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path: root/drivers/pwm/pwm-twl-led.c
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Diffstat (limited to 'drivers/pwm/pwm-twl-led.c')
-rw-r--r--drivers/pwm/pwm-twl-led.c215
1 files changed, 113 insertions, 102 deletions
diff --git a/drivers/pwm/pwm-twl-led.c b/drivers/pwm/pwm-twl-led.c
index 29d1bba4804e..a555cc3be4b3 100644
--- a/drivers/pwm/pwm-twl-led.c
+++ b/drivers/pwm/pwm-twl-led.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for TWL4030/6030 Pulse Width Modulator used as LED driver
*
@@ -7,23 +8,28 @@
* This driver is a complete rewrite of the former pwm-twl6030.c authorded by:
* Hemanth V <hemanthv@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.
+ * Reference manual for the twl6030 is available at:
+ * https://www.ti.com/lit/ds/symlink/twl6030.pdf
*
- * 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/>.
+ * Limitations:
+ * - The twl6030 hardware only supports two period lengths (128 clock ticks and
+ * 64 clock ticks), the driver only uses 128 ticks
+ * - The hardware doesn't support ON = 0, so the active part of a period doesn't
+ * start at its beginning.
+ * - The hardware could support inverted polarity (with a similar limitation as
+ * for normal: the last clock tick is always inactive).
+ * - The hardware emits a constant low output when disabled.
+ * - A request for .duty_cycle = 0 results in an output wave with one active
+ * clock tick per period. This should better use the disabled state.
+ * - The driver only implements setting the relative duty cycle.
+ * - The driver doesn't implement .get_state().
*/
#include <linux/module.h>
+#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
-#include <linux/i2c/twl.h>
+#include <linux/mfd/twl.h>
#include <linux/slab.h>
/*
@@ -55,14 +61,9 @@
#define TWL6040_LED_MODE_OFF 0x02
#define TWL6040_LED_MODE_MASK 0x03
-struct twl_pwmled_chip {
- struct pwm_chip chip;
- struct mutex mutex;
-};
-
static inline struct twl_pwmled_chip *to_twl(struct pwm_chip *chip)
{
- return container_of(chip, struct twl_pwmled_chip, chip);
+ return pwmchip_get_drvdata(chip);
}
static int twl4030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
@@ -94,59 +95,88 @@ static int twl4030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
ret = twl_i2c_write(TWL4030_MODULE_LED, pwm_config, base, 2);
if (ret < 0)
- dev_err(chip->dev, "%s: Failed to configure PWM\n", pwm->label);
+ dev_err(pwmchip_parent(chip), "%s: Failed to configure PWM\n", pwm->label);
return ret;
}
static int twl4030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
- struct twl_pwmled_chip *twl = to_twl(chip);
int ret;
u8 val;
- mutex_lock(&twl->mutex);
ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG);
if (ret < 0) {
- dev_err(chip->dev, "%s: Failed to read LEDEN\n", pwm->label);
- goto out;
+ dev_err(pwmchip_parent(chip), "%s: Failed to read LEDEN\n", pwm->label);
+ return ret;
}
val |= TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS);
ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG);
if (ret < 0)
- dev_err(chip->dev, "%s: Failed to enable PWM\n", pwm->label);
+ dev_err(pwmchip_parent(chip), "%s: Failed to enable PWM\n", pwm->label);
-out:
- mutex_unlock(&twl->mutex);
return ret;
}
static void twl4030_pwmled_disable(struct pwm_chip *chip,
struct pwm_device *pwm)
{
- struct twl_pwmled_chip *twl = to_twl(chip);
int ret;
u8 val;
- mutex_lock(&twl->mutex);
ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG);
if (ret < 0) {
- dev_err(chip->dev, "%s: Failed to read LEDEN\n", pwm->label);
- goto out;
+ dev_err(pwmchip_parent(chip), "%s: Failed to read LEDEN\n", pwm->label);
+ return;
}
val &= ~TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS);
ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG);
if (ret < 0)
- dev_err(chip->dev, "%s: Failed to disable PWM\n", pwm->label);
+ dev_err(pwmchip_parent(chip), "%s: Failed to disable PWM\n", pwm->label);
+}
+
+static int twl4030_pwmled_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+ const struct pwm_state *state)
+{
+ int ret;
+
+ if (state->polarity != PWM_POLARITY_NORMAL)
+ return -EINVAL;
+
+ if (!state->enabled) {
+ if (pwm->state.enabled)
+ twl4030_pwmled_disable(chip, pwm);
+
+ return 0;
+ }
-out:
- mutex_unlock(&twl->mutex);
+ /*
+ * We cannot skip calling ->config even if state->period ==
+ * pwm->state.period && state->duty_cycle == pwm->state.duty_cycle
+ * because we might have exited early in the last call to
+ * pwm_apply_might_sleep because of !state->enabled and so the two values in
+ * pwm->state might not be configured in hardware.
