Add Raspberry Pi voltage sensor driver

9 files changed, 416 insertions, 1 deletions

diff --git a/bcm2835-hwmon-Add-support-for-RPi-voltage-sensor.patch b/bcm2835-hwmon-Add-support-for-RPi-voltage-sensor.patch
new file mode 100644
index 000000000..3e65ab969
--- /dev/null
+++ b/bcm2835-hwmon-Add-support-for-RPi-voltage-sensor.patch
@@ -0,0 +1,403 @@
+From be3035e3627d2570de4c2c612ecd095968986437 Mon Sep 17 00:00:00 2001
+From: Stefan Wahren <stefan.wahren@i2se.com>
+Date: Fri, 25 May 2018 21:24:34 +0200
+Subject: [PATCH 1/4] ARM: bcm2835: Add GET_THROTTLED firmware property
+
+Recent Raspberry Pi firmware provides a mailbox property to detect
+under-voltage conditions. Here is the current definition.
+
+The u32 value returned by the firmware is divided into 2 parts:
+  - lower 16-bits are the live value
+  - upper 16-bits are the history or sticky value
+
+  Bits:
+  0: undervoltage
+  1: arm frequency capped
+  2: currently throttled
+  16: undervoltage has occurred
+  17: arm frequency capped has occurred
+  18: throttling has occurred
+
+Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
+Signed-off-by: Eric Anholt <eric@anholt.net>
+Reviewed-by: Eric Anholt <eric@anholt.net>
+---
+ include/soc/bcm2835/raspberrypi-firmware.h | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/include/soc/bcm2835/raspberrypi-firmware.h b/include/soc/bcm2835/raspberrypi-firmware.h
+index 8ee8991aa099a..c4a5c9e9fb478 100644
+--- a/include/soc/bcm2835/raspberrypi-firmware.h
++++ b/include/soc/bcm2835/raspberrypi-firmware.h
+@@ -75,6 +75,7 @@ enum rpi_firmware_property_tag {
+ 	RPI_FIRMWARE_GET_EDID_BLOCK =                         0x00030020,
+ 	RPI_FIRMWARE_GET_CUSTOMER_OTP =                       0x00030021,
+ 	RPI_FIRMWARE_GET_DOMAIN_STATE =                       0x00030030,
++	RPI_FIRMWARE_GET_THROTTLED =                          0x00030046,
+ 	RPI_FIRMWARE_SET_CLOCK_STATE =                        0x00038001,
+ 	RPI_FIRMWARE_SET_CLOCK_RATE =                         0x00038002,
+ 	RPI_FIRMWARE_SET_VOLTAGE =                            0x00038003,
+-- 
+2.17.1
+
+From 3c493c885cf8abf0986c9877875161dfd0a29273 Mon Sep 17 00:00:00 2001
+From: Stefan Wahren <stefan.wahren@i2se.com>
+Date: Fri, 25 May 2018 21:24:35 +0200
+Subject: [PATCH 2/4] hwmon: Add support for RPi voltage sensor
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Currently there is no easy way to detect undervoltage conditions on a
+remote Raspberry Pi. This hwmon driver retrieves the state of the
+undervoltage sensor via mailbox interface. The handling based on
+Noralf's modifications to the downstream firmware driver. In case of
+an undervoltage condition only an entry is written to the kernel log.
+
+CC: "Noralf Trønnes" <noralf@tronnes.org>
+Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
+Signed-off-by: Eric Anholt <eric@anholt.net>
+Acked-by: Guenter Roeck <linux@roeck-us.net>
+---
+ Documentation/hwmon/raspberrypi-hwmon |  22 ++++
+ drivers/hwmon/Kconfig                 |  10 ++
+ drivers/hwmon/Makefile                |   1 +
+ drivers/hwmon/raspberrypi-hwmon.c     | 166 ++++++++++++++++++++++++++
+ 4 files changed, 199 insertions(+)
+ create mode 100644 Documentation/hwmon/raspberrypi-hwmon
+ create mode 100644 drivers/hwmon/raspberrypi-hwmon.c
+
+diff --git a/Documentation/hwmon/raspberrypi-hwmon b/Documentation/hwmon/raspberrypi-hwmon
+new file mode 100644
+index 0000000000000..3c92e2cb52d60
+--- /dev/null
++++ b/Documentation/hwmon/raspberrypi-hwmon
+@@ -0,0 +1,22 @@
++Kernel driver raspberrypi-hwmon
++===============================
++
++Supported boards:
++  * Raspberry Pi A+ (via GPIO on SoC)
++  * Raspberry Pi B+ (via GPIO on SoC)
++  * Raspberry Pi 2 B (via GPIO on SoC)
++  * Raspberry Pi 3 B (via GPIO on port expander)
++  * Raspberry Pi 3 B+ (via PMIC)
++
++Author: Stefan Wahren <stefan.wahren@i2se.com>
++
++Description
++-----------
++
++This driver periodically polls a mailbox property of the VC4 firmware to detect
++undervoltage conditions.
