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Message-ID: <03b837de-ff25-2308-8a56-15bc3377cd5f@ti.com>
Date: Thu, 19 Mar 2020 18:22:41 +0530
From: Keerthy <j-keerthy@...com>
To: Daniel Lezcano <daniel.lezcano@...aro.org>, <rui.zhang@...el.com>,
<robh+dt@...nel.org>
CC: <amit.kucheria@...durent.com>, <t-kristo@...com>,
<devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>, <linux-pm@...r.kernel.org>,
<mark.rutland@....com>
Subject: Re: [RESEND PATCH v4 2/4] thermal: k3: Add support for bandgap
sensors
On 19/03/20 6:08 pm, Daniel Lezcano wrote:
> On 18/03/2020 09:30, Keerthy wrote:
>> The bandgap provides current and voltage reference for its internal
>> circuits and other analog IP blocks. The analog-to-digital
>> converter (ADC) produces an output value that is proportional
>> to the silicon temperature.
>>
>> Currently reading temperatures and creating work to periodically
>> read temperatures from the zones are supported.
>> There are no active/passive cooling agent supported.
>>
>> Signed-off-by: Keerthy <j-keerthy@...com>
>> ---
>>
>> Changes in v4:
>>
>> * Fixed comments from Daniel to remove trend function.
>> * Mostly cleaned up all the unused variables.
>> * Driver from bool to tristate.
>>
>> drivers/thermal/Kconfig | 11 ++
>> drivers/thermal/Makefile | 1 +
>> drivers/thermal/k3_bandgap.c | 287 +++++++++++++++++++++++++++++++++++
>> 3 files changed, 299 insertions(+)
>> create mode 100644 drivers/thermal/k3_bandgap.c
>>
>> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
>> index 5a05db5438d6..d848d9a3c4f1 100644
>> --- a/drivers/thermal/Kconfig
>> +++ b/drivers/thermal/Kconfig
>> @@ -251,6 +251,17 @@ config IMX_THERMAL
>> cpufreq is used as the cooling device to throttle CPUs when the
>> passive trip is crossed.
>>
>> +config K3_THERMAL
>> + tristate "Texas Instruments K3 thermal support"
>> + depends on ARCH_K3 || COMPILE_TEST
>> + help
>> + If you say yes here you get thermal support for the Texas Instruments
>> + K3 SoC family. The current chip supported is:
>> + - AM654
>> +
>> + This includes temperature reading functionality and also trend
>> + computation.
>
> trend is now removed :)
Oops missed this one here. I will remove.
>
>> 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 9fb88e26fb10..5ad6535139ae 100644
>> --- a/drivers/thermal/Makefile
>> +++ b/drivers/thermal/Makefile
>> @@ -28,6 +28,7 @@ thermal_sys-$(CONFIG_CLOCK_THERMAL) += clock_cooling.o
>> # devfreq cooling
>> thermal_sys-$(CONFIG_DEVFREQ_THERMAL) += devfreq_cooling.o
>>
>> +obj-$(CONFIG_K3_THERMAL) += k3_bandgap.o
>> # platform thermal drivers
>> obj-y += broadcom/
>> obj-$(CONFIG_THERMAL_MMIO) += thermal_mmio.o
>> diff --git a/drivers/thermal/k3_bandgap.c b/drivers/thermal/k3_bandgap.c
>> new file mode 100644
>> index 000000000000..d16e60335721
>> --- /dev/null
>> +++ b/drivers/thermal/k3_bandgap.c
>> @@ -0,0 +1,287 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * TI Bandgap temperature sensor driver for K3 SoC Family
>> + *
>> + * Copyright (C) 2020 Texas Instruments Incorporated - http://www.ti.com/
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/init.h>
>> +#include <linux/kernel.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/err.h>
>> +#include <linux/types.h>
>> +#include <linux/spinlock.h>
>> +#include <linux/of_platform.h>
>> +#include <linux/io.h>
>> +#include <linux/workqueue.h>
>
> Please check all the headers are needed, AFAICT workqueue.h and
> spinlock.h are not.
