+++ /dev/null
-From 1c0d3626312369837bc18051ed6c9611323fce87 Mon Sep 17 00:00:00 2001
-From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
-Date: Wed, 12 Jun 2019 20:24:56 +0200
-Subject: [PATCH] cpufreq: add driver for Raspberry Pi
-
-Commit d3df18a97e586702920337056540267807b23f8e upstream.
-
-Raspberry Pi's firmware offers and interface though which update it's
-performance requirements. It allows us to request for specific runtime
-frequencies, which the firmware might or might not respect, depending on
-the firmware configuration and thermals.
-
-As the maximum and minimum frequencies are configurable in the firmware
-there is no way to know in advance their values. So the Raspberry Pi
-cpufreq driver queries them, builds an opp frequency table to then
-launch cpufreq-dt.
-
-Also, as the firmware interface might be configured as a module, making
-the cpu clock unavailable during init, this implements a full fledged
-driver, as opposed to most drivers registering cpufreq-dt, which only
-make use of an init routine.
-
-Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
-Acked-by: Eric Anholt <eric@anholt.net>
-Reviewed-by: Stephen Boyd <sboyd@kernel.org>
-Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
-Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
----
- drivers/cpufreq/Kconfig.arm | 8 +++
- drivers/cpufreq/Makefile | 1 +
- drivers/cpufreq/raspberrypi-cpufreq.c | 97 +++++++++++++++++++++++++++
- 3 files changed, 106 insertions(+)
- create mode 100644 drivers/cpufreq/raspberrypi-cpufreq.c
-
---- a/drivers/cpufreq/Kconfig.arm
-+++ b/drivers/cpufreq/Kconfig.arm
-@@ -121,6 +121,14 @@ config ARM_QCOM_CPUFREQ_KRYO
-
- If in doubt, say N.
-
-+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
---- a/drivers/cpufreq/Makefile
-+++ b/drivers/cpufreq/Makefile
-@@ -65,6 +65,7 @@ obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ) += o
- obj-$(CONFIG_ARM_PXA2xx_CPUFREQ) += pxa2xx-cpufreq.o
- obj-$(CONFIG_PXA3xx) += pxa3xx-cpufreq.o
- obj-$(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
---- /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");
projects / openwrt / staging / chunkeey.git / blobdiff