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https://gitlab.rtems.org/rtems/rtos/rtems.git
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3b053f6919
The EOZ9 RTC has a similar register interface like the MCP7940M (and quite some other I2C RTCs). This commit: * Extracts the generic parts from MCP7940M and moves it into a generic i2c-rtc driver. * Uses the new i2c-rtc for the MCP7940M. * Uses the new i2c-rtc for the new Abracom EOZ9.
98 lines
3.3 KiB
C
98 lines
3.3 KiB
C
/* SPDX-License-Identifier: BSD-2-Clause */
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/**
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* @file
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*
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* @ingroup shared_tod_mcp7940m_rtc
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*
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* @brief This file provides the interfaces of @ref shared_tod_mcp7940m_rtc.
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*/
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/*
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* Copyright (C) 2023 embedded brains GmbH & Co. KG
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Only 24 hour format is supported. If this driver is the only ones who write
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* the RTC, that shouldn't be a problem.
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*
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* The weekday register is not used. It has a user-defined representation anyway
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* and therefore doesn't really matter.
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*/
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#include <libchip/mcp7940m-rtc.h>
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#define REG_MCP7940M_RTCSEC 0x00u
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#define REG_MCP7940M_RTCMIN 0x01u
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#define REG_MCP7940M_RTCHOUR 0x02u
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#define REG_MCP7940M_RTCWKDAY 0x03u
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#define REG_MCP7940M_RTCDATE 0x04u
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#define REG_MCP7940M_RTCMTH 0x05u
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#define REG_MCP7940M_RTCYEAR 0x06u
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#define MCP7940M_RTCSEC_ST (0x01u << 7)
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#define MCP7940M_RTCMTH_LPYR (0x01u << 5)
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#define REG_MCP7940M_CONTROL 0x07
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#define MCP7940M_CONTROL_OUT (0x1u << 7)
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#define MCP7940M_CONTROL_SQWEN (0x1u << 6)
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#define MCP7940M_CONTROL_ALM1EN (0x1u << 5)
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#define MCP7940M_CONTROL_ALM0EN (0x1u << 4)
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#define MCP7940M_CONTROL_EXTOSC (0x1u << 3)
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#define MCP7940M_CONTROL_CRSTRIM (0x1u << 2)
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#define MCP7940M_CONTROL_SQWFS1 (0x1u << 1)
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#define MCP7940M_CONTROL_SQWFS0 (0x1u << 0)
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int mcp7940m_hw_init(struct i2c_rtc_base *base)
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{
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uint8_t reg;
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ssize_t rv;
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struct mcp7940m_rtc *ctx =
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RTEMS_CONTAINER_OF(base, struct mcp7940m_rtc, base);
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/*
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* Make sure that all alarms and outputs are disabled. Enable or disable
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* oscillator.
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*
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* This makes sure that we can start with an uninitialized device that has a
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* random value in the control register.
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*/
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reg = 0;
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if (!ctx->crystal) {
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reg |= MCP7940M_CONTROL_EXTOSC;
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}
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rv = i2c_rtc_write(&ctx->base, REG_MCP7940M_CONTROL, ®, 1);
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if (rv == 0 && ctx->crystal) {
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rv = i2c_rtc_read(&ctx->base, REG_MCP7940M_RTCSEC, ®, 1);
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if (rv == 0 && (reg & MCP7940M_RTCSEC_ST) == 0) {
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reg |= MCP7940M_RTCSEC_ST;
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rv = i2c_rtc_write(&ctx->base, REG_MCP7940M_RTCSEC, ®, 1);
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}
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}
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return rv;
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}
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