Date:   Mon, 24 Jun 2019 14:07:32 +0200
From:   Ondřej Jirman <megous@...ous.com>
To:     Yangtao Li <tiny.windzz@...il.com>
Cc:     rui.zhang@...el.com, edubezval@...il.com,
        daniel.lezcano@...aro.org, robh+dt@...nel.org,
        mark.rutland@....com, maxime.ripard@...tlin.com, wens@...e.org,
        davem@...emloft.net, gregkh@...uxfoundation.org,
        mchehab+samsung@...nel.org, linus.walleij@...aro.org,
        nicolas.ferre@...rochip.com, paulmck@...ux.ibm.com,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH v4 01/11] thermal: sun8i: add thermal driver for h6

Hello Yangtao,

On Sun, Jun 23, 2019 at 12:41:56PM -0400, Yangtao Li wrote:
> This patch adds the support for allwinner thermal sensor, within
> allwinner SoC. It will register sensors for thermal framework
> and use device tree to bind cooling device.
> 
> Signed-off-by: Yangtao Li <tiny.windzz@...il.com>
> ---
>  MAINTAINERS                     |   7 +
>  drivers/thermal/Kconfig         |  14 ++
>  drivers/thermal/Makefile        |   1 +
>  drivers/thermal/sun8i_thermal.c | 405 ++++++++++++++++++++++++++++++++
>  4 files changed, 427 insertions(+)
>  create mode 100644 drivers/thermal/sun8i_thermal.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 36a84614d6c3..67e7fcfaded2 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -674,6 +674,13 @@ L:	linux-crypto@...r.kernel.org
>  S:	Maintained
>  F:	drivers/crypto/sunxi-ss/
>  
> +ALLWINNER THERMAL DRIVER
> +M:	Yangtao Li <tiny.windzz@...il.com>
> +L:	linux-pm@...r.kernel.org
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/thermal/sun8i-thermal.yaml
> +F:	drivers/thermal/sun8i_thermal.c
> +
>  ALLWINNER VPU DRIVER
>  M:	Maxime Ripard <maxime.ripard@...tlin.com>
>  M:	Paul Kocialkowski <paul.kocialkowski@...tlin.com>
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index 9966364a6deb..f8b73b32b92d 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -262,6 +262,20 @@ config SPEAR_THERMAL
>  	  Enable this to plug the SPEAr thermal sensor driver into the Linux
>  	  thermal framework.
>  
> +config SUN8I_THERMAL
> +	tristate "Allwinner sun8i thermal driver"
> +	depends on ARCH_SUNXI || COMPILE_TEST
> +	depends on HAS_IOMEM
> +	depends on NVMEM
> +	depends on OF
> +	depends on RESET_CONTROLLER
> +	help
> +	  Support for the sun8i thermal sensor driver into the Linux thermal
> +	  framework.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called sun8i-thermal.
> +
>  config ROCKCHIP_THERMAL
>  	tristate "Rockchip thermal driver"
>  	depends on ARCH_ROCKCHIP || COMPILE_TEST
> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
> index 74a37c7f847a..fa6f8b206281 100644
> --- a/drivers/thermal/Makefile
> +++ b/drivers/thermal/Makefile
> @@ -31,6 +31,7 @@ thermal_sys-$(CONFIG_DEVFREQ_THERMAL) += devfreq_cooling.o
>  obj-y				+= broadcom/
>  obj-$(CONFIG_THERMAL_MMIO)		+= thermal_mmio.o
>  obj-$(CONFIG_SPEAR_THERMAL)	+= spear_thermal.o
> +obj-$(CONFIG_SUN8I_THERMAL)     += sun8i_thermal.o
>  obj-$(CONFIG_ROCKCHIP_THERMAL)	+= rockchip_thermal.o
>  obj-$(CONFIG_RCAR_THERMAL)	+= rcar_thermal.o
>  obj-$(CONFIG_RCAR_GEN3_THERMAL)	+= rcar_gen3_thermal.o
> diff --git a/drivers/thermal/sun8i_thermal.c b/drivers/thermal/sun8i_thermal.c
> new file mode 100644
> index 000000000000..d6918c62682b
> --- /dev/null
> +++ b/drivers/thermal/sun8i_thermal.c
> @@ -0,0 +1,405 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Thermal sensor driver for Allwinner SOC
> + * Copyright (C) 2019 Yangtao Li
> + *
> + * Based on the work of Icenowy Zheng <icenowy@...c.io>
> + * Based on the work of Ondrej Jirman <megous@...ous.com>
> + * Based on the work of Josef Gajdusek <atx@....name>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/device.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/nvmem-consumer.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/reset.h>
> +#include <linux/slab.h>
