hwmon.rst in MAINTAINERS
- encorporate Gunter's feedback:
 - switch to SENSOR_DEVICE_ATTR_{RW,RO}
 - use tmp value to avoid excessive pointer deference
 - simplify shift operation
 - scale voffset once
 - simplify is_visible function
 - remove empty line at end of file

v4:
- adjust for uV offset from device-tree
- remove unnecessary optional write function
- remove register range check
- change dev_err prints to use gsc dev
- hard-code resolution/scaling for raw adcs
- describe units of ADC resolution
- move to using pwm<n>_auto_point<m>_{pwm,temp} for FAN PWM
- ensure space before/after operators
- remove unnecessary parens
- remove more debugging
- add default case and comment for type_voltage
- remove unnecessary index bounds checks for channel
- remove unnecessary clearing of struct fields
- added Documentation/hwmon/gsc-hwmon.rst

v3:
- add voltage_raw input type and supporting fields
- add channel validation to is_visible function
- remove unnecessary channel validation from read/write functions

v2:
- change license comment style
- remove DEBUG
- simplify regmap_bulk_read err check
- remove break after returns in switch statement
- fix fan setpoint buffer address
- remove unnecessary parens
- consistently use struct device *dev pointer
- change license/comment block
- add validation for hwmon child node props
- move parsing of of to own function
- use strlcpy to ensure null termination
- fix static array sizes and removed unnecessary initializers
- dynamically allocate channels
- fix fan input label
- support platform data
- fixed whitespace issues
---
 Documentation/hwmon/gsc-hwmon.rst       |  53 +++++
 Documentation/hwmon/index.rst           |   1 +
 MAINTAINERS                             |   3 +
 drivers/hwmon/Kconfig                   |   9 +
 drivers/hwmon/Makefile                  |   1 +
 drivers/hwmon/gsc-hwmon.c               | 390 ++++++++++++++++++++++++++++++++
 include/linux/platform_data/gsc_hwmon.h |  44 ++++
 7 files changed, 501 insertions(+)
 create mode 100644 Documentation/hwmon/gsc-hwmon.rst
 create mode 100644 drivers/hwmon/gsc-hwmon.c
 create mode 100644 include/linux/platform_data/gsc_hwmon.h

diff --git a/Documentation/hwmon/gsc-hwmon.rst b/Documentation/hwmon/gsc-hwmon.rst
new file mode 100644
index 00000000..ffac392
--- /dev/null
+++ b/Documentation/hwmon/gsc-hwmon.rst
@@ -0,0 +1,53 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver gsc-hwmon
+=======================
+
+Supported chips: Gateworks GSC
+Datasheet: http://trac.gateworks.com/wiki/gsc
+Author: Tim Harvey <tharvey@gateworks.com>
+
+Description:
+------------
+
+This driver supports hardware monitoring for the temperature sensor,
+various ADC's connected to the GSC, and optional FAN controller available
+on some boards.
+
+
+Voltage Monitoring
+------------------
+
+The voltage inputs are scaled either internally or by the driver depending
+on the GSC version and firmware. The values returned by the driver do not need
+further scaling. The voltage input labels provide the voltage rail name:
+
+inX_input                  Measured voltage (mV).
+inX_label                  Name of voltage rail.
+
+
+Temperature Monitoring
+----------------------
+
+Temperatures are measured with 12-bit or 10-bit resolution and are scaled
+either internally or by the driver depending on the GSC version and firmware.
+The values returned by the driver reflect millidegree Celcius:
+
+tempX_input                Measured temperature.
+tempX_label                Name of temperature input.
+
+
+PWM Output Control
+------------------
+
+The GSC features 1 PWM output that operates in automatic mode where the
+PWM value will be scalled depending on 6 temperature boundaries.
+The tempeature boundaries are read-write and in millidegree Celcius and the
+read-only PWM values range from 0 (off) to 255 (full speed).
+Fan speed will be set to minimum (off) when the temperature sensor reads
+less than pwm1_auto_point1_temp and maximum when the temperature sensor
+equals or exceeds pwm1_auto_point6_temp.
+
+pwm1_auto_point[1-6]_pwm       PWM value.
+pwm1_auto_point[1-6]_temp      Temperature boundary.
+
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 8ef62fd..1c02aa6 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -60,6 +60,7 @@ Hardware Monitoring Kernel Drivers
    ftsteutates
    g760a
    g762
+   gsc-hwmon
    gl518sm
    hih6130
    ibmaem
diff --git a/MAINTAINERS b/MAINTAINERS
index c78a014..7f8ece8 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7035,6 +7035,9 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml
 F:	drivers/mfd/gateworks-gsc.c
 F:	include/linux/mfd/gsc.h
+F:	Documentation/hwmon/gsc-hwmon.rst
+F:	drivers/hwmon/gsc-hwmon.c
+F:	include/linux/platform_data/gsc_hwmon.h
 
