Hey Martin,
Very sorry for the late feedback. Not so sure if this one got queued
already or not. Anyways, just minor questions as follows:
On Wed, Nov 02, 2016 at 10:18:22AM +0000, kernel@xxxxxxxxxxxxxxxx wrote:
> From: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
>
> Add basic thermal driver for bcm2835 SOC.
>
> This driver currently relies on the firmware setting up the
> tsense HW block and does not set it up itself.
>
> Signed-off-by: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
> Acked-by: Eric Anholt <eric@xxxxxxxxxx>
> Acked-by: Stefan Wahren <stefan.wahren@xxxxxxxx>
>
> ChangeLog:
> V1 -> V2: added specific settings depending on compatiblity
> added trip point based on register
> setting up ctrl-register if HW is not enabled by firmware
> as per recommendation of Eric (untested)
> check that clock frequency is in range
> (1.9 - 5MHz - as per comment in clk-bcm2835.c)
> V2 -> V4: moved back to thermal (not using bcm sub-directory)
> set polling interval to 1second (was 0ms, so interrupt driven)
> V5 -> V6: added correct depends in KConfig
> removed defined default for RESET_DELAY
> removed obvious comments
> clarify HW setup comments if not set up by FW already
> move clk_prepare_enable to an earlier stage and add error handling
> clarify warning when TS-clock runs out of recommended range
> clk_disable_unprepare added in bcm2835_thermal_remove
> added comment on recommended temperature ranges for SOC
> V6 -> V7: removed depends on ARCH_BCM2836 || ARCH_BCM2837 in Kconfig
> V7 -> V8: rebased
> ---
> drivers/thermal/Kconfig | 8 +
> drivers/thermal/Makefile | 1 +
> drivers/thermal/bcm2835_thermal.c | 340 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 349 insertions(+)
> create mode 100644 drivers/thermal/bcm2835_thermal.c
>
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index a13541b..ab946ff 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -434,4 +434,12 @@ depends on (ARCH_QCOM && OF) || COMPILE_TEST
> source "drivers/thermal/qcom/Kconfig"
> endmenu
>
> +config BCM2835_THERMAL
> + tristate "Thermal sensors on bcm2835 SoC"
> + depends on ARCH_BCM2835 || COMPILE_TEST
> + depends on HAS_IOMEM
> + depends on OF
> + help
> + Support for thermal sensors on Broadcom bcm2835 SoCs.
> +
> endif
> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
> index c92eb22..a10ebe0 100644
> --- a/drivers/thermal/Makefile
> +++ b/drivers/thermal/Makefile
> @@ -55,3 +55,4 @@ obj-$(CONFIG_TEGRA_SOCTHERM) += tegra/
> obj-$(CONFIG_HISI_THERMAL) += hisi_thermal.o
> obj-$(CONFIG_MTK_THERMAL) += mtk_thermal.o
> obj-$(CONFIG_GENERIC_ADC_THERMAL) += thermal-generic-adc.o
> +obj-$(CONFIG_BCM2835_THERMAL) += bcm2835_thermal.o
> diff --git a/drivers/thermal/bcm2835_thermal.c b/drivers/thermal/bcm2835_thermal.c
> new file mode 100644
> index 0000000..3468c7b
> --- /dev/null
> +++ b/drivers/thermal/bcm2835_thermal.c
> @@ -0,0 +1,340 @@
> +/*
> + * Driver for Broadcom BCM2835 soc temperature sensor
> + *
> + * Copyright (C) 2016 Martin Sperl
