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312 lines
7.9 KiB
312 lines
7.9 KiB
// 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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