 GASKET DRIVER FRAMEWORK
 M:	Rob Springer <rspringer@google.com>
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 4c62f90..5549906 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -523,6 +523,15 @@ config SENSORS_F75375S
 	  This driver can also be built as a module. If so, the module
 	  will be called f75375s.
 
+config SENSORS_GSC
+	tristate "Gateworks System Controller ADC"
+	depends on MFD_GATEWORKS_GSC
+	help
+	  Support for the Gateworks System Controller A/D converters.
+
+	  To compile this driver as a module, choose M here:
+	  the module will be called gsc-hwmon.
+
 config SENSORS_MC13783_ADC
         tristate "Freescale MC13783/MC13892 ADC"
         depends on MFD_MC13XXX
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index b0b9c8e..a6564d0 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -74,6 +74,7 @@ obj-$(CONFIG_SENSORS_G760A)	+= g760a.o
 obj-$(CONFIG_SENSORS_G762)	+= g762.o
 obj-$(CONFIG_SENSORS_GL518SM)	+= gl518sm.o
 obj-$(CONFIG_SENSORS_GL520SM)	+= gl520sm.o
+obj-$(CONFIG_SENSORS_GSC)	+= gsc-hwmon.o
 obj-$(CONFIG_SENSORS_GPIO_FAN)	+= gpio-fan.o
 obj-$(CONFIG_SENSORS_HIH6130)	+= hih6130.o
 obj-$(CONFIG_SENSORS_ULTRA45)	+= ultra45_env.o
diff --git a/drivers/hwmon/gsc-hwmon.c b/drivers/hwmon/gsc-hwmon.c
new file mode 100644
index 00000000..2137bc6
--- /dev/null
+++ b/drivers/hwmon/gsc-hwmon.c
@@ -0,0 +1,390 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for Gateworks System Controller Hardware Monitor module
+ *
+ * Copyright (C) 2020 Gateworks Corporation
+ */
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/mfd/gsc.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#include <linux/platform_data/gsc_hwmon.h>
+
+#define GSC_HWMON_MAX_TEMP_CH	16
+#define GSC_HWMON_MAX_IN_CH	16
+
+#define GSC_HWMON_RESOLUTION	12
+#define GSC_HWMON_VREF		2500
+
+struct gsc_hwmon_data {
+	struct gsc_dev *gsc;
+	struct gsc_hwmon_platform_data *pdata;
+	struct regmap *regmap;
+	const struct gsc_hwmon_channel *temp_ch[GSC_HWMON_MAX_TEMP_CH];
+	const struct gsc_hwmon_channel *in_ch[GSC_HWMON_MAX_IN_CH];
+	u32 temp_config[GSC_HWMON_MAX_TEMP_CH + 1];
+	u32 in_config[GSC_HWMON_MAX_IN_CH + 1];
+	struct hwmon_channel_info temp_info;
+	struct hwmon_channel_info in_info;
+	const struct hwmon_channel_info *info[3];
+	struct hwmon_chip_info chip;
+};
+
+static struct regmap_bus gsc_hwmon_regmap_bus = {
+	.reg_read = gsc_read,
+	.reg_write = gsc_write,
+};
+
+static const struct regmap_config gsc_hwmon_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.cache_type = REGCACHE_NONE,
+};
+
+static ssize_t pwm_auto_point_temp_show(struct device *dev,
+					struct device_attribute *devattr,
+					char *buf)
+{
+	struct gsc_hwmon_data *hwmon = dev_get_drvdata(dev);
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	u8 reg = hwmon->pdata->fan_base + (2 * attr->index);
+	u8 regs[2];
+	int ret;
+
+	ret = regmap_bulk_read(hwmon->regmap, reg, regs, 2);
+	if (ret)
+		return ret;
+
+	ret = regs[0] | regs[1] << 8;
+	return sprintf(buf, "%d\n", ret * 10);
+}
+
+static ssize_t pwm_auto_point_temp_store(struct device *dev,
+					 struct device_attribute *devattr,
+					 const char *buf, size_t count)
+{
+	struct gsc_hwmon_data *hwmon = dev_get_drvdata(dev);
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	u8 reg = hwmon->pdata->fan_base + (2 * attr->index);
+	u8 regs[2];
+	long temp;
+	int err;
+
+	if (kstrtol(buf, 10, &temp))
+		return -EINVAL;