okay
>
>> +#include <linux/thermal.h>
>> +#include <linux/of.h>
>> +
>> +#define K3_VTM_DEVINFO_PWR0_OFFSET 0x4
>> +#define K3_VTM_DEVINFO_PWR0_CVD_CT_MASK 0xf
>> +#define K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK 0xf0
>> +#define K3_VTM_TMPSENS0_CTRL_OFFSET 0x80
>> +#define K3_VTM_REGS_PER_TS 0x10
>> +#define K3_VTM_TS_STAT_DTEMP_MASK 0x3ff
>> +#define K3_VTM_MAX_NUM_TS 8
>> +#define K3_VTM_TMPSENS_CTRL_CBIASSEL BIT(0)
>> +#define K3_VTM_TMPSENS_CTRL_SOC BIT(5)
>> +#define K3_VTM_TMPSENS_CTRL_CLRZ BIT(6)
>> +#define K3_VTM_TMPSENS_CTRL_CLKON_REQ BIT(7)
>> +
>> +#define K3_VTM_ADC_BEGIN_VAL 540
>> +#define K3_VTM_ADC_END_VAL 944
>> +
>> +static const int k3_adc_to_temp[] = {
>> + -40000, -40000, -40000, -40000, -39800, -39400, -39000, -38600, -38200,
>> + -37800, -37400, -37000, -36600, -36200, -35800, -35300, -34700, -34200,
>> + -33800, -33400, -33000, -32600, -32200, -31800, -31400, -31000, -30600,
>> + -30200, -29800, -29400, -29000, -28600, -28200, -27700, -27100, -26600,
>> + -26200, -25800, -25400, -25000, -24600, -24200, -23800, -23400, -23000,
>> + -22600, -22200, -21800, -21400, -21000, -20500, -19900, -19400, -19000,
>> + -18600, -18200, -17800, -17400, -17000, -16600, -16200, -15800, -15400,
>> + -15000, -14600, -14200, -13800, -13400, -13000, -12500, -11900, -11400,
>> + -11000, -10600, -10200, -9800, -9400, -9000, -8600, -8200, -7800, -7400,
>> + -7000, -6600, -6200, -5800, -5400, -5000, -4500, -3900, -3400, -3000,
>> + -2600, -2200, -1800, -1400, -1000, -600, -200, 200, 600, 1000, 1400,
>> + 1800, 2200, 2600, 3000, 3400, 3900, 4500, 5000, 5400, 5800, 6200, 6600,
>> + 7000, 7400, 7800, 8200, 8600, 9000, 9400, 9800, 10200, 10600, 11000,
>> + 11400, 11800, 12200, 12700, 13300, 13800, 14200, 14600, 15000, 15400,
>> + 15800, 16200, 16600, 17000, 17400, 17800, 18200, 18600, 19000, 19400,
>> + 19800, 20200, 20600, 21000, 21400, 21900, 22500, 23000, 23400, 23800,
>> + 24200, 24600, 25000, 25400, 25800, 26200, 26600, 27000, 27400, 27800,
>> + 28200, 28600, 29000, 29400, 29800, 30200, 30600, 31000, 31400, 31900,
>> + 32500, 33000, 33400, 33800, 34200, 34600, 35000, 35400, 35800, 36200,
>> + 36600, 37000, 37400, 37800, 38200, 38600, 39000, 39400, 39800, 40200,
>> + 40600, 41000, 41400, 41800, 42200, 42600, 43100, 43700, 44200, 44600,
>> + 45000, 45400, 45800, 46200, 46600, 47000, 47400, 47800, 48200, 48600,
>> + 49000, 49400, 49800, 50200, 50600, 51000, 51400, 51800, 52200, 52600,
>> + 53000, 53400, 53800, 54200, 54600, 55000, 55400, 55900, 56500, 57000,
>> + 57400, 57800, 58200, 58600, 59000, 59400, 59800, 60200, 60600, 61000,
>> + 61400, 61800, 62200, 62600, 63000, 63400, 63800, 64200, 64600, 65000,
>> + 65400, 65800, 66200, 66600, 67000, 67400, 67800, 68200, 68600, 69000,
>> + 69400, 69800, 70200, 70600, 71000, 71500, 72100, 72600, 73000, 73400,
>> + 73800, 74200, 74600, 75000, 75400, 75800, 76200, 76600, 77000, 77400,
>> + 77800, 78200, 78600, 79000, 79400, 79800, 80200, 80600, 81000, 81400,
>> + 81800, 82200, 82600, 83000, 83400, 83800, 84200, 84600, 85000, 85400,
>> + 85800, 86200, 86600, 87000, 87400, 87800, 88200, 88600, 89000, 89400,
>> + 89800, 90200, 90600, 91000, 91400, 91800, 92200, 92600, 93000, 93400,
>> + 93800, 94200, 94600, 95000, 95400, 95800, 96200, 96600, 97000, 97500,
>> + 98100, 98600, 99000, 99400, 99800, 100200, 100600, 101000, 101400,
>> + 101800, 102200, 102600, 103000, 103400, 103800, 104200, 104600, 105000,
>> + 105400, 105800, 106200, 106600, 107000, 107400, 107800, 108200, 108600,
>> + 109000, 109400, 109800, 110200, 110600, 111000, 111400, 111800, 112200,
>> + 112600, 113000, 113400, 113800, 114200, 114600, 115000, 115400, 115800,
>> + 116200, 116600, 117000, 117400, 117800, 118200, 118600, 119000, 119400,
>> + 119800, 120200, 120600, 121000, 121400, 121800, 122200, 122600, 123000,
>> + 123400, 123800, 124200, 124600, 124900, 125000,
>> +};
>
> Can be this array replaced by an initialization array with a formula?
