This patch add the support of Tachometer which can use to monitor the
frequency of the input. The tach supports up to 16 channels and it's part
function of multi-function device "pwm-tach controller".
Signed-off-by: Billy Tsai <billy_tsai@xxxxxxxxxxxxxx>
Reported-by: kernel test robot <lkp@xxxxxxxxx>
---
Documentation/hwmon/index.rst | 1 +
Documentation/hwmon/tach-aspeed-ast2600.rst | 28 ++
drivers/hwmon/Kconfig | 9 +
drivers/hwmon/Makefile | 1 +
drivers/hwmon/tach-aspeed-ast2600.c | 476 ++++++++++++++++++++
5 files changed, 515 insertions(+)
create mode 100644 Documentation/hwmon/tach-aspeed-ast2600.rst
create mode 100644 drivers/hwmon/tach-aspeed-ast2600.c
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index f790f1260c33..c4c0559fd4fa 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -179,6 +179,7 @@ Hardware Monitoring Kernel Drivers
smsc47m1
sparx5-temp
stpddc60
+ tach-aspeed-ast2600
tc654
tc74
thmc50
diff --git a/Documentation/hwmon/tach-aspeed-ast2600.rst b/Documentation/hwmon/tach-aspeed-ast2600.rst
new file mode 100644
index 000000000000..8967f60672dc
--- /dev/null
+++ b/Documentation/hwmon/tach-aspeed-ast2600.rst
@@ -0,0 +1,28 @@
+Kernel driver tach-aspeed-ast2600
+==============================
+
+Supported chips:
+ ASPEED AST2600
+
+Authors:
+ <billy_tsai@xxxxxxxxxxxxxx>
+
+Description:
+------------
+This driver implements support for ASPEED AST2600 Fan Tacho controller.
+The controller supports up to 16 tachometer inputs.
+
+The driver provides the following sensor accesses in sysfs:
+=============== ======= =====================================================
+fanX_input ro provide current fan rotation value in RPM as reported
+ by the fan to the device.
+fanX_div rw Fan divisor: Supported value are power of 4 (1, 4, 16
+ 64, ... 4194304)
+ The larger divisor, the less rpm accuracy and the less
+ affected by fan signal glitch.
+fanX_min rw Fan minimum RPM which can used to change the timeout
+ value for controller polling the result.
+fanX_max rw Fan maximum RPM which can used to change the polling
+ period of the driver.
+fanX_pulses rw Fan pulses per resolution.
+=============== ======= ======================================================
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index fa2356398744..a84c15b73aa6 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -397,6 +397,15 @@ config SENSORS_ASPEED
This driver can also be built as a module. If so, the module
will be called aspeed_pwm_tacho.
+config SENSORS_TACH_ASPEED_AST2600
+ tristate "ASPEED ast2600 Tachometer support"
+ select REGMAP
+ help
+ This driver provides support for Aspeed ast2600 Tachometer.
+
+ To compile this driver as a module, choose M here: the module
+ will be called tach-aspeed-ast2600.
+
config SENSORS_ATXP1
tristate "Attansic ATXP1 VID controller"
depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index d2497b2644e6..7e2d708e93b8 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -51,6 +51,7 @@ obj-$(CONFIG_SENSORS_ARM_SCMI) += scmi-hwmon.o
obj-$(CONFIG_SENSORS_ARM_SCPI) += scpi-hwmon.o
obj-$(CONFIG_SENSORS_AS370) += as370-hwmon.o
obj-$(CONFIG_SENSORS_ASC7621) += asc7621.o
+obj-$(CONFIG_SENSORS_TACH_ASPEED_AST2600) += tach-aspeed-ast2600.o
obj-$(CONFIG_SENSORS_ASPEED) += aspeed-pwm-tacho.o
obj-$(CONFIG_SENSORS_ATXP1) += atxp1.o