+
+	temp = clamp_val(temp, 0, 10000);
+	temp = DIV_ROUND_CLOSEST(temp, 10);
+
+	regs[0] = temp & 0xff;
+	regs[1] = (temp >> 8) & 0xff;
+	err = regmap_bulk_write(hwmon->regmap, reg, regs, 2);
+	if (err)
+		return err;
+
+	return count;
+}
+
+static ssize_t pwm_auto_point_pwm_show(struct device *dev,
+				       struct device_attribute *devattr,
+				       char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+
+	return sprintf(buf, "%d\n", 255 * (50 + (attr->index * 10)) / 100);
+}
+
+static SENSOR_DEVICE_ATTR_RO(pwm1_auto_point1_pwm, pwm_auto_point_pwm, 0);
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point1_temp, pwm_auto_point_temp, 0);
+
+static SENSOR_DEVICE_ATTR_RO(pwm1_auto_point2_pwm, pwm_auto_point_pwm, 1);
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point2_temp, pwm_auto_point_temp, 1);
+
+static SENSOR_DEVICE_ATTR_RO(pwm1_auto_point3_pwm, pwm_auto_point_pwm, 2);
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point3_temp, pwm_auto_point_temp, 2);
+
+static SENSOR_DEVICE_ATTR_RO(pwm1_auto_point4_pwm, pwm_auto_point_pwm, 3);
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point4_temp, pwm_auto_point_temp, 3);
+
+static SENSOR_DEVICE_ATTR_RO(pwm1_auto_point5_pwm, pwm_auto_point_pwm, 4);
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point5_temp, pwm_auto_point_temp, 4);
+
+static SENSOR_DEVICE_ATTR_RO(pwm1_auto_point6_pwm, pwm_auto_point_pwm, 5);
+static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point6_temp, pwm_auto_point_temp, 5);
+
+static struct attribute *gsc_hwmon_attributes[] = {
+	&sensor_dev_attr_pwm1_auto_point1_pwm.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point1_temp.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point2_pwm.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point2_temp.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point3_pwm.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point3_temp.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point4_pwm.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point4_temp.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point5_pwm.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point5_temp.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point6_pwm.dev_attr.attr,
+	&sensor_dev_attr_pwm1_auto_point6_temp.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group gsc_hwmon_group = {
+	.attrs = gsc_hwmon_attributes,
+};
+__ATTRIBUTE_GROUPS(gsc_hwmon);
+
+static int
+gsc_hwmon_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
+	       int channel, long *val)
+{
+	struct gsc_hwmon_data *hwmon = dev_get_drvdata(dev);
+	const struct gsc_hwmon_channel *ch;
+	int sz, ret;
+	long tmp;
+	u8 buf[3];
+
+	switch (type) {
+	case hwmon_in:
+		ch = hwmon->in_ch[channel];
+		break;
+	case hwmon_temp:
+		ch = hwmon->temp_ch[channel];
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	sz = (ch->mode == mode_voltage) ? 3 : 2;
+	ret = regmap_bulk_read(hwmon->regmap, ch->reg, buf, sz);
+	if (ret)
+		return ret;
+
+	tmp = 0;
+	while (sz-- > 0)
+		tmp |= (buf[sz] << (8 * sz));
+
+	switch (ch->mode) {
+	case mode_temperature:
+		if (tmp > 0x8000)
+			tmp -= 0xffff;
+		break;
+	case mode_voltage_raw:
+		tmp = clamp_val(tmp, 0, BIT(GSC_HWMON_RESOLUTION));
+		/* scale based on ref voltage and ADC resolution */
+		tmp *= GSC_HWMON_VREF;
+		tmp >>= GSC_HWMON_RESOLUTION;
+		/* scale based on optional voltage divider */
