mirror of
https://github.com/RIOT-OS/RIOT.git
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kinetis: Refactor PWM periph implementation
- Set the proper prescaler value depending on requested frequency - Return the actual achieved frequency in pwm_init - Handle 1-8 channels depending on periph_conf.h instead of 4 fixed - Perform function argument verification before touching the hardware - Turn on PORT clock gate before touching PORT registers - Eliminate some magic numbers
This commit is contained in:
Joakim Gebart
parent
fc926e57bf
commit
c85cc83a5a
@ -1,6 +1,7 @@
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/*
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* Copyright (C) 2014 Freie Universität Berlin
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* Copyright (C) 2014 PHYTEC Messtechnik GmbH
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* Copyright (C) 2015 Eistec AB
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*
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* This file is subject to the terms and conditions of the GNU Lesser General
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* Public License v2.1. See the file LICENSE in the top level directory for more
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@ -18,6 +19,7 @@
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* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
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* @author Johann Fischer <j.fischer@phytec.de>
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* @author Jonas Remmert <j.remmert@phytec.de>
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* @author Joakim Gebart <joakim.gebart@eistec.se>
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*
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* @}
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*/
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@ -34,131 +36,188 @@
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/* ignore file in case no PWM devices are defined */
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#if PWM_NUMOF
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/* FTM channel look up tables */
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#if PWM_0_EN
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static const uint8_t ftm0chan[] = {
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#if PWM_0_CHANNELS > 0
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PWM_0_FTMCHAN_CH0,
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#endif
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#if PWM_0_CHANNELS > 1
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PWM_0_FTMCHAN_CH1,
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#endif
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#if PWM_0_CHANNELS > 2
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PWM_0_FTMCHAN_CH2,
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#endif
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#if PWM_0_CHANNELS > 3
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PWM_0_FTMCHAN_CH3,
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#endif
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#if PWM_0_CHANNELS > 4
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PWM_0_FTMCHAN_CH4,
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#endif
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#if PWM_0_CHANNELS > 5
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PWM_0_FTMCHAN_CH5,
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#endif
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#if PWM_0_CHANNELS > 6
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PWM_0_FTMCHAN_CH6,
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#endif
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#if PWM_0_CHANNELS > 7
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PWM_0_FTMCHAN_CH7,
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#endif
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};
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#endif
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#if PWM_1_EN
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static const uint8_t ftm1chan[] = {
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#if PWM_1_CHANNELS > 0
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PWM_1_FTMCHAN_CH0,
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#endif
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#if PWM_1_CHANNELS > 1
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PWM_1_FTMCHAN_CH1,
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#endif
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#if PWM_1_CHANNELS > 2
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PWM_1_FTMCHAN_CH2,
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#endif
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#if PWM_1_CHANNELS > 3
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PWM_1_FTMCHAN_CH3,
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#endif
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#if PWM_1_CHANNELS > 4
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PWM_1_FTMCHAN_CH4,
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#endif
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#if PWM_1_CHANNELS > 5
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PWM_1_FTMCHAN_CH5,
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#endif
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#if PWM_1_CHANNELS > 6
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PWM_1_FTMCHAN_CH6,
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#endif
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#if PWM_1_CHANNELS > 7
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PWM_1_FTMCHAN_CH7,
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#endif
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};
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#endif
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int pwm_init(pwm_t dev, pwm_mode_t mode, unsigned int frequency, unsigned int resolution)
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{
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FTM_Type *tim = NULL;
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PORT_Type *port[PWM_MAX_CHANNELS];
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/* cppcheck-suppress unassignedVariable */
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uint8_t pins[PWM_MAX_CHANNELS];
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uint8_t af[PWM_MAX_CHANNELS];
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/* cppcheck-suppress unassignedVariable */
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uint8_t ftmchan[PWM_MAX_CHANNELS];
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FTM_Type *ftm;
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int channels = 0;
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uint32_t pwm_clk = 0;
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const uint8_t *ftmchan = NULL;
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switch (dev) {
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#if PWM_0_EN
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case PWM_0:
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channels = PWM_0_CHANNELS;
