mirror of
https://github.com/Telecominfraproject/OpenCellular.git
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c21f07e58e
Instead of using a runtime callback to register the console commands, put them in a special linker section. So we can do a macro to "register" them during the build. It saves 684 bytes and a few microseconds at startup. Signed-off-by: Vincent Palatin <vpalatin@chromium.org> BUG=None TEST=run a few commands from the BDS command line. Change-Id: Id33ea210b9035bf76ed720373c74c5dd24ccd1b1
159 lines
3.9 KiB
C
159 lines
3.9 KiB
C
/* Copyright (c) 2012 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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/* ADC module for Chrome EC */
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#include "board.h"
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#include "console.h"
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#include "adc.h"
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#include "timer.h"
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#include "registers.h"
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#include "uart.h"
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#include "util.h"
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static void configure_gpio(void)
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{
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volatile uint32_t scratch __attribute__((unused));
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/* Enable GPIOE module and delay a few clocks */
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LM4_SYSTEM_RCGCGPIO |= 0x0010;
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scratch = LM4_SYSTEM_RCGCGPIO;
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/* Use analog function for PE3 (AIN0) */
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LM4_GPIO_DEN(LM4_GPIO_E) &= ~0x08;
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LM4_GPIO_AMSEL(LM4_GPIO_E) |= 0x08;
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}
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int adc_read(enum adc_channel ch)
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{
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volatile uint32_t scratch __attribute__((unused));
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/* TODO: right now we have only a single channel so this is
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* simple. When we have multiple channels, should we...
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*
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* 1) Read them all using a timer interrupt, and then return
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* the most recent value? This is lowest-latency for the
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* caller, but won't return accurate data if read frequently.
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*
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* 2) Reserve SS3 for reading a single value, and configure it
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* on each read? Needs mutex if we could have multiple
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* callers; doesn't matter if just used for debugging.
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*
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* 3) Both? */
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if (ch != ADC_CH_POT)
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return ADC_READ_ERROR;
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/* Empty the FIFO of any previous results */
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while (!(LM4_ADC_SSFSTAT(0) & 0x100))
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scratch = LM4_ADC_SSFIFO(0);
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/* Clear the interrupt status */
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LM4_ADC_ADCISC |= 0x01;
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/* Initiate sample sequence */
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LM4_ADC_ADCPSSI |= 0x01;
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/* Wait for interrupt */
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/* TODO: use a real interrupt */
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while (!(LM4_ADC_ADCRIS & 0x01));
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/* Read the FIFO */
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return LM4_ADC_SSFIFO(0);
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}
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int adc_read_ec_temperature(void)
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{
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volatile uint32_t scratch __attribute__((unused));
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int a;
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/* Empty the FIFO of any previous results */
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while (!(LM4_ADC_SSFSTAT(3) & 0x100))
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scratch = LM4_ADC_SSFIFO(3);
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/* Clear the interrupt status */
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LM4_ADC_ADCISC |= 0x08;
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/* Initiate sample sequence */
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LM4_ADC_ADCPSSI |= 0x08;
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/* Wait for interrupt */
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/* TODO: use a real interrupt */
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/* TODO: timeout */
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while (!(LM4_ADC_ADCRIS & 0x08));
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/* Read the FIFO and convert to temperature */
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a = LM4_ADC_SSFIFO(3);
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return 273 + (295 - (225 * 2 * a) / ADC_READ_MAX) / 2;
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}
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/*****************************************************************************/
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/* Console commands */
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static int command_adc(int argc, char **argv)
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{
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uart_printf("ADC channel %d = 0x%03x\n", ADC_IN0,
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adc_read(ADC_CH_POT));
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return EC_SUCCESS;
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}
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DECLARE_CONSOLE_COMMAND(adc, command_adc);
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static int command_ectemp(int argc, char **argv)
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{
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int t = adc_read_ec_temperature();
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uart_printf("EC temperature is %d K = %d C\n", t, t-273);
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return EC_SUCCESS;
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}
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DECLARE_CONSOLE_COMMAND(ectemp, command_ectemp);
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/* Initialization */
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int adc_init(void)
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{
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volatile uint32_t scratch __attribute__((unused));
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/* Enable ADC0 module and delay a few clocks */
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LM4_SYSTEM_RCGCADC |= 0x01;
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scratch = LM4_SYSTEM_RCGCADC;
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/* Configure GPIOs */
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configure_gpio();
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/* Use external voltage references (VREFA+, VREFA-) instead of
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* VDDA and GNDA. */
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LM4_ADC_ADCCTL = 0x01;
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/* TODO: set up clock using ADCCC register? */
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/* Configure sample sequencer 0 */
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LM4_ADC_ADCACTSS &= ~0x01;
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/* Trigger SS0 by processor request */
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LM4_ADC_ADCEMUX = (LM4_ADC_ADCEMUX & 0xfffffff0) | 0x00;
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/* Sample only our one channel */
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LM4_ADC_SSMUX(0) = ADC_IN0 & 0x0f;
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LM4_ADC_SSEMUX(0) = (ADC_IN0 >> 4) & 0x0f;
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LM4_ADC_SSCTL(0) = 0x06; /* IE0 | END0 */
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/* Enable sample sequencer 0 */
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LM4_ADC_ADCACTSS |= 0x01;
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/* Configure sample sequencer 3 */
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LM4_ADC_ADCACTSS &= ~0x08;
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/* Trigger SS3 by processor request */
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LM4_ADC_ADCEMUX = (LM4_ADC_ADCEMUX & 0xffffff0f) | 0x00;
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/* Sample internal temp sensor */
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LM4_ADC_SSMUX(3) = 0x00;
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LM4_ADC_SSEMUX(3) = 0x00;
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LM4_ADC_SSCTL(3) = 0x0e; /* TS0 | IE0 | END0 */
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/* Enable sample sequencer 3 */
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LM4_ADC_ADCACTSS |= 0x08;
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return EC_SUCCESS;
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}
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