++
++Sysfs entries
++-------------
++
++in0_lcrit_alarm		Undervoltage alarm
+diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
+index f10840ad465c2..fdaab8229686f 100644
+--- a/drivers/hwmon/Kconfig
++++ b/drivers/hwmon/Kconfig
+@@ -1298,6 +1298,16 @@ config SENSORS_PWM_FAN
+ 	  This driver can also be built as a module.  If so, the module
+ 	  will be called pwm-fan.
+ 
++config SENSORS_RASPBERRYPI_HWMON
++	tristate "Raspberry Pi voltage monitor"
++	depends on RASPBERRYPI_FIRMWARE || COMPILE_TEST
++	help
++	  If you say yes here you get support for voltage sensor on the
++	  Raspberry Pi.
++
++	  This driver can also be built as a module. If so, the module
++	  will be called raspberrypi-hwmon.
++
+ config SENSORS_SHT15
+ 	tristate "Sensiron humidity and temperature sensors. SHT15 and compat."
+ 	depends on GPIOLIB || COMPILE_TEST
+diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
+index e7d52a36e6c4f..a9297703fd6e4 100644
+--- a/drivers/hwmon/Makefile
++++ b/drivers/hwmon/Makefile
+@@ -141,6 +141,7 @@ obj-$(CONFIG_SENSORS_PC87427)	+= pc87427.o
+ obj-$(CONFIG_SENSORS_PCF8591)	+= pcf8591.o
+ obj-$(CONFIG_SENSORS_POWR1220)  += powr1220.o
+ obj-$(CONFIG_SENSORS_PWM_FAN)	+= pwm-fan.o
++obj-$(CONFIG_SENSORS_RASPBERRYPI_HWMON)	+= raspberrypi-hwmon.o
+ obj-$(CONFIG_SENSORS_S3C)	+= s3c-hwmon.o
+ obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o
+ obj-$(CONFIG_SENSORS_SCH5627)	+= sch5627.o
+diff --git a/drivers/hwmon/raspberrypi-hwmon.c b/drivers/hwmon/raspberrypi-hwmon.c
+new file mode 100644
+index 0000000000000..fb4e4a6bb1f63
+--- /dev/null
++++ b/drivers/hwmon/raspberrypi-hwmon.c
+@@ -0,0 +1,166 @@
++// SPDX-License-Identifier: GPL-2.0+
++/*
++ * Raspberry Pi voltage sensor driver
++ *
++ * Based on firmware/raspberrypi.c by Noralf Trønnes
++ *
++ * Copyright (C) 2018 Stefan Wahren <stefan.wahren@i2se.com>
++ */
++#include <linux/device.h>
++#include <linux/err.h>
++#include <linux/hwmon.h>
++#include <linux/module.h>
++#include <linux/platform_device.h>
++#include <linux/slab.h>
++#include <linux/workqueue.h>
++#include <soc/bcm2835/raspberrypi-firmware.h>
++
++#define UNDERVOLTAGE_STICKY_BIT	BIT(16)
++
++struct rpi_hwmon_data {
++	struct device *hwmon_dev;
++	struct rpi_firmware *fw;
++	u32 last_throttled;
++	struct delayed_work get_values_poll_work;
++};
++
++static void rpi_firmware_get_throttled(struct rpi_hwmon_data *data)
++{
++	u32 new_uv, old_uv, value;
++	int ret;
++
++	/* Request firmware to clear sticky bits */
++	value = 0xffff;
++
++	ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED,
++				    &value, sizeof(value));
++	if (ret) {
++		dev_err_once(data->hwmon_dev, "Failed to get throttled (%d)\n",
++			     ret);
++		return;
++	}
++
++	new_uv = value & UNDERVOLTAGE_STICKY_BIT;
++	old_uv = data->last_throttled & UNDERVOLTAGE_STICKY_BIT;
++	data->last_throttled = value;
++
++	if (new_uv == old_uv)
++		return;
++
++	if (new_uv)
++		dev_crit(data->hwmon_dev, "Undervoltage detected!\n");
++	else
++		dev_info(data->hwmon_dev, "Voltage normalised\n");
++
++	sysfs_notify(&data->hwmon_dev->kobj, NULL, "in0_lcrit_alarm");
++}
++
++static void get_values_poll(struct work_struct *work)
++{
++	struct rpi_hwmon_data *data;
++
++	data = container_of(work, struct rpi_hwmon_data,
++			    get_values_poll_work.work);
++
++	rpi_firmware_get_throttled(data);
++
++	/*
++	 * We can't run faster than the sticky shift (100ms) since we get
++	 * flipping in the sticky bits that are cleared.
