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912b843904
There is a chip connected to i2c bus on Intel Galileo Gen2 board. Enable it via ACPI ID INT3492. Cc: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
398 lines
9.8 KiB
C
398 lines
9.8 KiB
C
/*
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* Driver for PCA9685 16-channel 12-bit PWM LED controller
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*
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* Copyright (C) 2013 Steffen Trumtrar <s.trumtrar@pengutronix.de>
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* Copyright (C) 2015 Clemens Gruber <clemens.gruber@pqgruber.com>
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*
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* based on the pwm-twl-led.c driver
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/acpi.h>
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#include <linux/i2c.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/property.h>
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#include <linux/pwm.h>
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#include <linux/regmap.h>
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#include <linux/slab.h>
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#include <linux/delay.h>
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/*
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* Because the PCA9685 has only one prescaler per chip, changing the period of
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* one channel affects the period of all 16 PWM outputs!
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* However, the ratio between each configured duty cycle and the chip-wide
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* period remains constant, because the OFF time is set in proportion to the
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* counter range.
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*/
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#define PCA9685_MODE1 0x00
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#define PCA9685_MODE2 0x01
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#define PCA9685_SUBADDR1 0x02
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#define PCA9685_SUBADDR2 0x03
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#define PCA9685_SUBADDR3 0x04
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#define PCA9685_ALLCALLADDR 0x05
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#define PCA9685_LEDX_ON_L 0x06
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#define PCA9685_LEDX_ON_H 0x07
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#define PCA9685_LEDX_OFF_L 0x08
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#define PCA9685_LEDX_OFF_H 0x09
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#define PCA9685_ALL_LED_ON_L 0xFA
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#define PCA9685_ALL_LED_ON_H 0xFB
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#define PCA9685_ALL_LED_OFF_L 0xFC
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#define PCA9685_ALL_LED_OFF_H 0xFD
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#define PCA9685_PRESCALE 0xFE
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#define PCA9685_PRESCALE_MIN 0x03 /* => max. frequency of 1526 Hz */
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#define PCA9685_PRESCALE_MAX 0xFF /* => min. frequency of 24 Hz */
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#define PCA9685_COUNTER_RANGE 4096
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#define PCA9685_DEFAULT_PERIOD 5000000 /* Default period_ns = 1/200 Hz */
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#define PCA9685_OSC_CLOCK_MHZ 25 /* Internal oscillator with 25 MHz */
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#define PCA9685_NUMREGS 0xFF
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#define PCA9685_MAXCHAN 0x10
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#define LED_FULL (1 << 4)
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#define MODE1_RESTART (1 << 7)
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#define MODE1_SLEEP (1 << 4)
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#define MODE2_INVRT (1 << 4)
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#define MODE2_OUTDRV (1 << 2)
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#define LED_N_ON_H(N) (PCA9685_LEDX_ON_H + (4 * (N)))
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#define LED_N_ON_L(N) (PCA9685_LEDX_ON_L + (4 * (N)))
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#define LED_N_OFF_H(N) (PCA9685_LEDX_OFF_H + (4 * (N)))
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#define LED_N_OFF_L(N) (PCA9685_LEDX_OFF_L + (4 * (N)))
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struct pca9685 {
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struct pwm_chip chip;
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struct regmap *regmap;
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int active_cnt;
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int duty_ns;
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int period_ns;
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};
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static inline struct pca9685 *to_pca(struct pwm_chip *chip)
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{
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return container_of(chip, struct pca9685, chip);
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}
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static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
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int duty_ns, int period_ns)
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{
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struct pca9685 *pca = to_pca(chip);
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unsigned long long duty;
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unsigned int reg;
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int prescale;
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if (period_ns != pca->period_ns) {
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prescale = DIV_ROUND_CLOSEST(PCA9685_OSC_CLOCK_MHZ * period_ns,
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PCA9685_COUNTER_RANGE * 1000) - 1;
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if (prescale >= PCA9685_PRESCALE_MIN &&
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prescale <= PCA9685_PRESCALE_MAX) {
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/* Put chip into sleep mode */
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regmap_update_bits(pca->regmap, PCA9685_MODE1,
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MODE1_SLEEP, MODE1_SLEEP);
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/* Change the chip-wide output frequency */
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regmap_write(pca->regmap, PCA9685_PRESCALE, prescale);
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/* Wake the chip up */
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regmap_update_bits(pca->regmap, PCA9685_MODE1,
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MODE1_SLEEP, 0x0);
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/* Wait 500us for the oscillator to be back up */
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udelay(500);
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pca->period_ns = period_ns;
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/*
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* If the duty cycle did not change, restart PWM with
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* the same duty cycle to period ratio and return.
