From patchwork Fri Oct 21 02:40:59 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: cy_huang X-Patchwork-Id: 617335 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8904EC43219 for ; Fri, 21 Oct 2022 02:41:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229983AbiJUClO (ORCPT ); Thu, 20 Oct 2022 22:41:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58258 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229968AbiJUClN (ORCPT ); Thu, 20 Oct 2022 22:41:13 -0400 Received: from mail-pj1-x1029.google.com (mail-pj1-x1029.google.com [IPv6:2607:f8b0:4864:20::1029]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 985D21B2333; Thu, 20 Oct 2022 19:41:11 -0700 (PDT) Received: by mail-pj1-x1029.google.com with SMTP id h12so1223568pjk.0; Thu, 20 Oct 2022 19:41:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=references:in-reply-to:message-id:date:subject:cc:to:from:from:to :cc:subject:date:message-id:reply-to; bh=tdwtzHR+xQdJbDyYyz1o5nHG0wEHYVT1LmuGtsV2+G8=; b=AIj89l8hB/UEivEc5ndGL3hkToljAhZdcSwqJ6G9FUDRP1aK7KR2Bo+RJ4Zzm1zBwi qfUm8xKxLwTmMkL6nN5Ym4G/eXAPfMKsxLI6hRWYeL4jztidE9QS1HSh9E14dm9GFe1c lHn/dJhRxiJmh53CldI/vY2JqxlwQt+TVp9V5H+g7fllhNQjL0EK2uysotqp31ltYsRD IEcCCaQcuHa/LFbS9x3BJ1QfDsgxG7U/5Mk+i98L/h/SKyGugEL+6OolN6Sa7F8In1CJ rp3UsXtbXNHUB36bjgxC+brXSj6xqZdcWbF/5dHcDCaqLaqKRtEJmt/k3NFmFESmVX6h 07Mw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=references:in-reply-to:message-id:date:subject:cc:to:from :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=tdwtzHR+xQdJbDyYyz1o5nHG0wEHYVT1LmuGtsV2+G8=; b=hrZUyDKyV1VmLuEmcdToXlFiL5e9xG2+I2r9VKPnkgRbsrYxnrzHjfiOtt0GYjOkG5 LEN2IZDqHuqEiUuXaTt4ZgrgFduFLh5BY6csr+1vXKMYboPutYKg2RmkGG2Qkl6Y3F4t ERbhzuVfm/+Rf0FxpA/+OS/bwC7HIZI040Ev22K/8iL5Chx6pwlH0WsoR/Aid+bzg7tx /+/rYlCodSNV+Zo1x/nzoHbWunWSVBTu0vJ8LXlHUuwf2H1KRZyzuB67+rZtvCu403vd WrH7xv8KDoHiLWQLa0BchwY2o7FzRoEL4m9lFNig7hTR5qR98O0cCa0DaQ93jUUjTsGX ic8w== X-Gm-Message-State: ACrzQf1Nbk0lXQOZGpnJeth1DLBXwV0RKJyuNM3EWi2IDDsn2l28igJZ 8FMBML18wTg92vw+3h/mDJY= X-Google-Smtp-Source: AMsMyM6axG8b38IMIwgkL5BUOtaBK2jJz7MLUAsa9EvlTcBRE5H34M7JkPSOTna8QxWuYzSieoEVnw== X-Received: by 2002:a17:902:e74e:b0:181:b25e:e7b8 with SMTP id p14-20020a170902e74e00b00181b25ee7b8mr16919939plf.10.1666320070847; Thu, 20 Oct 2022 19:41:10 -0700 (PDT) Received: from localhost.localdomain ([2402:7500:577:b022:150a:a87e:ab3a:9736]) by smtp.gmail.com with ESMTPSA id a19-20020aa794b3000000b0053e42167a33sm14033023pfl.53.2022.10.20.19.41.08 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 20 Oct 2022 19:41:10 -0700 (PDT) From: cy_huang To: robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, broonie@kernel.org Cc: lgirdwood@gmail.com, cy_huang@richtek.