+		if (ch->vdiv[0] && ch->vdiv[1]) {
+			tmp *= (ch->vdiv[0] + ch->vdiv[1]);
+			tmp /= ch->vdiv[1];
+		}
+		/* adjust by uV offset */
+		tmp += ch->mvoffset;
+		break;
+	case mode_voltage:
+		/* no adjustment needed */
+		break;
+	}
+
+	*val = tmp;
+
+	return 0;
+}
+
+static int
+gsc_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type,
+		      u32 attr, int channel, const char **buf)
+{
+	struct gsc_hwmon_data *hwmon = dev_get_drvdata(dev);
+
+	switch (type) {
+	case hwmon_in:
+		*buf = hwmon->in_ch[channel]->name;
+		break;
+	case hwmon_temp:
+		*buf = hwmon->temp_ch[channel]->name;
+		break;
+	default:
+		return -ENOTSUPP;
+	}
+
+	return 0;
+}
+
+static umode_t
+gsc_hwmon_is_visible(const void *_data, enum hwmon_sensor_types type, u32 attr,
+		     int ch)
+{
+	return 0444;
+}
+
+static const struct hwmon_ops gsc_hwmon_ops = {
+	.is_visible = gsc_hwmon_is_visible,
+	.read = gsc_hwmon_read,
+	.read_string = gsc_hwmon_read_string,
+};
+
+static struct gsc_hwmon_platform_data *
+gsc_hwmon_get_devtree_pdata(struct device *dev)
+{
+	struct gsc_hwmon_platform_data *pdata;
+	struct gsc_hwmon_channel *ch;
+	struct fwnode_handle *child;
+	struct device_node *fan;
+	int nchannels;
+
+	nchannels = device_get_child_node_count(dev);
+	if (nchannels == 0)
+		return ERR_PTR(-ENODEV);
+
+	pdata = devm_kzalloc(dev,
+			     sizeof(*pdata) + nchannels * sizeof(*ch),
+			     GFP_KERNEL);
+	if (!pdata)
+		return ERR_PTR(-ENOMEM);
+	ch = (struct gsc_hwmon_channel *)(pdata + 1);
+	pdata->channels = ch;
+	pdata->nchannels = nchannels;
+
+	/* fan controller base address */
+	fan = of_find_compatible_node(dev->parent->of_node, NULL, "gw,gsc-fan");
+	if (fan && of_property_read_u32(fan, "reg", &pdata->fan_base)) {
+		dev_err(dev, "fan node without base\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	/* allocate structures for channels and count instances of each type */
+	device_for_each_child_node(dev, child) {
+		if (fwnode_property_read_string(child, "label", &ch->name)) {
+			dev_err(dev, "channel without label\n");
+			fwnode_handle_put(child);
+			return ERR_PTR(-EINVAL);
+		}
+		if (fwnode_property_read_u32(child, "reg", &ch->reg)) {
+			dev_err(dev, "channel without reg\n");
+			fwnode_handle_put(child);
+			return ERR_PTR(-EINVAL);
+		}
+		if (fwnode_property_read_u32(child, "gw,mode", &ch->mode)) {
+			dev_err(dev, "channel without mode\n");
+			fwnode_handle_put(child);
+			return ERR_PTR(-EINVAL);
+		}
+		if (ch->mode > mode_max) {
+			dev_err(dev, "invalid channel mode\n");
+			fwnode_handle_put(child);
+			return ERR_PTR(-EINVAL);
+		}
+
+		if (!fwnode_property_read_u32(child,
+					      "gw,voltage-offset-microvolt",
+					      &ch->mvoffset))
+			ch->mvoffset /= 1000;
+		fwnode_property_read_u32_array(child,
+					       "gw,voltage-divider-ohms",
+					       ch->vdiv, ARRAY_SIZE(ch->vdiv));
+		ch++;
+	}
+
+	return pdata;
+}
+
+static int gsc_hwmon_probe(struct platform_device *pdev)
+{
+	struct gsc_dev *gsc = dev_get_drvdata(pdev->dev.parent);
+	struct device *dev = &pdev->dev;
+	struct device *hwmon_dev;
+	struct gsc_hwmon_platform_data *pdata = dev_get_platdata(dev);
+	struct gsc_hwmon_data *hwmon;
+	const struct attribute_group **groups;
+	int i, i_in, i_temp;
+
+	if (!pdata) {
+		pdata = gsc_hwmon_get_devtree_pdata(dev);
+		if (IS_ERR(pdata))
+			return PTR_ERR(pdata);
+	}
+
+	hwmon = devm_kzalloc(dev, sizeof(*hwmon), GFP_KERNEL);
