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([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id x53-20020a056830247500b0066c7733be43sm7349128otr.30.2022.11.23.07.44.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 23 Nov 2022 07:44:58 -0800 (PST) Sender: Guenter Roeck Message-ID: Date: Wed, 23 Nov 2022 07:44:56 -0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.2 Content-Language: en-US To: Billy Tsai , jdelvare@suse.com, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, joel@jms.id.au, andrew@aj.id.au, lee@kernel.org, thierry.reding@gmail.com, u.kleine-koenig@pengutronix.de, corbet@lwn.net, p.zabel@pengutronix.de, linux-hwmon@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org, linux-doc@vger.kernel.org Cc: kernel test robot References: <20221123061635.32025-1-billy_tsai@aspeedtech.com> <20221123061635.32025-6-billy_tsai@aspeedtech.com> From: Guenter Roeck Subject: Re: [v4 5/5] hwmon: Add Aspeed ast2600 TACH support In-Reply-To: <20221123061635.32025-6-billy_tsai@aspeedtech.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/22/22 22:16, Billy Tsai wrote: > 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 > Reported-by: kernel test robot The above Reported-by: tag does not make sense for new drivers. Please drop. Also, PATCH in subject is missing. > --- > Documentation/hwmon/index.rst | 1 + > Documentation/hwmon/tach-aspeed-ast2600.rst | 24 ++ > drivers/hwmon/Kconfig | 9 + > drivers/hwmon/Makefile | 1 + > drivers/hwmon/tach-aspeed-ast2600.c | 399 ++++++++++++++++++++ > 5 files changed, 434 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 c1d11cf13eef..8aed4c42ca89 100644 > --- a/Documentation/hwmon/index.rst > +++ b/Documentation/hwmon/index.rst > @@ -193,6 +193,7 @@ 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..4f9501b783a1 > --- /dev/null > +++ b/Documentation/hwmon/tach-aspeed-ast2600.rst > @@ -0,0 +1,24 @@ > +Kernel driver tach-aspeed-ast2600 > +============================== > + > +Supported chips: > + ASPEED AST2600 > + > +Authors: > + > + > +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 code doesn't support 1. > + The larger divisor, the less rpm accuracy and the less > + affected by fan signal glitch. > +fanX_pulses rw Fan pulses per resolution. > +=============== ======= ====================================================== > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig > index 7ac3daaf59ce..3196087a7b3e 100644 > --- a/drivers/hwmon/Kconfig > +++ b/drivers/hwmon/Kconfig > @@ -403,6 +403,15 @@ 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 11d076cad8a2..50a139c7c4ca 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..2b8dd5eeb6ec > --- /dev/null > +++ b/drivers/hwmon/tach-aspeed-ast2600.c > @@ -0,0 +1,399 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * Copyright (C) ASPEED Technology Inc. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +/* 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_PULSE_PR 2 > +struct aspeed_tach_channel_params { > + int limited_inverse; > + u16 threshold; > + u8 tach_edge; > + u8 tach_debounce; > + u8 pulse_pr; > + 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_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 u64 aspeed_tach_val_to_rpm(struct aspeed_tach_data *priv, u8 fan_tach_ch, > + u32 tach_val) > +{ > + unsigned long clk_source; > + u64 rpm; > + u32 tach_div; > + > + /* > + * We need the mode to determine if the tach_val is double (from > + * counting both edges). > + */ > + if (priv->tach_channel[fan_tach_ch].tach_edge == BOTH_EDGES) > + tach_val <<= 1; > + > + tach_div = tach_val * (priv->tach_channel[fan_tach_ch].divisor) * > + (priv->tach_channel[fan_tach_ch].pulse_pr); > + > + clk_source = clk_get_rate(priv->clk); Unless the clock rate can change (which is unlikely, I would suggest to read it once during probe and re-use the value instead of reading it repeatedly. > + dev_dbg(priv->dev, "clk %ld, tach_val %d , tach_div %d\n", clk_source, > + tach_val, tach_div); > + > + rpm = (u64)clk_source * 60; > + do_div(rpm, tach_div); > + > + return rpm; > +} > + > +static int aspeed_get_fan_tach_ch_rpm(struct aspeed_tach_data *priv, > + u8 fan_tach_ch) > +{ > + u32 val; > + u64 rpm; > + int ret; > + > + ret = regmap_read(priv->regmap, TACH_ASPEED_STS(fan_tach_ch), &val); > + Please drop this empty line. The existence of a status register makes me wonder what is in there. Does the controller report any errors ? If so, it might be worthwile adding attribute(s) for it. > + if (ret) > + return ret; > + > + if (!(val & TACH_ASPEED_FULL_MEASUREMENT)) > + return 0; > + rpm = aspeed_tach_val_to_rpm(priv, fan_tach_ch, > + val & TACH_ASPEED_VALUE_MASK); > + > + 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_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_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); Please refrain from error messages here. This only clogs the log as result of user input. The arithmetic is confusing. if (!is_power_of_2(val) || (ilog2(val) % 2))) would be much less confusing and easier to understand. > + return -EINVAL; > + } There should be a range check. The above accepts a divisor value larger than 1024. > + 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; > + 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_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, > + HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_PULSES, > + HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_PULSES, > + HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_PULSES, > + HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_PULSES, > + HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_PULSES, > + HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_PULSES, > + HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_PULSES, > + HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_PULSES, > + HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_PULSES, > + HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_PULSES, > + HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_PULSES, > + HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_PULSES, > + HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_PULSES, > + HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_PULSES, > + 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_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); > + What is the purpose of the above code ? limited_inverse is always 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); > + limited_inverse, tach_debounce, and tach_edge are constants. There is no need to keep constants as per-channel variables. > + 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); > + The above applies to threshold as well. > + priv->tach_channel[tach_ch].pulse_pr = DEFAULT_FAN_PULSE_PR; > + > + aspeed_tach_ch_enable(priv, tach_ch, true); > +} > + I kind of can understand that there are no devicetree properties given the discussion around it. It is still unfortunate since being involved in that discussion might help ensure that a generic property such as fan divisor value ends up being supported in the upcoming generic properties. > +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); > + if (!priv->tach_channel) > + return -ENOMEM; Why not allocate tach_channel as array within aspeed_tach_data ? > + > + 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); Isn't that the same as dev->parent ? > + 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; Why not return the error ? Either it is an error or it isn't. If it is not an error, dev_err_probe() is not appropriate. If it is, the error should be returned. Either case, if this is on purpose, it needs an explanation. > +} > + > +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 "); > +MODULE_DESCRIPTION("Aspeed ast2600 TACH device driver"); > +MODULE_LICENSE("GPL");