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/2] regulator: rt6190: Add support for Richtek RT6190 regulator Date: Fri, 21 Oct 2022 10:40:59 +0800 Message-Id: <1666320059-17544-3-git-send-email-u0084500@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1666320059-17544-1-git-send-email-u0084500@gmail.com> References: <1666320059-17544-1-git-send-email-u0084500@gmail.com> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org From: ChiYuan Huang Add support for Richtek RT6190 4-Switch BuckBoost controller. Signed-off-by: ChiYuan Huang --- drivers/regulator/Kconfig | 11 + drivers/regulator/Makefile | 1 + drivers/regulator/rt6190-regulator.c | 495 +++++++++++++++++++++++++++++++++++ 3 files changed, 507 insertions(+) create mode 100644 drivers/regulator/rt6190-regulator.c diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig index 070e440..4e4614d 100644 --- a/drivers/regulator/Kconfig +++ b/drivers/regulator/Kconfig @@ -1124,6 +1124,17 @@ config REGULATOR_RT6160 The wide output range is from 2025mV to 5200mV and can be used on most common application scenario. +config REGULATOR_RT6190 + tristate "Richtek RT6190 4-Switch BuckBoost controller" + depends on I2C + select REGMAP_I2C + help + The RT6190 is a 4-Switch BuckBoost controller designed for converting + input voltage to output voltage that can be equal to, higher or lower + than input voltage. It operates with wide input voltage range from + 4.5V to 36V, and the output voltage can be set from 3V to 36V by + external FB pin. + config REGULATOR_RT6245 tristate "Richtek RT6245 voltage regulator" depends on I2C diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile index 5962307..c3b5cf6 100644 --- a/drivers/regulator/Makefile +++ b/drivers/regulator/Makefile @@ -134,6 +134,7 @@ obj-$(CONFIG_REGULATOR_RT5120) += rt5120-regulator.o obj-$(CONFIG_REGULATOR_RT5190A) += rt5190a-regulator.o obj-$(CONFIG_REGULATOR_RT5759) += rt5759-regulator.o obj-$(CONFIG_REGULATOR_RT6160) += rt6160-regulator.o +obj-$(CONFIG_REGULATOR_RT6190) += rt6190-regulator.o obj-$(CONFIG_REGULATOR_RT6245) += rt6245-regulator.o obj-$(CONFIG_REGULATOR_RTMV20) += rtmv20-regulator.o obj-$(CONFIG_REGULATOR_RTQ2134) += rtq2134-regulator.o diff --git a/drivers/regulator/rt6190-regulator.c b/drivers/regulator/rt6190-regulator.c new file mode 100644 index 00000000..995e028 --- /dev/null +++ b/drivers/regulator/rt6190-regulator.c @@ -0,0 +1,495 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2022 Richtek Technology Corp. + * + * Author: ChiYuan Huang + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define RT6190_REG_VID 0x00 +#define RT6190_REG_OUTV 0x01 +#define RT6190_REG_OUTC 0x03 +#define RT6190_REG_SET1 0x0D +#define RT6190_REG_SET2 0x0E +#define RT6190_REG_SET4 0x10 +#define RT6190_REG_RATIO 0x11 +#define RT6190_REG_OUT_VOLT_L 0x12 +#define RT6190_REG_TEMP_H 0x1B +#define RT6190_REG_STAT1 0x1C +#define RT6190_REG_ALERT1 0x1E +#define RT6190_REG_ALERT2 0x1F +#define RT6190_REG_MASK2 0x21 +#define RT6190_REG_OCPEN 0x28 +#define RT6190_REG_SET5 0x29 +#define RT6190_REG_VBUSC_ADC 0x32 +#define RT6190_REG_BUSC_VOLT_L 0x33 +#define RT6190_REG_BUSC_VOLT_H 