+ */
+ ret = twl4030_pwmled_config(chip, pwm,
+ state->duty_cycle, state->period);
+ if (ret)
+ return ret;
+
+ if (!pwm->state.enabled)
+ ret = twl4030_pwmled_enable(chip, pwm);
+
+ return ret;
}
+
+static const struct pwm_ops twl4030_pwmled_ops = {
+ .apply = twl4030_pwmled_apply,
+};
+
static int twl6030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
@@ -159,23 +189,21 @@ static int twl6030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, on_time,
TWL6030_LED_PWM_CTRL1);
if (ret < 0)
- dev_err(chip->dev, "%s: Failed to configure PWM\n", pwm->label);
+ dev_err(pwmchip_parent(chip), "%s: Failed to configure PWM\n", pwm->label);
return ret;
}
static int twl6030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
- struct twl_pwmled_chip *twl = to_twl(chip);
int ret;
u8 val;
- mutex_lock(&twl->mutex);
ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
if (ret < 0) {
- dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
+ dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n",
pwm->label);
- goto out;
+ return ret;
}
val &= ~TWL6040_LED_MODE_MASK;
@@ -183,26 +211,22 @@ static int twl6030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
if (ret < 0)
- dev_err(chip->dev, "%s: Failed to enable PWM\n", pwm->label);
+ dev_err(pwmchip_parent(chip), "%s: Failed to enable PWM\n", pwm->label);
-out:
- mutex_unlock(&twl->mutex);
return ret;
}
static void twl6030_pwmled_disable(struct pwm_chip *chip,
struct pwm_device *pwm)
{
- struct twl_pwmled_chip *twl = to_twl(chip);
int ret;
u8 val;
- mutex_lock(&twl->mutex);
ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
if (ret < 0) {
- dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
+ dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n",
pwm->label);
- goto out;
+ return;
}
val &= ~TWL6040_LED_MODE_MASK;
@@ -210,24 +234,45 @@ static void twl6030_pwmled_disable(struct pwm_chip *chip,
ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
if (ret < 0)
- dev_err(chip->dev, "%s: Failed to disable PWM\n", pwm->label);
+ dev_err(pwmchip_parent(chip), "%s: Failed to disable PWM\n", pwm->label);
+}
-out:
- mutex_unlock(&twl->mutex);
+static int twl6030_pwmled_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+ const struct pwm_state *state)
+{
+ int err;
+
+ if (state->polarity != pwm->state.polarity)
+ return -EINVAL;
+
+ if (!state->enabled) {
+ if (pwm->state.enabled)
+ twl6030_pwmled_disable(chip, pwm);
+
+ return 0;
+ }
+
+ err = twl6030_pwmled_config(chip, pwm,
+ state->duty_cycle, state->period);
+ if (err)
+ return err;
+
+ if (!pwm->state.enabled)
+ err = twl6030_pwmled_enable(chip, pwm);
+
+ return err;
}
static int twl6030_pwmled_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
- struct twl_pwmled_chip *twl = to_twl(chip);
int ret;
u8 val;
- mutex_lock(&twl->mutex);
ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
if (ret < 0) {
- dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
+ dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n",
pwm->label);
- goto out;
