diff options
Diffstat (limited to 'drivers/pwm/pwm-pca9685.c')
-rw-r--r-- | drivers/pwm/pwm-pca9685.c | 300 |
1 files changed, 300 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-pca9685.c b/drivers/pwm/pwm-pca9685.c new file mode 100644 index 0000000..3fb775d --- /dev/null +++ b/drivers/pwm/pwm-pca9685.c @@ -0,0 +1,300 @@ +/* + * Driver for PCA9685 16-channel 12-bit PWM LED controller + * + * Copyright (C) 2013 Steffen Trumtrar <s.trumtrar@pengutronix.de> + * + * based on the pwm-twl-led.c driver + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/i2c.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> +#include <linux/regmap.h> +#include <linux/slab.h> + +#define PCA9685_MODE1 0x00 +#define PCA9685_MODE2 0x01 +#define PCA9685_SUBADDR1 0x02 +#define PCA9685_SUBADDR2 0x03 +#define PCA9685_SUBADDR3 0x04 +#define PCA9685_ALLCALLADDR 0x05 +#define PCA9685_LEDX_ON_L 0x06 +#define PCA9685_LEDX_ON_H 0x07 +#define PCA9685_LEDX_OFF_L 0x08 +#define PCA9685_LEDX_OFF_H 0x09 + +#define PCA9685_ALL_LED_ON_L 0xFA +#define PCA9685_ALL_LED_ON_H 0xFB +#define PCA9685_ALL_LED_OFF_L 0xFC +#define PCA9685_ALL_LED_OFF_H 0xFD +#define PCA9685_PRESCALE 0xFE + +#define PCA9685_NUMREGS 0xFF +#define PCA9685_MAXCHAN 0x10 + +#define LED_FULL (1 << 4) +#define MODE1_SLEEP (1 << 4) +#define MODE2_INVRT (1 << 4) +#define MODE2_OUTDRV (1 << 2) + +#define LED_N_ON_H(N) (PCA9685_LEDX_ON_H + (4 * (N))) +#define LED_N_ON_L(N) (PCA9685_LEDX_ON_L + (4 * (N))) +#define LED_N_OFF_H(N) (PCA9685_LEDX_OFF_H + (4 * (N))) +#define LED_N_OFF_L(N) (PCA9685_LEDX_OFF_L + (4 * (N))) + +struct pca9685 { + struct pwm_chip chip; + struct regmap *regmap; + int active_cnt; +}; + +static inline struct pca9685 *to_pca(struct pwm_chip *chip) +{ + return container_of(chip, struct pca9685, chip); +} + +static int pca9685_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + struct pca9685 *pca = to_pca(chip); + unsigned long long duty; + unsigned int reg; + + if (duty_ns < 1) { + if (pwm->hwpwm >= PCA9685_MAXCHAN) + reg = PCA9685_ALL_LED_OFF_H; + else + reg = LED_N_OFF_H(pwm->hwpwm); + + regmap_write(pca->regmap, reg, LED_FULL); + + return 0; + } + + if (duty_ns == period_ns) { + if (pwm->hwpwm >= PCA9685_MAXCHAN) + reg = PCA9685_ALL_LED_ON_H; + else + reg = LED_N_ON_H(pwm->hwpwm); + + regmap_write(pca->regmap, reg, LED_FULL); + + return 0; + } + + duty = 4096 * (unsigned long long)duty_ns; + duty = DIV_ROUND_UP_ULL(duty, period_ns); + + if (pwm->hwpwm >= PCA9685_MAXCHAN) + reg = PCA9685_ALL_LED_OFF_L; + else + reg = LED_N_OFF_L(pwm->hwpwm); + + regmap_write(pca->regmap, reg, (int)duty & 0xff); + + if (pwm->hwpwm >= PCA9685_MAXCHAN) + reg = PCA9685_ALL_LED_OFF_H; + else + reg = LED_N_OFF_H(pwm->hwpwm); + + regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf); + + return 0; +} + +static int pca9685_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct pca9685 *pca = to_pca(chip); + unsigned int reg; + + /* + * The PWM subsystem does not support a pre-delay. + * So, set the ON-timeout to 0 + */ + if (pwm->hwpwm >= PCA9685_MAXCHAN) + reg = PCA9685_ALL_LED_ON_L; + else + reg = LED_N_ON_L(pwm->hwpwm); + + regmap_write(pca->regmap, reg, 0); + + if (pwm->hwpwm >= PCA9685_MAXCHAN) + reg = PCA9685_ALL_LED_ON_H; + else + reg = LED_N_ON_H(pwm->hwpwm); + + regmap_write(pca->regmap, reg, 0); + + /* + * Clear the full-off bit. + * It has precedence over the others and must be off. + */ + if (pwm->hwpwm >= PCA9685_MAXCHAN) + reg = PCA9685_ALL_LED_OFF_H; + else + reg = LED_N_OFF_H(pwm->hwpwm); + + regmap_update_bits(pca->regmap, reg, LED_FULL, 