pwm: New driver to support PWMs on TWL4030/6030 series of PMICs

The driver supports the following PWM outputs:
TWL4030 PWM0 and PWM1
TWL6030 PWM1 and PWM2

On TWL4030 the PWM signals are muxed. Upon requesting the PWM the driver
will select the correct mux so the PWM can be used. When the PWM has been
freed the original configuration is going to be restored.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

3 files changed, 369 insertions, 0 deletions

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 3dcb76d86a97..e1792d5e3861 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -173,6 +173,15 @@ config PWM_TWL6030
           To compile this driver as a module, choose M here: the module
           will be called pwm-twl6030.
 
+config PWM_TWL
+        tristate "TWL4030/6030 PWM support"
+        depends on TWL4030_CORE
+        help
+          Generic PWM framework driver for TWL4030/6030.
+
+          To compile this driver as a module, choose M here: the module
+          will be called pwm-twl.
+
 config PWM_VT8500
         tristate "vt8500 pwm support"
         depends on ARCH_VT8500
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 4fb39f8b6ba9..3b7efa7a40aa 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -14,4 +14,5 @@ obj-$(CONFIG_PWM_TIECAP)	+= pwm-tiecap.o
 obj-$(CONFIG_PWM_TIEHRPWM)      += pwm-tiehrpwm.o
 obj-$(CONFIG_PWM_TIPWMSS)       += pwm-tipwmss.o
 obj-$(CONFIG_PWM_TWL6030)       += pwm-twl6030.o
+obj-$(CONFIG_PWM_TWL)           += pwm-twl.o
 obj-$(CONFIG_PWM_VT8500)        += pwm-vt8500.o
diff --git a/drivers/pwm/pwm-twl.c b/drivers/pwm/pwm-twl.c
new file mode 100644
index 000000000000..e65db95d5e59
--- /dev/null
+++ b/drivers/pwm/pwm-twl.c
@@ -0,0 +1,359 @@
+/*
+ * Driver for TWL4030/6030 Generic Pulse Width Modulator
+ *
+ * Copyright (C) 2012 Texas Instruments
+ * Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
+ *
+ * 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/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/i2c/twl.h>
+#include <linux/slab.h>
+
+/*
+ * This driver handles the PWMs of TWL4030 and TWL6030.
+ * The TRM names for the PWMs on TWL4030 are: PWM0, PWM1
+ * TWL6030 also have two PWMs named in the TRM as PWM1, PWM2
+ */
+
+#define TWL_PWM_MAX             0x7f
+
+/* Registers, bits and macro for TWL4030 */
+#define TWL4030_GPBR1_REG       0x0c
+#define TWL4030_PMBR1_REG       0x0d
+
+/* GPBR1 register bits */
+#define TWL4030_PWMXCLK_ENABLE  (1 << 0)
+#define TWL4030_PWMX_ENABLE     (1 << 2)
+#define TWL4030_PWMX_BITS       (TWL4030_PWMX_ENABLE | TWL4030_PWMXCLK_ENABLE)
+#define TWL4030_PWM_TOGGLE(pwm, x)      ((x) << (pwm))
+
+/* PMBR1 register bits */
+#define TWL4030_GPIO6_PWM0_MUTE_MASK            (0x03 << 2)
+#define TWL4030_GPIO6_PWM0_MUTE_PWM0            (0x01 << 2)
+#define TWL4030_GPIO7_VIBRASYNC_PWM1_MASK       (0x03 << 4)
+#define TWL4030_GPIO7_VIBRASYNC_PWM1_PWM1       (0x03 << 4)
+
+/* Register, bits and macro for TWL6030 */
+#define TWL6030_TOGGLE3_REG     0x92
+
+#define TWL6030_PWMXR           (1 << 0)
+#define TWL6030_PWMXS           (1 << 1)
+#define TWL6030_PWMXEN          (1 << 2)
