Messages in this thread Patch in this message | | | Date | Wed, 7 Jun 2023 22:01:02 -0700 | From | Guenter Roeck <> | Subject | Re: [v6 4/4] hwmon: Add Aspeed ast2600 TACH support |
| |
On 6/7/23 19:18, Billy Tsai wrote: > Add the support of Tachometer which can use to monitor the frequency of > the input. In Aspeed AST2600 SoC features 16 TACH controllers, with each > controller capable of supporting up to 1 input. >
You mean there will be 16 instances of this driver ? That is weird, confusing, and warrants a detailed explanation.
> Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com> > --- > Documentation/hwmon/index.rst | 1 + > Documentation/hwmon/tach-aspeed-ast2600.rst | 25 ++ > drivers/hwmon/Kconfig | 10 + > drivers/hwmon/Makefile | 1 + > drivers/hwmon/tach-aspeed-ast2600.c | 305 ++++++++++++++++++++ > 5 files changed, 342 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 ddff3c5713d7..4c3dd74675ef 100644 > --- a/Documentation/hwmon/index.rst > +++ b/Documentation/hwmon/index.rst > @@ -194,6 +194,7 @@ Hardware Monitoring Kernel Drivers > sparx5-temp > stpddc60 > sy7636a-hwmon > + 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..b08c73a4237f > --- /dev/null > +++ b/Documentation/hwmon/tach-aspeed-ast2600.rst > @@ -0,0 +1,25 @@ > +Kernel driver tach-aspeed-ast2600 > +================================= > + > +Supported chips: > + ASPEED AST2600 > + > +Authors: > + <billy_tsai@aspeedtech.com> > + > +Description: > +------------ > +This driver implements support for ASPEED AST2600 Fan Tacho controller. > +The controller supports up to 1 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_pulses rw Fan pulses per resolution.
Presumably, as implemented, that would be 16 instances, each with fan1_{input,div}.
> +=============== ======= ====================================================== > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > index a5253abb7ea7..5948a63e44e7 100644 > --- a/drivers/hwmon/Kconfig > +++ b/drivers/hwmon/Kconfig > @@ -411,6 +411,16 @@ 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" > + depends on ARCH_ASPEED || COMPILE_TEST > + depends on HAVE_CLK && HAS_IOMEM > + 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 c5cd7e3a67ff..a3bf5b438e0f 100644 > --- a/drivers/hwmon/Makefile > +++ b/drivers/hwmon/Makefile > @@ -53,6 +53,7 @@ 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..8be66ee25a31 > --- /dev/null > +++ b/drivers/hwmon/tach-aspeed-ast2600.c > @@ -0,0 +1,305 @@ > +// 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/module.h> > +#include <linux/of_device.h> > +#include <linux/platform_device.h> > +#include <linux/reset.h> > +#include <linux/sysfs.h> > + > +/* TACH Control Register */ > +#define TACH_ASPEED_CTRL (0x00) > +#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 (0x04) Unnecesarry ()
> + > +/*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_PULSE_PR 2 > + > +struct aspeed_tach_channel_params { > + u8 pulse_pr; > + u32 divisor; > +}; > + > +struct aspeed_tach_data { > + struct device *dev; > + void __iomem *base; > + struct clk *clk; > + struct reset_control *reset; > + bool tach_present; > + struct aspeed_tach_channel_params tach_channel;
Assuming that all channels have the same divisor, this structure is really unnecessary (especially since pulse_pr should be dropped - see below).
> + unsigned long clk_source; > +}; > + > +static void aspeed_tach_ch_enable(struct aspeed_tach_data *priv, bool enable) > +{ > + if (enable) > + writel(readl(priv->base + TACH_ASPEED_CTRL) | > + (TACH_ASPEED_ENABLE), > + priv->base + TACH_ASPEED_CTRL); > + else > + writel(readl(priv->base + TACH_ASPEED_CTRL) & > + ~(TACH_ASPEED_ENABLE),
Unnecessary () around TACH_ASPEED_ENABLE.
> + priv->base + TACH_ASPEED_CTRL); > +} > + > +static u64 aspeed_tach_val_to_rpm(struct aspeed_tach_data *priv, u32 tach_val) > +{ > + u64 rpm; > + u32 tach_div; > + > + tach_div = tach_val * (priv->tach_channel.divisor) * > + (priv->tach.channel.pulse_pr); > +
Unnecessary () around priv->tach_channel.pulse_pr and priv->tach_channel.divisor. I am not going to look further for those. Please make sure you drop them all.
