thermal: add brcmstb AVS TMON driver

The AVS TMON core provides temperature readings, a pair of configurable
high- and low-temperature threshold interrupts, and an emergency
over-temperature chip reset. The driver utilizes the first two to
provide temperature readings and high-temperature notifications to
applications. The over-temperature reset is not exposed to
applications; this reset threshold is critical to the system and should
be set with care within the bootloader.

Applications may choose to utilize the notification mechanism, the
temperature reading mechanism (e.g., through polling), or both.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: Markus Mayer <mmayer@broadcom.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>

1 files changed, 387 insertions, 0 deletions

diff --git a/drivers/thermal/broadcom/brcmstb_thermal.c b/drivers/thermal/broadcom/brcmstb_thermal.c
new file mode 100644
index 000000000000..1919f91fa756
--- /dev/null
+++ b/drivers/thermal/broadcom/brcmstb_thermal.c
@@ -0,0 +1,387 @@
+/*
+ * Broadcom STB AVS TMON thermal sensor driver
+ *
+ * Copyright (c) 2015-2017 Broadcom
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#define DRV_NAME	"brcmstb_thermal"
+
+#define pr_fmt(fmt)	DRV_NAME ": " fmt
+
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/irqreturn.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/of_device.h>
+#include <linux/thermal.h>
+
+#define AVS_TMON_STATUS			0x00
+ #define AVS_TMON_STATUS_valid_msk	BIT(11)
+ #define AVS_TMON_STATUS_data_msk	GENMASK(10, 1)
+ #define AVS_TMON_STATUS_data_shift	1
+
+#define AVS_TMON_EN_OVERTEMP_RESET	0x04
+ #define AVS_TMON_EN_OVERTEMP_RESET_msk	BIT(0)
+
+#define AVS_TMON_RESET_THRESH		0x08
+ #define AVS_TMON_RESET_THRESH_msk	GENMASK(10, 1)
+ #define AVS_TMON_RESET_THRESH_shift	1
+
+#define AVS_TMON_INT_IDLE_TIME		0x10
+
+#define AVS_TMON_EN_TEMP_INT_SRCS	0x14
+ #define AVS_TMON_EN_TEMP_INT_SRCS_high	BIT(1)
+ #define AVS_TMON_EN_TEMP_INT_SRCS_low	BIT(0)
+
+#define AVS_TMON_INT_THRESH		0x18
+ #define AVS_TMON_INT_THRESH_high_msk	GENMASK(26, 17)
+ #define AVS_TMON_INT_THRESH_high_shift	17
+ #define AVS_TMON_INT_THRESH_low_msk	GENMASK(10, 1)
+ #define AVS_TMON_INT_THRESH_low_shift	1
+
+#define AVS_TMON_TEMP_INT_CODE		0x1c
+#define AVS_TMON_TP_TEST_ENABLE		0x20
+
+/* Default coefficients */
+#define AVS_TMON_TEMP_SLOPE		-487
+#define AVS_TMON_TEMP_OFFSET		410040
+
+/* HW related temperature constants */
+#define AVS_TMON_TEMP_MAX		0x3ff
+#define AVS_TMON_TEMP_MIN		-88161
+#define AVS_TMON_TEMP_MASK		AVS_TMON_TEMP_MAX
+
+enum avs_tmon_trip_type {
+	TMON_TRIP_TYPE_LOW = 0,
+	TMON_TRIP_TYPE_HIGH,
+	TMON_TRIP_TYPE_RESET,
+	TMON_TRIP_TYPE_MAX,
+};
+
+struct avs_tmon_trip {
+	/* HW bit to enable the trip */
+	u32 enable_offs;
+	u32 enable_mask;
+
+	/* HW field to read the trip temperature */
+	u32 reg_offs;
+	u32 reg_msk;
+	int reg_shift;
+};
+
+static struct avs_tmon_trip avs_tmon_trips[] = {
+	/* Trips when temperature is below threshold */
+	[TMON_TRIP_TYPE_LOW] = {
+		.enable_offs	= AVS_TMON_EN_TEMP_INT_SRCS,
+		.enable_mask	= AVS_TMON_EN_TEMP_INT_SRCS_low,
+		.reg_offs	= AVS_TMON_INT_THRESH,
+		.reg_msk	= AVS_TMON_INT_THRESH_low_msk,
+		.reg_shift	= AVS_TMON_INT_THRESH_low_shift,
+	},
+	/* Trips when temperature is above threshold */
+	[TMON_TRIP_TYPE_HIGH] = {
+		.enable_offs	= AVS_TMON_EN_TEMP_INT_SRCS,
+		.enable_mask	= AVS_TMON_EN_TEMP_INT_SRCS_high,
+		.reg_offs	= AVS_TMON_INT_THRESH,
+		.reg_msk	= AVS_TMON_INT_THRESH_high_msk,
+		.reg_shift	= AVS_TMON_INT_THRESH_high_shift,
+	},
+	/* Automatically resets chip when above threshold */
+	[TMON_TRIP_TYPE_RESET] = {