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*/
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if (duty_ns == pca->duty_ns) {
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regmap_update_bits(pca->regmap, PCA9685_MODE1,
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MODE1_RESTART, 0x1);
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return 0;
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}
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} else {
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dev_err(chip->dev,
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"prescaler not set: period out of bounds!\n");
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return -EINVAL;
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}
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}
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pca->duty_ns = duty_ns;
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if (duty_ns < 1) {
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if (pwm->hwpwm >= PCA9685_MAXCHAN)
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reg = PCA9685_ALL_LED_OFF_H;
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else
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reg = LED_N_OFF_H(pwm->hwpwm);
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regmap_write(pca->regmap, reg, LED_FULL);
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return 0;
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}
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if (duty_ns == period_ns) {
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/* Clear both OFF registers */
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if (pwm->hwpwm >= PCA9685_MAXCHAN)
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reg = PCA9685_ALL_LED_OFF_L;
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else
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reg = LED_N_OFF_L(pwm->hwpwm);
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regmap_write(pca->regmap, reg, 0x0);
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if (pwm->hwpwm >= PCA9685_MAXCHAN)
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reg = PCA9685_ALL_LED_OFF_H;
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else
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reg = LED_N_OFF_H(pwm->hwpwm);
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regmap_write(pca->regmap, reg, 0x0);
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/* Set the full ON bit */
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if (pwm->hwpwm >= PCA9685_MAXCHAN)
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reg = PCA9685_ALL_LED_ON_H;
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else
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reg = LED_N_ON_H(pwm->hwpwm);
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regmap_write(pca->regmap, reg, LED_FULL);
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return 0;
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}
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duty = PCA9685_COUNTER_RANGE * (unsigned long long)duty_ns;
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duty = DIV_ROUND_UP_ULL(duty, period_ns);
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if (pwm->hwpwm >= PCA9685_MAXCHAN)
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reg = PCA9685_ALL_LED_OFF_L;
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else
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reg = LED_N_OFF_L(pwm->hwpwm);
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regmap_write(pca->regmap, reg, (int)duty & 0xff);
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if (pwm->hwpwm >= PCA9685_MAXCHAN)
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reg = PCA9685_ALL_LED_OFF_H;
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else
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reg = LED_N_OFF_H(pwm->hwpwm);
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regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf);
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/* Clear the full ON bit, otherwise the set OFF time has no effect */
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if (pwm->hwpwm >= PCA9685_MAXCHAN)
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reg = PCA9685_ALL_LED_ON_H;
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else
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reg = LED_N_ON_H(pwm->hwpwm);
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regmap_write(pca->regmap, reg, 0);
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return 0;
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}
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static int pca9685_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct pca9685 *pca = to_pca(chip);
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unsigned int reg;
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/*
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* The PWM subsystem does not support a pre-delay.
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* So, set the ON-timeout to 0
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*/
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if (pwm->hwpwm >= PCA9685_MAXCHAN)
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reg = PCA9685_ALL_LED_ON_L;
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else
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reg = LED_N_ON_L(pwm->hwpwm);
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regmap_write(pca->regmap, reg, 0);
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if (pwm->hwpwm >= PCA9685_MAXCHAN)
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reg = PCA9685_ALL_LED_ON_H;
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else
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reg = LED_N_ON_H(pwm->hwpwm);
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regmap_write(pca->regmap, reg, 0);
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/*
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* Clear the full-off bit.
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* It has precedence over the others and must be off.
