[PATCH 6/6] clk: tegra: add Tegra114 FCPU DFLL clocksource platform driver

Paul Walmsley
2013-12-19T12:49:56Z

Add basic platform driver support for the fast CPU cluster DFLL
clocksource found on Tegra114 SoCs. This small driver selects the
appropriate Tegra114-specific characterization data and integration
code. It relies on the DFLL common code to do most of the work.

Signed-off-by: Paul Walmsley <pwalmsley@nvidia.com>
Cc: Aleksandr Frid <afrid@nvidia.com>
Cc: Matthew Longnecker <mlongnecker@nvidia.com>
Cc: Peter De Schrijver <pdeschrijver@nvidia.com>
Cc: Prashant Gaikwad <pgaikwad@nvidia.com>
---
drivers/clk/tegra/Kconfig | 9 +
drivers/clk/tegra/Makefile | 5 +
drivers/clk/tegra/clk-tegra114-dfll-fcpu.c | 169 ++++++++++++++++++++++++++++
3 files changed, 182 insertions(+), 1 deletion(-)
create mode 100644 drivers/clk/tegra/clk-tegra114-dfll-fcpu.c

diff --git a/drivers/clk/tegra/Kconfig b/drivers/clk/tegra/Kconfig
index 5c5d1a841ef8..b5b5069017de 100644
--- a/drivers/clk/tegra/Kconfig
+++ b/drivers/clk/tegra/Kconfig
@@ -5,5 +5,14 @@ config CLK_TEGRA_DFLL
tristate
depends on COMMON_CLK

+config CLK_TEGRA114_DFLL_FCPU
+ tristate "Clock driver for the Tegra T114 DFLL FCPU"
+ select CLK_TEGRA_DFLL
+ ---help---
+ Select this if you'd like to use the DFLL root clocksource
+ present on NVIDIA Tegra114 chips. This DFLL clocksource can
+ be used to clock the fast CPU cluster. Say 'y' or 'm' here
+ if you're building a kernel intended for use on T114 chips.
+
endmenu

diff --git a/drivers/clk/tegra/Makefile b/drivers/clk/tegra/Makefile
index 03277f640bfe..9b4b7357b97d 100644
--- a/drivers/clk/tegra/Makefile
+++ b/drivers/clk/tegra/Makefile
@@ -16,10 +16,13 @@ obj-$(CONFIG_ARCH_TEGRA_3x_SOC) += clk-tegra30.o
obj-$(CONFIG_ARCH_TEGRA_114_SOC) += clk-tegra114.o
obj-$(CONFIG_ARCH_TEGRA_124_SOC) += clk-tegra124.o
obj-$(CONFIG_CLK_TEGRA_DFLL) += clk-dfll.o
+obj-$(CONFIG_CLK_TEGRA114_DFLL_FCPU) += clk-tegra114-dfll-fcpu.o

