From b2adf788e6037cea0109313934f432f458190992 Mon Sep 17 00:00:00 2001 From: ChiYuan Huang Date: Fri, 5 Aug 2022 15:06:04 +0800 Subject: [PATCH] mfd: mt6370: Add MediaTek MT6370 support This adds support for the MediaTek MT6370 SubPMIC. MediaTek MT6370 is a SubPMIC consisting of a single cell battery charger with ADC monitoring, RGB LEDs, dual channel flashlight, WLED backlight driver, display bias voltage supply, one general purpose LDO, and the USB Type-C & PD controller complies with the latest USB Type-C and PD standards. Reviewed-by: Andy Shevchenko Signed-off-by: ChiYuan Huang Signed-off-by: ChiaEn Wu Signed-off-by: Lee Jones Link: https://lore.kernel.org/r/20220805070610.3516-8-peterwu.pub@gmail.com --- drivers/mfd/Kconfig | 16 +++ drivers/mfd/Makefile | 1 + drivers/mfd/mt6370.c | 312 +++++++++++++++++++++++++++++++++++++++++++++++++++ drivers/mfd/mt6370.h | 99 ++++++++++++++++ 4 files changed, 428 insertions(+) create mode 100644 drivers/mfd/mt6370.c create mode 100644 drivers/mfd/mt6370.h diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig index 644cfe5..c65fcca 100644 --- a/drivers/mfd/Kconfig +++ b/drivers/mfd/Kconfig @@ -938,6 +938,22 @@ config MFD_MT6360 PMIC part includes 2-channel BUCKs and 2-channel LDOs LDO part includes 4-channel LDOs +config MFD_MT6370 + tristate "MediaTek MT6370 SubPMIC" + select MFD_CORE + select REGMAP_I2C + select REGMAP_IRQ + depends on I2C + help + Say Y here to enable MT6370 SubPMIC functional support. + It consists of a single cell battery charger with ADC monitoring, RGB + LEDs, dual channel flashlight, WLED backlight driver, display bias + voltage supply, one general purpose LDO, and the USB Type-C & PD + controller complies with the latest USB Type-C and PD standards. + + This driver can also be built as a module. If so, the module + will be called "mt6370". + config MFD_MT6397 tristate "MediaTek MT6397 PMIC Support" select MFD_CORE diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile index 21ee5a7..bcfb8d3 100644 --- a/drivers/mfd/Makefile +++ b/drivers/mfd/Makefile @@ -176,6 +176,7 @@ obj-$(CONFIG_MFD_MAX8998) += max8998.o max8998-irq.o obj-$(CONFIG_MFD_MP2629) += mp2629.o obj-$(CONFIG_MFD_MT6360) += mt6360-core.o +obj-$(CONFIG_MFD_MT6370) += mt6370.o mt6397-objs := mt6397-core.o mt6397-irq.o mt6358-irq.o obj-$(CONFIG_MFD_MT6397) += mt6397.o diff --git a/drivers/mfd/mt6370.c b/drivers/mfd/mt6370.c new file mode 100644 index 0000000..cf19cce --- /dev/null +++ b/drivers/mfd/mt6370.c @@ -0,0 +1,312 @@ +// 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 "mt6370.h" + +#define MT6370_REG_DEV_INFO 0x100 +#define MT6370_REG_CHG_IRQ1 0x1C0 +#define MT6370_REG_CHG_MASK1 0x1E0 +#define MT6370_REG_MAXADDR 0x1FF + +#define MT6370_VENID_MASK GENMASK(7, 4) + +#define MT6370_NUM_IRQREGS 16 +#define MT6370_USBC_I2CADDR 0x4E +#define MT6370_MAX_ADDRLEN 2 + +#define MT6370_VENID_RT5081 0x8 +#define MT6370_VENID_RT5081A 0xA +#define MT6370_VENID_MT6370 0xE +#define MT6370_VENID_MT6371 0xF +#define MT6370_VENID_MT6372P 0x9 +#define MT6370_VENID_MT6372CP 0xB + +static const struct regmap_irq