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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
| commit | 4352b8aee98005853aa63f57d6377282de17a33f (patch) | |
| tree | 27614d7a9ef05c32d089004e104364ce42324837 /drivers/rtc/rtc-meson.c | |
| download | linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip | |
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni:
"A new driver this cycle, for the AMD AXI I3C controller.
There are also new features such as IBI wakeup support, SETAASA device
discovery and ACPI support for the the DAA methods, meaning we can now
communicate with the SPD devices on DDR5 modules.
New driver:
- AMD AXI I3C master controller
Subsystem:
- I3C Common Command Code (CCC) handling improvements, especially
around GET CCCs
- SETAASA device discovery support
- ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
well as I2C devices on I3C bus
- IBI-based wakeup support
Drivers:
- dw: SETAASA support
- mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
controller support, PIO queue management support for HCI v1.2
- renesas: improve suspend to RAM support, add runtime PM support"
* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
i3c: dw: reduce do_daa time if there's no client
i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
i3c: dw: rename "pclk" to "apb" to match dt-binding
i3c: dw: make struct dw_i3c_cmd smaller
i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
i3c: renesas: Don't register devices when ENTDAA times out
i3c: master: dw-i3c-master: fix OD timing for first broadcast
i3c: mipi-i3c-hci: Advertise IBI wakeup capability
i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
i3c: master: Reject IBI requests from non-IBI-capable devices
i3c: master: Add helper to query bus wakeup requirements
i3c: master: Report wakeup events for IBIs
i3c: master: Support IBI-based wakeup capability
i3c: master: Fix potential UAF in i3c_device_match()
i3c: master: Fix potential UAF in i3c_device_uevent()
i3c: Make dev->desc locking assumptions explicit
i3c: master: Fix use-after-free of master->this
...
Diffstat (limited to 'drivers/rtc/rtc-meson.c')
| -rw-r--r-- | drivers/rtc/rtc-meson.c | 404 |
1 files changed, 404 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-meson.c b/drivers/rtc/rtc-meson.c new file mode 100644 index 000000000..21eceb9e2 --- /dev/null +++ b/drivers/rtc/rtc-meson.c @@ -0,0 +1,404 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * RTC driver for the interal RTC block in the Amlogic Meson6, Meson8, + * Meson8b and Meson8m2 SoCs. + * + * The RTC is split in to two parts, the AHB front end and a simple serial + * connection to the actual registers. This driver manages both parts. + * + * Copyright (c) 2018 Martin Blumenstingl <martin.blumenstingl@googlemail.com> + * Copyright (c) 2015 Ben Dooks <ben.dooks@codethink.co.uk> for Codethink Ltd + * Based on origin by Carlo Caione <carlo@endlessm.com> + */ + +#include <linux/bitfield.h> +#include <linux/delay.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/nvmem-provider.