> +#include <linux/thermal.h>
> +
> +#define MAX_SENSOR_NUM	4
> +
> +#define SUN50I_H6_SENSOR_NUM	2
> +#define SUN50I_H6_OFFSET	-2794
> +#define SUN50I_H6_SCALE		-67
> +
> +#define FT_TEMP_MASK				GENMASK(11, 0)
> +#define TEMP_CALIB_MASK				GENMASK(11, 0)
> +#define TEMP_TO_REG				672
> +#define CALIBRATE_DEFAULT			0x800
> +
> +#define SUN50I_THS_CTRL0			0x00
> +#define SUN50I_H6_THS_ENABLE			0x04
> +#define SUN50I_H6_THS_PC			0x08
> +#define SUN50I_H6_THS_DIC			0x10
> +#define SUN50I_H6_THS_DIS			0x20
> +#define SUN50I_H6_THS_MFC			0x30
> +#define SUN50I_H6_THS_TEMP_CALIB		0xa0
> +#define SUN50I_H6_THS_TEMP_DATA			0xc0
> +
> +#define SUN50I_THS_CTRL0_T_ACQ(x)		((GENMASK(15, 0) & (x)) << 16)
> +#define SUN50I_THS_FILTER_EN			BIT(2)
> +#define SUN50I_THS_FILTER_TYPE(x)		(GENMASK(1, 0) & (x))
> +#define SUN50I_H6_THS_PC_TEMP_PERIOD(x)		((GENMASK(19, 0) & (x)) << 12)
> +#define SUN50I_H6_THS_DATA_IRQ_STS(x)		BIT(x)
> +
> +/* millidegree celsius */
> +#define SUN50I_H6_FT_DEVIATION			7000
> +
> +struct ths_device;
> +
> +struct tsensor {
> +	struct ths_device		*tmdev;
> +	struct thermal_zone_device	*tzd;
> +	int				id;
> +};
> +
> +struct ths_device {
> +	struct device				*dev;
> +	struct regmap				*regmap;
> +	struct reset_control			*reset;
> +	struct clk				*bus_clk;
> +	struct tsensor				sensor[MAX_SENSOR_NUM];
> +};
> +
> +/* Temp Unit: millidegree Celsius */
> +static int sun8i_ths_reg2temp(struct ths_device *tmdev,
> +			      int reg)
> +{
> +	return (reg + SUN50I_H6_OFFSET) * SUN50I_H6_SCALE;
> +}
> +
> +static int sun8i_ths_get_temp(void *data, int *temp)
> +{
> +	struct tsensor *s = data;
> +	struct ths_device *tmdev = s->tmdev;
> +	int val;
> +
> +	regmap_read(tmdev->regmap, SUN50I_H6_THS_TEMP_DATA +
> +		    0x4 * s->id, &val);
> +
> +	/* ths have no data yet */
> +	if (!val)
> +		return -EBUSY;

You should return -EAGAIN here to avoid the warning (failed to read out thermal
zone (%d)) if you believe this error is temporary.

regards,
	o.

> +	*temp = sun8i_ths_reg2temp(tmdev, val);
> +	/*
> +	 * XX - According to the original sdk, there are some platforms(rarely)
> +	 * that add a fixed offset value after calculating the temperature
> +	 * value. We can't simply put it on the formula for calculating the
> +	 * temperature above, because the formula for calculating the
> +	 * temperature above is also used when the sensor is calibrated. If
> +	 * do this, the correct calibration formula is hard to know.
> +	 */
> +	*temp += SUN50I_H6_FT_DEVIATION;
> +
> +	return 0;
> +}
> +
> +static const struct thermal_zone_of_device_ops ths_ops = {
> +	.get_temp = sun8i_ths_get_temp,
> +};
> +
> +static const struct regmap_config config = {
> +	.reg_bits = 32,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +	.fast_io = true,
> +};
> +
> +static irqreturn_t sun50i_h6_irq_thread(int irq, void *data)
> +{
> +	struct ths_device *tmdev = data;
> +	int i, state;
> +
> +	regmap_read(tmdev->regmap, SUN50I_H6_THS_DIS, &state);
> +
> +	for (i = 0; i < SUN50I_H6_SENSOR_NUM; i++) {
> +
> +		if (state & SUN50I_H6_THS_DATA_IRQ_STS(i)) {
> +			/* clear data irq pending */
> +			regmap_write(tmdev->regmap, SUN50I_H6_THS_DIS,
> +				     SUN50I_H6_THS_DATA_IRQ_STS(i));
> +
> +			thermal_zone_device_update(tmdev->sensor[i].tzd,
> +						   THERMAL_EVENT_UNSPECIFIED);
> +		}
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int sun50i_ths_calibrate(struct ths_device *tmdev)
> +{
> +	struct nvmem_cell *calcell;
> +	struct device *dev = tmdev->dev;
> +	u16 *caldata;
> +	size_t callen;
> +	int ft_temp;
> +	int i, ret = 0;
> +
> +	calcell = devm_nvmem_cell_get(dev, "calib");
> +	if (IS_ERR(calcell)) {
> +		if (PTR_ERR(calcell) == -EPROBE_DEFER)
> +			return -EPROBE_DEFER;
> +		/*
> +		 * Even if the external calibration data stored in sid is
> +		 * not accessible, the THS hardware can still work, although
> +		 * the data won't be so accurate.
