Hi Leonard,
As I replied on v1 mail thread, it needs a dt-binding document
under Documentation/devicetree/bindings/devfreq.
And I add one comment below. Except for them, looks good to me.
On 4/1/20 11:33 PM, Leonard Crestez wrote:
> Add initial support for dynamic frequency switching on pieces of the imx
> interconnect fabric.
>
> All this driver does is set a clk rate based on an opp table, it does
> not map register areas.
>
> Signed-off-by: Leonard Crestez <leonard.crestez@xxxxxxx>
> Tested-by: Martin Kepplinger <martin.kepplinger@xxxxxxx>
> ---
> drivers/devfreq/Kconfig | 8 +++
> drivers/devfreq/Makefile | 1 +
> drivers/devfreq/imx-bus.c | 139 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 148 insertions(+)
> create mode 100644 drivers/devfreq/imx-bus.c
>
> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
> index 0b1df12e0f21..37dc40d1fcfb 100644
> --- a/drivers/devfreq/Kconfig
> +++ b/drivers/devfreq/Kconfig
> @@ -89,10 +89,18 @@ config ARM_EXYNOS_BUS_DEVFREQ
> Each memory bus group could contain many memoby bus block. It reads
> PPMU counters of memory controllers by using DEVFREQ-event device
> and adjusts the operating frequencies and voltages with OPP support.
> This does not yet operate with optimal voltages.
>
> +config ARM_IMX_BUS_DEVFREQ
> + tristate "i.MX Generic Bus DEVFREQ Driver"
> + depends on ARCH_MXC || COMPILE_TEST
> + select DEVFREQ_GOV_USERSPACE
> + help
> + This adds the generic DEVFREQ driver for i.MX interconnects. It
> + allows adjusting NIC/NOC frequency.
> +
> config ARM_IMX8M_DDRC_DEVFREQ
> tristate "i.MX8M DDRC DEVFREQ Driver"
> depends on (ARCH_MXC && HAVE_ARM_SMCCC) || \
> (COMPILE_TEST && HAVE_ARM_SMCCC)
> select DEVFREQ_GOV_SIMPLE_ONDEMAND
> diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
> index 3eb4d5e6635c..3ca1ad0ecb97 100644
> --- a/drivers/devfreq/Makefile
> +++ b/drivers/devfreq/Makefile
> @@ -7,10 +7,11 @@ obj-$(CONFIG_DEVFREQ_GOV_POWERSAVE) += governor_powersave.o
> obj-$(CONFIG_DEVFREQ_GOV_USERSPACE) += governor_userspace.o
> obj-$(CONFIG_DEVFREQ_GOV_PASSIVE) += governor_passive.o
>
> # DEVFREQ Drivers
> obj-$(CONFIG_ARM_EXYNOS_BUS_DEVFREQ) += exynos-bus.o
> +obj-$(CONFIG_ARM_IMX_BUS_DEVFREQ) += imx-bus.o
> obj-$(CONFIG_ARM_IMX8M_DDRC_DEVFREQ) += imx8m-ddrc.o
> obj-$(CONFIG_ARM_RK3399_DMC_DEVFREQ) += rk3399_dmc.o
> obj-$(CONFIG_ARM_TEGRA_DEVFREQ) += tegra30-devfreq.o
> obj-$(CONFIG_ARM_TEGRA20_DEVFREQ) += tegra20-devfreq.o
>
> diff --git a/drivers/devfreq/imx-bus.c b/drivers/devfreq/imx-bus.c
> new file mode 100644
> index 000000000000..7915d7277349
> --- /dev/null
> +++ b/drivers/devfreq/imx-bus.c
> @@ -0,0 +1,139 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2019 NXP
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/devfreq.h>
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/pm_opp.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +struct imx_bus {
> + struct devfreq_dev_profile profile;
> + struct devfreq *devfreq;
> + struct clk *clk;
> +};
> +
> +static int imx_bus_target(struct device *dev,
> + unsigned long *freq, u32 flags)
> +{
> + struct imx_bus *priv = dev_get_drvdata(dev);
It is not used. Need to remove it.