+ return ret;
}
val &= ~TWL6040_LED_MODE_MASK;
@@ -235,25 +280,21 @@ static int twl6030_pwmled_request(struct pwm_chip *chip, struct pwm_device *pwm)
ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
if (ret < 0)
- dev_err(chip->dev, "%s: Failed to request PWM\n", pwm->label);
+ dev_err(pwmchip_parent(chip), "%s: Failed to request PWM\n", pwm->label);
-out:
- mutex_unlock(&twl->mutex);
return ret;
}
static void twl6030_pwmled_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
- struct twl_pwmled_chip *twl = to_twl(chip);
int ret;
u8 val;
- mutex_lock(&twl->mutex);
ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
if (ret < 0) {
- dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
+ dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n",
pwm->label);
- goto out;
+ return;
}
val &= ~TWL6040_LED_MODE_MASK;
@@ -261,65 +302,36 @@ static void twl6030_pwmled_free(struct pwm_chip *chip, struct pwm_device *pwm)
ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
if (ret < 0)
- dev_err(chip->dev, "%s: Failed to free PWM\n", pwm->label);
-
-out:
- mutex_unlock(&twl->mutex);
+ dev_err(pwmchip_parent(chip), "%s: Failed to free PWM\n", pwm->label);
}
-static const struct pwm_ops twl4030_pwmled_ops = {
- .enable = twl4030_pwmled_enable,
- .disable = twl4030_pwmled_disable,
- .config = twl4030_pwmled_config,
- .owner = THIS_MODULE,
-};
-
static const struct pwm_ops twl6030_pwmled_ops = {
- .enable = twl6030_pwmled_enable,
- .disable = twl6030_pwmled_disable,
- .config = twl6030_pwmled_config,
+ .apply = twl6030_pwmled_apply,
.request = twl6030_pwmled_request,
.free = twl6030_pwmled_free,
- .owner = THIS_MODULE,
};
static int twl_pwmled_probe(struct platform_device *pdev)
{
- struct twl_pwmled_chip *twl;
- int ret;
-
- twl = devm_kzalloc(&pdev->dev, sizeof(*twl), GFP_KERNEL);
- if (!twl)
- return -ENOMEM;
+ struct pwm_chip *chip;
+ unsigned int npwm;
+ const struct pwm_ops *ops;
if (twl_class_is_4030()) {
- twl->chip.ops = &twl4030_pwmled_ops;
- twl->chip.npwm = 2;
+ ops = &twl4030_pwmled_ops;
+ npwm = 2;
} else {
- twl->chip.ops = &twl6030_pwmled_ops;
- twl->chip.npwm = 1;
+ ops = &twl6030_pwmled_ops;
+ npwm = 1;
}
- twl->chip.dev = &pdev->dev;
- twl->chip.base = -1;
- twl->chip.can_sleep = true;
+ chip = devm_pwmchip_alloc(&pdev->dev, npwm, 0);
+ if (IS_ERR(chip))
+ return PTR_ERR(chip);
- mutex_init(&twl->mutex);
-
- ret = pwmchip_add(&twl->chip);
- if (ret < 0)
- return ret;
-
- platform_set_drvdata(pdev, twl);
-
- return 0;
-}
-
-static int twl_pwmled_remove(struct platform_device *pdev)
-{
- struct twl_pwmled_chip *twl = platform_get_drvdata(pdev);
+ chip->ops = ops;
- return pwmchip_remove(&twl->chip);
+ return devm_pwmchip_add(&pdev->dev, chip);
}
#ifdef CONFIG_OF
@@ -337,7 +349,6 @@ static struct platform_driver twl_pwmled_driver = {
.of_match_table = of_match_ptr(twl_pwmled_of_match),
},
.probe = twl_pwmled_probe,
- .remove = twl_pwmled_remove,
};
module_platform_driver(twl_pwmled_driver);
generated by cgit (git 2.34.1) at 2025-12-21 22:49:15 +0000