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> +#include <linux/regulator/consumer.h> +#include <linux/reset.h> +#include <linux/rtc.h> + +/* registers accessed from cpu bus */ +#define RTC_ADDR0 0x00 + #define RTC_ADDR0_LINE_SCLK BIT(0) + #define RTC_ADDR0_LINE_SEN BIT(1) + #define RTC_ADDR0_LINE_SDI BIT(2) + #define RTC_ADDR0_START_SER BIT(17) + #define RTC_ADDR0_WAIT_SER BIT(22) + #define RTC_ADDR0_DATA GENMASK(31, 24) + +#define RTC_ADDR1 0x04 + #define RTC_ADDR1_SDO BIT(0) + #define RTC_ADDR1_S_READY BIT(1) + +#define RTC_ADDR2 0x08 +#define RTC_ADDR3 0x0c + +#define RTC_REG4 0x10 + #define RTC_REG4_STATIC_VALUE GENMASK(7, 0) + +/* rtc registers accessed via rtc-serial interface */ +#define RTC_COUNTER (0) +#define RTC_SEC_ADJ (2) +#define RTC_REGMEM_0 (4) +#define RTC_REGMEM_1 (5) +#define RTC_REGMEM_2 (6) +#define RTC_REGMEM_3 (7) + +#define RTC_ADDR_BITS (3) /* number of address bits to send */ +#define RTC_DATA_BITS (32) /* number of data bits to tx/rx */ + +#define MESON_STATIC_BIAS_CUR (0x5 << 1) +#define MESON_STATIC_VOLTAGE (0x3 << 11) +#define MESON_STATIC_DEFAULT (MESON_STATIC_BIAS_CUR | MESON_STATIC_VOLTAGE) + +struct meson_rtc { + struct device *dev; /* device we bound from */ + struct reset_control *reset; /* reset source */ + struct regulator *vdd; /* voltage input */ + struct regmap *peripheral; /* peripheral registers */ + struct regmap *serial; /* serial registers */ +}; + +static const struct regmap_config meson_rtc_peripheral_regmap_config = { + .name = "peripheral-registers", + .reg_bits = 8, + .val_bits = 32, + .reg_stride = 4, + .max_register = RTC_REG4, +}; + +/* RTC front-end serialiser controls */ + +static void meson_rtc_sclk_pulse(struct meson_rtc *rtc) +{ + udelay(5); + regmap_update_bits(rtc->peripheral, RTC_ADDR0, RTC_ADDR0_LINE_SCLK, 0); + udelay(5); + regmap_update_bits(rtc->peripheral, RTC_ADDR0, RTC_ADDR0_LINE_SCLK, + RTC_ADDR0_LINE_SCLK); +} + +static void meson_rtc_send_bit(struct meson_rtc *rtc, unsigned int bit) +{ + regmap_update_bits(rtc->peripheral, RTC_ADDR0, RTC_ADDR0_LINE_SDI, + bit ? RTC_ADDR0_LINE_SDI : 0); + meson_rtc_sclk_pulse(rtc); +} + +static void meson_rtc_send_bits(struct meson_rtc *rtc, u32 data, + unsigned int nr) +{ + u32 bit = 1 << (nr - 1); + + while (bit) { + meson_rtc_send_bit(rtc, data & bit); + bit >>= 1; + } +} + +static void meson_rtc_set_dir(struct meson_rtc *rtc, u32 mode) +{ + regmap_update_bits(rtc->peripheral, RTC_ADDR0, RTC_ADDR0_LINE_SEN, 0); + regmap_update_bits(rtc->peripheral, RTC_ADDR0, RTC_ADDR0_LINE_SDI, 0); + meson_rtc_send_bit(rtc, mode); + regmap_update_bits(rtc->peripheral, RTC_ADDR0, RTC_ADDR0_LINE_SDI, 0); +} + +static u32 meson_rtc_get_data(struct meson_rtc *rtc) +{ + u32 tmp, val = 0; + int bit; + + for (bit = 0; bit < RTC_DATA_BITS; bit++) { + meson_rtc_sclk_pulse(rtc); + val <<= 1; + + regmap_read(rtc->peripheral, RTC_ADDR1, &tmp); + val |= tmp & RTC_ADDR1_SDO; + } + + return val; +} + +static int meson_rtc_get_bus(struct meson_rtc *rtc) +{ + int ret, retries; + u32 val; + + /* prepare bus for transfers, set all lines low */ + val = RTC_ADDR0_LINE_SDI | RTC_ADDR0_LINE_SEN | RTC_ADDR0_LINE_SCLK; + regmap_update_bits(rtc->peripheral, RTC_ADDR0, val, 0); + + for (retries = 0; retries < 3; retries++) { + /* wait for the bus to be ready */ + if (!regmap_read_poll_timeout(rtc->peripheral, RTC_ADDR1, val, + val & RTC_ADDR1_S_READY, 10, + 10000)) + return 0; + + dev_warn(rtc->dev, "failed to get bus, resetting RTC\n"); + + ret = reset_control_reset(rtc->reset); + if (ret) + return ret; + } + + dev_err(rtc->dev, "bus is not ready\n"); + return -ETIMEDOUT; +} + +static int meson_rtc_serial_bus_reg_read(void *context, unsigned int reg, + unsigned int *data) +{ + struct meson_rtc *rtc = context; + int ret; + + ret = meson_rtc_get_bus(rtc); + if (ret) + return ret; + + regmap_update_bits(rtc->peripheral, RTC_ADDR0, RTC_ADDR0_LINE_SEN, + RTC_ADDR0_LINE_SEN); + meson_rtc_send_bits(rtc, reg, RTC_ADDR_BITS); + meson_rtc_set_dir(rtc, 0); + *data = meson_rtc_get_data(rtc); + + return 0; +} + +static int meson_rtc_serial_bus_reg_write(void *context, unsigned int reg, + unsigned int data) +{ + struct meson_rtc *rtc = context; + int ret; + + ret = meson_rtc_get_bus(rtc); + if (ret) + return ret; + + regmap_update_bits(rtc->peripheral, RTC_ADDR0, RTC_ADDR0_LINE_SEN, + RTC_ADDR0_LINE_SEN); + meson_rtc_send_bits(rtc, data, RTC_DATA_BITS); + meson_rtc_send_bits(rtc, reg, RTC_ADDR_BITS); + meson_rtc_set_dir(rtc, 1); + + return 0; +} + +static const struct regmap_bus meson_rtc_serial_bus = { + .reg_read = meson_rtc_serial_bus_reg_read, + .reg_write = meson_rtc_serial_bus_reg_write, +}; + +static const struct regmap_config meson_rtc_serial_regmap_config = { + .name = "serial-registers", + .reg_bits = 4, + .reg_stride = 1, + .val_bits = 32, + .max_register = RTC_REGMEM_3, + .fast_io = false, +}; + +static int meson_rtc_write_static(struct meson_rtc *rtc, u32 data) +{ + u32 tmp; + + regmap_write(rtc->peripheral, RTC_REG4, + FIELD_PREP(RTC_REG4_STATIC_VALUE, (data >> 8))); + + /* write the static value and start the auto serializer */ + tmp = FIELD_PREP(RTC_ADDR0_DATA, (data & 0xff)) | RTC_ADDR0_START_SER; + regmap_update_bits(rtc->peripheral, RTC_ADDR0, + RTC_ADDR0_DATA | RTC_ADDR0_START_SER, tmp); + + /* wait for the auto serializer to complete */ + return regmap_read_poll_timeout(rtc->peripheral, RTC_REG4, tmp, + !(tmp & RTC_ADDR0_WAIT_SER), 10, + 10000); +} + +/* RTC interface layer functions */ + +static int meson_rtc_gettime(struct device *dev, struct rtc_time *tm) +{ + struct meson_rtc *rtc = dev_get_drvdata(dev); + u32 time; + int ret; + + ret = regmap_read(rtc->serial, RTC_COUNTER, &time); + if (!ret) + rtc_time64_to_tm(time, tm); + + return ret; +} + +static int meson_rtc_settime(struct device *dev, struct rtc_time *tm) +{ + struct meson_rtc *rtc = dev_get_drvdata(dev); + + return regmap_write(rtc->serial, RTC_COUNTER, rtc_tm_to_time64(tm)); +} + +static const struct rtc_class_ops meson_rtc_ops = { + .read_time = meson_rtc_gettime, + .set_time = meson_rtc_settime, +}; + +/* NVMEM interface layer functions */ + +static int meson_rtc_regmem_read(void *context, unsigned int offset, + void *buf, size_t bytes) +{ + struct meson_rtc *rtc = context; + unsigned int read_offset, read_size; + + read_offset = RTC_REGMEM_0 + (offset / 4); + read_size = bytes / 4; + + return regmap_bulk_read(rtc->serial, read_offset, buf, read_size); +} + +static int meson_rtc_regmem_write(void *context, unsigned int offset, + void *buf, size_t bytes) +{ + struct meson_rtc *rtc = context; + unsigned int write_offset, write_size; + + write_offset = RTC_REGMEM_0 + (offset / 4); + write_size = bytes / 4; + + return regmap_bulk_write(rtc->serial, write_offset, buf, write_size); +} + +static