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 remote > >Raspberry Pi. This hwmon driver retrieves the state of the under-voltage > >sensor > >via mailbox interface. The handling based on Noralf's modifications to the > >downstream firmware driver. In case of an under-voltage condition only an > >entry > >is written to the kernel log. > > > >CC: "Noralf Trønnes" <[email protected]> > >Signed-off-by: Stefan Wahren <[email protected]> > >--- > > 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=y combined with RASPBERRYPI_FIRMWARE=m, 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-$(CONFIG_SENSORS_PC87427) += pc87427.o > > obj-$(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 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 Trønnes > >+ * > >+ * Copyright (C) 2018 Stefan Wahren <[email protected]> > >+ */ > >+#include <linux/device.h> > >+#include <linux/err.h> > >+#include <linux/hwmon.h> > >+#include <linux/hwmon-sysfs.h> > >+#include <linux/module.h> > >+#include <linux/of_device.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; > >+ > >+ /* 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, "%s: Failed to get throttled > >(%d)\n", > >+ __func__, 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, "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 = 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); > >+ > >+ if (type != hwmon_in) > >+ return -EOPNOTSUPP; > >+ > >+ if (attr != hwmon_in_lcrit_alarm) > >+ return -EOPNOTSUPP; > >+ > >+ if (channel) > >+ return -EOPNOTSUPP; > >+ > >+ *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) > >+{ > >+ if (type != hwmon_in) > >+ return 0; > >+ > >+ if (attr != hwmon_in_lcrit_alarm) > >+ return 0; > >+ > >+ if (channel) > >+ return 0; > >+ > >+ 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 device_node *fw_node; > >+ struct rpi_hwmon_data *data; > >+ int ret; > >+ > >+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); > >+ if (!data) > >+ return -ENOMEM; > >+ > >+ fw_node = of_get_parent(dev->of_node); > >+ if (!fw_node) { > >+ dev_err(dev, "Missing firmware node\n"); > >+ return -ENOENT; > >+ } > >+ > >+ data->fw = rpi_firmware_get(fw_node); > >+ of_node_put(fw_node); > >+ if (!data->fw) > >+ return -EPROBE_DEFER; > >+ > >+ ret = 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 = 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 const struct of_device_id rpi_hwmon_of_match[] = { > >+ { .compatible = "raspberrypi,bcm2835-hwmon", }, > >+ { /* sentinel */}, > >+}; > >+MODULE_DEVICE_TABLE(of, rpi_hwmon_of_match); > >+ > >+static struct platform_driver rpi_hwmon_driver = { > >+ .probe = rpi_hwmon_probe, > >+ .remove = rpi_hwmon_remove, > >+ .driver = { > >+ .name = "raspberrypi-hwmon", > >+ .of_match_table = rpi_hwmon_of_match, > >+ }, > >+}; > >+module_platform_driver(rpi_hwmon_driver); > >+ > >+MODULE_AUTHOR("Stefan Wahren <[email protected]>"); > >+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 [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