++	 */
++	schedule_delayed_work(&data->get_values_poll_work, 2 * HZ);
++}
++
++static int rpi_read(struct device *dev, enum hwmon_sensor_types type,
++		    u32 attr, int channel, long *val)
++{
++	struct rpi_hwmon_data *data = dev_get_drvdata(dev);
++
++	*val = !!(data->last_throttled & UNDERVOLTAGE_STICKY_BIT);
++	return 0;
++}
++
++static umode_t rpi_is_visible(const void *_data, enum hwmon_sensor_types type,
++			      u32 attr, int channel)
++{
++	return 0444;
++}
++
++static const u32 rpi_in_config[] = {
++	HWMON_I_LCRIT_ALARM,
++	0
++};
++
++static const struct hwmon_channel_info rpi_in = {
++	.type = hwmon_in,
++	.config = rpi_in_config,
++};
++
++static const struct hwmon_channel_info *rpi_info[] = {
++	&rpi_in,
++	NULL
++};
++
++static const struct hwmon_ops rpi_hwmon_ops = {
++	.is_visible = rpi_is_visible,
++	.read = rpi_read,
++};
++
++static const struct hwmon_chip_info rpi_chip_info = {
++	.ops = &rpi_hwmon_ops,
++	.info = rpi_info,
++};
++
++static int rpi_hwmon_probe(struct platform_device *pdev)
++{
++	struct device *dev = &pdev->dev;
++	struct rpi_hwmon_data *data;
++	int ret;
++
++	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
++	if (!data)
++		return -ENOMEM;
++
++	/* Parent driver assure that firmware is correct */
++	data->fw = dev_get_drvdata(dev->parent);
++
++	/* Init throttled */
++	ret = rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED,
++				    &data->last_throttled,
++				    sizeof(data->last_throttled));
++
++	data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "rpi_volt",
++							       data,
++							       &rpi_chip_info,
++							       NULL);
++
++	INIT_DELAYED_WORK(&data->get_values_poll_work, get_values_poll);
++	platform_set_drvdata(pdev, data);
++
++	if (!PTR_ERR_OR_ZERO(data->hwmon_dev))
++		schedule_delayed_work(&data->get_values_poll_work, 2 * HZ);
++
++	return PTR_ERR_OR_ZERO(data->hwmon_dev);
++}
++
++static int rpi_hwmon_remove(struct platform_device *pdev)
++{
++	struct rpi_hwmon_data *data = platform_get_drvdata(pdev);
++
++	cancel_delayed_work_sync(&data->get_values_poll_work);
++
++	return 0;
++}
++
++static struct platform_driver rpi_hwmon_driver = {
++	.probe = rpi_hwmon_probe,
++	.remove = rpi_hwmon_remove,
++	.driver = {
++		.name = "raspberrypi-hwmon",
++	},
++};
++module_platform_driver(rpi_hwmon_driver);
++
++MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>");
++MODULE_DESCRIPTION("Raspberry Pi voltage sensor driver");
++MODULE_LICENSE("GPL v2");
+-- 
+2.17.1
+
+From 4ebe8673279b7afbbcbcf92094c9012a3c91f240 Mon Sep 17 00:00:00 2001
+From: Stefan Wahren <stefan.wahren@i2se.com>
+Date: Fri, 25 May 2018 21:24:36 +0200
+Subject: [PATCH 3/4] firmware: raspberrypi: Register hwmon driver
+
+Since the raspberrypi-hwmon driver is tied to the VC4 firmware instead of
+particular hardware its registration should be in the firmware driver.