mt6370_irqs[] = { + REGMAP_IRQ_REG_LINE(MT6370_IRQ_DIRCHGON, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_TREG, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_AICR, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_MIVR, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_PWR_RDY, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_FL_CHG_VINOVP, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_VSYSUV, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_VSYSOV, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_VBATOV, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_VINOVPCHG, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_TS_BAT_COLD, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_TS_BAT_COOL, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_TS_BAT_WARM, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_TS_BAT_HOT, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_TS_STATC, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_FAULT, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_STATC, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_TMR, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_BATABS, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_ADPBAD, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_RVP, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_TSHUTDOWN, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_IINMEAS, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_ICCMEAS, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHGDET_DONE, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_WDTMR, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_SSFINISH, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_RECHG, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_TERM, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHG_IEOC, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_ADC_DONE, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_PUMPX_DONE, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_BST_BATUV, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_BST_MIDOV, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_BST_OLP, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_ATTACH, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_DETACH, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_HVDCP_STPDONE, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_HVDCP_VBUSDET_DONE, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_HVDCP_DET, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_CHGDET, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_DCDT, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_DIRCHG_VGOK, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_DIRCHG_WDTMR, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_DIRCHG_UC, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_DIRCHG_OC, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_DIRCHG_OV, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_OVPCTRL_SWON, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_OVPCTRL_UVP_D, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_OVPCTRL_UVP, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_OVPCTRL_OVP_D, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_OVPCTRL_OVP, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED_STRBPIN, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED_TORPIN, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED_TX, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED_LVF, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED2_SHORT, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED1_SHORT, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED2_STRB, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED1_STRB, 