From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guenter Roeck Subject: Re: [PATCH RFC 3/6] hwmon: Add support for RPi voltage sensor Date: Wed, 16 May 2018 11:05:49 -0700 Message-ID: <20180516180549.GA22705@roeck-us.net> References: <1526477827-10859-1-git-send-email-stefan.wahren@i2se.com> <1526477827-10859-4-git-send-email-stefan.wahren@i2se.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Robin Murphy Cc: Stefan Wahren , Mark Rutland , Jean Delvare , Scott Branden , devicetree@vger.kernel.org, Ray Jui , Phil Elwell , Eric Anholt , Rob Herring , bcm-kernel-feedback-list@broadcom.com, linux-rpi-kernel@lists.infradead.org, Florian Fainelli , linux-hwmon@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Noralf =?iso-8859-1?Q?Tr=F8nnes?= List-Id: devicetree@vger.kernel.org On Wed, May 16, 2018 at 02:51:49PM +0100, Robin Murphy wrote: > Hi Stefan, > = > On 16/05/18 14:37, Stefan Wahren wrote: > >Currently there is no easy way to detect under-voltage conditions on a r= emote > >Raspberry Pi. This hwmon driver retrieves the state of the under-voltage= sensor > >via mailbox interface. The handling based on Noralf's modifications to t= he > >downstream firmware driver. In case of an under-voltage condition only a= n entry > >is written to the kernel log. > > > >CC: "Noralf Tr=F8nnes" > >Signed-off-by: Stefan Wahren > >--- > > drivers/hwmon/Kconfig | 10 ++ > > drivers/hwmon/Makefile | 1 + > > drivers/hwmon/raspberrypi-hwmon.c | 207 ++++++++++++++++++++++++++++++= ++++++++ > > 3 files changed, 218 insertions(+) > > create mode 100644 drivers/hwmon/raspberrypi-hwmon.c > > > >diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > >index 768aed5..7f935cf 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 (ARCH_BCM2835 && RASPBERRYPI_FIRMWARE) || (COMPILE_TEST && = !RASPBERRYPI_FIRMWARE) > = > Since RASPBERRYPI_FIRMWARE already implies ARCH_BCM2835 (via BCM2835_MBOX= ), > this is just a very roundabout way to say: > = > depends on RASPBERRYPI_FIRMWARE || COMPILE_TEST > = That would permit SENSORS_RASPBERRYPI_HWMON=3Dy combined with RASPBERRYPI_FIRMWARE=3Dm, which AFAICS would result in a build error because include/soc/bcm2835/raspberrypi-firmware.h uses IS_ENABLED() and not IS_REACHABLE(). Guenter > Robin. > = > >+ 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 e7d52a3..a929770 100644 > >--- a/drivers/hwmon/Makefile > >+++ b/drivers/hwmon/Makefile > >@@ -141,6 +141,7 @@ obj-$(CONFIG_SENSORS_PC87427) +=3D pc87427.o > > obj-$(CONFIG_SENSORS_PCF8591) +=3D pcf8591.o > > obj-$(CONFIG_SENSORS_POWR1220) +=3D powr1220.o > > obj-$(CONFIG_SENSORS_PWM_FAN) +=3D pwm-fan.o > >+obj-$(CONFIG_SENSORS_RASPBERRYPI_HWMON) +=3D raspberrypi-hwmon.o > > obj-$(CONFIG_SENSORS_S3C) +=3D s3c-hwmon.o > > obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+=3D sch56xx-common.o > > obj-$(CONFIG_SENSORS_SCH5627) +=3D sch5627.o > >diff --git a/drivers/hwmon/raspberrypi-hwmon.c b/drivers/hwmon/raspberry= pi-hwmon.c > >new file mode 100644 > >index 0000000..2003f6c > >--- /dev/null > >+++ b/drivers/hwmon/raspberrypi-hwmon.c > >@@ -0,0 +1,207 @@ > >+// SPDX-License-Identifier: GPL-2.0+ > >+/* > >+ * Raspberry Pi voltage sensor driver > >+ * > >+ * Based on firmware/raspberrypi.c by Noralf Tr=F8nnes > >+ * > >+ * Copyright (C) 2018 Stefan Wahren > >+ */ > >+#include > >+#include > >+#include > >+#include > >+#include > >+#include > >+#include > >+#include > >+#include > >+#include > >+ > >+#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; > >+ > >+ /* Clear sticky bits */ > >+ value =3D 0xffff; > >+ > >+ ret =3D rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED, > >+ &value, sizeof(value)); > >+ if (ret) { > >+ dev_err_once(data->hwmon_dev, "%s: Failed to get throttled (%d)\n", > >+ __func__, ret); > >+ return; > >+ } > >+ > >+ new_uv =3D value & UNDERVOLTAGE_STICKY_BIT; > >+ old_uv =3D data->last_throttled & UNDERVOLTAGE_STICKY_BIT; > >+ data->last_throttled =3D value; > >+ > >+ if (new_uv =3D=3D old_uv) > >+ return; > >+ > >+ if (new_uv) > >+ dev_crit(data->hwmon_dev, "Under-voltage detected! (0x%08x)\n", > >+ value); > >+ else > >+ dev_info(data->hwmon_dev, "Voltage normalised (0x%08x)\n", > >+ value); > >+ > >+ 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 =3D 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 =3D dev_get_drvdata(dev); > >+ > >+ if (type !=3D hwmon_in) > >+ return -EOPNOTSUPP; > >+ > >+ if (attr !=3D hwmon_in_lcrit_alarm) > >+ return -EOPNOTSUPP; > >+ > >+ if (channel) > >+ return -EOPNOTSUPP; > >+ > >+ *val =3D !!(data->last_throttled & UNDERVOLTAGE_STICKY_BIT); > >+ return 0; > >+} > >+ > >+static umode_t rpi_is_visible(const void *_data, enum hwmon_sensor_type= s type, > >+ u32 attr, int channel) > >+{ > >+ if (type !=3D hwmon_in) > >+ return 0; > >+ > >+ if (attr !=3D hwmon_in_lcrit_alarm) > >+ return 0; > >+ > >+ if (channel) > >+ return 0; > >+ > >+ return 0444; > >+} > >+ > >+static const u32 rpi_in_config[] =3D { > >+ HWMON_I_LCRIT_ALARM, > >+ 0 > >+}; > >+ > >+static const struct hwmon_channel_info rpi_in =3D { > >+ .type =3D hwmon_in, > >+ .config =3D rpi_in_config, > >+}; > >+ > >+static const struct hwmon_channel_info *rpi_info[] =3D { > >+ &rpi_in, > >+ NULL > >+}; > >+ > >+static const struct hwmon_ops rpi_hwmon_ops =3D { > >+ .is_visible =3D rpi_is_visible, > >+ .read =3D rpi_read, > >+}; > >+ > >+static const struct hwmon_chip_info rpi_chip_info =3D { > >+ .ops =3D &rpi_hwmon_ops, > >+ .info =3D rpi_info, > >+}; > >+ > >+static int rpi_hwmon_probe(struct platform_device *pdev) > >+{ > >+ struct device *dev =3D &pdev->dev; > >+ struct device_node *fw_node; > >+ struct rpi_hwmon_data *data; > >+ int ret; > >+ > >+ data =3D devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); > >+ if (!data) > >+ return -ENOMEM; > >+ > >+ fw_node =3D of_get_parent(dev->of_node); > >+ if (!fw_node) { > >+ dev_err(dev, "Missing firmware node\n"); > >+ return -ENOENT; > >+ } > >+ > >+ data->fw =3D rpi_firmware_get(fw_node); > >+ of_node_put(fw_node); > >+ if (!data->fw) > >+ return -EPROBE_DEFER; > >+ > >+ ret =3D rpi_firmware_property(data->fw, RPI_FIRMWARE_GET_THROTTLED, > >+ &data->last_throttled, > >+ sizeof(data->last_throttled)); > >+ if (ret) { > >+ dev_info(dev, "Firmware doesn't support GET_THROTTLED\n"); > >+ return -EOPNOTSUPP; > >+ } > >+ > >+ data->hwmon_dev =3D devm_hwmon_device_register_with_info(dev, "rpi_vol= t", > >+ 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 =3D platform_get_drvdata(pdev); > >+ > >+ cancel_delayed_work_sync(&data->get_values_poll_work); > >+ > >+ return 0; > >+} > >+ > >+static const struct of_device_id rpi_hwmon_of_match[] =3D { > >+ { .compatible =3D "raspberrypi,bcm2835-hwmon", }, > >+ { /* sentinel */}, > >+}; > >+MODULE_DEVICE_TABLE(of, rpi_hwmon_of_match); > >+ > >+static struct platform_driver rpi_hwmon_driver =3D { > >+ .probe =3D rpi_hwmon_probe, > >+ .remove =3D rpi_hwmon_remove, > >+ .driver =3D { > >+ .name =3D "raspberrypi-hwmon", > >+ .of_match_table =3D rpi_hwmon_of_match, > >+ }, > >+}; > >+module_platform_driver(rpi_hwmon_driver); > >+ > >+MODULE_AUTHOR("Stefan Wahren "); > >+MODULE_DESCRIPTION("Raspberry Pi voltage sensor driver"); > >+MODULE_LICENSE("GPL v2"); > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html