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-rw-r--r--common/onewire.c147
1 files changed, 0 insertions, 147 deletions
diff --git a/common/onewire.c b/common/onewire.c
deleted file mode 100644
index cdb5837255..0000000000
--- a/common/onewire.c
+++ /dev/null
@@ -1,147 +0,0 @@
-/* Copyright 2012 The Chromium OS Authors. All rights reserved.
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-/* 1-wire interface module for Chrome EC */
-
-#include "common.h"
-#include "gpio.h"
-#include "task.h"
-#include "timer.h"
-
-/*
- * Standard speed; all timings padded by 2 usec for safety.
- *
- * Note that these timing are actually _longer_ than legacy 1-wire standard
- * speed because we're running the 1-wire bus at 3.3V instead of 5V.
- */
-#define T_RSTL 602 /* Reset low pulse; 600-960 us */
-#define T_MSP 72 /* Presence detect sample time; 70-75 us */
-#define T_RSTH (68 + 260 + 5 + 2) /* Reset high; tPDHmax + tPDLmax + tRECmin */
-#define T_SLOT 70 /* Timeslot; >67 us */
-#define T_W0L 63 /* Write 0 low; 62-120 us */
-#define T_W1L 7 /* Write 1 low; 5-15 us */
-#define T_RL 7 /* Read low; 5-15 us */
-#define T_MSR 9 /* Read sample time; <15 us. Must be at least 200 ns after
- * T_RL since that's how long the signal takes to be pulled
- * up on our board. */
-
-/**
- * Output low on the bus for <usec> us, then switch back to open-drain input.
- */
-static void output0(int usec)
-{
- gpio_set_flags(GPIO_ONEWIRE,
- GPIO_OPEN_DRAIN | GPIO_OUTPUT | GPIO_OUT_LOW);
- udelay(usec);
- gpio_set_flags(GPIO_ONEWIRE, GPIO_INPUT);
-}
-
-/**
- * Read a bit.
- */
-static int readbit(void)
-{
- int bit;
-
- /*
- * The delay between sending the output pulse and reading the bit is
- * extremely timing sensitive, so disable interrupts.
- */
- interrupt_disable();
-
- /* Output low */
- output0(T_RL);
-
- /*
- * Delay to let peripheral release the line if it wants to send
- * a 1-bit
- */
- udelay(T_MSR - T_RL);
-
- /* Read bit */
- bit = gpio_get_level(GPIO_ONEWIRE);
-
- /*
- * Enable interrupt as soon as we've read the bit. The delay to the
- * end of the timeslot is a lower bound, so additional latency here is
- * harmless.
- */
- interrupt_enable();
-
- /* Delay to end of timeslot */
- udelay(T_SLOT - T_MSR);
- return bit;
-}
-
-/**
- * Write a bit.
- */
-static void writebit(int bit)
-{
- /*
- * The delays in the output-low signal for sending 0 and 1 bits are
- * extremely timing sensitive, so disable interrupts during that time.
- * Interrupts can be enabled again as soon as the output is switched
- * back to open-drain, since the delay for the rest of the timeslot is
- * a lower bound.
- */
- if (bit) {
- interrupt_disable();
- output0(T_W1L);
- interrupt_enable();
- udelay(T_SLOT - T_W1L);
- } else {
- interrupt_disable();
- output0(T_W0L);
- interrupt_enable();
- udelay(T_SLOT - T_W0L);
- }
-
-}
-
-int onewire_reset(void)
-{
- /* Start transaction with controller reset pulse */
- output0(T_RSTL);
-
- /* Wait for presence detect sample time.
- *
- * (Alternately, we could poll waiting for a 1-bit indicating our pulse
- * has let go, then poll up to max time waiting for a 0-bit indicating
- * the peripheral has responded.)
- */
- udelay(T_MSP);
-
- if (gpio_get_level(GPIO_ONEWIRE))
- return EC_ERROR_UNKNOWN;
-
- /*
- * Wait for end of presence pulse.
- *
- * (Alternately, we could poll waiting for a 1-bit.)
- */
- udelay(T_RSTH - T_MSP);
-
- return EC_SUCCESS;
-}
-
-int onewire_read(void)
-{
- int data = 0;
- int i;
-
- for (i = 0; i < 8; i++)
- data |= readbit() << i; /* LSB first */
-
- return data;
-}
-
-void onewire_write(int data)
-{
- int i;
-
- for (i = 0; i < 8; i++)
- writebit((data >> i) & 0x01); /* LSB first */
-}