obj-$(CONFIG_SENSORS_AXI_FAN_CONTROL) += axi-fan-control.o
diff --git a/drivers/hwmon/tach-aspeed-ast2600.c b/drivers/hwmon/tach-aspeed-ast2600.c
new file mode 100644
index 000000000000..c10e6bc3c035
--- /dev/null
+++ b/drivers/hwmon/tach-aspeed-ast2600.c
@@ -0,0 +1,476 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) ASPEED Technology Inc.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/hwmon.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <linux/sysfs.h>
+
+/* The channel number of Aspeed tach controller */
+#define TACH_ASPEED_NR_TACHS 16
+/* TACH Control Register */
+#define TACH_ASPEED_CTRL(ch) (((ch) * 0x10) + 0x08)
+#define TACH_ASPEED_IER BIT(31)
+#define TACH_ASPEED_INVERS_LIMIT BIT(30)
+#define TACH_ASPEED_LOOPBACK BIT(29)
+#define TACH_ASPEED_ENABLE BIT(28)
+#define TACH_ASPEED_DEBOUNCE_MASK GENMASK(27, 26)
+#define TACH_ASPEED_DEBOUNCE_BIT 26
+#define TACH_ASPEED_IO_EDGE_MASK GENMASK(25, 24)
+#define TACH_ASPEED_IO_EDGE_BIT 24
+#define TACH_ASPEED_CLK_DIV_T_MASK GENMASK(23, 20)
+#define TACH_ASPEED_CLK_DIV_BIT 20
+#define TACH_ASPEED_THRESHOLD_MASK GENMASK(19, 0)
+/* [27:26] */
+#define DEBOUNCE_3_CLK 0x00
+#define DEBOUNCE_2_CLK 0x01
+#define DEBOUNCE_1_CLK 0x02
+#define DEBOUNCE_0_CLK 0x03
+/* [25:24] */
+#define F2F_EDGES 0x00
+#define R2R_EDGES 0x01
+#define BOTH_EDGES 0x02
+/* [23:20] */
+/* divisor = 4 to the nth power, n = register value */
+#define DEFAULT_TACH_DIV 1024
+#define DIV_TO_REG(divisor) (ilog2(divisor) >> 1)
+
+/* TACH Status Register */
+#define TACH_ASPEED_STS(ch) (((ch) * 0x10) + 0x0C)
+
+/*PWM_TACH_STS */
+#define TACH_ASPEED_ISR BIT(31)
+#define TACH_ASPEED_PWM_OUT BIT(25)
+#define TACH_ASPEED_PWM_OEN BIT(24)
+#define TACH_ASPEED_DEB_INPUT BIT(23)
+#define TACH_ASPEED_RAW_INPUT BIT(22)
+#define TACH_ASPEED_VALUE_UPDATE BIT(21)
+#define TACH_ASPEED_FULL_MEASUREMENT BIT(20)
+#define TACH_ASPEED_VALUE_MASK GENMASK(19, 0)
+/**********************************************************
+ * Software setting
+ *********************************************************/
+#define DEFAULT_FAN_MIN_RPM 1000
+#define DEFAULT_FAN_PULSE_PR 2
+/*
+ * Add this value to avoid CPU consuming a lot of resources in waiting rpm
+ * updating. Assume the max rpm of fan is 60000, the fastest period of updating
+ * tach value will be equal to (1000000 * 2 * 60) / (2 * max_rpm) = 1000us.
+ */
+#define DEFAULT_FAN_MAX_RPM 60000
+
+struct aspeed_tach_channel_params {
+ int limited_inverse;
+ u16 threshold;
+ u8 tach_edge;
+ u8 tach_debounce;
+ u8 pulse_pr;
+ u32 min_rpm;
+ u32 max_rpm;
+ u32 divisor;
+ u32 sample_period; /* unit is us */
+ u32 polling_period; /* unit is us */
+};
+
+struct aspeed_tach_data {
+ struct device *dev;
+ struct regmap *regmap;
+ struct clk *clk;
+ struct reset_control *reset;
+ bool tach_present[TACH_ASPEED_NR_TACHS];
+ struct aspeed_tach_channel_params *tach_channel;
+};
+
+static void aspeed_update_tach_sample_period(struct aspeed_tach_data *priv,
+ u8 fan_tach_ch)
+{
+ u32 tach_period_us;
+ u8 pulse_pr = priv->tach_channel[fan_tach_ch].pulse_pr;
+ u32 min_rpm = priv->tach_channel[fan_tach_ch].min_rpm;
+
+ /*
+ * min(Tach input clock) = (PulsePR * minRPM) / 60
+ * max(Tach input period) = 60 / (PulsePR * minRPM)
+ * Tach sample period > 2 * max(Tach input period) = (2*60) / (PulsePR * minRPM)
+ */
+ tach_period_us = (USEC_PER_SEC * 2 * 60) / (pulse_pr * min_rpm);
