diff options
Diffstat (limited to 'drivers/pwm')
| -rw-r--r-- | drivers/pwm/core.c | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 60b8ccc1fd7c..c1dbb5f6ebd2 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -19,6 +19,7 @@ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ +#include <linux/acpi.h> #include <linux/module.h> #include <linux/pwm.h> #include <linux/radix-tree.h> @@ -750,6 +751,85 @@ put: } EXPORT_SYMBOL_GPL(of_pwm_get); +#if IS_ENABLED(CONFIG_ACPI) +static struct pwm_chip *device_to_pwmchip(struct device *dev) +{ + struct pwm_chip *chip; + + mutex_lock(&pwm_lock); + + list_for_each_entry(chip, &pwm_chips, list) { + struct acpi_device *adev = ACPI_COMPANION(chip->dev); + + if ((chip->dev == dev) || (adev && &adev->dev == dev)) { + mutex_unlock(&pwm_lock); + return chip; + } + } + + mutex_unlock(&pwm_lock); + + return ERR_PTR(-EPROBE_DEFER); +} +#endif + +/** + * acpi_pwm_get() - request a PWM via parsing "pwms" property in ACPI + * @fwnode: firmware node to get the "pwm" property from + * + * Returns the PWM device parsed from the fwnode and index specified in the + * "pwms" property or a negative error-code on failure. + * Values parsed from the device tree are stored in the returned PWM device + * object. + * + * This is analogous to of_pwm_get() except con_id is not yet supported. + * ACPI entries must look like + * Package () {"pwms", Package () + * { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}} + * + * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded + * error code on failure. + */ +static struct pwm_device *acpi_pwm_get(struct fwnode_handle *fwnode) +{ + struct pwm_device *pwm = ERR_PTR(-ENODEV); +#if IS_ENABLED(CONFIG_ACPI) + struct fwnode_reference_args args; + struct acpi_device *acpi; + struct pwm_chip *chip; + int ret; + + memset(&args, 0, sizeof(args)); + + ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args); + if (ret < 0) + return ERR_PTR(ret); + + acpi = to_acpi_device_node(args.fwnode); + if (!acpi) + return ERR_PTR(-EINVAL); + + if (args.nargs < 2) + return ERR_PTR(-EPROTO); + + chip = device_to_pwmchip(&acpi->dev); + if (IS_ERR(chip)) + return ERR_CAST(chip); + + pwm = pwm_request_from_chip(chip, args.args[0], NULL); + if (IS_ERR(pwm)) + return pwm; + + pwm->args.period = args.args[1]; + pwm->args.polarity = PWM_POLARITY_NORMAL; + + if (args.nargs > 2 && args.args[2] & PWM_POLARITY_INVERTED) + pwm->args.polarity = PWM_POLARITY_INVERSED; +#endif + + return pwm; +} + /** * pwm_add_table() - register PWM device consumers * @table: array of consumers to register @@ -814,6 +894,10 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) return of_pwm_get(dev, dev->of_node, con_id); + /* then lookup via ACPI */ + if (dev && is_acpi_node(dev->fwnode)) + return acpi_pwm_get(dev->fwnode); + /* * We look up the provider in the static table typically provided by * board setup code. We first try to lookup the consumer device by @@ -999,6 +1083,44 @@ struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np, } EXPORT_SYMBOL_GPL(devm_of_pwm_get); +/** + * devm_fwnode_pwm_get() - request a resource managed PWM from firmware node + * @dev: device for PWM consumer + * @fwnode: firmware node to get the PWM from + * @con_id: consumer name + * + * Returns the PWM device parsed from the firmware node. See of_pwm_get() and + * acpi_pwm_get() for a detailed description. + * + * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded + * error code on failure. + */ +struct pwm_device *devm_fwnode_pwm_get(struct device *dev, + struct fwnode_handle *fwnode, + const char *con_id) +{ + struct pwm_device **ptr, *pwm = ERR_PTR(-ENODEV); + + ptr = devres_alloc(devm_pwm_release, sizeof(*ptr), GFP_KERNEL); + if (!ptr) + return ERR_PTR(-ENOMEM); + + if (is_of_node(fwnode)) + pwm = of_pwm_get(dev, to_of_node(fwnode), con_id); + else if (is_acpi_node(fwnode)) + pwm = acpi_pwm_get(fwnode); + + if (!IS_ERR(pwm)) { + *ptr = pwm; + devres_add(dev, ptr); + } else { + devres_free(ptr); + } + + return pwm; +} +EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get); + static int devm_pwm_match(struct device *dev, void *res, void *data) { struct pwm_device **p = res; |