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Date:   Fri, 7 Jun 2019 19:18:21 +0200
From:   =?utf-8?Q?Ond=C5=99ej?= Jirman <megous@megous.com>
To:     Frank Lee <tiny.windzz@gmail.com>
Cc:     rui.zhang@intel.com, Eduardo Valentin <edubezval@gmail.com>,
        Daniel Lezcano <daniel.lezcano@linaro.org>, robh+dt@kernel.org,
        Mark Rutland <mark.rutland@arm.com>,
        Maxime Ripard <maxime.ripard@bootlin.com>,
        Chen-Yu Tsai <wens@csie.org>,
        David Miller <davem@davemloft.net>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Nicolas Ferre <nicolas.ferre@microchip.com>,
        paulmck@linux.ibm.com, devicetree@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux PM <linux-pm@vger.kernel.org>
Subject: Re: [PATCH v3 1/3] thermal: sun8i: add thermal driver for h6
Message-ID: <20190607171821.zpb5e6aurdfcflpb@core.my.home>
Mail-Followup-To: Frank Lee <tiny.windzz@gmail.com>, rui.zhang@intel.com,
        Eduardo Valentin <edubezval@gmail.com>,
        Daniel Lezcano <daniel.lezcano@linaro.org>, robh+dt@kernel.org,
        Mark Rutland <mark.rutland@arm.com>,
        Maxime Ripard <maxime.ripard@bootlin.com>,
        Chen-Yu Tsai <wens@csie.org>, David Miller <davem@davemloft.net>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Nicolas Ferre <nicolas.ferre@microchip.com>, paulmck@linux.ibm.com,
        devicetree@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux PM <linux-pm@vger.kernel.org>
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Hello Frank,

On Fri, Jun 07, 2019 at 09:50:08PM +0800, Frank Lee wrote:
> HI Ondřej,
> 
> 
> On Mon, May 27, 2019 at 10:25 PM Ondřej Jirman <megous@megous.com> wrote:
> >
> > Hi Yangtao,
> >
> > On Sat, May 25, 2019 at 02:13:27PM -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@gmail.com>
> > > ---
> > >  MAINTAINERS                     |   7 +
> > >  drivers/thermal/Kconfig         |  14 +
> > >  drivers/thermal/Makefile        |   1 +
> > >  drivers/thermal/sun8i_thermal.c | 437 ++++++++++++++++++++++++++++++++
> > >  4 files changed, 459 insertions(+)
> > >  create mode 100644 drivers/thermal/sun8i_thermal.c
> > >
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index 2336dd26ece4..d312f9eecf0d 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -674,6 +674,13 @@ L:       linux-crypto@vger.kernel.org
> > >  S:   Maintained
> > >  F:   drivers/crypto/sunxi-ss/
> > >
> > > +ALLWINNER THERMAL DRIVER
> > > +M:   Yangtao Li <tiny.windzz@gmail.com>
> > > +L:   linux-pm@vger.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@bootlin.com>
> > >  M:   Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> > > diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> > > index 9966364a6deb..e5465053d66f 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_SUNXI_SID
> > > +     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..a9cc2197f4cb
> > > --- /dev/null
> > > +++ b/drivers/thermal/sun8i_thermal.c
> > > @@ -0,0 +1,437 @@
> > > +// 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@aosc.io>
> > > + * Based on the work of Ondrej Jirman <megous@megous.com>
> > > + * Based on the work of Josef Gajdusek <atx@atx.name>
> > > + */
> > > +
> > > +#include <linux/clk.h>
> > > +#include <linux/device.h>
> > > +#include <linux/interrupt.h>
> > > +#include <linux/wait.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 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;
> > > +     wait_queue_head_t               wait_queue;
> > > +};
> > > +
> > > +struct ths_thermal_chip {
> > > +     int             sensor_num;
> > > +     int             offset;
> > > +     int             scale;
> > > +     int             ft_deviation;
> > > +     int             temp_calib_base;
> > > +     int             temp_data_base;
> > > +     int             (*calibrate)(struct ths_device *tmdev);
> > > +     int             (*init)(struct ths_device *tmdev);
> > > +     irqreturn_t     (*irq_thread)(int irq, void *data);
> > > +};
> > > +
> > > +struct ths_device {
> > > +     const struct ths_thermal_chip           *chip;
> > > +     struct device                           *dev;
> > > +     struct regmap                           *regmap;
> > > +     struct reset_control                    *reset;
> > > +     struct clk                              *bus_clk;
> > > +     struct tsensor                          sensor[MAX_SENSOR_NUM];
> > > +     int                                     data_ready;
> > > +};
> > > +
> > > +/* Temp Unit: millidegree Celsius */
> > > +static int sun8i_ths_reg2temp(struct ths_device *tmdev,
> > > +                           int reg)
> > > +{
> > > +     return (reg + tmdev->chip->offset) * tmdev->chip->scale;
> > > +}
> > > +
> > > +static int sun8i_ths_get_temp(void *data, int *temp)
> > > +{
> > > +     struct tsensor *s = data;
> > > +     struct ths_device *tmdev = s->tmdev;
> > > +     int val;
> > > +
> > > +     wait_event(s->wait_queue, tmdev->data_ready & BIT(s->id));
> > > +     tmdev->data_ready &= ~BIT(s->id);
> >
> > I've looked at thermal_core.c and it looks like that the proper way to handle
> > this situation is just returning -EAGAIN.
> 
> What we are doing now is to turn it into an interrupt-based program.
> Every time we use temperature data, we need to wait until new data is collected.