+ /* Add the margin (about 1.5) of tach sample period to avoid sample miss */
+ tach_period_us = (tach_period_us * 1500) >> 10;
+ dev_dbg(priv->dev, "tach%d sample period = %dus", fan_tach_ch, tach_period_us);
+ priv->tach_channel[fan_tach_ch].sample_period = tach_period_us;
+}
+
+static void aspeed_update_tach_polling_period(struct aspeed_tach_data *priv,
+ u8 fan_tach_ch)
+{
+ u32 tach_period_us;
+ u8 pulse_pr = priv->tach_channel[fan_tach_ch].pulse_pr;
+ u32 max_rpm = priv->tach_channel[fan_tach_ch].max_rpm;
+
+ tach_period_us = (USEC_PER_SEC * 2 * 60) / (pulse_pr * max_rpm);
+ dev_dbg(priv->dev, "tach%d polling period = %dus", fan_tach_ch, tach_period_us);
+ priv->tach_channel[fan_tach_ch].polling_period = tach_period_us;
+}
+
+static void aspeed_tach_ch_enable(struct aspeed_tach_data *priv, u8 tach_ch,
+ bool enable)
+{
+ if (enable)
+ regmap_set_bits(priv->regmap, TACH_ASPEED_CTRL(tach_ch),
+ TACH_ASPEED_ENABLE);
+ else
+ regmap_clear_bits(priv->regmap, TACH_ASPEED_CTRL(tach_ch),
+ TACH_ASPEED_ENABLE);
+}
+
+static int aspeed_get_fan_tach_ch_rpm(struct aspeed_tach_data *priv,
+ u8 fan_tach_ch)
+{
+ u32 raw_data, tach_div, val;
+ unsigned long clk_source;
+ u64 rpm;
+ int ret;
+
+ ret = regmap_read_poll_timeout(priv->regmap, TACH_ASPEED_STS(fan_tach_ch), val,
+ (val & TACH_ASPEED_FULL_MEASUREMENT) &&
+ (val & TACH_ASPEED_VALUE_UPDATE),
+ priv->tach_channel[fan_tach_ch].polling_period,
+ priv->tach_channel[fan_tach_ch].sample_period);
+
+ if (ret) {
+ /* return 0 if we didn't get an answer because of timeout */
+ if (ret == -ETIMEDOUT)
+ return 0;
+ return ret;
+ }
+
+ raw_data = val & TACH_ASPEED_VALUE_MASK;
+ /*
+ * We need the mode to determine if the raw_data is double (from
+ * counting both edges).
+ */
+ if (priv->tach_channel[fan_tach_ch].tach_edge == BOTH_EDGES)
+ raw_data <<= 1;
+
+ tach_div = raw_data * (priv->tach_channel[fan_tach_ch].divisor) *
+ (priv->tach_channel[fan_tach_ch].pulse_pr);
+
+ clk_source = clk_get_rate(priv->clk);
+ dev_dbg(priv->dev, "clk %ld, raw_data %d , tach_div %d\n", clk_source,
+ raw_data, tach_div);
+
+ if (tach_div == 0)
+ return -EDOM;
+
+ rpm = (u64)clk_source * 60;
+ do_div(rpm, tach_div);
+
+ return rpm;
+}
+
+static int aspeed_tach_hwmon_read(struct device *dev,
+ enum hwmon_sensor_types type, u32 attr,
+ int channel, long *val)
+{
+ struct aspeed_tach_data *priv = dev_get_drvdata(dev);
+ u32 reg_val;
+ int ret;
+
+ switch (attr) {
+ case hwmon_fan_input:
+ ret = aspeed_get_fan_tach_ch_rpm(priv, channel);
+ if (ret < 0)
+ return ret;
+ *val = ret;
+ break;
+ case hwmon_fan_min:
+ *val = priv->tach_channel[channel].min_rpm;
+ break;
+ case hwmon_fan_max:
+ *val = priv->tach_channel[channel].max_rpm;
+ break;
+ case hwmon_fan_div:
+ regmap_read(priv->regmap, TACH_ASPEED_CTRL(channel), ®_val);
+ reg_val = FIELD_GET(TACH_ASPEED_CLK_DIV_T_MASK, reg_val);
+ *val = BIT(reg_val << 1);
+ break;
+ case hwmon_fan_pulses:
+ *val = priv->tach_channel[channel].pulse_pr;
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+ return 0;
+}
+
+static int aspeed_tach_hwmon_write(struct device *dev,
+ enum hwmon_sensor_types type, u32 attr,
+ int channel, long val)
+{
+ struct aspeed_tach_data *priv = dev_get_drvdata(dev);
+
+ switch (attr) {
+ case hwmon_fan_min:
+ priv->tach_channel[channel].min_rpm = val;