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pwm_clk = PWM_0_CLK;
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ftm = PWM_0_DEV;
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ftmchan = &ftm0chan[0];
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break;
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#endif
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#if PWM_1_EN
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case PWM_1:
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channels = PWM_1_CHANNELS;
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pwm_clk = PWM_1_CLK;
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ftm = PWM_1_DEV;
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ftmchan = &ftm1chan[0];
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break;
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#endif
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default:
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return -1;
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}
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switch (mode) {
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case PWM_LEFT:
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case PWM_RIGHT:
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case PWM_CENTER:
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break;
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default:
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return -1;
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}
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if (resolution > (PWM_MAX_VALUE + 1) || (resolution * frequency) > pwm_clk) {
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return -2;
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}
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/* Try to find a good prescaler value */
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/* The prescaler divides the module clock by a power of two, between 2^0 and 2^7 */
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uint8_t prescaler = 0;
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/* (resolution * frequency) is the number of timer ticks per second */
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while ((pwm_clk >> prescaler) > (resolution * frequency)) {
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++prescaler;
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if (prescaler > 7) {
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/* Module clock is too fast to reach the requested frequency using the
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* hardware supported prescaler values */
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/* Note: The frequency might be reachable if the requested resolution
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* is increased. */
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return -2;
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}
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}
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/* The chosen prescaler yields a timer frequency which is the
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* nearest possible frequency less than the requested frequency */
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/* Turn on the peripheral */
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pwm_poweron(dev);
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switch (dev) {
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#if PWM_0_EN
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case PWM_0:
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tim = PWM_0_DEV;
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port[0] = PWM_0_PORT_CH0;
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port[1] = PWM_0_PORT_CH1;
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port[2] = PWM_0_PORT_CH2;
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port[3] = PWM_0_PORT_CH3;
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pins[0] = PWM_0_PIN_CH0;
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pins[1] = PWM_0_PIN_CH1;
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pins[2] = PWM_0_PIN_CH2;
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pins[3] = PWM_0_PIN_CH3;
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ftmchan[0] = PWM_0_FTMCHAN_CH0;
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ftmchan[1] = PWM_0_FTMCHAN_CH1;
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ftmchan[2] = PWM_0_FTMCHAN_CH2;
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ftmchan[3] = PWM_0_FTMCHAN_CH3;
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af[0] = PWM_0_PIN_AF_CH0;
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af[1] = PWM_0_PIN_AF_CH1;
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af[2] = PWM_0_PIN_AF_CH2;
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af[3] = PWM_0_PIN_AF_CH3;
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channels = PWM_0_CHANNELS;
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pwm_clk = PWM_0_CLK;
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PWM_0_PORT_CLKEN();
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break;
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#endif
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default:
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return -1;
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}
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if (channels > PWM_MAX_CHANNELS) {
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return -1;
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}
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/* cppcheck-suppress nullPointer */
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tim->MODE = (1 << FTM_MODE_WPDIS_SHIFT);
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/* setup pins, reset timer match value */
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for (int i = 0; i < channels; i++) {
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port[i]->PCR[pins[i]] = PORT_PCR_MUX(af[i]);
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/* cppcheck-suppress nullPointer */
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tim->CONTROLS[i].CnV = 0;
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}
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/* reset timer configuration registers */
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/* cppcheck-suppress nullPointer */
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tim->COMBINE = 0;
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/* set prescale and mod registers to matching values for resolution and frequency */
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if (resolution > 0xffff || (resolution * frequency) > pwm_clk) {
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return -2;
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}
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/* cppcheck-suppress nullPointer */
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tim->SC = FTM_SC_PS((pwm_clk / (resolution * frequency)) - 1);
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/* cppcheck-suppress nullPointer */
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tim->MOD = resolution;