+	if (!hwmon)
+		return -ENOMEM;
+	hwmon->gsc = gsc;
+	hwmon->pdata = pdata;
+
+	hwmon->regmap = devm_regmap_init(dev, &gsc_hwmon_regmap_bus,
+					 gsc->i2c_hwmon,
+					 &gsc_hwmon_regmap_config);
+	if (IS_ERR(hwmon->regmap))
+		return PTR_ERR(hwmon->regmap);
+
+	for (i = 0, i_in = 0, i_temp = 0; i < hwmon->pdata->nchannels; i++) {
+		const struct gsc_hwmon_channel *ch = &pdata->channels[i];
+
+		switch (ch->mode) {
+		case mode_temperature:
+			if (i_temp == GSC_HWMON_MAX_TEMP_CH) {
+				dev_err(gsc->dev, "too many temp channels\n");
+				return -EINVAL;
+			}
+			hwmon->temp_ch[i_temp] = ch;
+			hwmon->temp_config[i_temp] = HWMON_T_INPUT |
+						     HWMON_T_LABEL;
+			i_temp++;
+			break;
+		case mode_voltage:
+		case mode_voltage_raw:
+			if (i_in == GSC_HWMON_MAX_IN_CH) {
+				dev_err(gsc->dev, "too many input channels\n");
+				return -EINVAL;
+			}
+			hwmon->in_ch[i_in] = ch;
+			hwmon->in_config[i_in] =
+				HWMON_I_INPUT | HWMON_I_LABEL;
+			i_in++;
+			break;
+		default:
+			dev_err(gsc->dev, "invalid mode: %d\n", ch->mode);
+			return -EINVAL;
+		}
+	}
+
+	/* setup config structures */
+	hwmon->chip.ops = &gsc_hwmon_ops;
+	hwmon->chip.info = hwmon->info;
+	hwmon->info[0] = &hwmon->temp_info;
+	hwmon->info[1] = &hwmon->in_info;
+	hwmon->temp_info.type = hwmon_temp;
+	hwmon->temp_info.config = hwmon->temp_config;
+	hwmon->in_info.type = hwmon_in;
+	hwmon->in_info.config = hwmon->in_config;
+
+	groups = pdata->fan_base ? gsc_hwmon_groups : NULL;
+	hwmon_dev = devm_hwmon_device_register_with_info(dev,
+							 KBUILD_MODNAME, hwmon,
+							 &hwmon->chip, groups);
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct of_device_id gsc_hwmon_of_match[] = {
+	{ .compatible = "gw,gsc-adc", },
+	{}
+};
+
+static struct platform_driver gsc_hwmon_driver = {
+	.driver = {
+		.name = "gsc-hwmon",
+		.of_match_table = gsc_hwmon_of_match,
+	},
+	.probe = gsc_hwmon_probe,
+};
+
+module_platform_driver(gsc_hwmon_driver);
+
+MODULE_AUTHOR("Tim Harvey <tharvey@gateworks.com>");
+MODULE_DESCRIPTION("GSC hardware monitor driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/platform_data/gsc_hwmon.h b/include/linux/platform_data/gsc_hwmon.h
new file mode 100644
index 00000000..ec1611a
--- /dev/null
+++ b/include/linux/platform_data/gsc_hwmon.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _GSC_HWMON_H
+#define _GSC_HWMON_H
+
+enum gsc_hwmon_mode {
+	mode_temperature,
+	mode_voltage,
+	mode_voltage_raw,
+	mode_max,
+};
+
+/**
+ * struct gsc_hwmon_channel - configuration parameters
+ * @reg:  I2C register offset
+ * @mode: channel mode
+ * @name: channel name
+ * @mvoffset: voltage offset
+ * @vdiv: voltage divider array (2 resistor values in milli-ohms)
+ */
+struct gsc_hwmon_channel {
+	unsigned int reg;
+	unsigned int mode;
+	const char *name;
+	unsigned int mvoffset;
+	unsigned int vdiv[2];
+};
+
+/**
+ * struct gsc_hwmon_platform_data - platform data for gsc_hwmon driver
+ * @channels:	pointer to array of gsc_hwmon_channel structures
+ *		describing channels
+ * @nchannels:	number of elements in @channels array
+ * @vreference: voltage reference (mV)
+ * @resolution: ADC bit resolution
+ * @fan_base: register base for FAN controller
+ */
+struct gsc_hwmon_platform_data {
+	const struct gsc_hwmon_channel *channels;
+	int nchannels;
+	unsigned int resolution;
+	unsigned int vreference;
+	unsigned int fan_base;
+};
+#endif
-- 
2.7.4