+
+Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
+Signed-off-by: Eric Anholt <eric@anholt.net>
+---
+ drivers/firmware/raspberrypi.c | 19 +++++++++++++++++++
+ 1 file changed, 19 insertions(+)
+
+diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c
+index 6692888f04cfb..0602626bf72d0 100644
+--- a/drivers/firmware/raspberrypi.c
++++ b/drivers/firmware/raspberrypi.c
+@@ -21,6 +21,8 @@
+ #define MBOX_DATA28(msg)		((msg) & ~0xf)
+ #define MBOX_CHAN_PROPERTY		8
+ 
++static struct platform_device *rpi_hwmon;
++
+ struct rpi_firmware {
+ 	struct mbox_client cl;
+ 	struct mbox_chan *chan; /* The property channel. */
+@@ -183,6 +185,20 @@ rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
+ 	}
+ }
+ 
++static void
++rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw)
++{
++	u32 packet;
++	int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED,
++					&packet, sizeof(packet));
++
++	if (ret)
++		return;
++
++	rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon",
++						  -1, NULL, 0);
++}
++
+ static int rpi_firmware_probe(struct platform_device *pdev)
+ {
+ 	struct device *dev = &pdev->dev;
+@@ -209,6 +225,7 @@ static int rpi_firmware_probe(struct platform_device *pdev)
+ 	platform_set_drvdata(pdev, fw);
+ 
+ 	rpi_firmware_print_firmware_revision(fw);
++	rpi_register_hwmon_driver(dev, fw);
+ 
+ 	return 0;
+ }
+@@ -217,6 +234,8 @@ static int rpi_firmware_remove(struct platform_device *pdev)
+ {
+ 	struct rpi_firmware *fw = platform_get_drvdata(pdev);
+ 
++	platform_device_unregister(rpi_hwmon);
++	rpi_hwmon = NULL;
+ 	mbox_free_channel(fw->chan);
+ 
+ 	return 0;
+-- 
+2.17.1
+
+From a0cf7704b6bc145a9f198a9b2bcf92ccc5d6b6be Mon Sep 17 00:00:00 2001
+From: Peter Robinson <pbrobinson@gmail.com>
+Date: Fri, 20 Jul 2018 12:58:37 +0100
+Subject: [PATCH] hwmon: rpi: add module alias to raspberrypi-hwmon
+
+The raspberrypi-hwmon driver doesn't automatically load, although it does work
+when loaded, by adding the alias it auto loads as expected when built as a
+module. Tested on RPi2/RPi3 on 32 bit kernel and RPi3B+ on aarch64 with
+Fedora 28 and a patched 4.18 RC kernel.
+
+Fixes: q3c493c885cf ("hwmon: Add support for RPi voltage sensor")
+Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
+CC: Stefan Wahren <stefan.wahren@i2se.com>
+CC: Eric Anholt <eric@anholt.net>
+---
+ drivers/hwmon/raspberrypi-hwmon.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/drivers/hwmon/raspberrypi-hwmon.c b/drivers/hwmon/raspberrypi-hwmon.c
+index fb4e4a6bb1f63..be5ba46908953 100644
+--- a/drivers/hwmon/raspberrypi-hwmon.c
++++ b/drivers/hwmon/raspberrypi-hwmon.c
+@@ -164,3 +164,4 @@ module_platform_driver(rpi_hwmon_driver);
+ MODULE_AUTHOR("Stefan Wahren <stefan.wahren@i2se.com>");
+ MODULE_DESCRIPTION("Raspberry Pi voltage sensor driver");
+ MODULE_LICENSE("GPL v2");
++MODULE_ALIAS("platform:raspberrypi-hwmon");
+-- 
+2.17.1
+
diff --git a/configs/fedora/generic/arm/CONFIG_SENSORS_RASPBERRYPI_HWMON b/configs/fedora/generic/arm/CONFIG_SENSORS_RASPBERRYPI_HWMON
new file mode 100644
index 000000000..cecf9cbfb
--- /dev/null
+++ b/configs/fedora/generic/arm/CONFIG_SENSORS_RASPBERRYPI_HWMON
@@ -0,0 +1 @@
+CONFIG_SENSORS_RASPBERRYPI_HWMON=m