> +		 *
> +		 * The default value of calibration register is 0x800 for
> +		 * every sensor, and the calibration value is usually 0x7xx
> +		 * or 0x8xx, so they won't be away from the default value
> +		 * for a lot.
> +		 *
> +		 * So here we do not return error if the calibartion data is
> +		 * not available, except the probe needs deferring.
> +		 */
> +		goto out;
> +	}
> +
> +	caldata = nvmem_cell_read(calcell, &callen);
> +	if (IS_ERR(caldata)) {
> +		ret = PTR_ERR(caldata);
> +		goto out;
> +	}
> +
> +	if (!caldata[0] || callen < 2 + 2 * SUN50I_H6_SENSOR_NUM) {
> +		ret = -EINVAL;
> +		goto out_free;
> +	}
> +
> +	/*
> +	 * efuse layout:
> +	 *
> +	 *	0   11  16	 32
> +	 *	+-------+-------+-------+
> +	 *	|temp|  |sensor0|sensor1|
> +	 *	+-------+-------+-------+
> +	 *
> +	 * The calibration data on the H6 is the ambient temperature and
> +	 * sensor values that are filled during the factory test stage.
> +	 *
> +	 * The unit of stored FT temperature is 0.1 degreee celusis.
> +	 * Through the stored ambient temperature and the data read
> +	 * by the sensor, after a certain calculation, the calibration
> +	 * value to be compensated can be obtained.
> +	 */
> +	ft_temp = caldata[0] & FT_TEMP_MASK;
> +
> +	for (i = 0; i < SUN50I_H6_SENSOR_NUM; i++) {
> +		int reg = (int)caldata[i + 1];
> +		int sensor_temp = sun8i_ths_reg2temp(tmdev, reg);
> +		int delta, cdata, calib_offest;
> +
> +		/*
> +		 * To calculate the calibration value:
> +		 *
> +		 * X(in Celsius) = Ts - ft_temp
> +		 * delta = X * 10000 / TEMP_TO_REG
> +		 * cdata = CALIBRATE_DEFAULT - delta
> +		 *
> +		 * cdata: calibration value
> +		 */
> +		delta = (sensor_temp - ft_temp * 100) * 10 / TEMP_TO_REG;
> +		cdata = CALIBRATE_DEFAULT - delta;
> +		if (cdata & ~TEMP_CALIB_MASK) {
> +			/*
> +			 * Calibration value more than 12-bit, but calibration
> +			 * register is 12-bit. In this case, ths hardware can
> +			 * still work without calibration, although the data
> +			 * won't be so accurate.
> +			 */
> +			dev_warn(dev, "sensor%d is not calibrated.\n", i);
> +
> +			continue;
> +		}
> +
> +		calib_offest = SUN50I_H6_THS_TEMP_CALIB + (i / 2) * 0x4;
> +
> +		if (i % 2) {
> +			int val;
> +
> +			regmap_read(tmdev->regmap, calib_offest, &val);
> +			val = (val & TEMP_CALIB_MASK) | (cdata << 16);
> +			regmap_write(tmdev->regmap, calib_offest, val);
> +		} else {
> +			regmap_write(tmdev->regmap, calib_offest, cdata);
> +		}
> +	}
> +
> +out_free:
> +	kfree(caldata);
> +out:
> +	return ret;
> +}
> +
> +static int sun8i_ths_resource_init(struct ths_device *tmdev)
> +{
> +	struct device *dev = tmdev->dev;
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct resource *mem;
> +	void __iomem *base;
> +	int ret;
> +
> +	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	base = devm_ioremap_resource(dev, mem);
> +	if (IS_ERR(base))
> +		return PTR_ERR(base);
> +
> +	tmdev->regmap = devm_regmap_init_mmio(dev, base, &config);
> +	if (IS_ERR(tmdev->regmap))
> +		return PTR_ERR(tmdev->regmap);
> +
> +	tmdev->reset = devm_reset_control_get(dev, 0);
> +	if (IS_ERR(tmdev->reset))
> +		return PTR_ERR(tmdev->reset);
> +
> +	tmdev->bus_clk = devm_clk_get(&pdev->dev, "bus");
> +	if (IS_ERR(tmdev->bus_clk))
> +		return PTR_ERR(tmdev->bus_clk);
> +
> +	ret = reset_control_deassert(tmdev->reset);
> +	if (ret)
> +		return ret;
> +
> +	ret = clk_prepare_enable(tmdev->bus_clk);
> +	if (ret)
> +		goto assert_reset;
