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SubjectRe: [PATCH RESEND 2/4] thermal: imx8mm: Add support for i.MX8MM thermal monitoring unit
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On 20/02/2020 09:17, Anson Huang wrote:
> i.MX8MM has a thermal monitoring unit(TMU) inside, it ONLY has one
> sensor for CPU, add support for reading immediate temperature of
> this sensor.
>
> Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
> ---
> This patch is base on patch series: https://lkml.org/lkml/2020/2/19/1258
> ---
> drivers/thermal/Kconfig | 10 +++
> drivers/thermal/Makefile | 1 +
> drivers/thermal/imx8mm_thermal.c | 134 +++++++++++++++++++++++++++++++++++++++
> 3 files changed, 145 insertions(+)
> create mode 100644 drivers/thermal/imx8mm_thermal.c
>
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index d1cb8dc..972b169 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -262,6 +262,16 @@ config IMX_SC_THERMAL
> sensor. It supports one critical trip point and one
> passive trip point for each thermal sensor.
>
> +config IMX8MM_THERMAL
> + tristate "Temperature sensor driver for Freescale i.MX8MM SoC"
> + depends on ARCH_MXC
> + depends on OF
> + help
> + Support for Thermal Monitoring Unit (TMU) found on Freescale i.MX8MM SoC.
> + It supports one critical trip point and one passive trip point. The
> + cpufreq is used as the cooling device to throttle CPUs when the passive
> + trip is crossed.
> +
> config MAX77620_THERMAL
> tristate "Temperature sensor driver for Maxim MAX77620 PMIC"
> depends on MFD_MAX77620
> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
> index a11a6d8..120a05e 100644
> --- a/drivers/thermal/Makefile
> +++ b/drivers/thermal/Makefile
> @@ -44,6 +44,7 @@ obj-$(CONFIG_ARMADA_THERMAL) += armada_thermal.o
> obj-$(CONFIG_TANGO_THERMAL) += tango_thermal.o
> obj-$(CONFIG_IMX_THERMAL) += imx_thermal.o
> obj-$(CONFIG_IMX_SC_THERMAL) += imx_sc_thermal.o
> +obj-$(CONFIG_IMX8MM_THERMAL) += imx8mm_thermal.o
> obj-$(CONFIG_MAX77620_THERMAL) += max77620_thermal.o
> obj-$(CONFIG_QORIQ_THERMAL) += qoriq_thermal.o
> obj-$(CONFIG_DA9062_THERMAL) += da9062-thermal.o
> diff --git a/drivers/thermal/imx8mm_thermal.c b/drivers/thermal/imx8mm_thermal.c
> new file mode 100644
> index 0000000..04f8a8f
> --- /dev/null
> +++ b/drivers/thermal/imx8mm_thermal.c
> @@ -0,0 +1,134 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2019 NXP.

Copyright (c) 2020, NXP Semiconductors

Authors: Anson Huang <Anson.Huang@nxp.com>

??

> + *
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/thermal.h>
> +
> +#include "thermal_core.h"
> +
> +#define TER 0x0 /* TMU enable */
> +#define TRITSR 0x20 /* TMU immediate temp */
> +
> +#define TER_EN BIT(31)
> +#define TRITSR_VAL_MASK 0xff
> +
> +#define TEMP_LOW_LIMIT 10
> +
> +struct imx8mm_tmu {
> + struct thermal_zone_device *tzd;
> + void __iomem *base;
> + struct clk *clk;
> +};
> +
> +static int tmu_get_temp(void *data, int *temp)
> +{
> + struct imx8mm_tmu *tmu = data;
> + u32 val;
> +
> + /* the temp sensor need about 1ms to finish the measurement */
> + usleep_range(1000, 2000);

Why do yo need to force a delay here? If the sensor can not be read more
than one time every 1ms, then specify that in the DT switching the
polling to the right value, no?

> + val = readl_relaxed(tmu->base + TRITSR) & TRITSR_VAL_MASK;
> + if (val < TEMP_LOW_LIMIT)
> + return -EAGAIN;>
> + *temp = val * 1000;
> + return 0;
> +}
> +
> +static struct thermal_zone_of_device_ops tmu_tz_ops = {
> + .get_temp = tmu_get_temp,
> +};
> +
> +static int imx8mm_tmu_probe(struct platform_device *pdev)
> +{
> + struct imx8mm_tmu *tmu;
> + u32 val;
> + int ret;
> +
> + tmu = devm_kzalloc(&pdev->dev, sizeof(struct imx8mm_tmu), GFP_KERNEL);
> + if (!tmu)
> + return -ENOMEM;
> +
> + tmu->base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(tmu->base))
> + return PTR_ERR(tmu->base);
> +
> + tmu->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(tmu->clk)) {
> + ret = PTR_ERR(tmu->clk);
> + if (ret != -EPROBE_DEFER)
> + dev_err(&pdev->dev,
> + "failed to get tmu clock: %d\n", ret);
> + return ret;
> + }
> +
> + ret = clk_prepare_enable(tmu->clk);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to enable tmu clock: %d\n", ret);
> + return ret;
> + }
> +
> + tmu->tzd = devm_thermal_zone_of_sensor_register(&pdev->dev, 0,
> + tmu, &tmu_tz_ops);
> + if (IS_ERR(tmu->tzd)) {
> + dev_err(&pdev->dev,
> + "failed to register thermal zone sensor: %d\n", ret);
> + return PTR_ERR(tmu->tzd);
> + }
> +
> + platform_set_drvdata(pdev, tmu);
> +
> + /* enable the monitor */
> + val = readl_relaxed(tmu->base + TER);
> + val |= TER_EN;
> + writel_relaxed(val, tmu->base + TER);

A side note perhaps you can wrap:

static int imx8mm_start(struct imx8mm_tmu *tmu)
{
clk_prepare_enable()
val = readl_relaxed(tmu->base + TER);
val |= TER_EN;
writel_relaxed(val, tmu->base + TER);
}

and

static void imx8mm_stop(struct imx8mm_tmu *tmu)
{
val = readl_relaxed(tmu->base + TER);
val &= ~TER_EN;
writel_relaxed(val, tmu->base + TER);
clk_disable_unprepare(tmu->clk);
}

So the suspend/resume callbacks can call them directly if you decide to
add them.

> + return 0;
> +}
> +
> +static int imx8mm_tmu_remove(struct platform_device *pdev)
> +{
> + struct imx8mm_tmu *tmu = platform_get_drvdata(pdev);
> + u32 val;
> +
> + /* disable TMU */
> + val = readl_relaxed(tmu->base + TER);
> + val &= ~TER_EN;
> + writel_relaxed(val, tmu->base + TER);
> +
> + clk_disable_unprepare(tmu->clk);
> + platform_set_drvdata(pdev, NULL);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id imx8mm_tmu_table[] = {
> + { .compatible = "fsl,imx8mm-tmu", },
> + { },
> +};
> +
> +static struct platform_driver imx8mm_tmu = {
> + .driver = {
> + .name = "i.mx8mm_thermal",
> + .of_match_table = imx8mm_tmu_table,
> + },
> + .probe = imx8mm_tmu_probe,
> + .remove = imx8mm_tmu_remove,
> +};
> +module_platform_driver(imx8mm_tmu);
> +
> +MODULE_AUTHOR("Anson Huang <Anson.Huang@nxp.com>");
> +MODULE_DESCRIPTION("i.MX8MM Thermal Monitor Unit driver");
> +MODULE_LICENSE("GPL v2");
>


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