>
> Why do we have most of the time a step of 400 then suddenly 500 and 400
> again? eg. 30600, 31000, 31400, 31900, 32500, 33000, 33400
This has come from a polynomial equation which i do not want to
calculate every time we read the temperature. Hence prefer Look up table.
>
>> +struct k3_thermal_data;
>
> forward declaration not needed.
okay
>
>> +struct k3_bandgap {
>> + void __iomem *base;
>> + const struct k3_bandgap_data *conf;
>> +};
>> +
>> +/* common data structures */
>> +struct k3_thermal_data {
>> + struct thermal_zone_device *ti_thermal;
>> + struct k3_bandgap *bgp;
>> + struct work_struct thermal_wq;
>> + int sensor_id;
>> + u32 ctrl_offset;
>> + u32 stat_offset;
>> + int prev_temp;
>
> prev_temp is assigned but not used.
Yes this can be removed.
>
>> +};
>> +
>> +static unsigned int vtm_get_best_value(unsigned int s0, unsigned int s1,
>> + unsigned int s2)
>> +{
>> + int d01 = abs(s0 - s1);
>> + int d02 = abs(s0 - s2);
>> + int d12 = abs(s1 - s2);
>> +
>> + if (d01 <= d02 && d01 <= d12)
>> + return (s0 + s1) / 2;
>> +
>> + if (d02 <= d01 && d02 <= d12)
>> + return (s0 + s2) / 2;
>> +
>> + return (s1 + s2) / 2;
>> +}
>> +
>> +static int k3_bgp_read_temp(struct k3_thermal_data *devdata,
>> + int *temp)
>> +{
>> + struct k3_bandgap *bgp;
>> + unsigned int dtemp, s0, s1, s2;
>> +
>> + bgp = devdata->bgp;
>> +
>> + /*
>> + * Errata is applicable for am654 pg 1.0 silicon. There
>> + * is a variation of the order for 8-10 degree centigrade.
>> + * Work around that by getting the average of two closest
>> + * readings out of three readings everytime we want to
>> + * report temperatures.
>> + *
>> + * Errata workaround.
>> + */
>> + s0 = readl(bgp->base + devdata->stat_offset) &
>> + K3_VTM_TS_STAT_DTEMP_MASK;
>> + s1 = readl(bgp->base + devdata->stat_offset) &
>> + K3_VTM_TS_STAT_DTEMP_MASK;
>> + s2 = readl(bgp->base + devdata->stat_offset) &
>> + K3_VTM_TS_STAT_DTEMP_MASK;
>> + dtemp = vtm_get_best_value(s0, s1, s2);
>> +
>> + if (dtemp < K3_VTM_ADC_BEGIN_VAL || dtemp > K3_VTM_ADC_END_VAL)
>> + return -EINVAL;
>> +
>> + *temp = k3_adc_to_temp[dtemp - K3_VTM_ADC_BEGIN_VAL];
>
> To be sure there is not a subtle memory corruption, I would recommend to
> check the consistency between K3_VTM_ADC_END_VAL - K3_VTM_ADC_BEGIN_VAL
> and the array size at init time.