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/* set PWM mode */
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switch (mode) {
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case PWM_LEFT:
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for (int i = 0; i < channels; i++) {
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/* cppcheck-suppress nullPointer */
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tim->CONTROLS[ftmchan[i]].CnSC = (1 << FTM_CnSC_MSB_SHIFT |
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1 << FTM_CnSC_ELSB_SHIFT);
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}
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break;
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case PWM_RIGHT:
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for (int i = 0; i < channels; i++) {
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/* cppcheck-suppress nullPointer */
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tim->CONTROLS[ftmchan[i]].CnSC = (1 << FTM_CnSC_MSB_SHIFT |
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1 << FTM_CnSC_ELSA_SHIFT);
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}
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break;
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case PWM_CENTER:
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for (int i = 0; i < channels; i++) {
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/* cppcheck-suppress nullPointer */
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tim->CONTROLS[ftmchan[i]].CnSC = (1 << FTM_CnSC_MSB_SHIFT);
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}
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/* cppcheck-suppress nullPointer */
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tim->SC |= (1 << FTM_SC_CPWMS_SHIFT);
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break;
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}
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/* enable timer ergo the PWM generation */
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pwm_start(dev);
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return 0;
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}
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int pwm_set(pwm_t dev, int channel, unsigned int value)
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{
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FTM_Type *tim = NULL;
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switch (dev) {
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#if PWM_0_EN
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case PWM_0:
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tim = PWM_0_DEV;
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#if PWM_0_CHANNELS > 0
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PWM_0_PORT_CH0->PCR[PWM_0_PIN_CH0] = PORT_PCR_MUX(PWM_0_PIN_AF_CH0);
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#endif
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#if PWM_0_CHANNELS > 1
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PWM_0_PORT_CH1->PCR[PWM_0_PIN_CH1] = PORT_PCR_MUX(PWM_0_PIN_AF_CH1);
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#endif
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#if PWM_0_CHANNELS > 2
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PWM_0_PORT_CH2->PCR[PWM_0_PIN_CH2] = PORT_PCR_MUX(PWM_0_PIN_AF_CH2);
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#endif
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#if PWM_0_CHANNELS > 3
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PWM_0_PORT_CH3->PCR[PWM_0_PIN_CH3] = PORT_PCR_MUX(PWM_0_PIN_AF_CH3);
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#endif
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#if PWM_0_CHANNELS > 4
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PWM_0_PORT_CH4->PCR[PWM_0_PIN_CH4] = PORT_PCR_MUX(PWM_0_PIN_AF_CH4);
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#endif
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#if PWM_0_CHANNELS > 5
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PWM_0_PORT_CH5->PCR[PWM_0_PIN_CH5] = PORT_PCR_MUX(PWM_0_PIN_AF_CH5);
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#endif
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#if PWM_0_CHANNELS > 6
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PWM_0_PORT_CH6->PCR[PWM_0_PIN_CH6] = PORT_PCR_MUX(PWM_0_PIN_AF_CH6);
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#endif
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#if PWM_0_CHANNELS > 7
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PWM_0_PORT_CH7->PCR[PWM_0_PIN_CH7] = PORT_PCR_MUX(PWM_0_PIN_AF_CH7);
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#endif
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break;
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#endif
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#if PWM_1_EN
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case PWM_1:
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tim = PWM_1_DEV;
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PWM_1_PORT_CLKEN();
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#if PWM_1_CHANNELS > 0
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PWM_1_PORT_CH0->PCR[PWM_1_PIN_CH0] = PORT_PCR_MUX(PWM_1_PIN_AF_CH0);
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#endif
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#if PWM_1_CHANNELS > 1
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PWM_1_PORT_CH1->PCR[PWM_1_PIN_CH1] = PORT_PCR_MUX(PWM_1_PIN_AF_CH1);
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#endif
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#if PWM_1_CHANNELS > 2
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PWM_1_PORT_CH2->PCR[PWM_1_PIN_CH2] = PORT_PCR_MUX(PWM_1_PIN_AF_CH2);
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#endif
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#if PWM_1_CHANNELS > 3
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PWM_1_PORT_CH3->PCR[PWM_1_PIN_CH3] = PORT_PCR_MUX(PWM_1_PIN_AF_CH3);
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#endif
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#if PWM_1_CHANNELS > 4
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PWM_1_PORT_CH4->PCR[PWM_1_PIN_CH4] = PORT_PCR_MUX(PWM_1_PIN_AF_CH4);
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#endif
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#if PWM_1_CHANNELS > 5
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PWM_1_PORT_CH5->PCR[PWM_1_PIN_CH5] = PORT_PCR_MUX(PWM_1_PIN_AF_CH5);
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#endif
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#if PWM_1_CHANNELS > 6
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PWM_1_PORT_CH6->PCR[PWM_1_PIN_CH6] = PORT_PCR_MUX(PWM_1_PIN_AF_CH6);
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#endif
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#if PWM_1_CHANNELS > 7
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PWM_1_PORT_CH7->PCR[PWM_1_PIN_CH7] = PORT_PCR_MUX(PWM_1_PIN_AF_CH7);
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#endif
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break;
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#endif
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@ -166,36 +225,96 @@ int pwm_set(pwm_t dev, int channel, unsigned int value)
