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-bus.c | 142 ++++++++++++++++++++++++++++++++++++++
3 files changed, 152 insertions(+)
create mode 100644 drivers/devfreq/imx-bus.c
diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
index 0b1df12e0f21..44d26192ddc4 100644
--- a/drivers/devfreq/Kconfig
+++ b/drivers/devfreq/Kconfig
@@ -99,10 +99,19 @@ 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_BUS_DEVFREQ
+ tristate "i.MX Generic Bus 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..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..285e0f1ae6b1
--- /dev/null
+++ b/drivers/devfreq/imx-bus.c
@@ -0,0 +1,142 @@
+// 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;
+ struct devfreq_passive_data passive_data;
+};
+
+static int imx_bus_target(struct device *dev,
+ unsigned long *freq, u32 flags)
+{
+ struct imx_bus *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_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 explictly 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");
--
2.17.1
