From: Dan Murphy <dmurphy@ti.com>
To: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Len Brown <lenb@kernel.org>,
Robert Moore <robert.moore@intel.com>,
Erik Schmauss <erik.schmauss@intel.com>,
Jacek Anaszewski <jacek.anaszewski@gmail.com>,
Pavel Machek <pavel@ucw.cz>,
Thierry Reding <thierry.reding@gmail.com>
Cc: <linux-acpi@vger.kernel.org>, <devel@acpica.org>,
<linux-leds@vger.kernel.org>, <linux-pwm@vger.kernel.org>
Subject: Re: [PATCH 2/3] PWM framework: add support referencing PWMs from ACPI
Date: Thu, 30 May 2019 09:54:29 -0500 [thread overview]
Message-ID: <d4e035b7-7419-cb69-9e22-6103d53d5aaf@ti.com> (raw)
In-Reply-To: <254cc03d5467ba7db0f5677646266768e5b24127.1559127603.git.nikolaus.voss@loewensteinmedical.de>
Nikolaus
On 5/29/19 7:18 AM, Nikolaus Voss wrote:
> In analogy to referencing a GPIO using the "gpios" property from ACPI,
> support referencing a PWM using the "pwms" property.
>
> ACPI entries must look like
> Package () {"pwms", Package ()
> { <PWM device reference>, <PWM index>, <PWM period> [, <PWM flags>]}}
>
> In contrast to the DT implementation, only _one_ PWM entry in the "pwms"
> property is supported. As a consequence "pwm-names"-property and
> con_id lookup aren't supported.
>
> Support for ACPI is added via the firmware-node framework which is an
> abstraction layer on top of ACPI/DT. To keep this patch clean, DT and
> ACPI paths are kept separate. The firmware-node framework could be used
> to unify both paths in a future patch.
>
> To support leds-pwm driver, an additional method devm_fwnode_pwm_get()
> which supports both ACPI and DT configuration is exported.
>
> Signed-off-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
> ---
> drivers/pwm/core.c | 112 ++++++++++++++++++++++++++++++++++++++++++++
> include/linux/pwm.h | 9 ++++
> 2 files changed, 121 insertions(+)
>
> diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
> index 275b5f399a1a..1d788c05193e 100644
> --- a/drivers/pwm/core.c
> +++ b/drivers/pwm/core.c
> @@ -6,6 +6,7 @@
> * Copyright (C) 2011-2012 Avionic Design GmbH
> */
>
> +#include <linux/acpi.h>
> #include <linux/module.h>
> #include <linux/pwm.h>
> #include <linux/radix-tree.h>
> @@ -700,6 +701,75 @@ struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
> }
> EXPORT_SYMBOL_GPL(of_pwm_get);
>
> +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);
> +}
> +
> +/**
> + * 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.
> + */
> +struct pwm_device *acpi_pwm_get(struct fwnode_handle *fwnode)
static?
> +{
> + struct fwnode_reference_args args;
> + struct pwm_chip *chip;
> + struct pwm_device *pwm = ERR_PTR(-ENODEV);
> + int ret;
> +
> + memset(&args, 0, sizeof(args));
args should be zero'd out when initialized on the stack so this is
necessary.
> + ret = __acpi_node_get_property_reference(fwnode, "pwms", 0, 3, &args);
> +
> + if (!to_acpi_device_node(args.fwnode))
> + return ERR_PTR(-EINVAL);
Add new line
> + if (args.nargs < 2)
> + return ERR_PTR(-EPROTO);
> +
> + chip = device_to_pwmchip(&to_acpi_device_node(args.fwnode)->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;
> +
> + return pwm;
> +}
> +
> /**
> * pwm_add_table() - register PWM device consumers
> * @table: array of consumers to register
> @@ -763,6 +833,10 @@ 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->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
> @@ -942,6 +1016,44 @@ 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)
I am wondering if it would be better just to convert the existing of_
calls to device_property calls and make it more generic.