Re: [PATCH v11 1/3] dt-bindings: mfd: Add Gateworks System Controller bindings

[Lee Jones]

On Fri, 15 May 2020, Tim Harvey wrote:

> This patch adds documentation of device-tree bindings for the
> Gateworks System Controller (GSC).
> 
> Signed-off-by: Tim Harvey <tharvey@gateworks.com>
> Reviewed-by: Rob Herring <robh@kernel.org>
> ---
> v11:
>  - no change
> 
> v10:
>  - no change
> 
> v9:
>  - added Reviewed-by: Rob Herring <robh@kernel.org>
>  - remove allOf: see https://lkml.org/lkml/2020/4/15/1930
>  - encorporate Lee's review comments for item descriptions
> 
> v8:
>  - add register to fan-controller node name
> 
> v7:
>  - change divider from mili-ohms to ohms
>  - add constraints for voltage divider and offset
>  - remove unnecessary ref for offset
>  - renamed fan to fan-controller and changed base prop to reg
> 
> v6:
>  - fix typo
>  - drop invalid description from #interrupt-cells property
>  - fix adc pattern property
>  - add unit suffix
>  - replace hwmon/adc with adc/channel
>  - changed adc type to mode and enum int
>  - add unit suffix and drop ref for voltage-divider
>  - moved fan to its own subnode with base register
> 
> v5:
>  - resolve dt_binding_check issues
> 
> v4:
>  - move to using pwm<n>_auto_point<m>_{pwm,temp} for FAN PWM
>  - remove unncessary resolution/scaling properties for ADCs
>  - update to yaml
>  - remove watchdog
> 
> v3:
>  - replaced _ with -
>  - remove input bindings
>  - added full description of hwmon
>  - fix unit address of hwmon child nodes
> ---
>  .../devicetree/bindings/mfd/gateworks-gsc.yaml     | 196 +++++++++++++++++++++
>  1 file changed, 196 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml

Applied, thanks.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v11 2/3] mfd: add Gateworks System Controller core driver

[Lee Jones]

On Fri, 15 May 2020, Tim Harvey wrote:

