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: Leonard Crestez <leonard.crestez@nxp.com>
Tested-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
index 0b1df12..37dc40d 100644 (file)
--- a/drivers/devfreq/Kconfig
+++ b/drivers/devfreq/Kconfig
@@ -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) || \

diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
index 3eb4d5e..3ca1ad0 100644 (file)
--- a/drivers/devfreq/Makefile
+++ b/drivers/devfreq/Makefile
@@ -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

diff --git a/drivers/devfreq/imx-bus.c b/drivers/devfreq/imx-bus.c
new file mode 100644 (file)
index 0000000..428f798
--- /dev/null
+++ b/drivers/devfreq/imx-bus.c
@@ -0,0 +1,138 @@
+// 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");