Hi Nicolas,
Am 04.06.19 um 19:32 schrieb Nicolas Saenz Julienne:
> 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.
>
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulie...@suse.de>
> ---
>
> Changes since RFC:
> - Alphabetically ordered relevant stuff
> - Updated Kconfig to select firmware interface
> - Correctly unref clk_dev after use
> - Remove all opps on failure
> - Remove use of dev_pm_opp_set_sharing_cpus()
>
> drivers/cpufreq/Kconfig.arm | 8 +++
> drivers/cpufreq/Makefile | 1 +
> drivers/cpufreq/raspberrypi-cpufreq.c | 84 +++++++++++++++++++++++++++
> 3 files changed, 93 insertions(+)
> create mode 100644 drivers/cpufreq/raspberrypi-cpufreq.c
>
> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> index f8129edc145e..556d432cc826 100644
> --- a/drivers/cpufreq/Kconfig.arm
> +++ b/drivers/cpufreq/Kconfig.arm
> @@ -133,6 +133,14 @@ 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"
> + select RASPBERRYPI_FIRMWARE
> + help
> + This adds the CPUFreq driver for Raspberry Pi
For the next version please add one patch which enables the driver and
its dependencies for bcm2835_defconfig and multi_v7_defconfig and
another patch to build as a module for arm64/defconfig.
> +
> + If in doubt, say N.
> +
> config ARM_S3C_CPUFREQ
> bool
> help
> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
> index 689b26c6f949..121c1acb66c0 100644
> --- a/drivers/cpufreq/Makefile
> +++ b/drivers/cpufreq/Makefile
> @@ -64,6 +64,7 @@ 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..2b3a195a9d37
> --- /dev/null
> +++ b/drivers/cpufreq/raspberrypi-cpufreq.c
> @@ -0,0 +1,84 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Raspberry Pi cpufreq driver
> + *
> + * Copyright (C) 2019, Nicolas Saenz Julienne <nsaenzjulie...@suse.de>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/cpu.h>
> +#include <linux/cpufreq.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_opp.h>
> +
> +static const struct of_device_id machines[] __initconst = {
> + { .compatible = "raspberrypi,3-model-b-plus" },
> + { .compatible = "raspberrypi,3-model-b" },
> + { .compatible = "raspberrypi,2-model-b" },
> + { /* sentinel */ }
> +};
> +
> +static int __init raspberrypi_cpufreq_driver_init(void)
> +{
> + struct platform_device *pdev;
> + struct device *cpu_dev;
> + unsigned long min, max;
> + unsigned long rate;
> + struct clk *clk;
> + int ret;
> +
> + if (!of_match_node(machines, of_root))
> + return -ENODEV;
> +
> + 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, 0);
Please use NULL in this context
Thanks