> The Gateworks System Controller (GSC) is an I2C slave controller
> implemented with an MSP430 micro-controller whose firmware embeds the
> following features:
>  - I/O expander (16 GPIO's) using PCA955x protocol
>  - Real Time Clock using DS1672 protocol
>  - User EEPROM using AT24 protocol
>  - HWMON using custom protocol
>  - Interrupt controller with tamper detect, user pushbotton
>  - Watchdog controller capable of full board power-cycle
>  - Power Control capable of full board power-cycle
> 
> see http://trac.gateworks.com/wiki/gsc for more details
> 
> Signed-off-by: Tim Harvey <tharvey@gateworks.com>
> Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>
> ---
> v11:
> - fix compile error
> 
> v10:
> - fix typo and gramatical errors in Kconfig and comment block
> - drop unused i2c device-id table
> - added Lee's ack in s-o-b
> 
> v9:
> - rebase against 5.7-rc2
> - cleanup gsc_powerdown() by using BIT(), put_unaligned_le32(), and avoid
>   unnecessary assignments
> - rename GSC_CTRL_1 SLEEP related defines to simplify
> - add better description and sub-module info to driver description
> - whitespace changes per review
> - remove unused irq_data pointer in ddata
> - remove unnecesary i2c_set_clientdata
> - use devm_i2c_new_dummy_device to avoid need of free's
> - change regsiter definitions to enum
> - export gsc_{read,write} instead of sharing them via ddata
> 
> v8:
> - whitespace fixes
> - describe sub-devices in Kconfig
> - add error print for invalid command
> - update copyright
> - use devm_of_platform_populate
> - use probe_new
> - move hwmon's regmap init to hwmon
> 
> v7:
> - remove irq from private data struct
> 
> v6:
> - remove duplicate signature and fix commit log
> 
> v5:
> - simplify powerdown function
> 
> v4:
> - remove hwmon max reg check/define
> - fix powerdown function
> 
> v3:
> - rename gsc->gateworks-gsc
> - remove uncecessary include for linux/mfd/core.h
> - upercase I2C in comments
> - remove i2c debug
> - remove uncecessary comments
> - don't use KBUILD_MODNAME for name
> - remove unnecessary v1/v2/v3 tracking
> - unregister hwmon i2c adapter on remove
> 
> v2:
> - change license comment block style
> - remove COMPILE_TEST (Randy)
> - fixed whitespace issues
> - replaced a printk with dev_err
> ---
>  MAINTAINERS                 |   8 ++
>  drivers/mfd/Kconfig         |  15 +++
>  drivers/mfd/Makefile        |   1 +
>  drivers/mfd/gateworks-gsc.c | 277 ++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/gsc.h     |  76 ++++++++++++
>  5 files changed, 377 insertions(+)
>  create mode 100644 drivers/mfd/gateworks-gsc.c
>  create mode 100644 include/linux/mfd/gsc.h

Applied, thanks.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH 3/3] hwmon: add Gateworks System Controller support

[Lee Jones]

On Fri, 15 May 2020, Tim Harvey wrote:

