* Driver for PCA9685 16-channel 12-bit PWM LED controller
*
* Copyright (C) 2013 Steffen Trumtrar <s.trumtrar@pengutronix.de>
+ * Copyright (C) 2015 Clemens Gruber <clemens.gruber@pqgruber.com>
*
* based on the pwm-twl-led.c driver
*
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include <linux/acpi.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/platform_device.h>
+#include <linux/property.h>
#include <linux/pwm.h>
#include <linux/regmap.h>
#include <linux/slab.h>
+#include <linux/delay.h>
+
+/*
+ * Because the PCA9685 has only one prescaler per chip, changing the period of
+ * one channel affects the period of all 16 PWM outputs!
+ * However, the ratio between each configured duty cycle and the chip-wide
+ * period remains constant, because the OFF time is set in proportion to the
+ * counter range.
+ */
#define PCA9685_MODE1 0x00
#define PCA9685_MODE2 0x01
#define PCA9685_ALL_LED_OFF_H 0xFD
#define PCA9685_PRESCALE 0xFE
+#define PCA9685_PRESCALE_MIN 0x03 /* => max. frequency of 1526 Hz */
+#define PCA9685_PRESCALE_MAX 0xFF /* => min. frequency of 24 Hz */
+
+#define PCA9685_COUNTER_RANGE 4096
+#define PCA9685_DEFAULT_PERIOD 5000000 /* Default period_ns = 1/200 Hz */
+#define PCA9685_OSC_CLOCK_MHZ 25 /* Internal oscillator with 25 MHz */
+
#define PCA9685_NUMREGS 0xFF
#define PCA9685_MAXCHAN 0x10
#define LED_FULL (1 << 4)
+#define MODE1_RESTART (1 << 7)
#define MODE1_SLEEP (1 << 4)
#define MODE2_INVRT (1 << 4)
#define MODE2_OUTDRV (1 << 2)
struct pwm_chip chip;
struct regmap *regmap;
int active_cnt;
+ int duty_ns;
+ int period_ns;
};
static inline struct pca9685 *to_pca(struct pwm_chip *chip)
struct pca9685 *pca = to_pca(chip);
unsigned long long duty;
unsigned int reg;
+ int prescale;
+
+ if (period_ns != pca->period_ns) {
+ prescale = DIV_ROUND_CLOSEST(PCA9685_OSC_CLOCK_MHZ * period_ns,
+ PCA9685_COUNTER_RANGE * 1000) - 1;
+
+ if (prescale >= PCA9685_PRESCALE_MIN &&
+ prescale <= PCA9685_PRESCALE_MAX) {
+ /* Put chip into sleep mode */
+ regmap_update_bits(pca->regmap, PCA9685_MODE1,
+ MODE1_SLEEP, MODE1_SLEEP);
+
+ /* Change the chip-wide output frequency */
+ regmap_write(pca->regmap, PCA9685_PRESCALE, prescale);
+
+ /* Wake the chip up */
+ regmap_update_bits(pca->regmap, PCA9685_MODE1,
+ MODE1_SLEEP, 0x0);
+
+ /* Wait 500us for the oscillator to be back up */
+ udelay(500);
+
+ pca->period_ns = period_ns;
+
+ /*
+ * If the duty cycle did not change, restart PWM with
+ * the same duty cycle to period ratio and return.
+ */
+ if (duty_ns == pca->duty_ns) {
+ regmap_update_bits(pca->regmap, PCA9685_MODE1,
+ MODE1_RESTART, 0x1);
+ return 0;
+ }
+ } else {
+ dev_err(chip->dev,
+ "prescaler not set: period out of bounds!\n");
+ return -EINVAL;
+ }
+ }
+
+ pca->duty_ns = duty_ns;
if (duty_ns < 1) {
if (pwm->hwpwm >= PCA9685_MAXCHAN)
}
if (duty_ns == period_ns) {
+ /* Clear both OFF registers */
+ 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);
+
+ if (pwm->hwpwm >= PCA9685_MAXCHAN)
+ reg = PCA9685_ALL_LED_OFF_H;
+ else
+ reg = LED_N_OFF_H(pwm->hwpwm);
+
+ regmap_write(pca->regmap, reg, 0x0);
+
+ /* Set the full ON bit */
if (pwm->hwpwm >= PCA9685_MAXCHAN)
reg = PCA9685_ALL_LED_ON_H;
else
return 0;
}
- duty = 4096 * (unsigned long long)duty_ns;
+ duty = PCA9685_COUNTER_RANGE * (unsigned long long)duty_ns;
duty = DIV_ROUND_UP_ULL(duty, period_ns);
if (pwm->hwpwm >= PCA9685_MAXCHAN)
regmap_write(pca->regmap, reg, ((int)duty >> 8) & 0xf);
+ /* Clear the full ON bit, otherwise the set OFF time has no effect */
+ 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);
+
return 0;
}
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;
ret);
return ret;
}
+ pca->duty_ns = 0;
+ pca->period_ns = PCA9685_DEFAULT_PERIOD;
i2c_set_clientdata(client, pca);
regmap_read(pca->regmap, PCA9685_MODE2, &mode2);
- if (of_property_read_bool(np, "invert"))
+ if (device_property_read_bool(&client->dev, "invert"))
mode2 |= MODE2_INVRT;
else
mode2 &= ~MODE2_INVRT;
- if (of_property_read_bool(np, "open-drain"))
+ if (device_property_read_bool(&client->dev, "open-drain"))
mode2 &= ~MODE2_OUTDRV;
else
mode2 |= MODE2_OUTDRV;
};
MODULE_DEVICE_TABLE(i2c, pca9685_id);
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id pca9685_acpi_ids[] = {
+ { "INT3492", 0 },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
+#endif
+
+#ifdef CONFIG_OF
static const struct of_device_id pca9685_dt_ids[] = {
{ .compatible = "nxp,pca9685-pwm", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
+#endif
static struct i2c_driver pca9685_i2c_driver = {
.driver = {
.name = "pca9685-pwm",
- .owner = THIS_MODULE,
- .of_match_table = pca9685_dt_ids,
+ .acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
+ .of_match_table = of_match_ptr(pca9685_dt_ids),
},
.probe = pca9685_pwm_probe,
.remove = pca9685_pwm_remove,
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