@@ -454,6 +454,16 @@ config PWM_TEGRA
To compile this driver as a module, choose M here: the module
will be called pwm-tegra.
+config PWM_TEGRA_TACHOMETER
+ tristate "NVIDIA Tegra Tachometer PWM driver"
+ depends on ARCH_TEGRA
+ help
+ NVIDIA Tegra Tachometer reads the PWM signal and reports the PWM
+ signal periods. This helps in measuring the fan speed where Fan
+ output for speed is PWM signal.
+
+ This driver support the Tachometer driver in PWM framework.
+
config PWM_TIECAP
tristate "ECAP PWM support"
depends on ARCH_OMAP2PLUS || ARCH_DAVINCI_DA8XX || ARCH_KEYSTONE
@@ -45,6 +45,7 @@ obj-$(CONFIG_PWM_STM32_LP) += pwm-stm32-lp.o
obj-$(CONFIG_PWM_STMPE) += pwm-stmpe.o
obj-$(CONFIG_PWM_SUN4I) += pwm-sun4i.o
obj-$(CONFIG_PWM_TEGRA) += pwm-tegra.o
+obj-$(CONFIG_PWM_TEGRA_TACHOMETER) += pwm-tegra-tachometer.o
obj-$(CONFIG_PWM_TIECAP) += pwm-tiecap.o
obj-$(CONFIG_PWM_TIEHRPWM) += pwm-tiehrpwm.o
obj-$(CONFIG_PWM_TIPWMSS) += pwm-tipwmss.o
new file mode 100644
@@ -0,0 +1,303 @@
+/*
+ * Tegra Tachometer Pulse-Width-Modulation driver
+ *
+ * Copyright (c) 2017-2018, NVIDIA CORPORATION. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+
+/* Since oscillator clock (38.4MHz) serves as a clock source for
+ * the tach input controller, 1.0105263MHz (i.e. 38.4/38) has to be
+ * used as a clock value in the RPM calculations
+ */
+#define TACH_COUNTER_CLK 1010526
+
+#define TACH_FAN_TACH0 0x0
+#define TACH_FAN_TACH0_PERIOD_MASK 0x7FFFF
+#define TACH_FAN_TACH0_PERIOD_MAX 0x7FFFF
+#define TACH_FAN_TACH0_PERIOD_MIN 0x0
+#define TACH_FAN_TACH0_WIN_LENGTH_SHIFT 25
+#define TACH_FAN_TACH0_WIN_LENGTH_MASK 0x3
+#define TACH_FAN_TACH0_OVERFLOW_MASK BIT(24)
+
+#define TACH_FAN_TACH1 0x4
+#define TACH_FAN_TACH1_HI_MASK 0x7FFFF
+/*
+ * struct pwm_tegra_tach - Tegra tachometer object
+ * @dev: device providing the Tachometer
+ * @pulse_per_rev: Pulses per revolution of a Fan
+ * @capture_window_len: Defines the window of the FAN TACH monitor
+ * @regs: physical base addresses of the controller
+ * @clk: phandle list of tachometer clocks
+ * @rst: phandle to reset the controller
+ * @chip: PWM chip providing this PWM device
+ */
+struct pwm_tegra_tach {
+ struct device *dev;
+ void __iomem *regs;
+ struct clk *clk;
+ struct reset_control *rst;
+ u32 pulse_per_rev;
+ u32 capture_window_len;
+ struct pwm_chip chip;
+};
+
+static struct pwm_tegra_tach *to_tegra_pwm_chip(struct pwm_chip *chip)
+{
+ return container_of(chip, struct pwm_tegra_tach, chip);
+}
+
+static u32 tachometer_readl(struct pwm_tegra_tach *ptt, unsigned long reg)
+{
+ return readl(ptt->regs + reg);
+}
+
+static inline void tachometer_writel(struct pwm_tegra_tach *ptt, u32 val,
+ unsigned long reg)
+{
+ writel(val, ptt->regs + reg);
+}
+
+static int pwm_tegra_tach_set_wlen(struct pwm_tegra_tach *ptt,
+ u32 window_length)
+{
+ u32 tach0, wlen;
+
+ /*
+ * As per FAN Spec, the window length value should be greater than or
+ * equal to Pulses Per Revolution value to measure the time period
+ * values accurately.
