[PATCH v3] pwm: add pca9685 driver

Steffen Trumtrar
2013-05-30T07:50:28Z

Add pwm driver for the NXP pca9685 16 channel pwm-led controller.

The driver is really barebones at this stage. E.g. the OE' pin and
therefore the corresponding registers are not supported.
The driver was tested on a HW where this pin is tied to GND.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
---
Changes since v2:
- s/pwm-pca9685-led/pwm-pca9685/g
- replace DT properties with booleans
- whitespace/blank line cleanup
- add "depends on REGMAP_I2C" in Kconfig
- rework code readability
- add pwm_ops.free function
- set SLEEP bit on request/free/remove

Changes since v1:
- fix typo in documentation example

.../devicetree/bindings/pwm/nxp,pca9685-pwm.txt | 27 ++
drivers/pwm/Kconfig | 9 +
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-pca9685.c | 291 +++++++++++++++++++++
4 files changed, 328 insertions(+)
create mode 100644 Documentation/devicetree/bindings/pwm/nxp,pca9685-pwm.txt
create mode 100644 drivers/pwm/pwm-pca9685.c

diff --git a/Documentation/devicetree/bindings/pwm/nxp,pca9685-pwm.txt b/Documentation/devicetree/bindings/pwm/nxp,pca9685-pwm.txt
new file mode 100644
index 0000000..1e3dfe7
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/nxp,pca9685-pwm.txt
@@ -0,0 +1,27 @@
+NXP PCA9685 16-channel 12-bit PWM LED controller
+================================================
+
+Required properties:
+ - compatible: "nxp,pca9685-pwm"
+ - #pwm-cells: should be 2. The first cell specifies the per-chip index
+ of the PWM to use and the second cell is the period in nanoseconds.
+ The index 16 is the ALLCALL channel, that sets all PWM channels at the same
+ time.
+
+Optional properties:
+ - invert (bool): boolean to enable inverted logic
+ - open-drain (bool): boolean to configure outputs with open-drain structure;
+ if omitted use totem-pole structure
+
+Example:
+
+For LEDs that are directly connected to the PCA, the following setting is
+applicable:
+
+pca: pca@41 {
+ compatible = "nxp,pca9685-pwm";
+ #pwm-cells = <2>;
+ reg = <0x41>;
+ invert;
+ open-drain;
+};
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 115b644..d3fe320 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -97,6 +97,15 @@ config PWM_MXS
To compile this driver as a module, choose M here: the module
will be called pwm-mxs.

+config PWM_PCA9685
+ tristate "NXP PCA9685 PWM driver"
+ depends on OF && REGMAP_I2C
+ help
+ Generic PWM framework driver for NXP PCA9685 LED controller.
+
+ To compile this driver as a module, choose M here: the module
+ will be called pwm-pca9685.
+
config PWM_PUV3
tristate "PKUnity NetBook-0916 PWM support"
depends on ARCH_PUV3
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 94ba21e..b3afc0a 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -6,6 +6,7 @@ obj-$(CONFIG_PWM_IMX) += pwm-imx.o
obj-$(CONFIG_PWM_JZ4740) += pwm-jz4740.o
obj-$(CONFIG_PWM_LPC32XX) += pwm-lpc32xx.o
obj-$(CONFIG_PWM_MXS) += pwm-mxs.o
+obj-$(CONFIG_PWM_PCA9685) += pwm-pca9685.o
obj-$(CONFIG_PWM_PUV3) += pwm-puv3.o
obj-$(CONFIG_PWM_PXA) += pwm-pxa.o
obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o
diff --git a/drivers/pwm/pwm-pca9685.c b/drivers/pwm/pwm-pca9685.c
new file mode 100644
index 0000000..576ec2a
--- /dev/null
+++ b/drivers/pwm/pwm-pca9685.c
@@ -0,0 +1,291 @@
+/*
+ * 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;
+ struct device *dev;
+ 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);
+
+ pca->active_cnt--;
+
+ if (pca->active_cnt == 0)
+ regmap_update_bits(pca->regmap, PCA9685_MODE1, MODE1_SLEEP, 0x1);
+}
+
+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,
+};
+
+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);
+ pca->dev = &client->dev;
+
+ 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, 0x1);
+ 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");
--
1.8.2.rc2