+#define TWL6030_PWM_TOGGLE(pwm, x)      ((x) << (pwm * 3))
+
+struct twl_pwm_chip {
+        struct pwm_chip chip;
+        struct mutex mutex;
+        u8 twl6030_toggle3;
+        u8 twl4030_pwm_mux;
+};
+
+static inline struct twl_pwm_chip *to_twl(struct pwm_chip *chip)
+{
+        return container_of(chip, struct twl_pwm_chip, chip);
+}
+
+static int twl_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+                              int duty_ns, int period_ns)
+{
+        int duty_cycle = DIV_ROUND_UP(duty_ns * TWL_PWM_MAX, period_ns) + 1;
+        u8 pwm_config[2] = { 1, 0 };
+        int base, ret;
+
+        /*
+         * To configure the duty period:
+         * On-cycle is set to 1 (the minimum allowed value)
+         * The off time of 0 is not configurable, so the mapping is:
+         * 0 -> off cycle = 2,
+         * 1 -> off cycle = 2,
+         * 2 -> off cycle = 3,
+         * 126 - > off cycle 127,
+         * 127 - > off cycle 1
+         * When on cycle == off cycle the PWM will be always on
+         */
+        if (duty_cycle == 1)
+                duty_cycle = 2;
+        else if (duty_cycle > TWL_PWM_MAX)
+                duty_cycle = 1;
+
+        base = pwm->hwpwm * 3;
+
+        pwm_config[1] = duty_cycle;
+
+        ret = twl_i2c_write(TWL_MODULE_PWM, pwm_config, base, 2);
+        if (ret < 0)
+                dev_err(chip->dev, "%s: Failed to configure PWM\n", pwm->label);
+
+        return ret;
+}
+
+static int twl4030_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+        struct twl_pwm_chip *twl = to_twl(chip);
+        int ret;
+        u8 val;
+
+        mutex_lock(&twl->mutex);
+        ret = twl_i2c_read_u8(TWL4030_MODULE_INTBR, &val, TWL4030_GPBR1_REG);
+        if (ret < 0) {
+                dev_err(chip->dev, "%s: Failed to read GPBR1\n", pwm->label);
+                goto out;
+        }
+
+        val |= TWL4030_PWM_TOGGLE(pwm->hwpwm, TWL4030_PWMXCLK_ENABLE);
+
+        ret = twl_i2c_write_u8(TWL4030_MODULE_INTBR, val, TWL4030_GPBR1_REG);
+        if (ret < 0)
+                dev_err(chip->dev, "%s: Failed to enable PWM\n", pwm->label);
+
+        val |= TWL4030_PWM_TOGGLE(pwm->hwpwm, TWL4030_PWMX_ENABLE);
+
+        ret = twl_i2c_write_u8(TWL4030_MODULE_INTBR, val, TWL4030_GPBR1_REG);
+        if (ret < 0)
+                dev_err(chip->dev, "%s: Failed to enable PWM\n", pwm->label);
+
+out:
+        mutex_unlock(&twl->mutex);
+        return ret;
+}
+
+static void twl4030_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+        struct twl_pwm_chip *twl = to_twl(chip);
+        int ret;
+        u8 val;
+
+        mutex_lock(&twl->mutex);
+        ret = twl_i2c_read_u8(TWL4030_MODULE_INTBR, &val, TWL4030_GPBR1_REG);
+        if (ret < 0) {
+                dev_err(chip->dev, "%s: Failed to read GPBR1\n", pwm->label);
+                goto out;
+        }
+
+        val &= ~TWL4030_PWM_TOGGLE(pwm->hwpwm, TWL4030_PWMX_ENABLE);
+
+        ret = twl_i2c_write_u8(TWL4030_MODULE_INTBR, val, TWL4030_GPBR1_REG);
+        if (ret < 0)
+                dev_err(chip->dev, "%s: Failed to disable PWM\n", pwm->label);
+
+        val &= ~TWL4030_PWM_TOGGLE(pwm->hwpwm, TWL4030_PWMXCLK_ENABLE);
+
+        ret = twl_i2c_write_u8(TWL4030_MODULE_INTBR, val, TWL4030_GPBR1_REG);
+        if (ret < 0)
+                dev_err(chip->dev, "%s: Failed to disable PWM\n", pwm->label);
+
+out:
+        mutex_unlock(&twl->mutex);
+}
+
+static int twl4030_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+        struct twl_pwm_chip *twl = to_twl(chip);
+        int ret;
+        u8 val, mask, bits;
+
+        if (pwm->hwpwm == 1) {
+                mask = TWL4030_GPIO7_VIBRASYNC_PWM1_MASK;
+                bits = TWL4030_GPIO7_VIBRASYNC_PWM1_PWM1;
+        } else {
+                mask = TWL4030_GPIO6_PWM0_MUTE_MASK;
+                bits = TWL4030_GPIO6_PWM0_MUTE_PWM0;
+        }
+
+        mutex_lock(&twl->mutex);
+        ret = twl_i2c_read_u8(TWL4030_MODULE_INTBR, &val, TWL4030_PMBR1_REG);
+        if (ret < 0) {
+                dev_err(chip->dev, "%s: Failed to read PMBR1\n", pwm->label);
+                goto out;
+        }
+
+        /* Save the current MUX configuration for the PWM */
+        twl->twl4030_pwm_mux &= ~mask;
+        twl->twl4030_pwm_mux |= (val & mask);
+
+        /* Select PWM functionality */
+        val &= ~mask;
+        val |= bits;
+
+        ret = twl_i2c_write_u8(TWL4030_MODULE_INTBR, val, TWL4030_PMBR1_REG);
+        if (ret < 0)
+                dev_err(chip->dev, "%s: Failed to request PWM\n", pwm->label);
+
+out:
+        mutex_unlock(&twl->mutex);
+        return ret;
+}
+
+static void twl4030_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+        struct twl_pwm_chip *twl = container_of(chip, struct twl_pwm_chip,
+                                                chip);
+        int ret;
+        u8 val, mask;
+
+        if (pwm->hwpwm == 1)
+                mask = TWL4030_GPIO7_VIBRASYNC_PWM1_MASK;
+        else
+                mask = TWL4030_GPIO6_PWM0_MUTE_MASK;
+
+        mutex_lock(&twl->mutex);
+        ret = twl_i2c_read_u8(TWL4030_MODULE_INTBR, &val, TWL4030_PMBR1_REG);
+        if (ret < 0) {
+                dev_err(chip->dev, "%s: Failed to read PMBR1\n", pwm->label);
+                goto out;
+        }
+
+        /* Restore the MUX configuration for the PWM */
+        val &= ~mask;
+        val |= (twl->twl4030_pwm_mux & mask);
+
+        ret = twl_i2c_write_u8(TWL4030_MODULE_INTBR, val, TWL4030_PMBR1_REG);
+        if (ret < 0)
+                dev_err(chip->dev, "%s: Failed to free PWM\n", pwm->label);
+
+out:
+        mutex_unlock(&twl->mutex);
+}
+
+static int twl6030_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+        struct twl_pwm_chip *twl = container_of(chip, struct twl_pwm_chip,
+                                                chip);
+        int ret;
+        u8 val;
+
+        mutex_lock(&twl->mutex);
+        val = twl->twl6030_toggle3;
+        val |= TWL6030_PWM_TOGGLE(pwm->hwpwm, TWL6030_PWMXS | TWL6030_PWMXEN);
+        val &= ~TWL6030_PWM_TOGGLE(pwm->hwpwm, TWL6030_PWMXR);
+
+        ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_TOGGLE3_REG);
+        if (ret < 0) {
+                dev_err(chip->dev, "%s: Failed to enable PWM\n", pwm->label);
+                goto out;
+        }
+