# XXX -Wno-sign-compare is only needed due to problems with
# some non-clock-related Linux header files, and can be removed
# once those headers are fixed
CFLAGS_clk-dfll.o += -Wall -Wextra -Wno-unused-parameter \
-Wno-sign-compare
-
+CFLAGS_clk-tegra114-dfll-fcpu.o += -Wall -Wextra -Wno-unused-parameter \
+ -Wno-missing-field-initializers \
+ -Wno-sign-compare
diff --git a/drivers/clk/tegra/clk-tegra114-dfll-fcpu.c b/drivers/clk/tegra/clk-tegra114-dfll-fcpu.c
new file mode 100644
index 000000000000..1665f3cbebeb
--- /dev/null
+++ b/drivers/clk/tegra/clk-tegra114-dfll-fcpu.c
@@ -0,0 +1,169 @@
+/*
+ * clk-tegra114-dfll-fcpu.c - Tegra114 DFLL FCPU clock source driver
+ *
+ * Copyright (C) 2012-2013 NVIDIA Corporation. All rights reserved.
+ *
+ * Aleksandr Frid <afrid@nvidia.com>
+ * Paul Walmsley <pwalmsley@nvidia.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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.
+ *
+ * To do:
+ * - add support for closed-loop mode
+ * - add support for characterization constant overrides via DT
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+
+#include <linux/tegra-soc.h>
+
+#include "clk.h"
+#include "clk-dfll.h"
+
+#define DRIVER_NAME "tegra_dfll_fcpu"
+
+/*
+ * DFLL characterization values
+ */
+
+/*
+ * TUNE0_LOW_0_X_VAL: the value to be programmed into the DFLL's TUNE0
+ * register for T114 chips with a CPU Speedo ID of 0 while the DVCO is
+ * in the low-voltage range. From device characterization.
+ */
+#define TUNE0_LOW_0_X_VAL 0x00b0019d
+
+/*
+ * MIN_MV_0_X_VAL: the minimum VDD_CPU voltage that the DFLL's
+ * characterization is valid for, for T114 chips with a CPU Speedo ID
+ * of 0. Can be overridden by fuse settings; see MIN_MV_OVERRIDE_VAL.
+ */
+#define MIN_MV_0_X_VAL 1000
+
+/*
+ * MIN_MV_OVERRIDE_VAL: value to override the VDD_CPU DFLL voltage
+ * floor to, if the VDD_CPU DFLL minimum voltage override fuse is set
+ */
+#define MIN_MV_OVERRIDE_VAL 900
+
+/*
+ * TUNE0_LOW_X_X_VAL: the value to be programmed into the DFLL's TUNE0
+ * register for T114 chips with a nonzero Speedo ID while the DVCO is
+ * in the low-voltage range. From device characterization.
+ */
+#define TUNE0_LOW_X_X_VAL 0x00b0039d
+
+/*
+ * MIN_MV_X_X_VAL: the minimum VDD_CPU voltage that the DFLL's
+ * characterization is valid for, for T114 chips with a nonzero CPU
+ * Speedo ID. Can be overridden by fuse settings; see
+ * MIN_MV_OVERRIDE_VAL.
+ */
+#define MIN_MV_X_X_VAL 900
+
+/*
+ * TUNE1_VAL: the value to be programmed into the DFLL's TUNE1
+ * register, from device characterization.
+ */
+#define TUNE1_VAL 0x0000001f
+
+/*
+ * DROOP_RATE_MIN: the highest DVCO rate at which the DFLL's voltage
+ * droop protection activates
+ */
+#define DROOP_RATE_MIN 1000000
+
+
+/*
+ * Platform driver integration
+ */
+
+/**
+ * tegra114_dfll_fcpu_probe - probe the FCPU DFLL IP block
+ * @pdev: DFLL platform_device *
+ *
+ * Called when a DFLL device is bound to this driver by the driver
+ * core. Takes characterization-specific tweaks into account and sets
+ * up an instance of the DFLL driver. Returns 0 upon success, or
+ * -ENOMEM if memory couldn't be allocated, or passes along the error
+ * code from tegra_dfll_register().
+ */
+static int tegra114_dfll_fcpu_probe(struct platform_device *pdev)
+{
+ struct tegra_dfll_soc_data soc;
+ int r, speedo_id, process_id;
+
+ speedo_id = tegra_get_cpu_speedo_id();
+ process_id = tegra_get_cpu_process_id();
+
+ memset(&soc, 0, sizeof(soc));
+ soc.driver_name = DRIVER_NAME;
+ soc.tune1 = TUNE1_VAL;
+ soc.output_clock_name = "dfllCPU_out";
+ soc.assert_dvco_reset = tegra114_clock_assert_dfll_dvco_reset;
+ soc.deassert_dvco_reset = tegra114_clock_deassert_dfll_dvco_reset;
+ soc.init_clock_trimmers = tegra114_clock_tune_cpu_trimmers_low;
+ soc.set_clock_trimmers_low = tegra114_clock_tune_cpu_trimmers_low;
+ soc.set_clock_trimmers_high = tegra114_clock_tune_cpu_trimmers_high;
+
+ if ((speedo_id == 1 && (process_id == 0 || process_id == 1)) ||
+ (speedo_id == 2)) {
+ soc.tune0_low = TUNE0_LOW_X_X_VAL;
+ soc.min_millivolts = MIN_MV_X_X_VAL;
+ } else {
+ if (speedo_id != 0)
+ dev_err(&pdev->dev, "Unrecognized SoC characterization - performance may be affected\n");
+ soc.tune0_low = TUNE0_LOW_0_X_VAL;
+ soc.min_millivolts = MIN_MV_0_X_VAL;
+ }
+
+ if (tegra114_fuse_read_min_vdd_cpu_override())
+ soc.min_millivolts = MIN_MV_OVERRIDE_VAL;
+
+ r = tegra_dfll_register(pdev, &soc);
+ if (!r)
+ return r;
+
+ return 0;
+}
+
+/* Match table for OF platform binding */
+static struct of_device_id tegra114_dfll_fcpu_of_match[] = {
+ { .compatible = "nvidia,tegra114-dfll-fcpu", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, tegra114_dfll_fcpu_of_match);
+
+static const struct dev_pm_ops tegra114_dfll_pm_ops = {
+ SET_RUNTIME_PM_OPS(tegra_dfll_runtime_suspend,
+ tegra_dfll_runtime_resume, NULL)
+};
+
+static struct platform_driver tegra114_dfll_fcpu_driver = {
+ .probe = tegra114_dfll_fcpu_probe,
+ .remove = tegra_dfll_unregister,
+ .driver = {
+ .name = DRIVER_NAME,
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(tegra114_dfll_fcpu_of_match),
+ .pm = &tegra114_dfll_pm_ops,
+ },
+};
+
+module_platform_driver(tegra114_dfll_fcpu_driver);
+
+MODULE_DESCRIPTION("Tegra114 DFLL clock source driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRIVER_NAME);
+MODULE_AUTHOR("Aleksandr Frid <afrid@nvidia.com>");
+MODULE_AUTHOR("Paul Walmsley <pwalmsley@nvidia.com>");