> The Gateworks System Controller has a hwmon sub-component that exposes
> up to 16 ADC's, some of which are temperature sensors, others which are
> voltage inputs. The ADC configuration (register mapping and name) is
> configured via device-tree and varies board to board.
> 
> Signed-off-by: Tim Harvey <tharvey@gateworks.com>
> Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> ---
> v11:
> - no change
> 
> v10:
> - no change
> 
> v9:
> - use exported gsc_{read,write}
> - added Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> 
> v8:
> - move regmap init to hwmon
> 
> v7:
> - fix whitespace in Kconfig
> - remove unnecessary device pointer in private data
> - change divider from mili-ohms to ohms
> - move fan base property to reg
> 
> v6:
> - fix size of info field
> - improve pwm output control documentation
> - include unit suffix in divider and offset
> - change subnode name to gsc-adc
> - change to fan subnode
> - fix voltage offset
> 
> v5:
> - fix various checkpatch issues
> - correct gsc-hwmon.rst in MAINTAINERS
> - encorporate Gunter's feedback:
>  - switch to SENSOR_DEVICE_ATTR_{RW,RO}
>  - use tmp value to avoid excessive pointer deference
>  - simplify shift operation
>  - scale voffset once
>  - simplify is_visible function
>  - remove empty line at end of file
> 
> v4:
> - adjust for uV offset from device-tree
> - remove unnecessary optional write function
> - remove register range check
> - change dev_err prints to use gsc dev
> - hard-code resolution/scaling for raw adcs
> - describe units of ADC resolution
> - move to using pwm<n>_auto_point<m>_{pwm,temp} for FAN PWM
> - ensure space before/after operators
> - remove unnecessary parens
> - remove more debugging
> - add default case and comment for type_voltage
> - remove unnecessary index bounds checks for channel
> - remove unnecessary clearing of struct fields
> - added Documentation/hwmon/gsc-hwmon.rst
> 
> v3:
> - add voltage_raw input type and supporting fields
> - add channel validation to is_visible function
> - remove unnecessary channel validation from read/write functions
> 
> v2:
> - change license comment style
> - remove DEBUG
> - simplify regmap_bulk_read err check
> - remove break after returns in switch statement
> - fix fan setpoint buffer address
> - remove unnecessary parens
> - consistently use struct device *dev pointer
> - change license/comment block
> - add validation for hwmon child node props
> - move parsing of of to own function
> - use strlcpy to ensure null termination
> - fix static array sizes and removed unnecessary initializers
> - dynamically allocate channels
> - fix fan input label
> - support platform data
> - fixed whitespace issues
> ---
>  Documentation/hwmon/gsc-hwmon.rst       |  53 +++++
>  Documentation/hwmon/index.rst           |   1 +
>  MAINTAINERS                             |   3 +
>  drivers/hwmon/Kconfig                   |   9 +
>  drivers/hwmon/Makefile                  |   1 +
>  drivers/hwmon/gsc-hwmon.c               | 390 ++++++++++++++++++++++++++++++++
>  include/linux/platform_data/gsc_hwmon.h |  44 ++++
>  7 files changed, 501 insertions(+)
>  create mode 100644 Documentation/hwmon/gsc-hwmon.rst
>  create mode 100644 drivers/hwmon/gsc-hwmon.c
>  create mode 100644 include/linux/platform_data/gsc_hwmon.h

Applied, thanks.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

[GIT PULL] Immutable branch between MFD and HWMON due for the v5.8 merge window

[Lee Jones]

Enjoy!

The following changes since commit 8f3d9f354286745c751374f5f1fcafee6b3f3136:

  Linux 5.7-rc1 (2020-04-12 12:35:55 -0700)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd.git ib-mfd-hwmon-v5.8

for you to fetch changes up to 3bce5377ef66a8700dcf7a9cb89b7aeb99326cb7:

  hwmon: Add Gateworks System Controller support (2020-05-20 10:29:17 +0100)

----------------------------------------------------------------
Immutable branch between MFD and HWMON due for the v5.8 merge window

----------------------------------------------------------------
Tim Harvey (3):
      dt-bindings: mfd: Add Gateworks System Controller bindings
      mfd: Add Gateworks System Controller core driver
      hwmon: Add Gateworks System Controller support

 .../devicetree/bindings/mfd/gateworks-gsc.yaml     | 196 +++++++++++
 Documentation/hwmon/gsc-hwmon.rst                  |  53 +++
 Documentation/hwmon/index.rst                      |   1 +
 MAINTAINERS                                        |  11 +
 drivers/hwmon/Kconfig                              |   9 +
 drivers/hwmon/Makefile                             |   1 +
 drivers/hwmon/gsc-hwmon.c                          | 390 +++++++++++++++++++++
 drivers/mfd/Kconfig                                |  15 +
 drivers/mfd/Makefile                               |   1 +
 drivers/mfd/gateworks-gsc.c                        | 277 +++++++++++++++
 include/linux/mfd/gsc.h                            |  76 ++++
 include/linux/platform_data/gsc_hwmon.h            |  44 +++
 12 files changed, 1074 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/gateworks-gsc.yaml
 create mode 100644 Documentation/hwmon/gsc-hwmon.rst
 create mode 100644 drivers/hwmon/gsc-hwmon.c
 create mode 100644 drivers/mfd/gateworks-gsc.c
 create mode 100644 include/linux/mfd/gsc.h
 create mode 100644 include/linux/platform_data/gsc_hwmon.h

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog