From 4352b8aee98005853aa63f57d6377282de17a33f Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 23 Aug 2026 13:28:57 -0700 Subject: Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux 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 ... --- drivers/clocksource/timer-cs5535.c | 189 +++++++++++++++++++++++++++++++++++++ 1 file changed, 189 insertions(+) create mode 100644 drivers/clocksource/timer-cs5535.c (limited to 'drivers/clocksource/timer-cs5535.c') diff --git a/drivers/clocksource/timer-cs5535.c b/drivers/clocksource/timer-cs5535.c new file mode 100644 index 000000000..8af666c39 --- /dev/null +++ b/drivers/clocksource/timer-cs5535.c @@ -0,0 +1,189 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Clock event driver for the CS5535/CS5536 + * + * Copyright (C) 2006, Advanced Micro Devices, Inc. + * Copyright (C) 2007 Andres Salomon + * Copyright (C) 2009 Andres Salomon + * + * The MFGPTs are documented in AMD Geode CS5536 Companion Device Data Book. + */ + +#include +#include +#include +#include +#include +#include + +#define DRV_NAME "cs5535-clockevt" + +static int timer_irq; +module_param_hw_named(irq, timer_irq, int, irq, 0644); +MODULE_PARM_DESC(irq, "Which IRQ to use for the clock source MFGPT ticks."); + +/* + * We are using the 32.768kHz input clock - it's the only one that has the + * ranges we find desirable. The following table lists the suitable + * divisors and the associated Hz, minimum interval and the maximum interval: + * + * Divisor Hz Min Delta (s) Max Delta (s) + * 1 32768 .00048828125 2.000 + * 2 16384 .0009765625 4.000 + * 4 8192 .001953125 8.000 + * 8 4096 .00390625 16.000 + * 16 2048 .0078125 32.000 + * 32 1024 .015625 64.000 + * 64 512 .03125 128.000 + * 128 256 .0625 256.000 + * 256 128 .125 512.000 + */ + +static struct cs5535_mfgpt_timer *cs5535_event_clock; + +/* Selected from the table above */ + +#define MFGPT_DIVISOR 16 +#define MFGPT_SCALE 4 /* divisor = 2^(scale) */ +#define MFGPT_HZ (32768 / MFGPT_DIVISOR) +#define MFGPT_PERIODIC (MFGPT_HZ / HZ) + +/* + * The MFGPT timers on the CS5536 provide us with suitable timers to use + * as clock event sources - not as good as a HPET or APIC, but certainly + * better than the PIT. This isn't a general purpose MFGPT driver, but + * a simplified one designed specifically to act as a clock event source. + * For full details about the MFGPT, please consult the CS5536 data sheet. + */ + +static void disable_timer(struct cs5535_mfgpt_timer *timer) +{ + /* avoid races by clearing CMP1 and CMP2 unconditionally */ + cs5535_mfgpt_write(timer, MFGPT_REG_SETUP, + (uint16_t) ~MFGPT_SETUP_CNTEN | MFGPT_SETUP_CMP1 | + MFGPT_SETUP_CMP2); +} + +static void start_timer(struct cs5535_mfgpt_timer *timer, uint16_t delta) +{ + cs5535_mfgpt_write(timer, MFGPT_REG_CMP2, delta); + cs5535_mfgpt_write(timer, MFGPT_REG_COUNTER, 0); + + cs5535_mfgpt_write(timer, MFGPT_REG_SETUP, + MFGPT_SETUP_CNTEN | MFGPT_SETUP_CMP2); +} + +static int mfgpt_shutdown(struct clock_event_device *evt) +{ + disable_timer(cs5535_event_clock); + return 0; +} + +static int mfgpt_set_periodic(struct clock_event_device *evt) +{ + disable_timer(cs5535_event_clock); + start_timer(cs5535_event_clock, MFGPT_PERIODIC); + return 0; +} + +static int mfgpt_next_event(unsigned long delta, struct clock_event_device *evt) +{ + start_timer(cs5535_event_clock, delta); + return 0; +} + +static struct clock_event_device cs5535_clockevent = { + .name = DRV_NAME, + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .set_state_shutdown = mfgpt_shutdown, + .set_state_periodic = mfgpt_set_periodic, + .set_state_oneshot = mfgpt_shutdown, + .tick_resume = mfgpt_shutdown, + .set_next_event = mfgpt_next_event, + .rating = 250, + .owner = THIS_MODULE, +}; + +static irqreturn_t mfgpt_tick(int irq, void *dev_id) +{ + uint16_t val = cs5535_mfgpt_read(cs5535_event_clock, MFGPT_REG_SETUP); + + /* See if the interrupt was for us */ + if (!(val & (MFGPT_SETUP_SETUP | MFGPT_SETUP_CMP2 | MFGPT_SETUP_CMP1))) + return IRQ_NONE; + + /* Turn off the clock (and clear the event) */ + disable_timer(cs5535_event_clock); + + if (clockevent_state_detached(&cs5535_clockevent) || + clockevent_state_shutdown(&cs5535_clockevent)) + return IRQ_HANDLED; + + /* Clear the counter */ + cs5535_mfgpt_write(cs5535_event_clock, MFGPT_REG_COUNTER, 0); + + /* Restart the clock in periodic mode */ + + if (clockevent_state_periodic(&cs5535_clockevent)) + cs5535_mfgpt_write(cs5535_event_clock, MFGPT_REG_SETUP, + MFGPT_SETUP_CNTEN | MFGPT_SETUP_CMP2); + + cs5535_clockevent.event_handler(&cs5535_clockevent); + return IRQ_HANDLED; +} + +static int __init cs5535_mfgpt_init(void) +{ + unsigned long flags = IRQF_NOBALANCING | IRQF_TIMER | IRQF_SHARED; + struct cs5535_mfgpt_timer *timer; + int ret; + uint16_t val; + + timer = cs5535_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING); + if (!timer) { + printk(KERN_ERR DRV_NAME ": Could not allocate MFGPT timer\n"); + return -ENODEV; + } + cs5535_event_clock = timer; + + /* Set up the IRQ on the MFGPT side */ + if (cs5535_mfgpt_setup_irq(timer, MFGPT_CMP2, &timer_irq)) { + printk(KERN_ERR DRV_NAME ": Could not set up IRQ %d\n", + timer_irq); + goto err_timer; + } + + /* And register it with the kernel */ + ret = request_irq(timer_irq, mfgpt_tick, flags, DRV_NAME, timer); + if (ret) { + printk(KERN_ERR DRV_NAME ": Unable to set up the interrupt.\n"); + goto err_irq; + } + + /* Set the clock scale and enable the event mode for CMP2 */ + val = MFGPT_SCALE | (3 << 8); + + cs5535_mfgpt_write(cs5535_event_clock, MFGPT_REG_SETUP, val); + + /* Set up the clock event */ + printk(KERN_INFO DRV_NAME + ": Registering MFGPT timer as a clock event, using IRQ %d\n", + timer_irq); + clockevents_config_and_register(&cs5535_clockevent, MFGPT_HZ, + 0xF, 0xFFFE); + + return 0; + +err_irq: + cs5535_mfgpt_release_irq(cs5535_event_clock, MFGPT_CMP2, &timer_irq); +err_timer: + cs5535_mfgpt_free_timer(cs5535_event_clock); + printk(KERN_ERR DRV_NAME ": Unable to set up the MFGPT clock source\n"); + return -EIO; +} + +module_init(cs5535_mfgpt_init); + +MODULE_AUTHOR("Andres Salomon "); +MODULE_DESCRIPTION("CS5535/CS5536 MFGPT clock event driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1