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * 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.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/debugfs.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/thermal.h>
> +
> +#define BCM2835_TS_TSENSCTL 0x00
> +#define BCM2835_TS_TSENSSTAT 0x04
> +
> +#define BCM2835_TS_TSENSCTL_PRWDW BIT(0)
> +#define BCM2835_TS_TSENSCTL_RSTB BIT(1)
> +#define BCM2835_TS_TSENSCTL_CTRL_BITS 3
> +#define BCM2835_TS_TSENSCTL_CTRL_SHIFT 2
> +#define BCM2835_TS_TSENSCTL_CTRL_MASK \
> + GENMASK(BCM2835_TS_TSENSCTL_CTRL_BITS + \
> + BCM2835_TS_TSENSCTL_CTRL_SHIFT - 1, \
> + BCM2835_TS_TSENSCTL_CTRL_SHIFT)
> +#define BCM2835_TS_TSENSCTL_CTRL_DEFAULT 1
> +#define BCM2835_TS_TSENSCTL_EN_INT BIT(5)
> +#define BCM2835_TS_TSENSCTL_DIRECT BIT(6)
> +#define BCM2835_TS_TSENSCTL_CLR_INT BIT(7)
> +#define BCM2835_TS_TSENSCTL_THOLD_SHIFT 8
> +#define BCM2835_TS_TSENSCTL_THOLD_BITS 10
> +#define BCM2835_TS_TSENSCTL_THOLD_MASK \
> + GENMASK(BCM2835_TS_TSENSCTL_THOLD_BITS + \
> + BCM2835_TS_TSENSCTL_THOLD_SHIFT - 1, \
> + BCM2835_TS_TSENSCTL_THOLD_SHIFT)
> +#define BCM2835_TS_TSENSCTL_RSTDELAY_SHIFT 18
> +#define BCM2835_TS_TSENSCTL_RSTDELAY_BITS 8
> +#define BCM2835_TS_TSENSCTL_REGULEN BIT(26)
> +
> +#define BCM2835_TS_TSENSSTAT_DATA_BITS 10
> +#define BCM2835_TS_TSENSSTAT_DATA_SHIFT 0
> +#define BCM2835_TS_TSENSSTAT_DATA_MASK \
> + GENMASK(BCM2835_TS_TSENSSTAT_DATA_BITS + \
> + BCM2835_TS_TSENSSTAT_DATA_SHIFT - 1, \
> + BCM2835_TS_TSENSSTAT_DATA_SHIFT)
> +#define BCM2835_TS_TSENSSTAT_VALID BIT(10)
> +#define BCM2835_TS_TSENSSTAT_INTERRUPT BIT(11)
> +
> +struct bcm2835_thermal_info {
> + int offset;
> + int slope;
> + int trip_temp;
> +};
> +
> +struct bcm2835_thermal_data {
> + const struct bcm2835_thermal_info *info;
> + void __iomem *regs;
> + struct clk *clk;
> + struct dentry *debugfsdir;
> +};
> +
> +static int bcm2835_thermal_adc2temp(
> + const struct bcm2835_thermal_info *info, u32 adc)
> +{
> + return info->offset + (adc * info->slope);
Any specific reason we cannot use thermal_zone_params->slope and
thermal_zone_params->offset?
> +}
> +
> +static int bcm2835_thermal_temp2adc(
> + const struct bcm2835_thermal_info *info, int temp)
> +{
> + temp -= info->offset;
> + temp /= info->slope;
> +
> + if (temp < 0)
> + temp = 0;
> + if (temp >= BIT(BCM2835_TS_TSENSSTAT_DATA_BITS))
> + temp = BIT(BCM2835_TS_TSENSSTAT_DATA_BITS) - 1;
> +
> + return temp;
> +}
> +
> +static int bcm2835_thermal_get_trip_type(
> + struct thermal_zone_device *tz, int trip,
> + enum thermal_trip_type *type)
> +{
> + *type = THERMAL_TRIP_CRITICAL;
> + return 0;
> +}
> +
> +static int bcm2835_thermal_get_trip_temp(
> + struct thermal_zone_device *tz, int trip, int *temp)
> +{
> + struct bcm2835_thermal_data *data = tz->devdata;
> + u32 val = readl(data->regs + BCM2835_TS_TSENSCTL);
> +
> + /* get the THOLD bits */
> + val &= BCM2835_TS_TSENSCTL_THOLD_MASK;
> + val >>= BCM2835_TS_TSENSCTL_THOLD_SHIFT;
> +
> + /* if it is zero then use the info value */
> + if (val)
Is this a read only register or is this driver supposed to program it?