+ aspeed_update_tach_sample_period(priv, channel);
+ break;
+ case hwmon_fan_max:
+ priv->tach_channel[channel].max_rpm = val;
+ aspeed_update_tach_polling_period(priv, channel);
+ break;
+ case hwmon_fan_div:
+ if (!(is_power_of_2(val) && !(ilog2(val) % 2))) {
+ dev_err(dev,
+ "fan_div value %ld not supported. Only support power of 4\n",
+ val);
+ return -EINVAL;
+ }
+ priv->tach_channel[channel].divisor = val;
+ regmap_write_bits(priv->regmap, TACH_ASPEED_CTRL(channel),
+ TACH_ASPEED_CLK_DIV_T_MASK,
+ DIV_TO_REG(priv->tach_channel[channel].divisor)
+ << TACH_ASPEED_CLK_DIV_BIT);
+ break;
+ case hwmon_fan_pulses:
+ priv->tach_channel[channel].pulse_pr = val;
+ aspeed_update_tach_sample_period(priv, channel);
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ return 0;
+}
+
+static umode_t aspeed_tach_dev_is_visible(const void *drvdata,
+ enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ const struct aspeed_tach_data *priv = drvdata;
+
+ if (!priv->tach_present[channel])
+ return 0;
+ switch (attr) {
+ case hwmon_fan_input:
+ return 0444;
+ case hwmon_fan_min:
+ case hwmon_fan_max:
+ case hwmon_fan_div:
+ case hwmon_fan_pulses:
+ return 0644;
+ }
+ return 0;
+}
+
+static const struct hwmon_ops aspeed_tach_ops = {
+ .is_visible = aspeed_tach_dev_is_visible,
+ .read = aspeed_tach_hwmon_read,
+ .write = aspeed_tach_hwmon_write,
+};
+
+static const struct hwmon_channel_info *aspeed_tach_info[] = {
+ HWMON_CHANNEL_INFO(fan,
+ HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
+ HWMON_F_DIV | HWMON_F_PULSES,
+ HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
+ HWMON_F_DIV | HWMON_F_PULSES,
+ HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
+ HWMON_F_DIV | HWMON_F_PULSES,
+ HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
+ HWMON_F_DIV | HWMON_F_PULSES,
+ HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
+ HWMON_F_DIV | HWMON_F_PULSES,
+ HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
+ HWMON_F_DIV | HWMON_F_PULSES,
+ HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
+ HWMON_F_DIV | HWMON_F_PULSES,
+ HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
+ HWMON_F_DIV | HWMON_F_PULSES,
+ HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
+ HWMON_F_DIV | HWMON_F_PULSES,
+ HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
+ HWMON_F_DIV | HWMON_F_PULSES,
+ HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
+ HWMON_F_DIV | HWMON_F_PULSES,
+ HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
+ HWMON_F_DIV | HWMON_F_PULSES,
+ HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
+ HWMON_F_DIV | HWMON_F_PULSES,
+ HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
+ HWMON_F_DIV | HWMON_F_PULSES,
+ HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
+ HWMON_F_DIV | HWMON_F_PULSES,
+ HWMON_F_INPUT | HWMON_F_MIN | HWMON_F_MAX |
+ HWMON_F_DIV | HWMON_F_PULSES),
+ NULL
+};
+
+static const struct hwmon_chip_info aspeed_tach_chip_info = {
+ .ops = &aspeed_tach_ops,
+ .info = aspeed_tach_info,
+};
+
+static void aspeed_create_fan_tach_channel(struct aspeed_tach_data *priv,
+ u32 tach_ch)
+{
+ priv->tach_present[tach_ch] = true;
+ priv->tach_channel[tach_ch].limited_inverse = 0;
+ regmap_write_bits(priv->regmap, TACH_ASPEED_CTRL(tach_ch),
+ TACH_ASPEED_INVERS_LIMIT,
+ priv->tach_channel[tach_ch].limited_inverse ?
