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![Greg Kroah-Hartman](/assets/img/avatar_default.png)
When calling debugfs functions, there is no need to ever check the return value. The function can work or not, but the code logic should never do something different based on this. Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Ray Jui <rjui@broadcom.com> Cc: Scott Branden <sbranden@broadcom.com> Cc: bcm-kernel-feedback-list@broadcom.com Cc: linux-pm@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
312 lines
7.9 KiB
C
312 lines
7.9 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Driver for Broadcom BCM2835 SoC temperature sensor
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*
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* Copyright (C) 2016 Martin Sperl
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*/
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#include <linux/clk.h>
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#include <linux/debugfs.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/thermal.h>
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#include "../thermal_hwmon.h"
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#define BCM2835_TS_TSENSCTL 0x00
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#define BCM2835_TS_TSENSSTAT 0x04
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#define BCM2835_TS_TSENSCTL_PRWDW BIT(0)
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#define BCM2835_TS_TSENSCTL_RSTB BIT(1)
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/*
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* bandgap reference voltage in 6 mV increments
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* 000b = 1178 mV, 001b = 1184 mV, ... 111b = 1220 mV
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*/
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#define BCM2835_TS_TSENSCTL_CTRL_BITS 3
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#define BCM2835_TS_TSENSCTL_CTRL_SHIFT 2
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#define BCM2835_TS_TSENSCTL_CTRL_MASK \
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GENMASK(BCM2835_TS_TSENSCTL_CTRL_BITS + \
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BCM2835_TS_TSENSCTL_CTRL_SHIFT - 1, \
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BCM2835_TS_TSENSCTL_CTRL_SHIFT)
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#define BCM2835_TS_TSENSCTL_CTRL_DEFAULT 1
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#define BCM2835_TS_TSENSCTL_EN_INT BIT(5)
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#define BCM2835_TS_TSENSCTL_DIRECT BIT(6)
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#define BCM2835_TS_TSENSCTL_CLR_INT BIT(7)
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#define BCM2835_TS_TSENSCTL_THOLD_SHIFT 8
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#define BCM2835_TS_TSENSCTL_THOLD_BITS 10
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#define BCM2835_TS_TSENSCTL_THOLD_MASK \
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GENMASK(BCM2835_TS_TSENSCTL_THOLD_BITS + \
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BCM2835_TS_TSENSCTL_THOLD_SHIFT - 1, \
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BCM2835_TS_TSENSCTL_THOLD_SHIFT)
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/*
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* time how long the block to be asserted in reset
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* which based on a clock counter (TSENS clock assumed)
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*/
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#define BCM2835_TS_TSENSCTL_RSTDELAY_SHIFT 18
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#define BCM2835_TS_TSENSCTL_RSTDELAY_BITS 8
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#define BCM2835_TS_TSENSCTL_REGULEN BIT(26)
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#define BCM2835_TS_TSENSSTAT_DATA_BITS 10
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#define BCM2835_TS_TSENSSTAT_DATA_SHIFT 0
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#define BCM2835_TS_TSENSSTAT_DATA_MASK \
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GENMASK(BCM2835_TS_TSENSSTAT_DATA_BITS + \
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BCM2835_TS_TSENSSTAT_DATA_SHIFT - 1, \
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BCM2835_TS_TSENSSTAT_DATA_SHIFT)
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#define BCM2835_TS_TSENSSTAT_VALID BIT(10)
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#define BCM2835_TS_TSENSSTAT_INTERRUPT BIT(11)
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struct bcm2835_thermal_data {
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struct thermal_zone_device *tz;
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void __iomem *regs;
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struct clk *clk;
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struct dentry *debugfsdir;
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};
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static int bcm2835_thermal_adc2temp(u32 adc, int offset, int slope)
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{
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return offset + slope * adc;
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}
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static int bcm2835_thermal_temp2adc(int temp, int offset, int slope)
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{
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temp -= offset;
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temp /= slope;
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if (temp < 0)
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temp = 0;
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if (temp >= BIT(BCM2835_TS_TSENSSTAT_DATA_BITS))
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temp = BIT(BCM2835_TS_TSENSSTAT_DATA_BITS) - 1;
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return temp;
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}
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static int bcm2835_thermal_get_temp(void *d, int *temp)
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{
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struct bcm2835_thermal_data *data = d;
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u32 val = readl(data->regs + BCM2835_TS_TSENSSTAT);
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if (!(val & BCM2835_TS_TSENSSTAT_VALID))
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return -EIO;
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val &= BCM2835_TS_TSENSSTAT_DATA_MASK;
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*temp = bcm2835_thermal_adc2temp(
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val,
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thermal_zone_get_offset(data->tz),
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thermal_zone_get_slope(data->tz));
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return 0;
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}
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static const struct debugfs_reg32 bcm2835_thermal_regs[] = {
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{
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.name = "ctl",
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.offset = 0
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},
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{
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.name = "stat",
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.offset = 4
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}
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};
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static void bcm2835_thermal_debugfs(struct platform_device *pdev)
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{
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struct bcm2835_thermal_data *data = platform_get_drvdata(pdev);
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struct debugfs_regset32 *regset;
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data->debugfsdir = debugfs_create_dir("bcm2835_thermal", NULL);
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regset = devm_kzalloc(&pdev->dev, sizeof(*regset), GFP_KERNEL);
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if (!regset)
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return;
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regset->regs = bcm2835_thermal_regs;
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regset->nregs = ARRAY_SIZE(bcm2835_thermal_regs);
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regset->base = data->regs;
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debugfs_create_regset32("regset", 0444, data->debugfsdir, regset);
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}
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static const struct thermal_zone_of_device_ops bcm2835_thermal_ops = {
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.get_temp = bcm2835_thermal_get_temp,
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};
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/*
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* Note: as per Raspberry Foundation FAQ
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* (https://www.raspberrypi.org/help/faqs/#performanceOperatingTemperature)
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* the recommended temperature range for the SoC -40C to +85C
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* so the trip limit is set to 80C.