8), + REGMAP_IRQ_REG_LINE(mT6370_IRQ_FLED2_STRB_TO, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED1_STRB_TO, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED2_TOR, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_FLED1_TOR, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_OTP, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_VDDA_OVP, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_VDDA_UV, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_LDO_OC, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_BLED_OCP, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_BLED_OVP, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_DSV_VNEG_OCP, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_DSV_VPOS_OCP, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_DSV_BST_OCP, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_DSV_VNEG_SCP, 8), + REGMAP_IRQ_REG_LINE(MT6370_IRQ_DSV_VPOS_SCP, 8), +}; + +static const struct regmap_irq_chip mt6370_irq_chip = { + .name = "mt6370-irqs", + .status_base = MT6370_REG_CHG_IRQ1, + .mask_base = MT6370_REG_CHG_MASK1, + .num_regs = MT6370_NUM_IRQREGS, + .irqs = mt6370_irqs, + .num_irqs = ARRAY_SIZE(mt6370_irqs), +}; + +static const struct resource mt6370_regulator_irqs[] = { + DEFINE_RES_IRQ_NAMED(MT6370_IRQ_DSV_VPOS_SCP, "db_vpos_scp"), + DEFINE_RES_IRQ_NAMED(MT6370_IRQ_DSV_VNEG_SCP, "db_vneg_scp"), + DEFINE_RES_IRQ_NAMED(MT6370_IRQ_DSV_BST_OCP, "db_vbst_ocp"), + DEFINE_RES_IRQ_NAMED(MT6370_IRQ_DSV_VPOS_OCP, "db_vpos_ocp"), + DEFINE_RES_IRQ_NAMED(MT6370_IRQ_DSV_VNEG_OCP, "db_vneg_ocp"), + DEFINE_RES_IRQ_NAMED(MT6370_IRQ_LDO_OC, "ldo_oc"), +}; + +static const struct mfd_cell mt6370_devices[] = { + MFD_CELL_OF("mt6370-adc", + NULL, NULL, 0, 0, "mediatek,mt6370-adc"), + MFD_CELL_OF("mt6370-charger", + NULL, NULL, 0, 0, "mediatek,mt6370-charger"), + MFD_CELL_OF("mt6370-flashlight", + NULL, NULL, 0, 0, "mediatek,mt6370-flashlight"), + MFD_CELL_OF("mt6370-indicator", + NULL, NULL, 0, 0, "mediatek,mt6370-indicator"), + MFD_CELL_OF("mt6370-tcpc", + NULL, NULL, 0, 0, "mediatek,mt6370-tcpc"), + MFD_CELL_RES("mt6370-regulator", mt6370_regulator_irqs), +}; + +static const struct mfd_cell mt6370_exclusive_devices[] = { + MFD_CELL_OF("mt6370-backlight", + NULL, NULL, 0, 0, "mediatek,mt6370-backlight"), +}; + +static const struct mfd_cell mt6372_exclusive_devices[] = { + MFD_CELL_OF("mt6370-backlight", + NULL, NULL, 0, 0, "mediatek,mt6372-backlight"), +}; + +static int mt6370_check_vendor_info(struct device *dev, struct regmap *rmap, + int *vid) +{ + unsigned int devinfo; + int ret; + + ret = regmap_read(rmap, MT6370_REG_DEV_INFO, &devinfo); + if (ret) + return ret; + + *vid = FIELD_GET(MT6370_VENID_MASK, devinfo); + switch (*vid) { + case MT6370_VENID_RT5081: + case MT6370_VENID_RT5081A: + case MT6370_VENID_MT6370: + case MT6370_VENID_MT6371: + case MT6370_VENID_MT6372P: + case MT6370_VENID_MT6372CP: + return 0; + default: + dev_err(dev, "Unknown Vendor ID 0x%02x\n", devinfo); + return -ENODEV; + } +} + +static int mt6370_regmap_read(void *context, const void *reg_buf, + size_t reg_size, void *val_buf, size_t val_size) +{ + struct mt6370_info *info = context; + const u8 *u8_buf = reg_buf; + u8 bank_idx, bank_addr; + int ret; + + bank_idx = u8_buf[0]; + bank_addr = u8_buf[1]; + + ret = i2c_smbus_read_i2c_block_data(info->i2c[bank_idx], bank_addr, + val_size, val_buf); + if (ret < 0) + return ret; + + if (ret != val_size) + return -EIO; + + return 0; +} + +static int mt6370_regmap_write(void *context, const void *data, size_t count) +{ + struct mt6370_info *info = context; + const u8 *u8_buf = data; + u8 bank_idx, bank_addr; + int len = count - MT6370_MAX_ADDRLEN; + + bank_idx = u8_buf[0]; + bank_addr = u8_buf[1]; + + return i2c_smbus_write_i2c_block_data(info->i2c[bank_idx], bank_addr, + len, data + MT6370_MAX_ADDRLEN); +} + +static const struct regmap_bus mt6370_regmap_bus = { + .read = mt6370_regmap_read, + .write = mt6370_regmap_write, +}; + +static const struct regmap_config mt6370_regmap_config = { + .reg_bits = 16, + .val_bits = 8, + .reg_format_endian = REGMAP_ENDIAN_BIG, + .max_register = MT6370_REG_MAXADDR, +}; + +static int mt6370_probe(struct i2c_client *i2c) +{ + struct mt6370_info *info; + struct i2c_client *usbc_i2c; + struct regmap *regmap; + struct device *dev = &i2c->dev; + int ret, vid; + + info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL); + if (!info) + return -ENOMEM; + + usbc_i2c = devm_i2c_new_dummy_device(dev, i2c->adapter, + MT6370_USBC_I2CADDR); + if (IS_ERR(usbc_i2c)) + return dev_err_probe(dev, PTR_ERR(usbc_i2c), + "Failed to register USBC I2C client\n"); + + /* Assign I2C client for PMU and TypeC */ + info->i2c[MT6370_PMU_I2C] = i2c; + info->i2c[MT6370_USBC_I2C] = usbc_i2c; + + regmap = devm_regmap_init(dev, &mt6370_regmap_bus, + info, &mt6370_regmap_config); + if (IS_ERR(regmap)) + return dev_err_probe(dev, PTR_ERR(regmap), + "Failed to init regmap\n"); + + ret = mt6370_check_vendor_info(dev, regmap, &vid); + if (ret) + return dev_err_probe(dev, ret, "Failed to check vendor info\n"); + + ret = devm_regmap_add_irq_chip(dev, regmap, i2c->irq, + IRQF_ONESHOT, -1, &mt6370_irq_chip, + &info->irq_data); + if (ret) + return dev_err_probe(dev, ret, "Failed to add irq chip\n"); + + switch (vid) { + case MT6370_VENID_MT6372P: + case MT6370_VENID_MT6372CP: + ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_AUTO, + mt6372_exclusive_devices, + ARRAY_SIZE(mt6372_exclusive_devices), + NULL, 0, + regmap_irq_get_domain(info->irq_data)); + break; + default: + ret = devm_mfd_add_devices(dev, PLATFORM_DEVID_AUTO, + mt6370_exclusive_devices, + ARRAY_SIZE(mt6370_exclusive_devices), + NULL, 0, + regmap_irq_get_domain(info->irq_data)); + break; + } + + if (ret) + return dev_err_probe(dev, ret, "Failed to add the exclusive devices\n"); + + return devm_mfd_add_devices(dev, PLATFORM_DEVID_AUTO, + mt6370_devices, ARRAY_SIZE(mt6370_devices), + NULL, 0, + regmap_irq_get_domain(info->irq_data)); +} + +static const struct of_device_id mt6370_match_table[] = { + { .compatible = "mediatek,mt6370" }, + {} +}; +MODULE_DEVICE_TABLE(of, mt6370_match_table); + +static struct i2c_driver mt6370_driver = { + .driver = { + .name = "mt6370", + .of_match_table = mt6370_match_table, + }, + .probe_new = mt6370_probe, +}; +module_i2c_driver(mt6370_driver); + +MODULE_AUTHOR("ChiYuan Huang "); +MODULE_DESCRIPTION("MediaTek MT6370 SubPMIC Driver"); +MODULE_LICENSE("GPL v2"); diff --git a/drivers/mfd/mt6370.h b/drivers/mfd/mt6370.h new file mode 100644 index 0000000..094e59e --- /dev/null +++ b/drivers/mfd/mt6370.h @@ -0,0 +1,99 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2022 Richtek Technology Corp. + * + * Author: ChiYuan Huang + */ + +#ifndef __MFD_MT6370_H__ +#define __MFD_MT6370_H__ + +/* IRQ definitions */ +#define MT6370_IRQ_DIRCHGON 0 +#define MT6370_IRQ_CHG_TREG 4 +#define MT6370_IRQ_CHG_AICR 5 +#define MT6370_IRQ_CHG_MIVR 6 +#define MT6370_IRQ_PWR_RDY 7 +#define MT6370_IRQ_FL_CHG_VINOVP 11 +#define MT6370_IRQ_CHG_VSYSUV 12 +#define MT6370_IRQ_CHG_VSYSOV 13 +#define MT6370_IRQ_CHG_VBATOV 14 +#define MT6370_IRQ_CHG_VINOVPCHG 15 +#define MT6370_IRQ_TS_BAT_COLD 20 +#define MT6370_IRQ_TS_BAT_COOL 21 +#define MT6370_IRQ_TS_BAT_WARM 22 +#define MT6370_IRQ_TS_BAT_HOT 23 +#define MT6370_IRQ_TS_STATC 24 +#define MT6370_IRQ_CHG_FAULT 25 +#define MT6370_IRQ_CHG_STATC 26 +#define MT6370_IRQ_CHG_TMR 27 +#define MT6370_IRQ_CHG_BATABS 28 +#define MT6370_IRQ_CHG_ADPBAD 29 +#define MT6370_IRQ_CHG_RVP 30 +#define MT6370_IRQ_TSHUTDOWN 31 +#define MT6370_IRQ_CHG_IINMEAS 32 +#define MT6370_IRQ_CHG_ICCMEAS 33 +#define MT6370_IRQ_CHGDET_DONE 34 +#define MT6370_IRQ_WDTMR 35 +#define MT6370_IRQ_SSFINISH 36 +#define MT6370_IRQ_CHG_RECHG 37 +#define MT6370_IRQ_CHG_TERM 38 +#define MT6370_IRQ_CHG_IEOC 39 +#define MT6370_IRQ_ADC_DONE 40 +#define MT6370_IRQ_PUMPX_DONE 41 +#define MT6370_IRQ_BST_BATUV 45 +#define MT6370_IRQ_BST_MIDOV 46 +#define MT6370_IRQ_BST_OLP 47 +#define MT6370_IRQ_ATTACH 48 +#define MT6370_IRQ_DETACH 49 +#define MT6370_IRQ_HVDCP_STPDONE 51 +#define MT6370_IRQ_HVDCP_VBUSDET_DONE 52 +#define MT6370_IRQ_HVDCP_DET 53 +#define MT6370_IRQ_CHGDET 54 +#define MT6370_IRQ_DCDT 55 +#define MT6370_IRQ_DIRCHG_VGOK 59 +#define MT6370_IRQ_DIRCHG_WDTMR 60 +#define MT6370_IRQ_DIRCHG_UC 61 +#define MT6370_IRQ_DIRCHG_OC 62 +#define MT6370_IRQ_DIRCHG_OV 63 +#define MT6370_IRQ_OVPCTRL_SWON 67 +#define MT6370_IRQ_OVPCTRL_UVP_D 68 +#define MT6370_IRQ_OVPCTRL_UVP 69 +#define MT6370_IRQ_OVPCTRL_OVP_D 70 +#define MT6370_IRQ_OVPCTRL_OVP 71 +#define MT6370_IRQ_FLED_STRBPIN 72 +#define MT6370_IRQ_FLED_TORPIN 73 +#define MT6370_IRQ_FLED_TX 74 +#define MT6370_IRQ_FLED_LVF 75 +#define MT6370_IRQ_FLED2_SHORT 78 +#define MT6370_IRQ_FLED1_SHORT 79 +#define MT6370_IRQ_FLED2_STRB 80 +#define MT6370_IRQ_FLED1_STRB 81 +#define mT6370_IRQ_FLED2_STRB_TO 82 +#define MT6370_IRQ_FLED1_STRB_TO 83 +#define MT6370_IRQ_FLED2_TOR 84 +#define MT6370_IRQ_FLED1_TOR 85 +#define MT6370_IRQ_OTP 93 +#define MT6370_IRQ_VDDA_OVP 94 +#define MT6370_IRQ_VDDA_UV 95 +#define MT6370_IRQ_LDO_OC 103 +#define MT6370_IRQ_BLED_OCP 118 +#define MT6370_IRQ_BLED_OVP 119 +#define MT6370_IRQ_DSV_VNEG_OCP 123 +#define MT6370_IRQ_DSV_VPOS_OCP 124 +#define MT6370_IRQ_DSV_BST_OCP 125 +#define MT6370_IRQ_DSV_VNEG_SCP 126 +#define MT6370_IRQ_DSV_VPOS_SCP 127 + +enum { + MT6370_USBC_I2C = 0, + MT6370_PMU_I2C, + MT6370_MAX_I2C +}; + +struct mt6370_info { + struct i2c_client *i2c[MT6370_MAX_I2C]; + struct regmap_irq_chip_data *irq_data; +}; + +#endif /* __MFD_MT6375_H__ */ -- 2.7.4