diff --git a/kernel-aarch64-debug.config b/kernel-aarch64-debug.config
index e7f0efd19..86cfd1c72 100644
--- a/kernel-aarch64-debug.config
+++ b/kernel-aarch64-debug.config
@@ -5272,6 +5272,7 @@ CONFIG_SENSORS_PCF8591=m
 CONFIG_SENSORS_PMBUS=m
 CONFIG_SENSORS_POWR1220=m
 CONFIG_SENSORS_PWM_FAN=m
+CONFIG_SENSORS_RASPBERRYPI_HWMON=m
 CONFIG_SENSORS_SCH5627=m
 CONFIG_SENSORS_SCH5636=m
 CONFIG_SENSORS_SHT15=m
diff --git a/kernel-aarch64.config b/kernel-aarch64.config
index 3eab68f2c..4d6003578 100644
--- a/kernel-aarch64.config
+++ b/kernel-aarch64.config
@@ -5249,6 +5249,7 @@ CONFIG_SENSORS_PCF8591=m
 CONFIG_SENSORS_PMBUS=m
 CONFIG_SENSORS_POWR1220=m
 CONFIG_SENSORS_PWM_FAN=m
+CONFIG_SENSORS_RASPBERRYPI_HWMON=m
 CONFIG_SENSORS_SCH5627=m
 CONFIG_SENSORS_SCH5636=m
 CONFIG_SENSORS_SHT15=m
diff --git a/kernel-armv7hl-debug.config b/kernel-armv7hl-debug.config
index 86110c519..04f93a6be 100644
--- a/kernel-armv7hl-debug.config
+++ b/kernel-armv7hl-debug.config
@@ -5596,6 +5596,7 @@ CONFIG_SENSORS_PCF8591=m
 CONFIG_SENSORS_PMBUS=m
 CONFIG_SENSORS_POWR1220=m
 CONFIG_SENSORS_PWM_FAN=m
+CONFIG_SENSORS_RASPBERRYPI_HWMON=m
 CONFIG_SENSORS_SCH5627=m
 CONFIG_SENSORS_SCH5636=m
 CONFIG_SENSORS_SHT15=m
diff --git a/kernel-armv7hl-lpae-debug.config b/kernel-armv7hl-lpae-debug.config
index f3118f300..005231928 100644
--- a/kernel-armv7hl-lpae-debug.config
+++ b/kernel-armv7hl-lpae-debug.config
@@ -5285,6 +5285,7 @@ CONFIG_SENSORS_PCF8591=m
 CONFIG_SENSORS_PMBUS=m
 CONFIG_SENSORS_POWR1220=m
 CONFIG_SENSORS_PWM_FAN=m
+CONFIG_SENSORS_RASPBERRYPI_HWMON=m
 CONFIG_SENSORS_SCH5627=m
 CONFIG_SENSORS_SCH5636=m
 CONFIG_SENSORS_SHT15=m
diff --git a/kernel-armv7hl-lpae.config b/kernel-armv7hl-lpae.config
index b49bd99ea..ca671a56a 100644
--- a/kernel-armv7hl-lpae.config
+++ b/kernel-armv7hl-lpae.config
@@ -5262,6 +5262,7 @@ CONFIG_SENSORS_PCF8591=m
 CONFIG_SENSORS_PMBUS=m
 CONFIG_SENSORS_POWR1220=m
 CONFIG_SENSORS_PWM_FAN=m
+CONFIG_SENSORS_RASPBERRYPI_HWMON=m
 CONFIG_SENSORS_SCH5627=m
 CONFIG_SENSORS_SCH5636=m
 CONFIG_SENSORS_SHT15=m
diff --git a/kernel-armv7hl.config b/kernel-armv7hl.config
index 169f14913..794edfdfa 100644
--- a/kernel-armv7hl.config
+++ b/kernel-armv7hl.config
@@ -5573,6 +5573,7 @@ CONFIG_SENSORS_PCF8591=m
 CONFIG_SENSORS_PMBUS=m
 CONFIG_SENSORS_POWR1220=m
 CONFIG_SENSORS_PWM_FAN=m
+CONFIG_SENSORS_RASPBERRYPI_HWMON=m
 CONFIG_SENSORS_SCH5627=m
 CONFIG_SENSORS_SCH5636=m
 CONFIG_SENSORS_SHT15=m
diff --git a/kernel.spec b/kernel.spec
index 801e5f9ff..ef1802205 100644
--- a/kernel.spec
+++ b/kernel.spec
@@ -587,7 +587,9 @@ Patch307: arm-tegra-fix-nouveau-crash.patch
 # Enabling Patches for the RPi3+
 Patch330: bcm2837-enable-pmu.patch
 
-Patch332: bcm2835-cpufreq-add-CPU-frequency-control-driver.patch
+Patch331: bcm2835-cpufreq-add-CPU-frequency-control-driver.patch
+
+Patch332: bcm2835-hwmon-Add-support-for-RPi-voltage-sensor.patch
 
 # Fix for AllWinner A64 Timer Errata, still not final
 # https://patchwork.kernel.org/patch/10392891/
@@ -1878,6 +1880,9 @@ fi
 #
 #
 %changelog
+* Thu Jul 26 2018 Peter Robinson <pbrobinson@fedoraproject.org>
+- Add Raspberry Pi voltage sensor driver
+
 * Wed Jul 25 2018 Laura Abbott <labbott@redhat.com> - 4.18.0-0.rc6.git1.1
 - Linux v4.18-rc6-93-g9981b4fb8684