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4e920054f9
Programmable Peripheral Interconnect is a shared resource. This CL adds code for allocating PPIs to devices. BUG=None BRANCH=None TEST=Modify the I2C code to use this PPI allocation code and test I2C communication (using experimental MXT touch controller code) Change-Id: I8ec27867d041982ef18e8515d6434c5de2c189c5 Signed-off-by: Myles Watson <mylesgw@google.com> Reviewed-on: https://chromium-review.googlesource.com/361405 Commit-Ready: Myles Watson <mylesgw@chromium.org> Tested-by: Myles Watson <mylesgw@chromium.org> Reviewed-by: Aseda Aboagye <aaboagye@chromium.org> Reviewed-by: Levi Oliver <levio@google.com>
70 lines
1.5 KiB
C
70 lines
1.5 KiB
C
/* Copyright 2016 The Chromium OS Authors. All rights reserved.
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#include "ppi.h"
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#include "registers.h"
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#include "util.h"
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#define NRF51_PPI_FIRST_PP_CH NRF51_PPI_CH_TIMER0_CC0__RADIO_TXEN
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#define NRF51_PPI_LAST_PP_CH NRF51_PPI_CH_RTC0_COMPARE0__TIMER0_START
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static uint32_t channels_in_use;
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static uint32_t channel_groups_in_use;
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int ppi_request_pre_programmed_channel(int ppi_chan)
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{
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ASSERT(ppi_chan >= NRF51_PPI_FIRST_PP_CH &&
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ppi_chan <= NRF51_PPI_LAST_PP_CH);
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if (channels_in_use & (1 << ppi_chan))
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return EC_ERROR_BUSY;
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channels_in_use |= (1 << ppi_chan);
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return EC_SUCCESS;
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}
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int ppi_request_channel(int *ppi_chan)
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{
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int chan;
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for (chan = 0; chan < NRF51_PPI_NUM_PROGRAMMABLE_CHANNELS; chan++)
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if ((channels_in_use & (1 << chan)) == 0)
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break;
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if (chan == NRF51_PPI_NUM_PROGRAMMABLE_CHANNELS)
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return EC_ERROR_BUSY;
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channels_in_use |= (1 << chan);
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*ppi_chan = chan;
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return EC_SUCCESS;
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}
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void ppi_release_channel(int ppi_chan)
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{
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channels_in_use &= ~(1 << ppi_chan);
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}
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void ppi_release_group(int ppi_group)
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{
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channel_groups_in_use &= ~(1 << ppi_group);
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}
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int ppi_request_group(int *ppi_group)
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{
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int group;
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for (group = 0; group < NRF51_PPI_NUM_GROUPS; group++)
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if ((channel_groups_in_use & (1 << group)) == 0)
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break;
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if (group == NRF51_PPI_NUM_GROUPS)
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return EC_ERROR_BUSY;
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channel_groups_in_use |= (1 << group);
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*ppi_group = group;
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return EC_SUCCESS;
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}
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