Add Raspberry Pi PoE+ HAT support

Signed-off-by: Serge Schneider <serge@raspberrypi.com>

diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index a61bb12..641e1c0 100644 (file)
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -28,6 +28,13 @@ config POWER_SUPPLY_HWMON
          Say 'Y' here if you want power supplies to
          have hwmon sysfs interface too.
 
+config RPI_POE_POWER
+       tristate "Raspberry Pi PoE+ HAT power supply driver"
+       depends on RASPBERRYPI_FIRMWARE
+       help
+         Say Y here to enable support for Raspberry Pi PoE+ (Power over Ethernet
+         Plus) HAT current measurement.
+
 config APM_POWER
        tristate "APM emulation for class batteries"
        depends on APM_EMULATION

diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index a8a9fa6..d7d78b7 100644 (file)
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_POWER_SUPPLY)      += power_supply.o
 obj-$(CONFIG_POWER_SUPPLY_HWMON) += power_supply_hwmon.o
 obj-$(CONFIG_GENERIC_ADC_BATTERY)      += generic-adc-battery.o
 
+obj-$(CONFIG_RPI_POE_POWER)    += rpi_poe_power.o
 obj-$(CONFIG_APM_POWER)                += apm_power.o
 obj-$(CONFIG_AXP20X_POWER)     += axp20x_usb_power.o
 obj-$(CONFIG_IP5XXX_POWER)     += ip5xxx_power.o

diff --git a/drivers/power/supply/rpi_poe_power.c b/drivers/power/supply/rpi_poe_power.c
new file mode 100644 (file)
index 0000000..0c96b2c
--- /dev/null
+++ b/drivers/power/supply/rpi_poe_power.c
@@ -0,0 +1,227 @@
+// 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");