int meson_rtc_probe(struct platform_device *pdev) +{ + struct nvmem_config meson_rtc_nvmem_config = { + .name = "meson-rtc-regmem", + .type = NVMEM_TYPE_BATTERY_BACKED, + .word_size = 4, + .stride = 4, + .size = 4 * 4, + .reg_read = meson_rtc_regmem_read, + .reg_write = meson_rtc_regmem_write, + }; + struct device *dev = &pdev->dev; + struct meson_rtc *rtc; + struct rtc_device *rtc_dev; + void __iomem *base; + int ret; + u32 tm; + + rtc = devm_kzalloc(dev, sizeof(struct meson_rtc), GFP_KERNEL); + if (!rtc) + return -ENOMEM; + + rtc_dev = devm_rtc_allocate_device(dev); + if (IS_ERR(rtc_dev)) + return PTR_ERR(rtc_dev); + + platform_set_drvdata(pdev, rtc); + + rtc->dev = dev; + + rtc_dev->ops = &meson_rtc_ops; + rtc_dev->range_max = U32_MAX; + + base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(base)) + return PTR_ERR(base); + + rtc->peripheral = devm_regmap_init_mmio(dev, base, + &meson_rtc_peripheral_regmap_config); + if (IS_ERR(rtc->peripheral)) { + dev_err(dev, "failed to create peripheral regmap\n"); + return PTR_ERR(rtc->peripheral); + } + + rtc->reset = devm_reset_control_get(dev, NULL); + if (IS_ERR(rtc->reset)) { + dev_err(dev, "missing reset line\n"); + return PTR_ERR(rtc->reset); + } + + rtc->vdd = devm_regulator_get(dev, "vdd"); + if (IS_ERR(rtc->vdd)) { + dev_err(dev, "failed to get the vdd-supply\n"); + return PTR_ERR(rtc->vdd); + } + + ret = regulator_enable(rtc->vdd); + if (ret) { + dev_err(dev, "failed to enable vdd-supply\n"); + return ret; + } + + ret = meson_rtc_write_static(rtc, MESON_STATIC_DEFAULT); + if (ret) { + dev_err(dev, "failed to set static values\n"); + goto out_disable_vdd; + } + + rtc->serial = devm_regmap_init(dev, &meson_rtc_serial_bus, rtc, + &meson_rtc_serial_regmap_config); + if (IS_ERR(rtc->serial)) { + dev_err(dev, "failed to create serial regmap\n"); + ret = PTR_ERR(rtc->serial); + goto out_disable_vdd; + } + + /* + * check if we can read RTC counter, if not then the RTC is probably + * not functional. If it isn't probably best to not bind. + */ + ret = regmap_read(rtc->serial, RTC_COUNTER, &tm); + if (ret) { + dev_err(dev, "cannot read RTC counter, RTC not functional\n"); + goto out_disable_vdd; + } + + meson_rtc_nvmem_config.priv = rtc; + ret = devm_rtc_nvmem_register(rtc_dev, &meson_rtc_nvmem_config); + if (ret) + goto out_disable_vdd; + + ret = devm_rtc_register_device(rtc_dev); + if (ret) + goto out_disable_vdd; + + return 0; + +out_disable_vdd: + regulator_disable(rtc->vdd); + return ret; +} + +static const __maybe_unused struct of_device_id meson_rtc_dt_match[] = { + { .compatible = "amlogic,meson6-rtc", }, + { .compatible = "amlogic,meson8-rtc", }, + { .compatible = "amlogic,meson8b-rtc", }, + { .compatible = "amlogic,meson8m2-rtc", }, + { }, +}; +MODULE_DEVICE_TABLE(of, meson_rtc_dt_match); + +static struct platform_driver meson_rtc_driver = { + .probe = meson_rtc_probe, + .driver = { + .name = "meson-rtc", + .of_match_table = of_match_ptr(meson_rtc_dt_match), + }, +}; +module_platform_driver(meson_rtc_driver); + +MODULE_DESCRIPTION("Amlogic Meson RTC Driver"); +MODULE_AUTHOR("Ben Dooks <ben.dooks@codethink.co.uk>"); +MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@googlemail.com>"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:meson-rtc"); |