In which scenario it would be 0? Can this be added as comments?
> + *temp = bcm2835_thermal_adc2temp(data->info, val);
> + else
> + *temp = data->info->trip_temp;
> +
> + return 0;
> +}
> +
> +static int bcm2835_thermal_get_temp(struct thermal_zone_device *tz,
> + int *temp)
> +{
> + struct bcm2835_thermal_data *data = tz->devdata;
> + u32 val = readl(data->regs + BCM2835_TS_TSENSSTAT);
> +
> + if (!(val & BCM2835_TS_TSENSSTAT_VALID))
What cases you would get the valid bit not set? Do you need to wait for
the conversion to finish?
> + return -EIO;
> +
> + val &= BCM2835_TS_TSENSSTAT_DATA_MASK;
> +
> + *temp = bcm2835_thermal_adc2temp(data->info, val);
> +
> + return 0;
> +}
> +
> +static const struct debugfs_reg32 bcm2835_thermal_regs[] = {
> + {
> + .name = "ctl",
> + .offset = 0
> + },
> + {
> + .name = "stat",
> + .offset = 4
> + }
> +};
> +
> +static void bcm2835_thermal_debugfs(struct platform_device *pdev)
> +{
> + struct thermal_zone_device *tz = platform_get_drvdata(pdev);
> + struct bcm2835_thermal_data *data = tz->devdata;
> + struct debugfs_regset32 *regset;
> +
> + data->debugfsdir = debugfs_create_dir("bcm2835_thermal", NULL);
> + if (!data->debugfsdir)
> + return;
> +
> + regset = devm_kzalloc(&pdev->dev, sizeof(*regset), GFP_KERNEL);
> + if (!regset)
> + return;
> +
> + regset->regs = bcm2835_thermal_regs;
> + regset->nregs = ARRAY_SIZE(bcm2835_thermal_regs);
> + regset->base = data->regs;
> +
> + debugfs_create_regset32("regset", S_IRUGO,
> + data->debugfsdir, regset);
> +}
> +
> +static struct thermal_zone_device_ops bcm2835_thermal_ops = {
> + .get_temp = bcm2835_thermal_get_temp,
> + .get_trip_temp = bcm2835_thermal_get_trip_temp,
> + .get_trip_type = bcm2835_thermal_get_trip_type,
> +};
> +
> +static const struct of_device_id bcm2835_thermal_of_match_table[];
> +static int bcm2835_thermal_probe(struct platform_device *pdev)
> +{
> + const struct of_device_id *match;
> + struct thermal_zone_device *tz;
> + struct bcm2835_thermal_data *data;
> + struct resource *res;
> + int err;
> + u32 val;
> + unsigned long rate;
> +
> + data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
> +
> + match = of_match_device(bcm2835_thermal_of_match_table,
> + &pdev->dev);
> + if (!match)
> + return -EINVAL;
> + data->info = match->data;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + data->regs = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(data->regs)) {
> + err = PTR_ERR(data->regs);
> + dev_err(&pdev->dev, "Could not get registers: %d\n", err);
> + return err;
> + }
> +
> + data->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(data->clk)) {
> + err = PTR_ERR(data->clk);
> + if (err != -EPROBE_DEFER)
> + dev_err(&pdev->dev, "Could not get clk: %d\n", err);
> + return err;
> + }
> +
> + err = clk_prepare_enable(data->clk);
> + if (err)
> + return err;
> +
> + rate = clk_get_rate(data->clk);
> + if ((rate < 1920000) || (rate > 5000000))
> + dev_warn(&pdev->dev,
> + "Clock %pCn running at %pCr Hz is outside of the recommended range: 1.92 to 5MHz\n",
> + data->clk, data->clk);
> +
> + /*
> + * right now the FW does set up the HW-block, so we are not
> + * touching the configuration registers.
> + * But if the HW is not enabled, then set it up
> + * using "sane" values used by the firmware right now.