> + dev_dbg(priv->dev, "clk %ld, tach_val %d , tach_div %d\n", > + priv->clk_source, tach_val, tach_div); > + > + rpm = (u64)priv->clk_source * 60; > + do_div(rpm, tach_div); > + > + return rpm;
This function should really return an integer.
> +} > + > +static int aspeed_get_fan_tach_ch_rpm(struct aspeed_tach_data *priv) > +{ > + u32 val; > + u64 rpm; > + > + val = readl(priv->base + TACH_ASPEED_STS); > + > + if (!(val & TACH_ASPEED_FULL_MEASUREMENT)) > + return 0; > + rpm = aspeed_tach_val_to_rpm(priv, val & TACH_ASPEED_VALUE_MASK); > + > + return rpm;
The 'rpm' variable is unnecessary.
> +} > + > +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); > + if (ret < 0) > + return ret;
Why ? The called code never returns a negative value.
> + *val = ret; > + break; > + case hwmon_fan_div: > + reg_val = readl(priv->base + TACH_ASPEED_CTRL); > + 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.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_div: > + if (!is_power_of_2(val) || (ilog2(val) % 2)) > + return -EINVAL; > + else if (DIV_TO_REG(val) > 0xb)
Else after return is unnecessary
> + return -ERANGE;
Math result not representable ? Not really.
> + priv->tach_channel.divisor = val; > + writel((readl(priv->base + TACH_ASPEED_CTRL) & > + ~(TACH_ASPEED_CLK_DIV_T_MASK)) |
Unnecessary () around TACH_ASPEED_CLK_DIV_T_MASK.
> + (DIV_TO_REG(priv->tach_channel.divisor) > + << TACH_ASPEED_CLK_DIV_BIT), > + priv->base + TACH_ASPEED_CTRL); > + break; > + case hwmon_fan_pulses: > + priv->tach_channel.pulse_pr = val;
The ABI says for the pulses atribute:
Should only be created if the chip has a register to configure the number of pulses. In the absence of such a register (and thus attribute) the value assumed by all devices is 2 pulses per fan revolution.
I see no evidence that there is a chip register for the number of pulses. Please drop this attribute.
> + 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) > + return 0;
What is the point of instantiating the driver in this case ?
> + switch (attr) { > + case hwmon_fan_input: > + return 0444; > + 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_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_present_fan_tach(struct aspeed_tach_data *priv) > +{ > + priv->tach_present = true; > + priv->tach_channel.divisor = DEFAULT_TACH_DIV; > + priv->tach_channel.pulse_pr = DEFAULT_FAN_PULSE_PR; > + > + writel((readl(priv->base + TACH_ASPEED_CTRL) & > + ~(TACH_ASPEED_INVERS_LIMIT | TACH_ASPEED_DEBOUNCE_MASK | > + TACH_ASPEED_IO_EDGE_MASK | TACH_ASPEED_CLK_DIV_T_MASK | > + TACH_ASPEED_THRESHOLD_MASK)) | > + ((DEBOUNCE_3_CLK << TACH_ASPEED_DEBOUNCE_BIT) | > + F2F_EDGES | > + (DIV_TO_REG(priv->tach_channel.divisor) > + << TACH_ASPEED_CLK_DIV_BIT)), > + priv->base + TACH_ASPEED_CTRL); > + > + aspeed_tach_ch_enable(priv, true); > +} > + > +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 aspeed_tach_data *priv; > + struct device *hwmon; > + int ret; > + > + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); > + if (!priv) > + return -ENOMEM; > + priv->dev = &pdev->dev; > + priv->base = devm_platform_ioremap_resource(pdev, 0); > + if (IS_ERR(priv->base)) > + return PTR_ERR(priv->base); > + priv->clk = devm_clk_get_enabled(dev, NULL); > + if (IS_ERR(priv->clk)) > + return dev_err_probe(dev, PTR_ERR(priv->clk), > + "Couldn't get clock\n"); > + > + priv->clk_source = clk_get_rate(priv->clk); > + priv->reset = devm_reset_control_get_shared(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; > + > + aspeed_present_fan_tach(priv); > + > + 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@aspeedtech.com>"); > +MODULE_DESCRIPTION("Aspeed ast2600 TACH device driver"); > +MODULE_LICENSE("GPL");
| |