No you don't need to wait, and by waiting you're blocking a lot of tings in
thermal_core.c for no reason.

> >
> > See update_temperature() function in thermal_core.c.
> >
> > That will suppress the warning about failure to read thermal zone. Also
> > it's much simpler than this wait_queue stuff. No other thermal driver uses this
> > either. Also get_temp is called under thermal_list_lock mutex and that would
> > block cooling device registrations and god knows what else.
> 
> Since there is no valid temperature data, it cannot be blocked.

Sorry, I don't understand your meaning here. get_temp will block in
wait_event, and the above mentioned lock in tz code will be held during all this
time, until you get data_ready condition satisified sometimes in the future.

https://elixir.bootlin.com/linux/latest/source/drivers/thermal/thermal_core.c#L43

This will prevent all time zones in the system from being updated, regsitered,
etc, because it's a driver level lock.

Given that this is called from __thermal_cooling_device_register:

https://elixir.bootlin.com/linux/latest/source/drivers/thermal/thermal_core.c#L997

This will stop all other thermal zones from registering for no reason.

Just return -EAGAIN, as expected here:

https://elixir.bootlin.com/linux/latest/source/drivers/thermal/thermal_core.c#L431

And the driver will work in both interrupt driven and polled mode just fine,
without any warnings or delays or taking this lock for no reason for too long.

thank you and regards,
	o.