> + */
> + val = readl(data->regs + BCM2835_TS_TSENSCTL);
> + if (!(val & BCM2835_TS_TSENSCTL_RSTB)) {
> + /* the basic required flags */
> + val = (BCM2835_TS_TSENSCTL_CTRL_DEFAULT <<
> + BCM2835_TS_TSENSCTL_CTRL_SHIFT) |
> + BCM2835_TS_TSENSCTL_REGULEN;
> +
> + /*
> + * reset delay using the current firmware value of 14
> + * - units of time are unknown.
> + */
> + val |= (14 << BCM2835_TS_TSENSCTL_RSTDELAY_SHIFT);
> +
> + /* trip_adc value from info */
> + val |= bcm2835_thermal_temp2adc(data->info,
> + data->info->trip_temp) <<
> + BCM2835_TS_TSENSCTL_THOLD_SHIFT;
> +
> + /* write the value back to the register as 2 steps */
> + writel(val, data->regs + BCM2835_TS_TSENSCTL);
> + val |= BCM2835_TS_TSENSCTL_RSTB;
> + writel(val, data->regs + BCM2835_TS_TSENSCTL);
> + }
> +
> + /* register thermal zone with 1 trip point an 1s polling */
> + tz = thermal_zone_device_register("bcm2835_thermal",
> + 1, 0, data,
> + &bcm2835_thermal_ops,
> + NULL,
> + 0, 1000);
> + if (IS_ERR(tz)) {
> + clk_disable_unprepare(data->clk);
> + err = PTR_ERR(tz);
> + dev_err(&pdev->dev,
> + "Failed to register the thermal device: %d\n",
> + err);
> + return err;
> + }
> +
> + platform_set_drvdata(pdev, tz);
> +
> + bcm2835_thermal_debugfs(pdev);
> +
> + return 0;
> +}
> +
> +static int bcm2835_thermal_remove(struct platform_device *pdev)
> +{
> + struct thermal_zone_device *tz = platform_get_drvdata(pdev);
> + struct bcm2835_thermal_data *data = tz->devdata;
> +
> + debugfs_remove_recursive(data->debugfsdir);
> + thermal_zone_device_unregister(tz);
> + clk_disable_unprepare(data->clk);
> +
> + return 0;
> +}
> +
> +/*
> + * Note: as per Raspberry Foundation FAQ
> + * (https://www.raspberrypi.org/help/faqs/#performanceOperatingTemperature)
> + * the recommended temperature range for the SOC -40C to +85C
> + * so the trip limit is set to 80C.
> + * this applies to all the BCM283X SOC
> + */
> +
> +static const struct of_device_id bcm2835_thermal_of_match_table[] = {
> + {
> + .compatible = "brcm,bcm2835-thermal",
> + .data = &(struct bcm2835_thermal_info) {
> + .offset = 407000,
> + .slope = -538,
> + .trip_temp = 80000
> + }
> + },
> + {
> + .compatible = "brcm,bcm2836-thermal",
> + .data = &(struct bcm2835_thermal_info) {
> + .offset = 407000,
> + .slope = -538,
> + .trip_temp = 80000
> + }
> + },
> + {
> + .compatible = "brcm,bcm2837-thermal",
> + .data = &(struct bcm2835_thermal_info) {
> + /* the bcm2837 needs adjustment of +5C */
> + .offset = 407000 + 5000,
> + .slope = -538,
> + .trip_temp = 80000
> + }
> + },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, bcm2835_thermal_of_match_table);
> +
> +static struct platform_driver bcm2835_thermal_driver = {
> + .probe = bcm2835_thermal_probe,
> + .remove = bcm2835_thermal_remove,
> + .driver = {
> + .name = "bcm2835_thermal",
> + .of_match_table = bcm2835_thermal_of_match_table,
> + },
> +};
> +module_platform_driver(bcm2835_thermal_driver);
> +
> +MODULE_AUTHOR("Martin Sperl");
> +MODULE_DESCRIPTION("Thermal driver for bcm2835 chip");
> +MODULE_LICENSE("GPL");
> --
> 2.1.4
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