+		.enable_offs	= AVS_TMON_EN_OVERTEMP_RESET,
+		.enable_mask	= AVS_TMON_EN_OVERTEMP_RESET_msk,
+		.reg_offs	= AVS_TMON_RESET_THRESH,
+		.reg_msk	= AVS_TMON_RESET_THRESH_msk,
+		.reg_shift	= AVS_TMON_RESET_THRESH_shift,
+	},
+};
+
+struct brcmstb_thermal_priv {
+	void __iomem *tmon_base;
+	struct device *dev;
+	struct thermal_zone_device *thermal;
+};
+
+static void avs_tmon_get_coeffs(struct thermal_zone_device *tz, int *slope,
+				int *offset)
+{
+	*slope = thermal_zone_get_slope(tz);
+	*offset = thermal_zone_get_offset(tz);
+}
+
+/* Convert a HW code to a temperature reading (millidegree celsius) */
+static inline int avs_tmon_code_to_temp(struct thermal_zone_device *tz,
+					u32 code)
+{
+	const int val = code & AVS_TMON_TEMP_MASK;
+	int slope, offset;
+
+	avs_tmon_get_coeffs(tz, &slope, &offset);
+
+	return slope * val + offset;
+}
+
+/*
+ * Convert a temperature value (millidegree celsius) to a HW code
+ *
+ * @temp: temperature to convert
+ * @low: if true, round toward the low side
+ */
+static inline u32 avs_tmon_temp_to_code(struct thermal_zone_device *tz,
+					int temp, bool low)
+{
+	int slope, offset;
+
+	if (temp < AVS_TMON_TEMP_MIN)
+		return AVS_TMON_TEMP_MAX; /* Maximum code value */
+
+	avs_tmon_get_coeffs(tz, &slope, &offset);
+
+	if (temp >= offset)
+		return 0;	/* Minimum code value */
+
+	if (low)
+		return (u32)(DIV_ROUND_UP(offset - temp, abs(slope)));
+	else
+		return (u32)((offset - temp) / abs(slope));
+}
+
+static int brcmstb_get_temp(void *data, int *temp)
+{
+	struct brcmstb_thermal_priv *priv = data;
+	u32 val;
+	long t;
+
+	val = __raw_readl(priv->tmon_base + AVS_TMON_STATUS);
+
+	if (!(val & AVS_TMON_STATUS_valid_msk)) {
+		dev_err(priv->dev, "reading not valid\n");
+		return -EIO;
+	}
+
+	val = (val & AVS_TMON_STATUS_data_msk) >> AVS_TMON_STATUS_data_shift;
+
+	t = avs_tmon_code_to_temp(priv->thermal, val);
+	if (t < 0)
+		*temp = 0;
+	else
+		*temp = t;
+
+	return 0;
+}
+
+static void avs_tmon_trip_enable(struct brcmstb_thermal_priv *priv,
+				 enum avs_tmon_trip_type type, int en)
+{
+	struct avs_tmon_trip *trip = &avs_tmon_trips[type];
+	u32 val = __raw_readl(priv->tmon_base + trip->enable_offs);
+
+	dev_dbg(priv->dev, "%sable trip, type %d\n", en ? "en" : "dis", type);
+
+	if (en)
+		val |= trip->enable_mask;
+	else
+		val &= ~trip->enable_mask;
+
+	__raw_writel(val, priv->tmon_base + trip->enable_offs);
+}
+
+static int avs_tmon_get_trip_temp(struct brcmstb_thermal_priv *priv,
+				  enum avs_tmon_trip_type type)
+{
+	struct avs_tmon_trip *trip = &avs_tmon_trips[type];
+	u32 val = __raw_readl(priv->tmon_base + trip->reg_offs);
+
+	val &= trip->reg_msk;
+	val >>= trip->reg_shift;
+
+	return avs_tmon_code_to_temp(priv->thermal, val);
+}
+
+static void avs_tmon_set_trip_temp(struct brcmstb_thermal_priv *priv,
+				   enum avs_tmon_trip_type type,
+				   int temp)
+{
+	struct avs_tmon_trip *trip = &avs_tmon_trips[type];
+	u32 val, orig;
+
+	dev_dbg(priv->dev, "set temp %d to %d\n", type, temp);
+
+	/* round toward low temp for the low interrupt */
+	val = avs_tmon_temp_to_code(priv->thermal, temp,
+				    type == TMON_TRIP_TYPE_LOW);
+
+	val <<= trip->reg_shift;
+	val &= trip->reg_msk;
+
+	orig = __raw_readl(priv->tmon_base + trip->reg_offs);
+	orig &= ~trip->reg_msk;
+	orig |= val;
+	__raw_writel(orig, priv->tmon_base + trip->reg_offs);
+}
+
+static int avs_tmon_get_intr_temp(struct brcmstb_thermal_priv *priv)
+{
+	u32 val;
+
+	val = __raw_readl(priv->tmon_base + AVS_TMON_TEMP_INT_CODE);
+	return avs_tmon_code_to_temp(priv->thermal, val);
+}
+
+static irqreturn_t brcmstb_tmon_irq_thread(int irq, void *data)
+{
+	struct brcmstb_thermal_priv *priv = data;