> + struct dev_pm_opp *new_opp;
> + int ret;
> +
> + new_opp = devfreq_recommended_opp(dev, freq, flags);
> + if (IS_ERR(new_opp)) {
> + ret = PTR_ERR(new_opp);
> + dev_err(dev, "failed to get recommended opp: %d\n", ret);
> + return ret;
> + }
> + dev_pm_opp_put(new_opp);
> +
> + return dev_pm_opp_set_rate(dev, *freq);
> +}
> +
> +static int imx_bus_get_cur_freq(struct device *dev, unsigned long *freq)
> +{
> + struct imx_bus *priv = dev_get_drvdata(dev);
> +
> + *freq = clk_get_rate(priv->clk);
> +
> + return 0;
> +}
> +
> +static int imx_bus_get_dev_status(struct device *dev,
> + struct devfreq_dev_status *stat)
> +{
> + struct imx_bus *priv = dev_get_drvdata(dev);
> +
> + stat->busy_time = 0;
> + stat->total_time = 0;
> + stat->current_frequency = clk_get_rate(priv->clk);
> +
> + return 0;
> +}
> +
> +static void imx_bus_exit(struct device *dev)
> +{
> + dev_pm_opp_of_remove_table(dev);
> +}
> +
> +static int imx_bus_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct imx_bus *priv;
> + const char *gov = DEVFREQ_GOV_USERSPACE;
> + int ret;
> +
> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + /*
> + * Fetch the clock to adjust but don't explicitly enable.
> + *
> + * For imx bus clock clk_set_rate is safe no matter if the clock is on
> + * or off and some peripheral side-buses might be off unless enabled by
> + * drivers for devices on those specific buses.
> + *
> + * Rate adjustment on a disabled bus clock just takes effect later.
> + */
> + priv->clk = devm_clk_get(dev, NULL);
> + if (IS_ERR(priv->clk)) {
> + ret = PTR_ERR(priv->clk);
> + dev_err(dev, "failed to fetch clk: %d\n", ret);
> + return ret;
> + }
> + platform_set_drvdata(pdev, priv);
> +
> + ret = dev_pm_opp_of_add_table(dev);
> + if (ret < 0) {
> + dev_err(dev, "failed to get OPP table\n");
> + return ret;
> + }
> +
> + priv->profile.polling_ms = 1000;
> + priv->profile.target = imx_bus_target;
> + priv->profile.get_dev_status = imx_bus_get_dev_status;
> + priv->profile.exit = imx_bus_exit;
> + priv->profile.get_cur_freq = imx_bus_get_cur_freq;
> + priv->profile.initial_freq = clk_get_rate(priv->clk);
> +
> + priv->devfreq = devm_devfreq_add_device(dev, &priv->profile,
> + gov, NULL);
> + if (IS_ERR(priv->devfreq)) {
> + ret = PTR_ERR(priv->devfreq);
> + dev_err(dev, "failed to add devfreq device: %d\n", ret);
> + goto err;
> + }
> +
> + return 0;
> +
> +err:
> + dev_pm_opp_of_remove_table(dev);
> + return ret;
> +}
> +
> +static const struct of_device_id imx_bus_of_match[] = {
> + { .compatible = "fsl,imx8m-noc", },
> + { .compatible = "fsl,imx8m-nic", },
> + { /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, imx_bus_of_match);
> +
> +static struct platform_driver imx_bus_platdrv = {
> + .probe = imx_bus_probe,
> + .driver = {
> + .name = "imx-bus-devfreq",
> + .of_match_table = of_match_ptr(imx_bus_of_match),
> + },
> +};
> +module_platform_driver(imx_bus_platdrv);
> +
> +MODULE_DESCRIPTION("Generic i.MX bus frequency scaling driver");
> +MODULE_AUTHOR("Leonard Crestez <leonard.crestez@xxxxxxx>");
> +MODULE_LICENSE("GPL v2");
>
--
Best Regards,
Chanwoo Choi
Samsung Electronics
