Message-ID: <4cb98266-6936-7668-fc88-199ac907b437@broadcom.com>
Date:   Tue, 26 Sep 2017 14:32:47 -0700
From:   Scott Branden <scott.branden@...adcom.com>
To:     Markus Mayer <code@...yer.net>, Zhang Rui <rui.zhang@...el.com>,
        Eduardo Valentin <edubezval@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Doug Berger <opendmb@...il.com>,
        Brian Norris <computersforpeace@...il.com>,
        Gregory Fong <gregory.0xf0@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Rafał Miłecki <rafal@...ecki.pl>
Cc:     Broadcom Kernel List <bcm-kernel-feedback-list@...adcom.com>,
        Power Management List <linux-pm@...r.kernel.org>,
        Device Tree List <devicetree@...r.kernel.org>,
        ARM Kernel List <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Markus Mayer <mmayer@...adcom.com>
Subject: Re: [PATCH v5 2/2] thermal: add brcmstb AVS TMON driver

Hi Markus,


On 17-09-26 02:27 PM, Markus Mayer wrote:
> From: Brian Norris <computersforpeace@...il.com>
>
> 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@...il.com>
> Signed-off-by: Doug Berger <opendmb@...il.com>
> Signed-off-by: Markus Mayer <mmayer@...adcom.com>
> ---
>   drivers/thermal/Kconfig                    |   2 +-
>   drivers/thermal/broadcom/Kconfig           |   7 +
>   drivers/thermal/broadcom/Makefile          |   1 +
>   drivers/thermal/broadcom/brcmstb_thermal.c | 387 +++++++++++++++++++++++++++++
>   4 files changed, 396 insertions(+), 1 deletion(-)
>   create mode 100644 drivers/thermal/broadcom/brcmstb_thermal.c
>
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index 07002df..96774a7 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -408,7 +408,7 @@ config MTK_THERMAL
>   	  controller present in Mediatek SoCs
>   
>   menu "Broadcom thermal drivers"
> -depends on ARCH_BCM || COMPILE_TEST
> +depends on ARCH_BCM || ARCH_BRCMSTB || COMPILE_TEST
No need for this additional depends.  ARCH_BCM is always defined before 
ARCH_BRCMSTB can be selected.
>   source "drivers/thermal/broadcom/Kconfig"
>   endmenu
>   
> diff --git a/drivers/thermal/broadcom/Kconfig b/drivers/thermal/broadcom/Kconfig
> index 42c098e..c106a15 100644
> --- a/drivers/thermal/broadcom/Kconfig
> +++ b/drivers/thermal/broadcom/Kconfig
> @@ -6,6 +6,13 @@ config BCM2835_THERMAL
>   	help
>   	  Support for thermal sensors on Broadcom bcm2835 SoCs.
>   
> +config BRCMSTB_THERMAL
> +	tristate "Broadcom STB AVS TMON thermal driver"
> +	depends on ARCH_BRCMSTB || COMPILE_TEST
> +	help
> +	  Enable this driver if you have a Broadcom STB SoC and would like
> +	  thermal framework support.
> +
>   config BCM_NS_THERMAL
>   	tristate "Northstar thermal driver"
>   	depends on ARCH_BCM_IPROC || COMPILE_TEST
> diff --git a/drivers/thermal/broadcom/Makefile b/drivers/thermal/broadcom/Makefile
> index c6f62e4..fae10ec 100644
> --- a/drivers/thermal/broadcom/Makefile
> +++ b/drivers/thermal/broadcom/Makefile
> @@ -1,2 +1,3 @@
>   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/brcmstb_thermal.c b/drivers/thermal/broadcom/brcmstb_thermal.c
> new file mode 100644
> index 0000000..1919f91
> --- /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");

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