--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * rpi-poe-power.c - Raspberry Pi PoE+ HAT power supply driver.
+ *
+ * Copyright (C) 2019 Raspberry Pi (Trading) Ltd.
+ * Based on axp20x_ac_power.c by Quentin Schulz <quentin.schulz@free-electrons.com>
+ *
+ * Author: Serge Schneider <serge@raspberrypi.org>
+ */
+
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
+#define RPI_POE_ADC_REG 0x2
+#define RPI_POE_FLAG_REG 0x4
+
+#define RPI_POE_FLAG_AT BIT(0)
+#define RPI_POE_FLAG_OC BIT(1)
+
+#define RPI_POE_CURRENT_AF_MAX (2500 * 1000)
+#define RPI_POE_CURRENT_AT_MAX (5000 * 1000)
+
+#define DRVNAME "rpi-poe-power-supply"
+
+struct rpi_poe_power_supply_ctx {
+ struct power_supply *supply;
+ struct rpi_firmware *fw;
+};
+
+struct fw_tag_data_s {
+ u32 reg;
+ u32 val;
+ u32 ret;
+};
+
+static int write_reg(struct rpi_firmware *fw, u32 reg, u32 *val)
+{
+ struct fw_tag_data_s fw_tag_data = {
+ .reg = reg,
+ .val = *val
+ };
+ int ret;
+
+ ret = rpi_firmware_property(fw, RPI_FIRMWARE_SET_POE_HAT_VAL,
+ &fw_tag_data, sizeof(fw_tag_data));
+ if (ret)
+ return ret;
+ else if (fw_tag_data.ret)
+ return -EIO;
+ return 0;
+}
+
+static int read_reg(struct rpi_firmware *fw, u32 reg, u32 *val)
+{
+ struct fw_tag_data_s fw_tag_data = {
+ .reg = reg,
+ .val = *val
+ };
+ int ret;
+
+ ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_POE_HAT_VAL,
+ &fw_tag_data, sizeof(fw_tag_data));
+ if (ret)
+ return ret;
+ else if (fw_tag_data.ret)
+ return -EIO;
+
+ *val = fw_tag_data.val;
+ return 0;
+}
+
+static int rpi_poe_power_supply_get_property(struct power_supply *psy,
+ enum power_supply_property psp,
+ union power_supply_propval *r_val)
+{
+ struct rpi_poe_power_supply_ctx *ctx = power_supply_get_drvdata(psy);
+ int ret;
+ unsigned int val = 0;
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_HEALTH:
+ ret = read_reg(ctx->fw, RPI_POE_FLAG_REG, &val);
+ if (ret)
+ return ret;
+
+ if (val & RPI_POE_FLAG_OC) {
+ r_val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+ val = RPI_POE_FLAG_OC;
+ ret = write_reg(ctx->fw, RPI_POE_FLAG_REG, &val);
+ if (ret)
+ return ret;
+ return 0;
+ }
+
+ r_val->intval = POWER_SUPPLY_HEALTH_GOOD;
+ return 0;
+
+ case POWER_SUPPLY_PROP_ONLINE:
+ ret = read_reg(ctx->fw, RPI_POE_ADC_REG, &val);
+ if (ret)
+ return ret;
+
+ r_val->intval = (val > 5);
+ return 0;
+
+ case POWER_SUPPLY_PROP_CURRENT_AVG:
+ val = 50;
+ ret = read_reg(ctx->fw, RPI_POE_ADC_REG, &val);
+ if (ret)
+ return ret;
+ val = (val * 3300)/9821;
+ r_val->intval = val * 1000;
+ return 0;
+
+ case POWER_SUPPLY_PROP_CURRENT_NOW:
+ ret = read_reg(ctx->fw, RPI_POE_ADC_REG, &val);
+ if (ret)
+ return ret;
+ val = (val * 3300)/9821;
+ r_val->intval = val * 1000;
+ return 0;
+
+ case POWER_SUPPLY_PROP_CURRENT_MAX:
+ ret = read_reg(ctx->fw, RPI_POE_FLAG_REG, &val);
+ if (ret)
+ return ret;
+
+ if (val & RPI_POE_FLAG_AT) {
+ r_val->intval = RPI_POE_CURRENT_AT_MAX;
+ return 0;
+ }
+ r_val->intval = RPI_POE_CURRENT_AF_MAX;
+ return 0;
+
+ default:
+ return -EINVAL;
+ }
+
+ return -EINVAL;
+}
+
+static enum power_supply_property rpi_poe_power_supply_properties[] = {
+ POWER_SUPPLY_PROP_HEALTH,
+ POWER_SUPPLY_PROP_ONLINE,
+ POWER_SUPPLY_PROP_CURRENT_AVG,
+ POWER_SUPPLY_PROP_CURRENT_NOW,
+ POWER_SUPPLY_PROP_CURRENT_MAX,
+};
+
+static const struct power_supply_desc rpi_poe_power_supply_desc = {
+ .name = "rpi-poe",
+ .type = POWER_SUPPLY_TYPE_MAINS,
+ .properties = rpi_poe_power_supply_properties,
+ .num_properties = ARRAY_SIZE(rpi_poe_power_supply_properties),
+ .get_property = rpi_poe_power_supply_get_property,
+};
+
+static int rpi_poe_power_supply_probe(struct platform_device *pdev)
+{
+ struct power_supply_config psy_cfg = {};
+ struct rpi_poe_power_supply_ctx *ctx;
+ struct device_node *fw_node;
+ u32 revision;
+
+ if (!of_device_is_available(pdev->dev.of_node))
+ return -ENODEV;
+
+ fw_node = of_parse_phandle(pdev->dev.of_node, "firmware", 0);
+ if (!fw_node) {
+ dev_err(&pdev->dev, "Missing firmware node\n");
+ return -ENOENT;
+ }
+
+ ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+
+ ctx->fw = rpi_firmware_get(fw_node);
+ if (!ctx->fw)
+ return -EPROBE_DEFER;
+ if (rpi_firmware_property(ctx->fw,
+ RPI_FIRMWARE_GET_FIRMWARE_REVISION,
+ &revision, sizeof(revision))) {
+ dev_err(&pdev->dev, "Failed to get firmware revision\n");
+ return -ENOENT;
+ }
+ if (revision < 0x60af72e8) {
+ dev_err(&pdev->dev, "Unsupported firmware\n");
+ return -ENOENT;
+ }
+ platform_set_drvdata(pdev, ctx);
+
+ psy_cfg.of_node = pdev->dev.of_node;
+ psy_cfg.drv_data = ctx;
+
+ ctx->supply = devm_power_supply_register(&pdev->dev,
+ &rpi_poe_power_supply_desc,
+ &psy_cfg);
+ if (IS_ERR(ctx->supply))
+ return PTR_ERR(ctx->supply);
+
+ return 0;
+}
+
+static const struct of_device_id of_rpi_poe_power_supply_match[] = {
+ { .compatible = "raspberrypi,rpi-poe-power-supply", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, of_rpi_poe_power_supply_match);
+
+static struct platform_driver rpi_poe_power_supply_driver = {
+ .probe = rpi_poe_power_supply_probe,
+ .driver = {
+ .name = DRVNAME,
+ .of_match_table = of_rpi_poe_power_supply_match
+ },
+};
+
+module_platform_driver(rpi_poe_power_supply_driver);
+
+MODULE_AUTHOR("Serge Schneider <serge@raspberrypi.org>");
+MODULE_ALIAS("platform:" DRVNAME);
+MODULE_DESCRIPTION("Raspberry Pi PoE+ HAT power supply driver");
+MODULE_LICENSE("GPL");