>
> For example:
>
> if (ARRAY_SIZE(k3_adc_to_temp) !=
> (K3_VTM_ADC_END_VAL - K3_VTM_ADC_BEGIN_VAL))
okay
>
>> + return 0;
>> +}
>> +
>> +static int k3_thermal_get_temp(void *devdata, int *temp)
>> +{
>> + struct k3_thermal_data *data = devdata;
>> + int ret = 0;
>> +
>> + ret = k3_bgp_read_temp(data, temp);
>> + if (ret)
>> + return ret;
>> +
>> + data->prev_temp = *temp;
>> +
>> + return ret;
>> +}
>> +
>> +static const struct thermal_zone_of_device_ops k3_of_thermal_ops = {
>> + .get_temp = k3_thermal_get_temp,
>> +};
>> +
>> +static void k3_thermal_work(struct work_struct *work)
>> +{
>> + struct k3_thermal_data *data = container_of(work,
>> + struct k3_thermal_data, thermal_wq);
>> +
>> + thermal_zone_device_update(data->ti_thermal, THERMAL_EVENT_UNSPECIFIED);
>> +
>> + dev_dbg(&data->ti_thermal->device, "updated thermal zone %s\n",
>> + data->ti_thermal->type);
>> +}
>> +
>> +static const struct of_device_id of_k3_bandgap_match[];
>> +
>> +static int k3_bandgap_probe(struct platform_device *pdev)
>> +{
>> + int ret = 0, cnt, val, id, reg_cnt = 0;
>> + struct resource *res;
>> + struct device *dev = &pdev->dev;
>> + struct k3_bandgap *bgp;
>> + struct k3_thermal_data *data;
>> +
>> + bgp = devm_kzalloc(&pdev->dev, sizeof(*bgp), GFP_KERNEL);
>> + if (!bgp)
>> + return -ENOMEM;
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + bgp->base = devm_ioremap_resource(dev, res);
>> + if (IS_ERR(bgp->base))
>> + return PTR_ERR(bgp->base);
>> +
>> + pm_runtime_enable(dev);
>> + ret = pm_runtime_get_sync(dev);
>> + if (ret < 0) {
>> + pm_runtime_put_noidle(dev);
>> + pm_runtime_disable(dev);
>> + return ret;
>> + }
>> +
>> + /* Get the sensor count in the VTM */
>> + val = readl(bgp->base + K3_VTM_DEVINFO_PWR0_OFFSET);
>> + cnt = val & K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK;
>> + cnt >>= __ffs(K3_VTM_DEVINFO_PWR0_TEMPSENS_CT_MASK);
>> +
>> + data = devm_kcalloc(dev, cnt, sizeof(*data), GFP_KERNEL);
>> + if (!data) {
>> + ret = -ENOMEM;
>> + goto err_alloc;
>> + }
>> +
>> + /* Register the thermal sensors */
>> + for (id = 0; id < cnt; id++) {
>> + data[id].sensor_id = id;
>> + data[id].bgp = bgp;
>> + data[id].ctrl_offset = K3_VTM_TMPSENS0_CTRL_OFFSET +
>> + id * K3_VTM_REGS_PER_TS;
>> + data[id].stat_offset = data[id].ctrl_offset + 0x8;
>> + INIT_WORK(&data[id].thermal_wq, k3_thermal_work);
>
> What is supposed to do ?
Periodically poll temperature. I know there is no passive cooling agent
like cpufreq at the moment but i do have a critical trip do you
recommend to remove that?
Thanks,
Keerthy
>
>> + val = readl(data[id].bgp->base + data[id].ctrl_offset);
>> + val |= (K3_VTM_TMPSENS_CTRL_SOC |
>> + K3_VTM_TMPSENS_CTRL_CLRZ |
>> + K3_VTM_TMPSENS_CTRL_CLKON_REQ);
>> + val &= ~K3_VTM_TMPSENS_CTRL_CBIASSEL;
>> + writel(val, data[id].bgp->base + data[id].ctrl_offset);
>> +
>> + data[id].ti_thermal =
>> + devm_thermal_zone_of_sensor_register(dev, id,
>> + &data[id],
>> + &k3_of_thermal_ops);
>> + if (IS_ERR(data[id].ti_thermal)) {
>> + dev_err(dev, "thermal zone device is NULL\n");
>> + ret = PTR_ERR(data[id].ti_thermal);
>> + goto err_alloc;
>> + }
>> +
>> + reg_cnt++;
>> +
>> + /* Initialize Previous temp */
>> + k3_thermal_get_temp(&data[id], &data[id].prev_temp);
>> + }
>> +
>> + platform_set_drvdata(pdev, bgp);
>> +
>> + return 0;
>> +
>> +err_alloc:
>> + pm_runtime_put_sync(&pdev->dev);
>> + pm_runtime_disable(&pdev->dev);
>> +
>> + return ret;
>> +}
>> +
>> +static int k3_bandgap_remove(struct platform_device *pdev)
>> +{
>> + pm_runtime_put_sync(&pdev->dev);
>> + pm_runtime_disable(&pdev->dev);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct of_device_id of_k3_bandgap_match[] = {
>> + {
>> + .compatible = "ti,am654-vtm",
>> + },
>> + { /* sentinel */ },
>> +};
>> +MODULE_DEVICE_TABLE(of, of_k3_bandgap_match);
>> +
>> +static struct platform_driver k3_bandgap_sensor_driver = {
>> + .probe = k3_bandgap_probe,
>> + .remove = k3_bandgap_remove,
>> + .driver = {
>> + .name = "k3-soc-thermal",
>> + .of_match_table = of_k3_bandgap_match,
>> + },
>> +};
>> +
>> +module_platform_driver(k3_bandgap_sensor_driver);
>> +
>> +MODULE_DESCRIPTION("K3 bandgap temperature sensor driver");
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_AUTHOR("J Keerthy <j-keerthy@...com>");
>>
>
>
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