+	int low, high, intr;
+
+	low = avs_tmon_get_trip_temp(priv, TMON_TRIP_TYPE_LOW);
+	high = avs_tmon_get_trip_temp(priv, TMON_TRIP_TYPE_HIGH);
+	intr = avs_tmon_get_intr_temp(priv);
+
+	dev_dbg(priv->dev, "low/intr/high: %d/%d/%d\n",
+			low, intr, high);
+
+	/* Disable high-temp until next threshold shift */
+	if (intr >= high)
+		avs_tmon_trip_enable(priv, TMON_TRIP_TYPE_HIGH, 0);
+	/* Disable low-temp until next threshold shift */
+	if (intr <= low)
+		avs_tmon_trip_enable(priv, TMON_TRIP_TYPE_LOW, 0);
+
+	/*
+	 * Notify using the interrupt temperature, in case the temperature
+	 * changes before it can next be read out
+	 */
+	thermal_zone_device_update(priv->thermal, intr);
+
+	return IRQ_HANDLED;
+}
+
+static int brcmstb_set_trips(void *data, int low, int high)
+{
+	struct brcmstb_thermal_priv *priv = data;
+
+	dev_dbg(priv->dev, "set trips %d <--> %d\n", low, high);
+
+	/*
+	 * Disable low-temp if "low" is too small. As per thermal framework
+	 * API, we use -INT_MAX rather than INT_MIN.
+	 */
+	if (low <= -INT_MAX) {
+		avs_tmon_trip_enable(priv, TMON_TRIP_TYPE_LOW, 0);
+	} else {
+		avs_tmon_set_trip_temp(priv, TMON_TRIP_TYPE_LOW, low);
+		avs_tmon_trip_enable(priv, TMON_TRIP_TYPE_LOW, 1);
+	}
+
+	/* Disable high-temp if "high" is too big. */
+	if (high == INT_MAX) {
+		avs_tmon_trip_enable(priv, TMON_TRIP_TYPE_HIGH, 0);
+	} else {
+		avs_tmon_set_trip_temp(priv, TMON_TRIP_TYPE_HIGH, high);
+		avs_tmon_trip_enable(priv, TMON_TRIP_TYPE_HIGH, 1);
+	}
+
+	return 0;
+}
+
+static struct thermal_zone_of_device_ops of_ops = {
+	.get_temp	= brcmstb_get_temp,
+	.set_trips	= brcmstb_set_trips,
+};
+
+static const struct of_device_id brcmstb_thermal_id_table[] = {
+	{ .compatible = "brcm,avs-tmon" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, brcmstb_thermal_id_table);
+
+static int brcmstb_thermal_probe(struct platform_device *pdev)
+{
+	struct thermal_zone_device *thermal;
+	struct brcmstb_thermal_priv *priv;
+	struct resource *res;
+	int irq, ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->tmon_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(priv->tmon_base))
+		return PTR_ERR(priv->tmon_base);
+
+	priv->dev = &pdev->dev;
+	platform_set_drvdata(pdev, priv);
+
+	thermal = thermal_zone_of_sensor_register(&pdev->dev, 0, priv, &of_ops);
+	if (IS_ERR(thermal)) {
+		ret = PTR_ERR(thermal);
+		dev_err(&pdev->dev, "could not register sensor: %d\n", ret);
+		return ret;
+	}
+
+	priv->thermal = thermal;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "could not get IRQ\n");
+		ret = irq;
+		goto err;
+	}
+	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+					brcmstb_tmon_irq_thread, IRQF_ONESHOT,
+					DRV_NAME, priv);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "could not request IRQ: %d\n", ret);
+		goto err;
+	}
+
+	dev_info(&pdev->dev, "registered AVS TMON of-sensor driver\n");
+
+	return 0;
+
+err:
+	thermal_zone_of_sensor_unregister(&pdev->dev, thermal);
+	return ret;
+}
+
+static int brcmstb_thermal_exit(struct platform_device *pdev)
+{
+	struct brcmstb_thermal_priv *priv = platform_get_drvdata(pdev);
+	struct thermal_zone_device *thermal = priv->thermal;
+
+	if (thermal)
+		thermal_zone_of_sensor_unregister(&pdev->dev, priv->thermal);
+
+	return 0;
+}
+
+static struct platform_driver brcmstb_thermal_driver = {
+	.probe = brcmstb_thermal_probe,
+	.remove = brcmstb_thermal_exit,
+	.driver = {
+		.name = DRV_NAME,
+		.of_match_table = brcmstb_thermal_id_table,
+	},
+};
+module_platform_driver(brcmstb_thermal_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Brian Norris");
+MODULE_DESCRIPTION("Broadcom STB AVS TMON thermal driver");