+ TACH_ASPEED_INVERS_LIMIT :
+ 0);
+
+ priv->tach_channel[tach_ch].tach_debounce = DEBOUNCE_3_CLK;
+ regmap_write_bits(priv->regmap, TACH_ASPEED_CTRL(tach_ch),
+ TACH_ASPEED_DEBOUNCE_MASK,
+ priv->tach_channel[tach_ch].tach_debounce
+ << TACH_ASPEED_DEBOUNCE_BIT);
+
+ priv->tach_channel[tach_ch].tach_edge = F2F_EDGES;
+ regmap_write_bits(priv->regmap, TACH_ASPEED_CTRL(tach_ch),
+ TACH_ASPEED_IO_EDGE_MASK,
+ priv->tach_channel[tach_ch].tach_edge
+ << TACH_ASPEED_IO_EDGE_BIT);
+
+ priv->tach_channel[tach_ch].divisor = DEFAULT_TACH_DIV;
+ regmap_write_bits(priv->regmap, TACH_ASPEED_CTRL(tach_ch),
+ TACH_ASPEED_CLK_DIV_T_MASK,
+ DIV_TO_REG(priv->tach_channel[tach_ch].divisor)
+ << TACH_ASPEED_CLK_DIV_BIT);
+
+ priv->tach_channel[tach_ch].threshold = 0;
+ regmap_write_bits(priv->regmap, TACH_ASPEED_CTRL(tach_ch),
+ TACH_ASPEED_THRESHOLD_MASK,
+ priv->tach_channel[tach_ch].threshold);
+
+ priv->tach_channel[tach_ch].pulse_pr = DEFAULT_FAN_PULSE_PR;
+ priv->tach_channel[tach_ch].min_rpm = DEFAULT_FAN_MIN_RPM;
+ aspeed_update_tach_sample_period(priv, tach_ch);
+
+ priv->tach_channel[tach_ch].max_rpm = DEFAULT_FAN_MAX_RPM;
+ aspeed_update_tach_polling_period(priv, tach_ch);
+
+ aspeed_tach_ch_enable(priv, tach_ch, true);
+}
+
+static int aspeed_tach_create_fan(struct device *dev, struct device_node *child,
+ struct aspeed_tach_data *priv)
+{
+ u32 tach_channel;
+ int ret;
+
+ ret = of_property_read_u32(child, "reg", &tach_channel);
+ if (ret)
+ return ret;
+
+ aspeed_create_fan_tach_channel(priv, tach_channel);
+
+ return 0;
+}
+
+static void aspeed_tach_reset_assert(void *data)
+{
+ struct reset_control *rst = data;
+
+ reset_control_assert(rst);
+}
+
+static int aspeed_tach_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np, *child;
+ struct aspeed_tach_data *priv;
+ struct device *hwmon;
+ struct platform_device *parent_dev;
+ int ret;
+
+ np = dev->parent->of_node;
+ if (!of_device_is_compatible(np, "aspeed,ast2600-pwm-tach"))
+ return dev_err_probe(dev, -ENODEV,
+ "Unsupported tach device binding\n");
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+ priv->dev = &pdev->dev;
+ priv->tach_channel =
+ devm_kcalloc(dev, TACH_ASPEED_NR_TACHS,
+ sizeof(*priv->tach_channel), GFP_KERNEL);
+
+ priv->regmap = syscon_node_to_regmap(np);
+ if (IS_ERR(priv->regmap))
+ return dev_err_probe(dev, PTR_ERR(priv->regmap),
+ "Couldn't get regmap\n");
+ parent_dev = of_find_device_by_node(np);
+ priv->clk = devm_clk_get_enabled(&parent_dev->dev, NULL);
+ if (IS_ERR(priv->clk))
+ return dev_err_probe(dev, PTR_ERR(priv->clk),
+ "Couldn't get clock\n");
+
+ priv->reset = devm_reset_control_get_shared(&parent_dev->dev, NULL);
+ if (IS_ERR(priv->reset))
+ return dev_err_probe(dev, PTR_ERR(priv->reset),
+ "Couldn't get reset control\n");
+
+ ret = reset_control_deassert(priv->reset);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "Couldn't deassert reset control\n");
+
+ ret = devm_add_action_or_reset(dev, aspeed_tach_reset_assert,
+ priv->reset);
+ if (ret)
+ return ret;
+
+ for_each_child_of_node(dev->of_node, child) {
+ ret = aspeed_tach_create_fan(dev, child, priv);
+ if (ret) {
+ of_node_put(child);
+ return ret;
+ }
+ }
+
+ hwmon = devm_hwmon_device_register_with_info(dev, "aspeed_tach", priv,
+ &aspeed_tach_chip_info, NULL);
+ ret = PTR_ERR_OR_ZERO(hwmon);
+ if (ret)
+ return dev_err_probe(dev, ret,
+ "Failed to register hwmon device\n");
+ return 0;
+}
+
+static const struct of_device_id of_stach_match_table[] = {
+ {
+ .compatible = "aspeed,ast2600-tach",
+ },
+ {},
+};
+MODULE_DEVICE_TABLE(of, of_stach_match_table);
+
+static struct platform_driver aspeed_tach_driver = {
+ .probe = aspeed_tach_probe,
+ .driver = {
+ .name = "aspeed_tach",
+ .of_match_table = of_stach_match_table,
+ },
+};
+
+module_platform_driver(aspeed_tach_driver);
+
+MODULE_AUTHOR("Billy Tsai <billy_tsai@xxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Aspeed ast2600 TACH device driver");
+MODULE_LICENSE("GPL v2");
+
--
2.25.1