+ */
+ if (ptt->pulse_per_rev > ptt->capture_window_len) {
+ dev_err(ptt->dev,
+ "Window length value < pulses per revolution value\n");
+ return -EINVAL;
+ }
+
+ if (hweight8(window_length) != 1) {
+ dev_err(ptt->dev,
+ "Valid value of window length is {1, 2, 4 or 8}\n");
+ return -EINVAL;
+ }
+
+ wlen = ffs(window_length) - 1;
+ tach0 = tachometer_readl(ptt, TACH_FAN_TACH0);
+ tach0 &= ~(TACH_FAN_TACH0_WIN_LENGTH_MASK <<
+ TACH_FAN_TACH0_WIN_LENGTH_SHIFT);
+ tach0 |= wlen << TACH_FAN_TACH0_WIN_LENGTH_SHIFT;
+ tachometer_writel(ptt, tach0, TACH_FAN_TACH0);
+
+ return 0;
+}
+
+static int pwm_tegra_tach_capture(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ struct pwm_capture *result,
+ unsigned long timeout)
+{
+ struct pwm_tegra_tach *ptt = to_tegra_pwm_chip(chip);
+ unsigned long period;
+ u32 tach;
+
+ tach = tachometer_readl(ptt, TACH_FAN_TACH1);
+ result->duty_cycle = tach & TACH_FAN_TACH1_HI_MASK;
+
+ tach = tachometer_readl(ptt, TACH_FAN_TACH0);
+ if (tach & TACH_FAN_TACH0_OVERFLOW_MASK) {
+ /* Fan is stalled, clear overflow state by writing 1 */
+ dev_dbg(ptt->dev, "Tachometer Overflow is detected\n");
+ tachometer_writel(ptt, tach, TACH_FAN_TACH0);
+ }
+
+ period = tach & TACH_FAN_TACH0_PERIOD_MASK;
+ if ((period == TACH_FAN_TACH0_PERIOD_MIN) ||
+ (period == TACH_FAN_TACH0_PERIOD_MAX)) {
+ dev_dbg(ptt->dev, "Period set to min/max 0x%lx, Invalid RPM\n",
+ period);
+ result->period = 0;
+ result->duty_cycle = 0;
+ return 0;
+ }
+
+ period = period + 1;
+
+ period = DIV_ROUND_CLOSEST_ULL(period * ptt->pulse_per_rev * 1000000ULL,
+ ptt->capture_window_len *
+ TACH_COUNTER_CLK);
+
+ /*
+ * period & duty cycle values are in units of micro seconds.
+ * Hence, convert them into nano seconds and store.