> MBR,
> Yangtao
> 
> >
> > Other than that, and what Maxime said, I don't see any more issues.
> >
> > thank you,
> >         o.
> >
> > > +     regmap_read(tmdev->regmap, tmdev->chip->temp_data_base +
> > > +                 0x4 * s->id, &val);
> > > +
> > > +     *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.
> > > +      */
> > > +     if (tmdev->chip->ft_deviation)
> > > +             *temp += tmdev->chip->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)
> > > +{
> > > +     wait_queue_head_t *data_wait;
> > > +     struct ths_device *tmdev = data;
> > > +     int i, state;
> > > +
> > > +     regmap_read(tmdev->regmap, SUN50I_H6_THS_DIS, &state);
> > > +
> > > +     for (i = 0; i < tmdev->chip->sensor_num; i++) {
> > > +             data_wait = &tmdev->sensor[i].wait_queue;
> > > +
> > > +             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));
> > > +
> > > +                     tmdev->data_ready |= BIT(i);
> > > +                     wake_up(data_wait);
> > > +             }
> > > +     }
> > > +
> > > +     return IRQ_HANDLED;
> > > +}
> > > +
> > > +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, irq;
> > > +
> > > +     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);
> > > +
> > > +     irq = platform_get_irq(pdev, 0);
> > > +     if (irq < 0)
> > > +             return irq;
> > > +
> > > +     ret = devm_request_threaded_irq(dev, irq, NULL,
> > > +                                     tmdev->chip->irq_thread,
> > > +                                     IRQF_ONESHOT, "ths", tmdev);
> > > +     if (ret)
> > > +             return ret;
> > > +
> > > +     ret = reset_control_deassert(tmdev->reset);
> > > +     if (ret)
> > > +             return ret;
> > > +
> > > +     ret = clk_prepare_enable(tmdev->bus_clk);
> > > +     if (ret)
> > > +             goto assert_reset;
> > > +
> > > +     ret = tmdev->chip->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_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 * tmdev->chip->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 < tmdev->chip->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 = tmdev->chip->temp_calib_base + (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_register(struct ths_device *tmdev)
> > > +{
> > > +     struct thermal_zone_device *tzd;
> > > +     int i;
> > > +
> > > +     for (i = 0; i < tmdev->chip->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 i, ret;
> > > +
> > > +     tmdev = devm_kzalloc(dev, sizeof(*tmdev), GFP_KERNEL);
> > > +     if (!tmdev)
> > > +             return -ENOMEM;
> > > +
> > > +     tmdev->dev = dev;
> > > +     tmdev->chip = of_device_get_match_data(&pdev->dev);
> > > +     if (!tmdev->chip)
> > > +             return -EINVAL;
> > > +
> > > +     /*
> > > +      * Initialize wait_queue in advance, to avoid calling wake_up
> > > +      * before ths is registered in isr.
> > > +      */
> > > +     for (i = 0; i < tmdev->chip->sensor_num; i++)
> > > +             init_waitqueue_head(&tmdev->sensor[i].wait_queue);
> > > +
> > > +     platform_set_drvdata(pdev, tmdev);
> > > +
> > > +     ret = sun8i_ths_resource_init(tmdev);
> > > +     if (ret)
> > > +             return ret;
> > > +
> > > +     ret = tmdev->chip->init(tmdev);
> > > +     if (ret)
> > > +             return ret;
> > > +
> > > +     ret = sun8i_ths_register(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 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(tmdev->chip->sensor_num - 1, 0);
> > > +     regmap_write(tmdev->regmap, SUN50I_H6_THS_ENABLE, val);
> > > +     /* thermal data interrupt enable */
> > > +     val = GENMASK(tmdev->chip->sensor_num - 1, 0);
> > > +     regmap_write(tmdev->regmap, SUN50I_H6_THS_DIC, val);
> > > +
> > > +     return 0;
> > > +}
> > > +
> > > +static const struct ths_thermal_chip sun50i_h6_ths = {
> > > +     .sensor_num = 2,
> > > +     .offset = -2794,
> > > +     .scale = -67,
> > > +     .ft_deviation = SUN50I_H6_FT_DEVIATION,
> > > +     .temp_calib_base = SUN50I_H6_THS_TEMP_CALIB,
> > > +     .temp_data_base = SUN50I_H6_THS_TEMP_DATA,
> > > +     .calibrate = sun50i_ths_calibrate,
> > > +     .init = sun50i_thermal_init,
> > > +     .irq_thread = sun50i_h6_irq_thread,
> > > +};
> > > +
> > > +static const struct of_device_id of_ths_match[] = {
> > > +     { .compatible = "allwinner,sun50i-h6-ths", .data = &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");
> > > --
> > > 2.17.0
> > >
> > >
> > > _______________________________________________
> > > linux-arm-kernel mailing list
> > > linux-arm-kernel@lists.infradead.org
> > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 
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