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| author | Kevin O'Connor <kevin@koconnor.net> | 2025-04-06 14:17:55 -0400 |
|---|---|---|
| committer | Kevin O'Connor <kevin@koconnor.net> | 2025-04-08 10:10:25 -0400 |
| commit | 655861cf121849b2fa74b7a07984c4c112b28c99 (patch) | |
| tree | 9c29bf7273d40661c0c9a577ce9944763c178c96 /src | |
| parent | 050bc332412c06357c5ff3a560eec0099c7fab69 (diff) | |
| download | kutter-655861cf121849b2fa74b7a07984c4c112b28c99.tar.gz kutter-655861cf121849b2fa74b7a07984c4c112b28c99.tar.xz kutter-655861cf121849b2fa74b7a07984c4c112b28c99.zip | |
i2c_software: Fix i2c_delay()
The i2c_delay() function did not properly handle counter rollovers.
It also performed an expensive run-time divide.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Diffstat (limited to 'src')
| -rw-r--r-- | src/i2c_software.c | 21 |
1 files changed, 9 insertions, 12 deletions
diff --git a/src/i2c_software.c b/src/i2c_software.c index 13acb766..99094864 100644 --- a/src/i2c_software.c +++ b/src/i2c_software.c @@ -1,11 +1,12 @@ // Software I2C emulation // -// Copyright (C) 2023 Kevin O'Connor <kevin@koconnor.net> +// Copyright (C) 2023-2025 Kevin O'Connor <kevin@koconnor.net> // Copyright (C) 2023 Alan.Ma <tech@biqu3d.com> // // This file may be distributed under the terms of the GNU GPLv3 license. #include <string.h> // memcpy +#include "autoconf.h" // CONFIG_CLOCK_FREQ #include "board/gpio.h" // gpio_out_setup #include "board/internal.h" // gpio_peripheral #include "board/misc.h" // timer_read_time @@ -17,7 +18,7 @@ struct i2c_software { struct gpio_out scl_out, sda_out; struct gpio_in scl_in, sda_in; uint8_t addr; - unsigned int ticks; + uint32_t ticks; }; void @@ -25,7 +26,7 @@ command_i2c_set_software_bus(uint32_t *args) { struct i2cdev_s *i2c = i2cdev_oid_lookup(args[0]); struct i2c_software *is = alloc_chunk(sizeof(*is)); - is->ticks = 1000000 / 100 / 2; // 100KHz + is->ticks = CONFIG_CLOCK_FREQ / (100000 * 2); // 100KHz is->addr = (args[4] & 0x7f) << 1; // address format shifted is->scl_in = gpio_in_setup(args[1], 1); is->scl_out = gpio_out_setup(args[1], 1); @@ -44,16 +45,12 @@ DECL_COMMAND(command_i2c_set_software_bus, #else -static unsigned int -nsecs_to_ticks(uint32_t ns) -{ - return timer_from_us(ns * 1000) / 1000000; -} - static void -i2c_delay(unsigned int ticks) { - unsigned int t = timer_read_time() + nsecs_to_ticks(ticks); - while (t > timer_read_time()); +i2c_delay(uint32_t ticks) +{ + uint32_t end = timer_read_time() + ticks; + while (timer_is_before(timer_read_time(), end)) + ; } #endif |