Dan
> +{
> + 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(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;
> diff --git a/include/linux/pwm.h b/include/linux/pwm.h
> index eaa5c6e3fc9f..1a635916cdfb 100644
> --- a/include/linux/pwm.h
> +++ b/include/linux/pwm.h
> @@ -411,6 +411,9 @@ void pwm_put(struct pwm_device *pwm);
> struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id);
> struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
> const char *con_id);
> +struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
> + struct fwnode_handle *fwnode,
> + const char *con_id);
> void devm_pwm_put(struct device *dev, struct pwm_device *pwm);
> #else
> static inline struct pwm_device *pwm_request(int pwm_id, const char *label)
> @@ -516,6 +519,12 @@ static inline struct pwm_device *devm_of_pwm_get(struct device *dev,
> return ERR_PTR(-ENODEV);
> }
>
> +static inline struct pwm_device *devm_fwnode_pwm_get(
> + struct device *dev, struct fwnode_handle *fwnode, const char *con_id)
> +{
> + return ERR_PTR(-ENODEV);
> +}
> +
> static inline void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
> {
> }
next prev parent reply other threads:[~2019-05-30 14:55 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-29 12:18 [PATCH 0/3] PWM framework: add support referencing PWMs from ACPI Nikolaus Voss
2019-05-29 12:18 ` [PATCH 1/3] ACPI: Resolve objects on host-directed table loads Nikolaus Voss
2019-05-30 14:42 ` Dan Murphy
2019-05-31 12:23 ` Pavel Machek
2019-05-31 12:45 ` Dan Murphy
2019-05-31 12:46 ` Dan Murphy
2019-06-03 9:12 ` Nikolaus Voss
2019-08-14 18:50 ` Andy Shevchenko
2019-08-14 20:27 ` Schmauss, Erik
2019-08-16 11:57 ` Nikolaus Voss
2019-08-30 14:53 ` Shevchenko, Andriy
2019-09-04 7:20 ` Nikolaus Voss
2019-09-06 17:46 ` Shevchenko, Andriy
2019-09-12 8:05 ` Nikolaus Voss
2019-09-12 8:07 ` [PATCH] ACPICA: make acpi_load_table() return table index Nikolaus Voss
2019-09-12 14:19 ` Moore, Robert
2019-09-12 19:36 ` Ferry Toth
2019-09-25 18:13 ` Schmauss, Erik
2019-09-26 8:09 ` Shevchenko, Andriy
2019-09-13 7:44 ` Nikolaus Voss
2019-09-13 14:20 ` Moore, Robert
2019-09-13 15:12 ` Shevchenko, Andriy
2019-09-13 16:48 ` Ferry Toth
2019-09-13 16:48 ` Ferry Toth
2019-09-13 17:40 ` Moore, Robert
2019-09-13 19:56 ` Rafael J. Wysocki
2019-09-16 9:46 ` Nikolaus Voss
2019-09-18 14:13 ` Moore, Robert
2019-09-18 14:31 ` Nikolaus Voss
2019-09-19 17:05 ` Moore, Robert
2019-09-23 9:05 ` Nikolaus Voss
2019-09-24 19:41 ` Moore, Robert
2019-09-25 10:18 ` Nikolaus Voss
2019-09-25 10:53 ` Shevchenko, Andriy
2019-09-19 8:13 ` Rafael J. Wysocki
2019-09-23 9:08 ` Nikolaus Voss
2019-09-23 9:47 ` [PATCH] ACPICA: Introduce acpi_load_table_with_index() Nikolaus Voss
2019-09-24 12:07 ` Shevchenko, Andriy
2019-09-24 12:08 ` Shevchenko, Andriy
2019-09-25 10:20 ` Nikolaus Voss
2019-09-24 15:11 ` Andy Shevchenko
2019-09-25 10:22 ` Nikolaus Voss
2019-09-26 16:09 ` [PATCH] ACPICA: make acpi_load_table() return table index Schmauss, Erik
2019-09-26 16:35 ` Shevchenko, Andriy
2019-09-26 16:51 ` Schmauss, Erik
2019-09-26 17:47 ` Shevchenko, Andriy
2019-09-26 18:44 ` Nikolaus Voss
2019-09-26 19:26 ` Rafael J. Wysocki
2019-09-26 19:41 ` Schmauss, Erik
2019-09-26 18:43 ` Nikolaus Voss
2019-05-29 12:18 ` [PATCH 2/3] PWM framework: add support referencing PWMs from ACPI Nikolaus Voss
2019-05-30 14:54 ` Dan Murphy [this message]
2019-05-31 12:24 ` Pavel Machek
2019-06-03 9:27 ` Nikolaus Voss
2019-05-29 12:18 ` [PATCH 3/3] leds-pwm.c: support ACPI via firmware-node framework Nikolaus Voss
2019-05-30 15:14 ` Dan Murphy
2019-06-03 9:44 ` Nikolaus Voss
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