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return -1;
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}
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/* norm value to maximum possible value */
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if (value > 0xffff) {
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value = 0xffff;
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/* disable write protect for changing settings */
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ftm->MODE = FTM_MODE_WPDIS_MASK;
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/* reset timer match value */
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for (int i = 0; i < channels; i++) {
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ftm->CONTROLS[i].CnV = 0;
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}
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switch (channel) {
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case 0:
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/* cppcheck-suppress nullPointer */
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tim->CONTROLS[PWM_0_FTMCHAN_CH0].CnV = value;
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/* reset timer configuration registers */
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ftm->COMBINE = 0;
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ftm->CNTIN = 0;
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ftm->SWOCTRL = 0;
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/* set prescale and mod registers to matching values for resolution and frequency */
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ftm->SC = FTM_SC_PS(prescaler);
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ftm->MOD = resolution - 1;
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/* set PWM mode */
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uint32_t mode_mask = 0;
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switch (mode) {
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case PWM_LEFT:
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mode_mask = (1 << FTM_CnSC_MSB_SHIFT) | (1 << FTM_CnSC_ELSB_SHIFT);
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break;
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case 1:
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/* cppcheck-suppress nullPointer */
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tim->CONTROLS[PWM_0_FTMCHAN_CH1].CnV = value;
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case PWM_RIGHT:
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mode_mask = (1 << FTM_CnSC_MSB_SHIFT) | (1 << FTM_CnSC_ELSA_SHIFT);
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break;
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case 2:
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/* cppcheck-suppress nullPointer */
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tim->CONTROLS[PWM_0_FTMCHAN_CH2].CnV = value;
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case PWM_CENTER:
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mode_mask = (1 << FTM_CnSC_MSB_SHIFT);
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ftm->SC |= (1 << FTM_SC_CPWMS_SHIFT);
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break;
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}
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for (int i = 0; i < channels; i++) {
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/* cppcheck thinks ftmchan may be NULL here, but the variable is
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* assigned in all non-returning branches of the switch at the top of
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* this function. */
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/* cppcheck-suppress nullPointer ftmchan */
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ftm->CONTROLS[ftmchan[i]].CnSC = mode_mask;
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}
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case 3:
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/* cppcheck-suppress nullPointer */
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tim->CONTROLS[PWM_0_FTMCHAN_CH3].CnV = value;
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/* enable timer ergo the PWM generation */
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pwm_start(dev);
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/* Return actual frequency */
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return (pwm_clk / (1 << prescaler)) / resolution;
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}
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int pwm_set(pwm_t dev, int channel, unsigned int value)
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{
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FTM_Type *ftm;
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const uint8_t *ftmchan = NULL;
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switch (dev) {
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#if PWM_0_EN
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case PWM_0:
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if (channel > PWM_0_CHANNELS) {
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return -1;
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}
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ftm = PWM_0_DEV;
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ftmchan = &ftm0chan[0];
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break;
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#endif
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#if PWM_1_EN
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case PWM_1:
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if (channel > PWM_1_CHANNELS) {
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return -1;
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}
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ftm = PWM_1_DEV;
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ftmchan = &ftm1chan[0];
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break;
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#endif
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default:
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return -1;
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}
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/* clamp value to maximum possible value */
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if (value > PWM_MAX_VALUE) {
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value = PWM_MAX_VALUE;
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}
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/* cppcheck thinks ftmchan may be NULL here, but the variable is
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* assigned in all non-returning branches of the switch at the top of
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* this function. */
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/* cppcheck-suppress nullPointer */
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ftm->CONTROLS[ftmchan[channel]].CnV = value;
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return 0;
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}
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