diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/cpufreq/Kconfig.arm | 8 | ||||
| -rw-r--r-- | drivers/cpufreq/Makefile | 1 | ||||
| -rw-r--r-- | drivers/cpufreq/raspberrypi-cpufreq.c | 97 |
3 files changed, 106 insertions, 0 deletions
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm index 982efdf9c7e5..2499d0bccb3a 100644 --- a/drivers/cpufreq/Kconfig.arm +++ b/drivers/cpufreq/Kconfig.arm @@ -141,6 +141,14 @@ config ARM_QCOM_CPUFREQ_HW The driver implements the cpufreq interface for this HW engine. Say Y if you want to support CPUFreq HW. +config ARM_RASPBERRYPI_CPUFREQ + tristate "Raspberry Pi cpufreq support" + depends on CLK_RASPBERRYPI || COMPILE_TEST + help + This adds the CPUFreq driver for Raspberry Pi + + If in doubt, say N. + config ARM_S3C_CPUFREQ bool help diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile index 7bcda2273d0c..5a6c70d26c98 100644 --- a/drivers/cpufreq/Makefile +++ b/drivers/cpufreq/Makefile @@ -65,6 +65,7 @@ obj-$(CONFIG_ARM_PXA2xx_CPUFREQ) += pxa2xx-cpufreq.o obj-$(CONFIG_PXA3xx) += pxa3xx-cpufreq.o obj-$(CONFIG_ARM_QCOM_CPUFREQ_HW) += qcom-cpufreq-hw.o obj-$(CONFIG_ARM_QCOM_CPUFREQ_KRYO) += qcom-cpufreq-kryo.o +obj-$(CONFIG_ARM_RASPBERRYPI_CPUFREQ) += raspberrypi-cpufreq.o obj-$(CONFIG_ARM_S3C2410_CPUFREQ) += s3c2410-cpufreq.o obj-$(CONFIG_ARM_S3C2412_CPUFREQ) += s3c2412-cpufreq.o obj-$(CONFIG_ARM_S3C2416_CPUFREQ) += s3c2416-cpufreq.o diff --git a/drivers/cpufreq/raspberrypi-cpufreq.c b/drivers/cpufreq/raspberrypi-cpufreq.c new file mode 100644 index 000000000000..2bc7d9734272 --- /dev/null +++ b/drivers/cpufreq/raspberrypi-cpufreq.c @@ -0,0 +1,97 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Raspberry Pi cpufreq driver + * + * Copyright (C) 2019, Nicolas Saenz Julienne <nsaenzjulienne@suse.de> + */ + +#include <linux/clk.h> +#include <linux/cpu.h> +#include <linux/cpufreq.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/pm_opp.h> + +#define RASPBERRYPI_FREQ_INTERVAL 100000000 + +static struct platform_device *cpufreq_dt; + +static int raspberrypi_cpufreq_probe(struct platform_device *pdev) +{ + struct device *cpu_dev; + unsigned long min, max; + unsigned long rate; + struct clk *clk; + int ret; + + cpu_dev = get_cpu_device(0); + if (!cpu_dev) { + pr_err("Cannot get CPU for cpufreq driver\n"); + return -ENODEV; + } + + clk = clk_get(cpu_dev, NULL); + if (IS_ERR(clk)) { + dev_err(cpu_dev, "Cannot get clock for CPU0\n"); + return PTR_ERR(clk); + } + + /* + * The max and min frequencies are configurable in the Raspberry Pi + * firmware, so we query them at runtime. + */ + min = roundup(clk_round_rate(clk, 0), RASPBERRYPI_FREQ_INTERVAL); + max = roundup(clk_round_rate(clk, ULONG_MAX), RASPBERRYPI_FREQ_INTERVAL); + clk_put(clk); + + for (rate = min; rate <= max; rate += RASPBERRYPI_FREQ_INTERVAL) { + ret = dev_pm_opp_add(cpu_dev, rate, 0); + if (ret) + goto remove_opp; + } + + cpufreq_dt = platform_device_register_simple("cpufreq-dt", -1, NULL, 0); + ret = PTR_ERR_OR_ZERO(cpufreq_dt); + if (ret) { + dev_err(cpu_dev, "Failed to create platform device, %d\n", ret); + goto remove_opp; + } + + return 0; + +remove_opp: + dev_pm_opp_remove_all_dynamic(cpu_dev); + + return ret; +} + +static int raspberrypi_cpufreq_remove(struct platform_device *pdev) +{ + struct device *cpu_dev; + + cpu_dev = get_cpu_device(0); + if (cpu_dev) + dev_pm_opp_remove_all_dynamic(cpu_dev); + + platform_device_unregister(cpufreq_dt); + + return 0; +} + +/* + * Since the driver depends on clk-raspberrypi, which may return EPROBE_DEFER, + * all the activity is performed in the probe, which may be defered as well. + */ +static struct platform_driver raspberrypi_cpufreq_driver = { + .driver = { + .name = "raspberrypi-cpufreq", + }, + .probe = raspberrypi_cpufreq_probe, + .remove = raspberrypi_cpufreq_remove, +}; +module_platform_driver(raspberrypi_cpufreq_driver); + +MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@suse.de"); +MODULE_DESCRIPTION("Raspberry Pi cpufreq driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:raspberrypi-cpufreq"); |