Hi,
On 11/15/19 5:09 AM, 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>
> ---
> drivers/devfreq/Kconfig | 9 ++
> drivers/devfreq/Makefile | 1 +
> drivers/devfreq/imx-devfreq.c | 150 ++++++++++++++++++++++++++++++++++
> 3 files changed, 160 insertions(+)
> create mode 100644 drivers/devfreq/imx-devfreq.c
>
> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
> index 923a6132e741..fef5ce831e90 100644
> --- a/drivers/devfreq/Kconfig
> +++ b/drivers/devfreq/Kconfig
> @@ -98,10 +98,19 @@ config ARM_IMX8M_DDRC_DEVFREQ
> select DEVFREQ_GOV_USERSPACE
> help
> This adds the DEVFREQ driver for the i.MX8M DDR Controller. It allows
> adjusting DRAM frequency.
>
> +config ARM_IMX_DEVFREQ
> + tristate "i.MX Generic DEVFREQ Driver"
> + depends on ARCH_MXC || COMPILE_TEST
> + select DEVFREQ_GOV_PASSIVE
> + select DEVFREQ_GOV_USERSPACE
> + help
> + This adds the generic DEVFREQ driver for i.MX interconnects. It
> + allows adjusting NIC/NOC frequency.
> +
> config ARM_TEGRA_DEVFREQ
> tristate "NVIDIA Tegra30/114/124/210 DEVFREQ Driver"
> depends on ARCH_TEGRA_3x_SOC || ARCH_TEGRA_114_SOC || \
> ARCH_TEGRA_132_SOC || ARCH_TEGRA_124_SOC || \
> ARCH_TEGRA_210_SOC || \
> diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
> index 3eb4d5e6635c..61d0edee16f7 100644
> --- a/drivers/devfreq/Makefile
> +++ b/drivers/devfreq/Makefile
> @@ -8,10 +8,11 @@ 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_IMX8M_DDRC_DEVFREQ) += imx8m-ddrc.o
> +obj-$(CONFIG_ARM_IMX_DEVFREQ) += imx-devfreq.o
> obj-$(CONFIG_ARM_RK3399_DMC_DEVFREQ) += rk3399_dmc.o
> obj-$(CONFIG_ARM_TEGRA_DEVFREQ) += tegra30-devfreq.o
> obj-$(CONFIG_ARM_TEGRA20_DEVFREQ) += tegra20-devfreq.o
>
> # DEVFREQ Event Drivers
> diff --git a/drivers/devfreq/imx-devfreq.c b/drivers/devfreq/imx-devfreq.c
> new file mode 100644
> index 000000000000..620b344e87aa
> --- /dev/null
> +++ b/drivers/devfreq/imx-devfreq.c
> @@ -0,0 +1,150 @@
> +// 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_devfreq {
> + struct devfreq_dev_profile profile;
> + struct devfreq *devfreq;
> + struct clk *clk;
> + struct devfreq_passive_data passive_data;
> +};
> +
> +static int imx_devfreq_target(struct device *dev,
> + unsigned long *freq, u32 flags)
Don't use space for the indentation. Please use only tab.
> +{
> + struct imx_devfreq *priv = dev_get_drvdata(dev);
> + struct dev_pm_opp *new_opp;
> + unsigned long new_freq;
> + 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;
> + }
> + new_freq = dev_pm_opp_get_freq(new_opp);
> + dev_pm_opp_put(new_opp);
> +
> + return clk_set_rate(priv->clk, new_freq);
> +}
> +
> +static int imx_devfreq_get_cur_freq(struct device *dev, unsigned long *freq)
> +{
> + struct imx_devfreq *priv = dev_get_drvdata(dev);
> +
> + *freq = clk_get_rate(priv->clk);
> +
> + return 0;
> +}
> +
> +static int imx_devfreq_get_dev_status(struct device *dev,
> + struct devfreq_dev_status *stat)
ditto. Please use tab for the indentation.
> +{
> + struct imx_devfreq *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_devfreq_exit(struct device *dev)
> +{
> + dev_pm_opp_of_remove_table(dev);
> +}
> +
> +static int imx_devfreq_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct imx_devfreq *priv;
How about changing the variable name 'priv' to 'imx' or 'imx_data'?
because it is not easy to catch the role of 'priv' from variable name.
> + const char *gov = DEVFREQ_GOV_USERSPACE;
> + void *govdata = NULL;
How about changing the variable name 'govdata' to 'gov_data'?
- govdata -> gov_data
> + int ret;
> +
> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->clk = devm_clk_get(dev, NULL);
nitpick: because the clock-name is not mandatory.
Don't need to specify the clock name to inform the role of clock
of other developer/user?
For example, "ddr", "bus" and so on.
> + 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_devfreq_target;
> + priv->profile.get_dev_status = imx_devfreq_get_dev_status;
> + priv->profile.exit = imx_devfreq_exit;
> + priv->profile.get_cur_freq = imx_devfreq_get_cur_freq;
> + priv->profile.initial_freq = clk_get_rate(priv->clk);
> +
> + /* Handle passive devfreq parent link */
> + priv->passive_data.parent = devfreq_get_devfreq_by_phandle(dev, 0);
> + if (!IS_ERR(priv->passive_data.parent)) {
> + dev_info(dev, "setup passive link to %s\n",
> + dev_name(priv->passive_data.parent->dev.parent));
> + gov = DEVFREQ_GOV_PASSIVE;
> + govdata = &priv->passive_data;
> + } else if (priv->passive_data.parent != ERR_PTR(-ENODEV)) {
> + // -ENODEV means no parent: not an error.
> + ret = PTR_ERR(priv->passive_data.parent);
> + if (ret != -EPROBE_DEFER)
> + dev_warn(dev, "failed to get initialize passive parent: %d\n",
> + ret);
> + goto err;
> + }
You better to change the exception handling as following: It is more simple.
} else if (PTR_ERR(priv->passive_data.parent) == -EPROBE_DEFER)
|| PTR_ERR(priv->passive_data.parent) == -ENODEV) {
goto err;
} else {
ret = PTR_ERR(priv->passive_data.parent);
dev_err(dev, "failed to get initialize passive parent: %d\n", ret);
goto err;
}
> +
> + priv->devfreq = devm_devfreq_add_device(dev, &priv->profile,
> + gov, govdata);
> + 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_devfreq_of_match[] = {
> + { .compatible = "fsl,imx8m-noc", },
> + { .compatible = "fsl,imx8m-nic", },
> + { /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, imx_devfreq_of_match);
> +
> +static struct platform_driver imx_devfreq_platdrv = {
> + .probe = imx_devfreq_probe,
> + .driver = {
> + .name = "imx-devfreq",
> + .of_match_table = of_match_ptr(imx_devfreq_of_match),
> + },
> +};
> +module_platform_driver(imx_devfreq_platdrv);
> +
> +MODULE_DESCRIPTION("Generic i.MX bus frequency driver");
If this driver is for bus frequency, you better to use 'bus' for the clock-name
for the readability.
> +MODULE_AUTHOR("Leonard Crestez <leonard.crestez@xxxxxxx>");
> +MODULE_LICENSE("GPL v2");
>
--
Best Regards,
Chanwoo Choi
Samsung Electronics
