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authorTuomas Tynkkynen <ttynkkynen@nvidia.com>2015-05-13 17:58:48 +0300
committerThierry Reding <treding@nvidia.com>2015-07-16 09:34:09 +0200
commit9eb15dbbfa1a23b5e65efaf1d5d6c47798e7264b (patch)
tree0cb5e613376fd40affefb2a340d0330cb905d487 /drivers/cpufreq
parent109e13eaa40dfebf8893234cc5f1535a04e23acf (diff)
downloadlinux-9eb15dbbfa1a23b5e65efaf1d5d6c47798e7264b.tar.bz2
cpufreq: Add cpufreq driver for Tegra124
Add a new cpufreq driver for Tegra124. Instead of using the PLLX as the CPU clocksource, switch immediately to the DFLL. It allows the use of higher clock rates, and will automatically scale the CPU voltage as well. Besides the CPU clocksource switch, we let the cpufreq-dt driver for all the cpufreq operations. This driver also relies on the DFLL driver to fill the OPP table for the CPU0 device, so that the cpufreq-dt driver knows what frequencies to use. Signed-off-by: Tuomas Tynkkynen <ttynkkynen@nvidia.com> Signed-off-by: Mikko Perttunen <mikko.perttunen@kapsi.fi> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Thierry Reding <treding@nvidia.com>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/Kconfig.arm7
-rw-r--r--drivers/cpufreq/Makefile1
-rw-r--r--drivers/cpufreq/tegra124-cpufreq.c214
3 files changed, 222 insertions, 0 deletions
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index ef402869576f..24e5c664683f 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -254,6 +254,13 @@ config ARM_TEGRA20_CPUFREQ
help
This adds the CPUFreq driver support for Tegra20 SOCs.
+config ARM_TEGRA124_CPUFREQ
+ tristate "Tegra124 CPUFreq support"
+ depends on ARCH_TEGRA && CPUFREQ_DT
+ default y
+ help
+ This adds the CPUFreq driver support for Tegra124 SOCs.
+
config ARM_PXA2xx_CPUFREQ
tristate "Intel PXA2xx CPUfreq driver"
depends on PXA27x || PXA25x
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index d0b70ce56dd7..032745de8fcc 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -77,6 +77,7 @@ obj-$(CONFIG_ARM_SA1100_CPUFREQ) += sa1100-cpufreq.o
obj-$(CONFIG_ARM_SA1110_CPUFREQ) += sa1110-cpufreq.o
obj-$(CONFIG_ARM_SPEAR_CPUFREQ) += spear-cpufreq.o
obj-$(CONFIG_ARM_TEGRA20_CPUFREQ) += tegra20-cpufreq.o
+obj-$(CONFIG_ARM_TEGRA124_CPUFREQ) += tegra124-cpufreq.o
obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ) += vexpress-spc-cpufreq.o
##################################################################################
diff --git a/drivers/cpufreq/tegra124-cpufreq.c b/drivers/cpufreq/tegra124-cpufreq.c
new file mode 100644
index 000000000000..20bcceb58ccc
--- /dev/null
+++ b/drivers/cpufreq/tegra124-cpufreq.c
@@ -0,0 +1,214 @@
+/*
+ * Tegra 124 cpufreq driver
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/clk.h>
+#include <linux/cpufreq-dt.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_opp.h>
+#include <linux/regulator/consumer.h>
+#include <linux/types.h>
+
+struct tegra124_cpufreq_priv {
+ struct regulator *vdd_cpu_reg;
+ struct clk *cpu_clk;
+ struct clk *pllp_clk;
+ struct clk *pllx_clk;
+ struct clk *dfll_clk;
+ struct platform_device *cpufreq_dt_pdev;
+};
+
+static int tegra124_cpu_switch_to_dfll(struct tegra124_cpufreq_priv *priv)
+{
+ struct clk *orig_parent;
+ int ret;
+
+ ret = clk_set_rate(priv->dfll_clk, clk_get_rate(priv->cpu_clk));
+ if (ret)
+ return ret;
+
+ orig_parent = clk_get_parent(priv->cpu_clk);
+ clk_set_parent(priv->cpu_clk, priv->pllp_clk);
+
+ ret = clk_prepare_enable(priv->dfll_clk);
+ if (ret)
+ goto out;
+
+ clk_set_parent(priv->cpu_clk, priv->dfll_clk);
+
+ return 0;
+
+out:
+ clk_set_parent(priv->cpu_clk, orig_parent);
+
+ return ret;
+}
+