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* this applies to all the BCM283X SoC
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*/
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static const struct of_device_id bcm2835_thermal_of_match_table[] = {
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{
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.compatible = "brcm,bcm2835-thermal",
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},
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{
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.compatible = "brcm,bcm2836-thermal",
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},
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{
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.compatible = "brcm,bcm2837-thermal",
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},
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{},
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};
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MODULE_DEVICE_TABLE(of, bcm2835_thermal_of_match_table);
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static int bcm2835_thermal_probe(struct platform_device *pdev)
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{
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const struct of_device_id *match;
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struct thermal_zone_device *tz;
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struct bcm2835_thermal_data *data;
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struct resource *res;
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int err = 0;
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u32 val;
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unsigned long rate;
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data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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match = of_match_device(bcm2835_thermal_of_match_table,
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&pdev->dev);
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if (!match)
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return -EINVAL;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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data->regs = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(data->regs)) {
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err = PTR_ERR(data->regs);
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dev_err(&pdev->dev, "Could not get registers: %d\n", err);
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return err;
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}
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data->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(data->clk)) {
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err = PTR_ERR(data->clk);
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if (err != -EPROBE_DEFER)
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dev_err(&pdev->dev, "Could not get clk: %d\n", err);
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return err;
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}
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err = clk_prepare_enable(data->clk);
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if (err)
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return err;
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rate = clk_get_rate(data->clk);
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if ((rate < 1920000) || (rate > 5000000))
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dev_warn(&pdev->dev,
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"Clock %pCn running at %lu Hz is outside of the recommended range: 1.92 to 5MHz\n",
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data->clk, rate);
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/* register of thermal sensor and get info from DT */
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tz = thermal_zone_of_sensor_register(&pdev->dev, 0, data,
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&bcm2835_thermal_ops);
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if (IS_ERR(tz)) {
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err = PTR_ERR(tz);
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dev_err(&pdev->dev,
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"Failed to register the thermal device: %d\n",
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err);
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goto err_clk;
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}
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/*
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* right now the FW does set up the HW-block, so we are not
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* touching the configuration registers.
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* But if the HW is not enabled, then set it up
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* using "sane" values used by the firmware right now.
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*/
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val = readl(data->regs + BCM2835_TS_TSENSCTL);
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if (!(val & BCM2835_TS_TSENSCTL_RSTB)) {
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int trip_temp, offset, slope;
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slope = thermal_zone_get_slope(tz);
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offset = thermal_zone_get_offset(tz);
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/*
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* For now we deal only with critical, otherwise
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* would need to iterate
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*/
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err = tz->ops->get_trip_temp(tz, 0, &trip_temp);
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if (err < 0) {
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dev_err(&pdev->dev,
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"Not able to read trip_temp: %d\n",
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err);
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goto err_tz;
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}
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/* set bandgap reference voltage and enable voltage regulator */
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val = (BCM2835_TS_TSENSCTL_CTRL_DEFAULT <<
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BCM2835_TS_TSENSCTL_CTRL_SHIFT) |
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BCM2835_TS_TSENSCTL_REGULEN;
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/* use the recommended reset duration */
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val |= (0xFE << BCM2835_TS_TSENSCTL_RSTDELAY_SHIFT);
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/* trip_adc value from info */
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val |= bcm2835_thermal_temp2adc(trip_temp,
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offset,
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slope)
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<< BCM2835_TS_TSENSCTL_THOLD_SHIFT;
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/* write the value back to the register as 2 steps */
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writel(val, data->regs + BCM2835_TS_TSENSCTL);
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val |= BCM2835_TS_TSENSCTL_RSTB;
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writel(val, data->regs + BCM2835_TS_TSENSCTL);
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}
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data->tz = tz;
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platform_set_drvdata(pdev, data);
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/*
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* Thermal_zone doesn't enable hwmon as default,
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* enable it here
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*/
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tz->tzp->no_hwmon = false;
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err = thermal_add_hwmon_sysfs(tz);
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if (err)
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goto err_tz;
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bcm2835_thermal_debugfs(pdev);
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return 0;
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err_tz:
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thermal_zone_of_sensor_unregister(&pdev->dev, tz);
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err_clk:
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clk_disable_unprepare(data->clk);
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return err;
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}
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static int bcm2835_thermal_remove(struct platform_device *pdev)
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{
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struct bcm2835_thermal_data *data = platform_get_drvdata(pdev);
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struct thermal_zone_device *tz = data->tz;
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debugfs_remove_recursive(data->debugfsdir);
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thermal_zone_of_sensor_unregister(&pdev->dev, tz);
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clk_disable_unprepare(data->clk);
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return 0;
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}
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static struct platform_driver bcm2835_thermal_driver = {
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.probe = bcm2835_thermal_probe,
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.remove = bcm2835_thermal_remove,
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.driver = {
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.name = "bcm2835_thermal",
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.of_match_table = bcm2835_thermal_of_match_table,
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},
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};
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module_platform_driver(bcm2835_thermal_driver);
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MODULE_AUTHOR("Martin Sperl");
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MODULE_DESCRIPTION("Thermal driver for bcm2835 chip");
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MODULE_LICENSE("GPL");
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