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*/
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if (pwm->hwpwm >= PCA9685_MAXCHAN)
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reg = PCA9685_ALL_LED_OFF_H;
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else
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reg = LED_N_OFF_H(pwm->hwpwm);
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regmap_update_bits(pca->regmap, reg, LED_FULL, 0x0);
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return 0;
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}
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static void pca9685_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct pca9685 *pca = to_pca(chip);
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unsigned int reg;
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if (pwm->hwpwm >= PCA9685_MAXCHAN)
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reg = PCA9685_ALL_LED_OFF_H;
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else
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reg = LED_N_OFF_H(pwm->hwpwm);
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regmap_write(pca->regmap, reg, LED_FULL);
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/* Clear the LED_OFF counter. */
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if (pwm->hwpwm >= PCA9685_MAXCHAN)
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reg = PCA9685_ALL_LED_OFF_L;
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else
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reg = LED_N_OFF_L(pwm->hwpwm);
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regmap_write(pca->regmap, reg, 0x0);
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}
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static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct pca9685 *pca = to_pca(chip);
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if (pca->active_cnt++ == 0)
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return regmap_update_bits(pca->regmap, PCA9685_MODE1,
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MODE1_SLEEP, 0x0);
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return 0;
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}
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static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct pca9685 *pca = to_pca(chip);
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if (--pca->active_cnt == 0)
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regmap_update_bits(pca->regmap, PCA9685_MODE1, MODE1_SLEEP,
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MODE1_SLEEP);
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}
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static const struct pwm_ops pca9685_pwm_ops = {
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.enable = pca9685_pwm_enable,
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.disable = pca9685_pwm_disable,
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.config = pca9685_pwm_config,
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.request = pca9685_pwm_request,
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.free = pca9685_pwm_free,
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.owner = THIS_MODULE,
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};
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static const struct regmap_config pca9685_regmap_i2c_config = {
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.reg_bits = 8,
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.val_bits = 8,
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.max_register = PCA9685_NUMREGS,
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.cache_type = REGCACHE_NONE,
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};
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static int pca9685_pwm_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct pca9685 *pca;
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int ret;
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int mode2;
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pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL);
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if (!pca)
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return -ENOMEM;
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pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config);
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if (IS_ERR(pca->regmap)) {
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ret = PTR_ERR(pca->regmap);
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dev_err(&client->dev, "Failed to initialize register map: %d\n",
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ret);
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return ret;
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}
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pca->duty_ns = 0;
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pca->period_ns = PCA9685_DEFAULT_PERIOD;
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i2c_set_clientdata(client, pca);
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regmap_read(pca->regmap, PCA9685_MODE2, &mode2);
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if (device_property_read_bool(&client->dev, "invert"))
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mode2 |= MODE2_INVRT;
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else
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mode2 &= ~MODE2_INVRT;
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if (device_property_read_bool(&client->dev, "open-drain"))
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mode2 &= ~MODE2_OUTDRV;
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else
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mode2 |= MODE2_OUTDRV;
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regmap_write(pca->regmap, PCA9685_MODE2, mode2);
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/* clear all "full off" bits */
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regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0);
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regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0);
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pca->chip.ops = &pca9685_pwm_ops;
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/* add an extra channel for ALL_LED */
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pca->chip.npwm = PCA9685_MAXCHAN + 1;
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pca->chip.dev = &client->dev;
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pca->chip.base = -1;
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pca->chip.can_sleep = true;
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return pwmchip_add(&pca->chip);
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}
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static int pca9685_pwm_remove(struct i2c_client *client)
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{
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struct pca9685 *pca = i2c_get_clientdata(client);
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regmap_update_bits(pca->regmap, PCA9685_MODE1, MODE1_SLEEP,
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MODE1_SLEEP);
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return pwmchip_remove(&pca->chip);
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}
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static const struct i2c_device_id pca9685_id[] = {
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{ "pca9685", 0 },
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{ /* sentinel */ },
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};
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MODULE_DEVICE_TABLE(i2c, pca9685_id);
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#ifdef CONFIG_ACPI
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static const struct acpi_device_id pca9685_acpi_ids[] = {
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{ "INT3492", 0 },
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{ /* sentinel */ },
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};
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MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
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#endif
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#ifdef CONFIG_OF
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static const struct of_device_id pca9685_dt_ids[] = {
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{ .compatible = "nxp,pca9685-pwm", },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
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#endif
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static struct i2c_driver pca9685_i2c_driver = {
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.driver = {
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.name = "pca9685-pwm",
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.acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
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.of_match_table = of_match_ptr(pca9685_dt_ids),
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},
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.probe = pca9685_pwm_probe,
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.remove = pca9685_pwm_remove,
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.id_table = pca9685_id,
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};
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module_i2c_driver(pca9685_i2c_driver);
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MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>");
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MODULE_DESCRIPTION("PWM driver for PCA9685");
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MODULE_LICENSE("GPL");
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