0x34 +#define RT6190_REG_STAT3 0x37 +#define RT6190_REG_ALERT3 0x38 +#define RT6190_REG_MASK3 0x39 + +#define RT6190_ENPWM_MASK BIT(7) +#define RT6190_ENDCHG_MASK BIT(4) +#define RT6190_ALERT_OTPEVT BIT(6) +#define RT6190_ALERT_UVPEVT BIT(5) +#define RT6190_ALERT_OVPEVT BIT(4) +#define RT6190_ENGCP_MASK BIT(1) +#define RT6190_FCCM_MASK BIT(7) + +#define RICHTEK_VID 0x82 +#define RT6190_OUT_MIN_UV 3000000 +#define RT6190_OUT_MAX_UV 32000000 +#define RT6190_OUT_STEP_UV 20000 +#define RT6190_OUT_N_VOLT (RT6190_OUT_MAX_UV / RT6190_OUT_STEP_UV + 1) +#define RT6190_OUTV_MINSEL 150 +#define RT6190_OUT_MIN_UA 306000 +#define RT6190_OUT_MAX_UA 12114000 +#define RT6190_OUT_STEP_UA 24000 +#define RT6190_OUTC_MINSEL 19 +#define RT6190_EN_TIME_US 500 + +#define RT6190_PSM_MODE 0 +#define RT6190_FCCM_MODE 1 + +struct rt6190_data { + struct device *dev; + struct regmap *regmap; + struct gpio_desc *enable_gpio; + unsigned int cached_alert_evt; +}; + +static int rt6190_out_set_voltage_sel(struct regulator_dev *rdev, + unsigned int selector) +{ + struct regmap *regmap = rdev_get_regmap(rdev); + __le16 le_sel = cpu_to_le16(selector); + + return regmap_raw_write(regmap, RT6190_REG_OUTV, &le_sel, + sizeof(le_sel)); +} + +static int rt6190_out_get_voltage_sel(struct regulator_dev *rdev) +{ + struct regmap *regmap = rdev_get_regmap(rdev); + __le16 le_sel; + int ret; + + ret = regmap_raw_read(regmap, RT6190_REG_OUTV, &le_sel, sizeof(le_sel)); + + return ret ?: le16_to_cpu(le_sel); +} + +static int rt6190_out_enable(struct regulator_dev *rdev) +{ + struct rt6190_data *data = rdev_get_drvdata(rdev); + struct regmap *regmap = rdev_get_regmap(rdev); + u8 out_cfg[4]; + int ret; + + pm_runtime_get_sync(data->dev); + + /* + * From off to on, vout config will restore to IC default. + * Read vout configs before enable, and restore them after enable + */ + ret = regmap_raw_read(regmap, RT6190_REG_OUTV, out_cfg, + sizeof(out_cfg)); + if (ret) + return ret; + + ret = regulator_enable_regmap(rdev); + if (ret) + return ret; + + ret = regmap_raw_write(regmap, RT6190_REG_OUTV, out_cfg, + sizeof(out_cfg)); + if (ret) + return ret; + + return regmap_update_bits(regmap, RT6190_REG_SET5, RT6190_ENGCP_MASK, + RT6190_ENGCP_MASK); +} + +static int rt6190_out_disable(struct regulator_dev *rdev) +{ + struct rt6190_data *data = rdev_get_drvdata(rdev); + struct regmap *regmap = rdev_get_regmap(rdev); + int ret; + + ret = regmap_update_bits(regmap, RT6190_REG_SET5, RT6190_ENGCP_MASK, 0); + if (ret) + return ret; + + ret = regulator_disable_regmap(rdev); + if (ret) + return ret; + + /* cleared cached alert event */ + data->cached_alert_evt = 0; + + pm_runtime_put(data->dev); + + return 0; +} + +static int rt6190_out_set_current_limit(struct regulator_dev *rdev, int min_uA, + int max_uA) +{ + struct regmap *regmap = rdev_get_regmap(rdev); + int csel, clim; + __le16 le_csel; + + if (min_uA < RT6190_OUT_MIN_UA || max_uA > RT6190_OUT_MAX_UA) + return -EINVAL; + + csel = DIV_ROUND_UP(min_uA - RT6190_OUT_MIN_UA, RT6190_OUT_STEP_UA); + + clim = RT6190_OUT_MIN_UA + RT6190_OUT_STEP_UA * csel; + if (clim > max_uA) + return -EINVAL; + + csel += RT6190_OUTC_MINSEL; + le_csel = cpu_to_le16(csel); + + return regmap_raw_write(regmap, RT6190_REG_OUTC, &le_csel, + sizeof(le_csel)); +} + +static int rt6190_out_get_current_limit(struct regulator_dev *rdev) +{ + struct regmap *regmap = rdev_get_regmap(rdev); + __le16 le_csel; + int csel, ret; + + ret = regmap_raw_read(regmap, RT6190_REG_OUTC, &le_csel, + sizeof(le_csel)); + if (ret) + return ret; + + csel = le16_to_cpu(le_csel); + csel -= RT6190_OUTC_MINSEL; + + return RT6190_OUT_MIN_UA + RT6190_OUT_STEP_UA * csel; +} + +static int rt6190_out_set_mode(struct regulator_dev *rdev, unsigned int mode) +{ + struct regmap *regmap = rdev_get_regmap(rdev); + unsigned int val; + + switch (mode) { + case REGULATOR_MODE_FAST: + val = RT6190_FCCM_MASK; + break; + case REGULATOR_MODE_NORMAL: + val = 0; + break; + default: + return -EINVAL; + } + + return regmap_update_bits(regmap, RT6190_REG_SET1, RT6190_FCCM_MASK, + val); +} + +static unsigned int rt6190_out_get_mode(struct regulator_dev *rdev) +{ + struct regmap *regmap = rdev_get_regmap(rdev); + unsigned int config; + int ret; + + ret = regmap_read(regmap, RT6190_REG_SET1, &config); + if (ret) + return REGULATOR_MODE_INVALID; + + if (config & RT6190_FCCM_MASK) + return REGULATOR_MODE_FAST; + + return REGULATOR_MODE_NORMAL; +} + +static int rt6190_out_get_error_flags(struct regulator_dev *rdev, + unsigned int *flags) +{ + struct rt6190_data *data = rdev_get_drvdata(rdev); + unsigned int state, rpt_flags = 0; + int ret; + + ret = regmap_read(data->regmap, RT6190_REG_STAT1, &state); + if (ret) + return ret; + + state |= data->cached_alert_evt; + + if (state & RT6190_ALERT_OTPEVT) + rpt_flags |= REGULATOR_ERROR_OVER_TEMP; + + if (state & RT6190_ALERT_UVPEVT) + rpt_flags |= REGULATOR_ERROR_UNDER_VOLTAGE; + + if (state & RT6190_ALERT_OVPEVT) + rpt_flags |= REGULATOR_ERROR_REGULATION_OUT; + + *flags = rpt_flags; + + return 0; +} + +static unsigned int rt6190_out_of_map_mode(unsigned int mode) +{ + switch (mode) { + case RT6190_PSM_MODE: + return REGULATOR_MODE_NORMAL; + case RT6190_FCCM_MODE: + return REGULATOR_MODE_FAST; + default: + return REGULATOR_MODE_INVALID; + } +} + +static const struct regulator_ops rt6190_regulator_ops = { + .list_voltage = regulator_list_voltage_linear, + .set_voltage_sel = rt6190_out_set_voltage_sel, + .get_voltage_sel = rt6190_out_get_voltage_sel, + .enable = rt6190_out_enable, + .disable = rt6190_out_disable, + .is_enabled = regulator_is_enabled_regmap, + .set_current_limit = rt6190_out_set_current_limit, + .get_current_limit = rt6190_out_get_current_limit, + .set_active_discharge = regulator_set_active_discharge_regmap, + .set_mode = rt6190_out_set_mode, + .get_mode = rt6190_out_get_mode, + .get_error_flags = rt6190_out_get_error_flags, +}; + +static const struct regulator_desc rt6190_regulator_desc = { + .name = "rt6190-regulator", + .type = REGULATOR_VOLTAGE, + .owner = THIS_MODULE, + .ops = &rt6190_regulator_ops, + .min_uV = RT6190_OUT_MIN_UV, + .uV_step = RT6190_OUT_STEP_UV, + .n_voltages = RT6190_OUT_N_VOLT, + .linear_min_sel = RT6190_OUTV_MINSEL, + .enable_reg = RT6190_REG_SET2, + .enable_mask = RT6190_ENPWM_MASK, + .active_discharge_reg = RT6190_REG_SET2, + .active_discharge_mask = RT6190_ENDCHG_MASK, + .active_discharge_on = RT6190_ENDCHG_MASK, + .of_map_mode = rt6190_out_of_map_mode, +}; + +static bool rt6190_is_volatile_reg(struct device *dev, unsigned int reg) +{ + switch (reg) { + case RT6190_REG_OUT_VOLT_L ... RT6190_REG_ALERT2: + case RT6190_REG_BUSC_VOLT_L ... RT6190_REG_BUSC_VOLT_H: + case RT6190_REG_STAT3 ... RT6190_REG_ALERT3: + return true; + default: + return false; + } +} + +static const struct regmap_config rt6190_regmap_config = { + .name = "rt6190", + .cache_type = REGCACHE_FLAT, + .reg_bits = 8, + .val_bits = 8, + .max_register = RT6190_REG_MASK3, + .num_reg_defaults_raw = RT6190_REG_MASK3 + 1, + .volatile_reg = rt6190_is_volatile_reg, +}; + +static irqreturn_t rt6190_irq_handler(int irq, void *devid) +{ + struct regulator_dev *rdev = devid; + struct rt6190_data *data = rdev_get_drvdata(rdev); + unsigned int alert; + int ret; + + ret = regmap_read(data->regmap, RT6190_REG_ALERT1, &alert); + if (ret) + return IRQ_NONE; + + /* Write clear alert events */ + ret = regmap_write(data->regmap, RT6190_REG_ALERT1, alert); + if (ret) + return IRQ_NONE; + + data->cached_alert_evt |= alert; + + if (alert & RT6190_ALERT_OTPEVT) + regulator_notifier_call_chain(rdev, REGULATOR_EVENT_OVER_TEMP, NULL); + + if (alert & RT6190_ALERT_UVPEVT) + regulator_notifier_call_chain(rdev, REGULATOR_EVENT_UNDER_VOLTAGE, NULL); + + if (alert & RT6190_ALERT_OVPEVT) + regulator_notifier_call_chain(rdev, REGULATOR_EVENT_REGULATION_OUT, NULL); + + return IRQ_HANDLED; +} + +static int rt6190_init_registers(struct regmap *regmap) +{ + int ret; + + /* Enable_ADC = 1 */ + ret = regmap_write(regmap, RT6190_REG_SET4, 0x82); + if (ret) + return ret; + + /* Config default VOUT ratio to be higher */ + ret = regmap_write(regmap, RT6190_REG_RATIO, 0x20); + + /* Mask unused alert */ + ret = regmap_write(regmap, RT6190_REG_MASK2, 0); + if (ret) + return ret; + + /* OCP config */ + ret = regmap_write(regmap, RT6190_REG_OCPEN, 0); + if (ret) + return ret; + + /* Enable VBUSC ADC */ + return regmap_write(regmap, RT6190_REG_VBUSC_ADC, 0x02); +} + +static int rt6190_probe(struct i2c_client *i2c) +{ + struct device *dev = &i2c->dev; + struct rt6190_data *data; + struct gpio_desc *enable_gpio; + struct regmap *regmap; + struct regulator_dev *rdev; + struct regulator_config cfg = {}; + unsigned int vid; + int ret; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + enable_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_HIGH); + if (IS_ERR(enable_gpio)) + return dev_err_probe(dev, PTR_ERR(enable_gpio), "Failed to get 'enable' gpio\n"); + else if (enable_gpio) + usleep_range(RT6190_EN_TIME_US, RT6190_EN_TIME_US * 2); + + regmap = devm_regmap_init_i2c(i2c, &rt6190_regmap_config); + if (IS_ERR(regmap)) + return dev_err_probe(dev, PTR_ERR(regmap), "Failed to init regmap\n"); + + data->dev = dev; + data->enable_gpio = enable_gpio; + data->regmap = regmap; + i2c_set_clientdata(i2c, data); + + ret = regmap_read(regmap, RT6190_REG_VID, &vid); + if (ret) + return dev_err_probe(dev, ret, "Failed to read VID\n"); + + if (vid != RICHTEK_VID) + return dev_err_probe(dev, -ENODEV, "Incorrect VID 0x%02x\n", vid); + + ret = rt6190_init_registers(regmap); + if (ret) + return dev_err_probe(dev, ret, "Failed to init registers\n"); + + pm_runtime_set_active(dev); + ret = devm_pm_runtime_enable(dev); + if (ret) + return dev_err_probe(dev, ret, "Failed to set pm_runtime enable\n"); + + cfg.dev = dev; + cfg.of_node = dev->of_node; + cfg.driver_data = data; + cfg.init_data = of_get_regulator_init_data(dev, dev->of_node, + &rt6190_regulator_desc); + + rdev = devm_regulator_register(dev, &rt6190_regulator_desc, &cfg); + if (IS_ERR(rdev)) + return dev_err_probe(dev, PTR_ERR(rdev), "Failed to register regulator\n"); + + if (i2c->irq) { + ret = devm_request_threaded_irq(dev, i2c->irq, NULL, + rt6190_irq_handler, + IRQF_ONESHOT, dev_name(dev), + rdev); + if (ret) + return dev_err_probe(dev, ret, "Failed to register interrupt\n"); + } + + return 0; +} + +static int rt6190_runtime_suspend(struct device *dev) +{ + struct rt6190_data *data = dev_get_drvdata(dev); + struct regmap *regmap = data->regmap; + + if (!data->enable_gpio) + return 0; + + regcache_cache_only(regmap, true); + regcache_mark_dirty(regmap); + + gpiod_set_value(data->enable_gpio, 0); + + return 0; +} + +static int rt6190_runtime_resume(struct device *dev) +{ + struct rt6190_data *data = dev_get_drvdata(dev); + struct regmap *regmap = data->regmap; + + if (!data->enable_gpio) + return 0; + + gpiod_set_value(data->enable_gpio, 1); + usleep_range(RT6190_EN_TIME_US, RT6190_EN_TIME_US * 2); + + regcache_cache_only(regmap, false); + return regcache_sync(regmap); +} + +static const struct dev_pm_ops __maybe_unused rt6190_dev_pm = { + RUNTIME_PM_OPS(rt6190_runtime_suspend, rt6190_runtime_resume, NULL) +}; + +static const struct of_device_id rt6190_of_dev_table[] = { + { .compatible = "richtek,rt6190" }, + {} +}; +MODULE_DEVICE_TABLE(of, rt6190_of_dev_table); + +static struct i2c_driver rt6190_driver = { + .driver = { + .name = "rt6190", + .of_match_table = rt6190_of_dev_table, + .pm = pm_ptr(&rt6190_dev_pm), + }, + .probe_new = rt6190_probe, +}; +module_i2c_driver(rt6190_driver); + +MODULE_DESCRIPTION("Richtek RT6190 regulator driver"); +MODULE_AUTHOR("ChiYuan Huang "); +MODULE_LICENSE("GPL");