> +
> +	ret = sun50i_ths_calibrate(tmdev);
> +	if (ret)
> +		goto bus_disable;
> +
> +	return 0;
> +
> +bus_disable:
> +	clk_disable_unprepare(tmdev->bus_clk);
> +assert_reset:
> +	reset_control_assert(tmdev->reset);
> +
> +	return ret;
> +}
> +
> +static int sun50i_thermal_init(struct ths_device *tmdev)
> +{
> +	int val;
> +
> +	/*
> +	 * clkin = 24MHz
> +	 * T acquire = clkin / (x + 1)
> +	 *           = 20us
> +	 */
> +	regmap_write(tmdev->regmap, SUN50I_THS_CTRL0,
> +		     SUN50I_THS_CTRL0_T_ACQ(479));
> +	/* average over 4 samples */
> +	regmap_write(tmdev->regmap, SUN50I_H6_THS_MFC,
> +		     SUN50I_THS_FILTER_EN |
> +		     SUN50I_THS_FILTER_TYPE(1));
> +	/* period = (x + 1) * 4096 / clkin; ~10ms */
> +	regmap_write(tmdev->regmap, SUN50I_H6_THS_PC,
> +		     SUN50I_H6_THS_PC_TEMP_PERIOD(58));
> +	/* enable sensor */
> +	val = GENMASK(SUN50I_H6_SENSOR_NUM - 1, 0);
> +	regmap_write(tmdev->regmap, SUN50I_H6_THS_ENABLE, val);
> +	/* thermal data interrupt enable */
> +	val = GENMASK(SUN50I_H6_SENSOR_NUM - 1, 0);
> +	regmap_write(tmdev->regmap, SUN50I_H6_THS_DIC, val);
> +
> +	return 0;
> +}
> +
> +static int sun8i_ths_register(struct ths_device *tmdev)
> +{
> +	struct thermal_zone_device *tzd;
> +	int i;
> +
> +	for (i = 0; i < SUN50I_H6_SENSOR_NUM; i++) {
> +		tmdev->sensor[i].tmdev = tmdev;
> +		tmdev->sensor[i].id = i;
> +		tmdev->sensor[i].tzd =
> +			devm_thermal_zone_of_sensor_register(tmdev->dev,
> +							     i,
> +							     &tmdev->sensor[i],
> +							     &ths_ops);
> +		if (IS_ERR(tmdev->sensor[i].tzd))
> +			return PTR_ERR(tzd);
> +	}
> +
> +	return 0;
> +}
> +
> +static int sun8i_ths_probe(struct platform_device *pdev)
> +{
> +	struct ths_device *tmdev;
> +	struct device *dev = &pdev->dev;
> +	int ret, irq;
> +
> +	tmdev = devm_kzalloc(dev, sizeof(*tmdev), GFP_KERNEL);
> +	if (!tmdev)
> +		return -ENOMEM;
> +
> +	tmdev->dev = dev;
> +	platform_set_drvdata(pdev, tmdev);
> +
> +	ret = sun8i_ths_resource_init(tmdev);
> +	if (ret)
> +		return ret;
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0)
> +		return irq;
> +
> +	ret = sun50i_thermal_init(tmdev);
> +	if (ret)
> +		return ret;
> +
> +	ret = sun8i_ths_register(tmdev);
> +	if (ret)
> +		return ret;
> +
> +	/*
> +	 * Avoid entering the interrupt handler, the thermal device is not
> +	 * registered yet, we deffer the registration of the interrupt to
> +	 * the end.
> +	 */
> +	ret = devm_request_threaded_irq(dev, irq, NULL,
> +					sun50i_h6_irq_thread,
> +					IRQF_ONESHOT, "ths", tmdev);
> +	if (ret)
> +		return ret;
> +
> +	return ret;
> +}
> +
> +static int sun8i_ths_remove(struct platform_device *pdev)
> +{
> +	struct ths_device *tmdev = platform_get_drvdata(pdev);
> +
> +	clk_disable_unprepare(tmdev->bus_clk);
> +	reset_control_assert(tmdev->reset);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id of_ths_match[] = {
> +	{ .compatible = "allwinner,sun50i-h6-ths"},
> +	{ /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, of_ths_match);
> +
> +static struct platform_driver ths_driver = {
> +	.probe = sun8i_ths_probe,
> +	.remove = sun8i_ths_remove,
> +	.driver = {
> +		.name = "sun8i-thermal",
> +		.of_match_table = of_ths_match,
> +	},
> +};
> +module_platform_driver(ths_driver);
> +
> +MODULE_DESCRIPTION("Thermal sensor driver for Allwinner SOC");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.17.1
> 
> 
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