+        twl->twl6030_toggle3 = val;
+out:
+        mutex_unlock(&twl->mutex);
+        return 0;
+}
+
+static void twl6030_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+        struct twl_pwm_chip *twl = container_of(chip, struct twl_pwm_chip,
+                                                chip);
+        int ret;
+        u8 val;
+
+        mutex_lock(&twl->mutex);
+        val = twl->twl6030_toggle3;
+        val |= TWL6030_PWM_TOGGLE(pwm->hwpwm, TWL6030_PWMXR);
+        val &= ~TWL6030_PWM_TOGGLE(pwm->hwpwm, TWL6030_PWMXS | TWL6030_PWMXEN);
+
+        ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_TOGGLE3_REG);
+        if (ret < 0) {
+                dev_err(chip->dev, "%s: Failed to read TOGGLE3\n", pwm->label);
+                goto out;
+        }
+
+        val |= TWL6030_PWM_TOGGLE(pwm->hwpwm, TWL6030_PWMXS | TWL6030_PWMXEN);
+
+        ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_TOGGLE3_REG);
+        if (ret < 0) {
+                dev_err(chip->dev, "%s: Failed to disable PWM\n", pwm->label);
+                goto out;
+        }
+
+        twl->twl6030_toggle3 = val;
+out:
+        mutex_unlock(&twl->mutex);
+}
+
+static const struct pwm_ops twl4030_pwm_ops = {
+        .config = twl_pwm_config,
+        .enable = twl4030_pwm_enable,
+        .disable = twl4030_pwm_disable,
+        .request = twl4030_pwm_request,
+        .free = twl4030_pwm_free,
+};
+
+static const struct pwm_ops twl6030_pwm_ops = {
+        .config = twl_pwm_config,
+        .enable = twl6030_pwm_enable,
+        .disable = twl6030_pwm_disable,
+};
+
+static int twl_pwm_probe(struct platform_device *pdev)
+{
+        struct twl_pwm_chip *twl;
+        int ret;
+
+        twl = devm_kzalloc(&pdev->dev, sizeof(*twl), GFP_KERNEL);
+        if (!twl)
+                return -ENOMEM;
+
+        if (twl_class_is_4030())
+                twl->chip.ops = &twl4030_pwm_ops;
+        else
+                twl->chip.ops = &twl6030_pwm_ops;
+
+        twl->chip.dev = &pdev->dev;
+        twl->chip.base = -1;
+        twl->chip.npwm = 2;
+
+        mutex_init(&twl->mutex);
+
+        ret = pwmchip_add(&twl->chip);
+        if (ret < 0)
+                return ret;
+
+        platform_set_drvdata(pdev, twl);
+
+        return 0;
+}
+
+static int twl_pwm_remove(struct platform_device *pdev)
+{
+        struct twl_pwm_chip *twl = platform_get_drvdata(pdev);
+
+        return pwmchip_remove(&twl->chip);
+}
+
+#ifdef CONFIG_OF
+static struct of_device_id twl_pwm_of_match[] = {
+        { .compatible = "ti,twl4030-pwm" },
+        { .compatible = "ti,twl6030-pwm" },
+        { },
+};
+MODULE_DEVICE_TABLE(of, twl_pwm_of_match);
+#endif
+
+static struct platform_driver twl_pwm_driver = {
+        .driver = {
+                .name = "twl-pwm",
+                .of_match_table = of_match_ptr(twl_pwm_of_match),
+        },
+        .probe = twl_pwm_probe,
+        .remove = twl_pwm_remove,
+};
+module_platform_driver(twl_pwm_driver);
+
+MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>");
+MODULE_DESCRIPTION("PWM driver for TWL4030 and TWL6030");
+MODULE_ALIAS("platform:twl-pwm");
+MODULE_LICENSE("GPL");