+ */
+ result->period = period * 1000;
+ result->duty_cycle = result->duty_cycle * 1000;
+
+ return 0;
+}
+
+static const struct pwm_ops pwm_tegra_tach_ops = {
+ .capture = pwm_tegra_tach_capture,
+ .owner = THIS_MODULE,
+};
+
+static int pwm_tegra_tach_read_platform_data(struct pwm_tegra_tach *ptt)
+{
+ struct device_node *np = ptt->dev->of_node;
+ u32 pval;
+ int err = 0;
+
+ err = of_property_read_u32(np, "nvidia,pulse-per-rev", &pval);
+ if (err < 0) {
+ dev_err(ptt->dev,
+ "\"nvidia,pulse-per-rev\" property is missing\n");
+ return err;
+ }
+ ptt->pulse_per_rev = pval;
+
+ err = of_property_read_u32(np, "nvidia,capture-window-len", &pval);
+ if (err < 0) {
+ dev_err(ptt->dev,
+ "\"nvidia,capture-window-len\" property is missing\n");
+ return err;
+ }
+ ptt->capture_window_len = pval;
+
+ return err;
+}
+
+static int pwm_tegra_tach_probe(struct platform_device *pdev)
+{
+ struct pwm_tegra_tach *ptt;
+ struct resource *res;
+ int err = 0;
+
+ ptt = devm_kzalloc(&pdev->dev, sizeof(*ptt), GFP_KERNEL);
+ if (!ptt)
+ return -ENOMEM;
+
+ ptt->dev = &pdev->dev;
+
+ err = pwm_tegra_tach_read_platform_data(ptt);
+ if (err < 0)
+ return err;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ ptt->regs = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(ptt->regs)) {
+ dev_err(&pdev->dev, "Failed to remap I/O memory\n");
+ return PTR_ERR(ptt->regs);
+ }
+
+ platform_set_drvdata(pdev, ptt);
+
+ ptt->clk = devm_clk_get(&pdev->dev, "tach");
+ if (IS_ERR(ptt->clk)) {
+ err = PTR_ERR(ptt->clk);
+ dev_err(&pdev->dev, "Failed to get Tachometer clk: %d\n", err);
+ return err;
+ }
+
+ ptt->rst = devm_reset_control_get(&pdev->dev, "tach");
+ if (IS_ERR(ptt->rst)) {
+ err = PTR_ERR(ptt->rst);
+ dev_err(&pdev->dev, "Failed to get reset handle: %d\n", err);
+ return err;
+ }
+
+ err = clk_prepare_enable(ptt->clk);
+ if (err < 0) {
+ dev_err(&pdev->dev, "Failed to prepare clock: %d\n", err);
+ return err;
+ }
+
+ err = clk_set_rate(ptt->clk, TACH_COUNTER_CLK);
+ if (err < 0) {
+ dev_err(&pdev->dev, "Failed to set clock rate %d: %d\n",
+ TACH_COUNTER_CLK, err);
+ goto clk_unprep;
+ }
+
+ reset_control_reset(ptt->rst);
+
+ ptt->chip.dev = &pdev->dev;
+ ptt->chip.ops = &pwm_tegra_tach_ops;
+ ptt->chip.base = -1;
+ ptt->chip.npwm = 1;
+
+ err = pwmchip_add(&ptt->chip);
+ if (err < 0) {
+ dev_err(&pdev->dev, "Failed to add tachometer PWM: %d\n", err);
+ goto reset_assert;
+ }
+
+ err = pwm_tegra_tach_set_wlen(ptt, ptt->capture_window_len);
+ if (err < 0) {
+ dev_err(ptt->dev, "Failed to set window length: %d\n", err);
+ goto pwm_remove;
+ }
+
+ return 0;
+
+pwm_remove:
+ pwmchip_remove(&ptt->chip);
+
+reset_assert:
+ reset_control_assert(ptt->rst);
+
+clk_unprep:
+ clk_disable_unprepare(ptt->clk);
+
+ return err;
+}
+
+static int pwm_tegra_tach_remove(struct platform_device *pdev)
+{
+ struct pwm_tegra_tach *ptt = platform_get_drvdata(pdev);
+
+ reset_control_assert(ptt->rst);
+
+ clk_disable_unprepare(ptt->clk);
+
+ return pwmchip_remove(&ptt->chip);
+}
+
+static const struct of_device_id pwm_tegra_tach_of_match[] = {
+ { .compatible = "nvidia,tegra186-pwm-tachometer" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, pwm_tegra_tach_of_match);
+
+static struct platform_driver tegra_tach_driver = {
+ .driver = {
+ .name = "pwm-tegra-tachometer",
+ .of_match_table = pwm_tegra_tach_of_match,
+ },
+ .probe = pwm_tegra_tach_probe,
+ .remove = pwm_tegra_tach_remove,
+};
+
+module_platform_driver(tegra_tach_driver);
+
+MODULE_DESCRIPTION("PWM based NVIDIA Tegra Tachometer driver");
+MODULE_AUTHOR("Rajkumar Rampelli <rrajk@nvidia.com>");
+MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
+MODULE_LICENSE("GPL v2");