[PATCH 2/4] thermal: Add BCM2711 thermal driver

[Stefan Wahren <wahrenst@gmx.net>]

This adds the thermal sensor driver for the Broadcom BCM2711 SoC,
which is placed on the Raspberry Pi 4. The driver only provides
SoC temperature reading so far.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
---
 drivers/thermal/broadcom/Kconfig           |   8 ++
 drivers/thermal/broadcom/Makefile          |   1 +
 drivers/thermal/broadcom/bcm2711_thermal.c | 146 +++++++++++++++++++++++++++++
 3 files changed, 155 insertions(+)
 create mode 100644 drivers/thermal/broadcom/bcm2711_thermal.c

diff --git a/drivers/thermal/broadcom/Kconfig b/drivers/thermal/broadcom/Kconfig
index cf43e15..b970295 100644
--- a/drivers/thermal/broadcom/Kconfig
+++ b/drivers/thermal/broadcom/Kconfig
@@ -1,4 +1,12 @@
 # SPDX-License-Identifier: GPL-2.0-only
+config BCM2711_THERMAL
+	tristate "Broadcom AVS RO thermal sensor driver"
+	depends on ARCH_BCM2835 || COMPILE_TEST
+	depends on HAS_IOMEM
+	depends on THERMAL_OF
+	help
+	  Support for thermal sensors on Broadcom BCM2711 SoCs.
+
 config BCM2835_THERMAL
 	tristate "Thermal sensors on bcm2835 SoC"
 	depends on ARCH_BCM2835 || COMPILE_TEST
diff --git a/drivers/thermal/broadcom/Makefile b/drivers/thermal/broadcom/Makefile
index 490ab1f..c917b24 100644
--- a/drivers/thermal/broadcom/Makefile
+++ b/drivers/thermal/broadcom/Makefile
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_BCM2711_THERMAL)		+= bcm2711_thermal.o
 obj-$(CONFIG_BCM2835_THERMAL)		+= bcm2835_thermal.o
 obj-$(CONFIG_BRCMSTB_THERMAL)		+= brcmstb_thermal.o
 obj-$(CONFIG_BCM_NS_THERMAL)		+= ns-thermal.o
diff --git a/drivers/thermal/broadcom/bcm2711_thermal.c b/drivers/thermal/broadcom/bcm2711_thermal.c
new file mode 100644
index 0000000..214a305
--- /dev/null
+++ b/drivers/thermal/broadcom/bcm2711_thermal.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Broadcom AVS RO thermal sensor driver
+ *
+ * based on brcmstb_thermal
+ *
+ * Copyright (C) 2019 Stefan Wahren
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/of_device.h>
+#include <linux/thermal.h>
+
+#include "../thermal_hwmon.h"
+
+#define AVS_RO_TEMP_STATUS		0x00
+ #define AVS_RO_TEMP_STATUS_valid_msk	(BIT(16) | BIT(10))
+ #define AVS_RO_TEMP_STATUS_data_msk	GENMASK(9, 0)
+
+struct bcm2711_thermal_priv {
+	void __iomem *base;
+	struct device *dev;
+	struct clk *clk;
+	struct thermal_zone_device *thermal;
+};
+
+static int bcm2711_get_temp(void *data, int *temp)
+{
+	struct bcm2711_thermal_priv *priv = data;
+	int slope = thermal_zone_get_slope(priv->thermal);
+	int offset = thermal_zone_get_offset(priv->thermal);
+	u32 val;
+	long t;
+
+	val = __raw_readl(priv->base + AVS_RO_TEMP_STATUS);
+
+	if (!(val & AVS_RO_TEMP_STATUS_valid_msk)) {
+		dev_err(priv->dev, "reading not valid\n");
+		return -EIO;
+	}
+
+	val &= AVS_RO_TEMP_STATUS_data_msk;
+
+	/* Convert a HW code to a temperature reading (millidegree celsius) */
+	t = slope * val + offset;
+	if (t < 0)
+		*temp = 0;
+	else
+		*temp = t;
+
+	return 0;
+}
+
+static const struct thermal_zone_of_device_ops bcm2711_thermal_of_ops = {
+	.get_temp	= bcm2711_get_temp,
+};
+
+static const struct of_device_id bcm2711_thermal_id_table[] = {
+	{ .compatible = "brcm,bcm2711-thermal" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, bcm2711_thermal_id_table);
+
+static int bcm2711_thermal_probe(struct platform_device *pdev)
+{
+	struct thermal_zone_device *thermal;
+	struct bcm2711_thermal_priv *priv;
+	struct resource *res;
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	priv->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(priv->clk)) {
+		ret = PTR_ERR(priv->clk);
+		if (ret != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "could not get clk: %d\n", ret);
+		return ret;
+	}
+
+	ret = clk_prepare_enable(priv->clk);
+	if (ret)
+		return ret;
+
+	priv->dev = &pdev->dev;
+	platform_set_drvdata(pdev, priv);
+
+	thermal = devm_thermal_zone_of_sensor_register(&pdev->dev, 0, priv,
+						       &bcm2711_thermal_of_ops);
+	if (IS_ERR(thermal)) {
+		ret = PTR_ERR(thermal);
+		dev_err(&pdev->dev, "could not register sensor: %d\n", ret);
+		goto err_clk;
+	}
+
+	priv->thermal = thermal;
+
+	thermal->tzp->no_hwmon = false;
+	ret = thermal_add_hwmon_sysfs(thermal);
+	if (ret)
+		return ret;
+
+	return 0;
+
+err_clk:
+	clk_disable_unprepare(priv->clk);
+
+	return ret;
+}
+
+static int bcm2711_thermal_remove(struct platform_device *pdev)
+{
+	struct bcm2711_thermal_priv *priv = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(priv->clk);
+
+	return 0;
+}
+
+static struct platform_driver bcm2711_thermal_driver = {
+	.probe = bcm2711_thermal_probe,
+	.remove = bcm2711_thermal_remove,
+	.driver = {
+		.name = "bcm2711_thermal",
+		.of_match_table = bcm2711_thermal_id_table,
+	},
+};
+module_platform_driver(bcm2711_thermal_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Stefan Wahren");
+MODULE_DESCRIPTION("Broadcom AVS RO thermal sensor driver");
--
2.7.4


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