Commit 5173a975 authored by Leonard Crestez's avatar Leonard Crestez Committed by Chanwoo Choi
Browse files

PM / devfreq: Add generic imx bus scaling driver 



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: default avatarLeonard Crestez <leonard.crestez@nxp.com>
Tested-by: default avatarMartin Kepplinger <martin.kepplinger@puri.sm>
Acked-by: default avatarChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: default avatarChanwoo Choi <cw00.choi@samsung.com>
parent 0716f9fd

drivers/devfreq/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -91,6 +91,14 @@ config ARM_EXYNOS_BUS_DEVFREQ 
	  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) || \

drivers/devfreq/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 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

drivers/devfreq/imx-bus.c

0 → 100644
+138 −0
Original line number Diff line number Diff line 
// 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 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@nxp.com>");

MODULE_LICENSE("GPL v2");