/* * 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 #include #include #include #include #include #include #include #include #include #include #include #define BCM2835_TS_TSENSCTL 0x00 #define BCM2835_TS_TSENSSTAT 0x04 #define BCM2835_TS_TSENSCTL_PRWDW BIT(0) #define BCM2835_TS_TSENSCTL_RSTB BIT(1) /* * bandgap reference voltage in 6 mV increments * 000b = 1178 mV, 001b = 1184 mV, ... 111b = 1220 mV */ #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) /* * time how long the block to be asserted in reset * which based on a clock counter (TSENS clock assumed) */ #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_data { struct thermal_zone_device *tz; void __iomem *regs; struct clk *clk; struct dentry *debugfsdir; }; static int bcm2835_thermal_adc2temp(u32 adc, int offset, int slope) { return offset + slope * adc; } static int bcm2835_thermal_temp2adc(int temp, int offset, int slope) { temp -= offset; temp /= 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_temp(void *d, int *temp) { struct bcm2835_thermal_data *data = d; u32 val = readl(data->regs + BCM2835_TS_TSENSSTAT); if (!(val & BCM2835_TS_TSENSSTAT_VALID)) return -EIO; val &= BCM2835_TS_TSENSSTAT_DATA_MASK; *temp = bcm2835_thermal_adc2temp( val, thermal_zone_get_offset(data->tz), thermal_zone_get_slope(data->tz)); 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", 0444, data->debugfsdir, regset); } static const struct thermal_zone_of_device_ops bcm2835_thermal_ops = { .get_temp = bcm2835_thermal_get_temp, }; /* * 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", }, { .compatible = "brcm,bcm2836-thermal", }, { .compatible = "brcm,bcm2837-thermal", }, {}, }; MODULE_DEVICE_TABLE(of, 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 = 0; 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; 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 %lu Hz is outside of the recommended range: 1.92 to 5MHz\n", data->clk, rate); /* register of thermal sensor and get info from DT */ tz = thermal_zone_of_sensor_register(&pdev->dev, 0, data, &bcm2835_thermal_ops); if (IS_ERR(tz)) { err = PTR_ERR(tz); dev_err(&pdev->dev, "Failed to register the thermal device: %d\n", err); goto err_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)) { int trip_temp, offset, slope; slope = thermal_zone_get_slope(tz); offset = thermal_zone_get_offset(tz); /* * For now we deal only with critical, otherwise * would need to iterate */ err = tz->ops->get_trip_temp(tz, 0, &trip_temp); if (err < 0) { dev_err(&pdev->dev, "Not able to read trip_temp: %d\n", err); goto err_tz; } /* set bandgap reference voltage and enable voltage regulator */ val = (BCM2835_TS_TSENSCTL_CTRL_DEFAULT << BCM2835_TS_TSENSCTL_CTRL_SHIFT) | BCM2835_TS_TSENSCTL_REGULEN; /* use the recommended reset duration */ val |= (0xFE << BCM2835_TS_TSENSCTL_RSTDELAY_SHIFT); /* trip_adc value from info */ val |= bcm2835_thermal_temp2adc(trip_temp, offset, slope) << 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); } data->tz = tz; platform_set_drvdata(pdev, tz); bcm2835_thermal_debugfs(pdev); return 0; err_tz: thermal_zone_of_sensor_unregister(&pdev->dev, tz); err_clk: clk_disable_unprepare(data->clk); return err; } 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_of_sensor_unregister(&pdev->dev, tz); clk_disable_unprepare(data->clk); return 0; } 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");