+static void tegra124_cpu_switch_to_pllx(struct tegra124_cpufreq_priv *priv)
+{
+ clk_set_parent(priv->cpu_clk, priv->pllp_clk);
+ clk_disable_unprepare(priv->dfll_clk);
+ regulator_sync_voltage(priv->vdd_cpu_reg);
+ clk_set_parent(priv->cpu_clk, priv->pllx_clk);
+}
+
+static struct cpufreq_dt_platform_data cpufreq_dt_pd = {
+ .independent_clocks = false,
+};
+
+static int tegra124_cpufreq_probe(struct platform_device *pdev)
+{
+ struct tegra124_cpufreq_priv *priv;
+ struct device_node *np;
+ struct device *cpu_dev;
+ struct platform_device_info cpufreq_dt_devinfo = {};
+ int ret;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ cpu_dev = get_cpu_device(0);
+ if (!cpu_dev)
+ return -ENODEV;
+
+ np = of_cpu_device_node_get(0);
+ if (!np)
+ return -ENODEV;
+
+ priv->vdd_cpu_reg = regulator_get(cpu_dev, "vdd-cpu");
+ if (IS_ERR(priv->vdd_cpu_reg)) {
+ ret = PTR_ERR(priv->vdd_cpu_reg);
+ goto out_put_np;
+ }
+
+ priv->cpu_clk = of_clk_get_by_name(np, "cpu_g");
+ if (IS_ERR(priv->cpu_clk)) {
+ ret = PTR_ERR(priv->cpu_clk);
+ goto out_put_vdd_cpu_reg;
+ }
+
+ priv->dfll_clk = of_clk_get_by_name(np, "dfll");
+ if (IS_ERR(priv->dfll_clk)) {
+ ret = PTR_ERR(priv->dfll_clk);
+ goto out_put_cpu_clk;
+ }
+
+ priv->pllx_clk = of_clk_get_by_name(np, "pll_x");
+ if (IS_ERR(priv->pllx_clk)) {
+ ret = PTR_ERR(priv->pllx_clk);
+ goto out_put_dfll_clk;
+ }
+
+ priv->pllp_clk = of_clk_get_by_name(np, "pll_p");
+ if (IS_ERR(priv->pllp_clk)) {
+ ret = PTR_ERR(priv->pllp_clk);
+ goto out_put_pllx_clk;
+ }
+
+ ret = tegra124_cpu_switch_to_dfll(priv);
+ if (ret)
+ goto out_put_pllp_clk;
+
+ cpufreq_dt_devinfo.name = "cpufreq-dt";
+ cpufreq_dt_devinfo.parent = &pdev->dev;
+ cpufreq_dt_devinfo.data = &cpufreq_dt_pd;
+ cpufreq_dt_devinfo.size_data = sizeof(cpufreq_dt_pd);
+
+ priv->cpufreq_dt_pdev =
+ platform_device_register_full(&cpufreq_dt_devinfo);
+ if (IS_ERR(priv->cpufreq_dt_pdev)) {
+ ret = PTR_ERR(priv->cpufreq_dt_pdev);
+ goto out_switch_to_pllx;
+ }
+
+ platform_set_drvdata(pdev, priv);
+
+ return 0;
+
+out_switch_to_pllx:
+ tegra124_cpu_switch_to_pllx(priv);
+out_put_pllp_clk:
+ clk_put(priv->pllp_clk);
+out_put_pllx_clk:
+ clk_put(priv->pllx_clk);
+out_put_dfll_clk:
+ clk_put(priv->dfll_clk);
+out_put_cpu_clk:
+ clk_put(priv->cpu_clk);
+out_put_vdd_cpu_reg:
+ regulator_put(priv->vdd_cpu_reg);
+out_put_np:
+ of_node_put(np);
+
+ return ret;
+}
+
+static int tegra124_cpufreq_remove(struct platform_device *pdev)
+{
+ struct tegra124_cpufreq_priv *priv = platform_get_drvdata(pdev);
+
+ platform_device_unregister(priv->cpufreq_dt_pdev);
+ tegra124_cpu_switch_to_pllx(priv);
+
+ clk_put(priv->pllp_clk);
+ clk_put(priv->pllx_clk);
+ clk_put(priv->dfll_clk);
+ clk_put(priv->cpu_clk);
+ regulator_put(priv->vdd_cpu_reg);
+
+ return 0;
+}
+
+static struct platform_driver tegra124_cpufreq_platdrv = {
+ .driver.name = "cpufreq-tegra124",
+ .probe = tegra124_cpufreq_probe,
+ .remove = tegra124_cpufreq_remove,
+};
+
+static int __init tegra_cpufreq_init(void)
+{
+ int ret;
+ struct platform_device *pdev;
+
+ if (!of_machine_is_compatible("nvidia,tegra124"))
+ return -ENODEV;
+
+ /*
+ * Platform driver+device required for handling EPROBE_DEFER with
+ * the regulator and the DFLL clock
+ */
+ ret = platform_driver_register(&tegra124_cpufreq_platdrv);
+ if (ret)
+ return ret;
+
+ pdev = platform_device_register_simple("cpufreq-tegra124", -1, NULL, 0);
+ if (IS_ERR(pdev)) {
+ platform_driver_unregister(&tegra124_cpufreq_platdrv);
+ return PTR_ERR(pdev);
+ }
+
+ return 0;
+}
+module_init(tegra_cpufreq_init);
+
+MODULE_AUTHOR("Tuomas Tynkkynen <ttynkkynen@nvidia.com>");
+MODULE_DESCRIPTION("cpufreq driver for NVIDIA Tegra124");
+MODULE_LICENSE("GPL v2");