0x0); + + return 0; +} + +static void pca9685_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct pca9685 *pca = to_pca(chip); + unsigned int reg; + + if (pwm->hwpwm >= PCA9685_MAXCHAN) + reg = PCA9685_ALL_LED_OFF_H; + else + reg = LED_N_OFF_H(pwm->hwpwm); + + regmap_write(pca->regmap, reg, LED_FULL); + + /* Clear the LED_OFF counter. */ + if (pwm->hwpwm >= PCA9685_MAXCHAN) + reg = PCA9685_ALL_LED_OFF_L; + else + reg = LED_N_OFF_L(pwm->hwpwm); + + regmap_write(pca->regmap, reg, 0x0); +} + +static int pca9685_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct pca9685 *pca = to_pca(chip); + + if (pca->active_cnt++ == 0) + return regmap_update_bits(pca->regmap, PCA9685_MODE1, + MODE1_SLEEP, 0x0); + + return 0; +} + +static void pca9685_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct pca9685 *pca = to_pca(chip); + + if (--pca->active_cnt == 0) + regmap_update_bits(pca->regmap, PCA9685_MODE1, MODE1_SLEEP, + MODE1_SLEEP); +} + +static const struct pwm_ops pca9685_pwm_ops = { + .enable = pca9685_pwm_enable, + .disable = pca9685_pwm_disable, + .config = pca9685_pwm_config, + .request = pca9685_pwm_request, + .free = pca9685_pwm_free, + .owner = THIS_MODULE, +}; + +static struct regmap_config pca9685_regmap_i2c_config = { + .reg_bits = 8, + .val_bits = 8, + .max_register = PCA9685_NUMREGS, + .cache_type = REGCACHE_NONE, +}; + +static int pca9685_pwm_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct device_node *np = client->dev.of_node; + struct pca9685 *pca; + int ret; + int mode2; + + pca = devm_kzalloc(&client->dev, sizeof(*pca), GFP_KERNEL); + if (!pca) + return -ENOMEM; + + pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config); + if (IS_ERR(pca->regmap)) { + ret = PTR_ERR(pca->regmap); + dev_err(&client->dev, "Failed to initialize register map: %d\n", + ret); + return ret; + } + + i2c_set_clientdata(client, pca); + + regmap_read(pca->regmap, PCA9685_MODE2, &mode2); + + if (of_property_read_bool(np, "invert")) + mode2 |= MODE2_INVRT; + else + mode2 &= ~MODE2_INVRT; + + if (of_property_read_bool(np, "open-drain")) + mode2 &= ~MODE2_OUTDRV; + else + mode2 |= MODE2_OUTDRV; + + regmap_write(pca->regmap, PCA9685_MODE2, mode2); + + /* clear all "full off" bits */ + regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0); + regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0); + + pca->chip.ops = &pca9685_pwm_ops; + /* add an extra channel for ALL_LED */ + pca->chip.npwm = PCA9685_MAXCHAN + 1; + + pca->chip.dev = &client->dev; + pca->chip.base = -1; + pca->chip.can_sleep = true; + + return pwmchip_add(&pca->chip); +} + +static int pca9685_pwm_remove(struct i2c_client *client) +{ + struct pca9685 *pca = i2c_get_clientdata(client); + + regmap_update_bits(pca->regmap, PCA9685_MODE1, MODE1_SLEEP, + MODE1_SLEEP); + + return pwmchip_remove(&pca->chip); +} + +static const struct i2c_device_id pca9685_id[] = { + { "pca9685", 0 }, + { /* sentinel */ }, +}; +MODULE_DEVICE_TABLE(i2c, pca9685_id); + +static const struct of_device_id pca9685_dt_ids[] = { + { .compatible = "nxp,pca9685-pwm", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, pca9685_dt_ids); + +static struct i2c_driver pca9685_i2c_driver = { + .driver = { + .name = "pca9685-pwm", + .owner = THIS_MODULE, + .of_match_table = pca9685_dt_ids, + }, + .probe = pca9685_pwm_probe, + .remove = pca9685_pwm_remove, + .id_table = pca9685_id, +}; + +module_i2c_driver(pca9685_i2c_driver); + +MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de>"); +MODULE_DESCRIPTION("PWM driver for PCA9685"); +MODULE_LICENSE("GPL"); |