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Message-Id: <20231222150133.732662-2-krzysztof.kozlowski@linaro.org>
Date: Fri, 22 Dec 2023 16:01:30 +0100
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: Bjorn Andersson <andersson@...nel.org>,
Konrad Dybcio <konrad.dybcio@...aro.org>,
Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
Banajit Goswami <bgoswami@...cinc.com>,
Liam Girdwood <lgirdwood@...il.com>,
Mark Brown <broonie@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Conor Dooley <conor+dt@...nel.org>,
Philipp Zabel <p.zabel@...gutronix.de>,
Jaroslav Kysela <perex@...ex.cz>,
Takashi Iwai <tiwai@...e.com>,
linux-arm-msm@...r.kernel.org,
alsa-devel@...a-project.org,
linux-sound@...r.kernel.org,
devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
Bartosz Golaszewski <brgl@...ev.pl>,
Sean Anderson <sean.anderson@...o.com>
Subject: [PATCH 1/4] reset: instantiate reset GPIO controller for shared reset-gpios
Devices sharing a reset GPIO could use the reset framework for
coordinated handling of that shared GPIO line. We have several cases of
such needs, at least for Devicetree-based platforms.
If Devicetree-based device requests a reset line which is missing but
there is a reset-gpios property, instantiate a new "reset-gpio" platform
device which will handle such reset line. This allows seamless handling
of such shared reset-gpios without need of changing Devicetree binding [1].
The "reset-gpio" driver follows shortly.
Link: https://lore.kernel.org/all/YXi5CUCEi7YmNxXM@robh.at.kernel.org/
Cc: Bartosz Golaszewski <brgl@...ev.pl>
Cc: Sean Anderson <sean.anderson@...o.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
---
drivers/reset/core.c | 70 +++++++++++++++++++++++++++-----
include/linux/reset-controller.h | 2 +
2 files changed, 61 insertions(+), 11 deletions(-)
diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index 4d5a78d3c085..a1f0f515a7e0 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -10,9 +10,12 @@
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/kref.h>
+#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/of.h>
+#include <linux/of_gpio.h>
#include <linux/acpi.h>
+#include <linux/platform_device.h>
#include <linux/reset.h>
#include <linux/reset-controller.h>
#include <linux/slab.h>
@@ -813,13 +816,59 @@ static void __reset_control_put_internal(struct reset_control *rstc)
kref_put(&rstc->refcnt, __reset_control_release);
}
+static int __reset_add_reset_gpio_device(struct device_node *node,
+ const struct gpio_desc **out)
+{
+ struct platform_device *pdev;
+ int gpio;
+
+ /* Don't care about deprecated '-gpio' suffix. */
+ gpio = of_get_named_gpio(node, "reset-gpios", 0);
+ if (!gpio_is_valid(gpio))
+ return gpio;
+
+ pdev = platform_device_register_data(NULL, "reset-gpio",
+ PLATFORM_DEVID_AUTO, &node,
+ sizeof(node));
+ if (!IS_ERR(pdev))
+ *out = gpio_to_desc(gpio);
+
+ return PTR_ERR_OR_ZERO(pdev);
+}
+
+static struct reset_controller_dev *__reset_find_rcdev(const struct of_phandle_args *args,
+ const void *cookie)
+{
+ struct reset_controller_dev *r, *rcdev;
+
+ lockdep_assert_held(&reset_list_mutex);
+
+ rcdev = NULL;
+ list_for_each_entry(r, &reset_controller_list, list) {
+ if (args && args->np) {
+ if (args->np == r->of_node) {
+ rcdev = r;
+ break;
+ }
+ } else if (cookie) {
+ if (cookie == r->cookie) {
+ rcdev = r;
+ break;
+ }
+ }
+ }
+
+ return rcdev;
+}
+
struct reset_control *
__of_reset_control_get(struct device_node *node, const char *id, int index,
bool shared, bool optional, bool acquired)
{
+ const struct gpio_desc *gpio = NULL;
+ struct of_phandle_args args = {0};
struct reset_control *rstc;
- struct reset_controller_dev *r, *rcdev;
- struct of_phandle_args args;
+ struct reset_controller_dev *rcdev;
int rstc_id;
int ret;
@@ -839,17 +888,16 @@ __of_reset_control_get(struct device_node *node, const char *id, int index,
index, &args);
if (ret == -EINVAL)
return ERR_PTR(ret);
- if (ret)
- return optional ? NULL : ERR_PTR(ret);
+ if (ret) {
+ ret = __reset_add_reset_gpio_device(node, &gpio);
+ if (ret)
+ return optional ? NULL : ERR_PTR(ret);
+
+ args.args_count = 1; /* reset-gpio has only one reset line */
+ }
mutex_lock(&reset_list_mutex);
- rcdev = NULL;
- list_for_each_entry(r, &reset_controller_list, list) {
- if (args.np == r->of_node) {
- rcdev = r;
- break;
- }
- }
+ rcdev = __reset_find_rcdev(&args, gpio);
if (!rcdev) {
rstc = ERR_PTR(-EPROBE_DEFER);
diff --git a/include/linux/reset-controller.h b/include/linux/reset-controller.h
index 0fa4f60e1186..c0a99a8ea29e 100644
--- a/include/linux/reset-controller.h
+++ b/include/linux/reset-controller.h
@@ -61,6 +61,7 @@ struct reset_control_lookup {
* @dev: corresponding driver model device struct
* @of_node: corresponding device tree node as phandle target
* @of_reset_n_cells: number of cells in reset line specifiers
+ * @cookie: for reset-gpios controllers: corresponding GPIO instead of of_node
* @of_xlate: translation function to translate from specifier as found in the
* device tree to id as given to the reset control ops, defaults
* to :c:func:`of_reset_simple_xlate`.
@@ -74,6 +75,7 @@ struct reset_controller_dev {
struct device *dev;
struct device_node *of_node;
int of_reset_n_cells;
+ const void *cookie;
int (*of_xlate)(struct reset_controller_dev *rcdev,
const struct of_phandle_args *reset_spec);
unsigned int nr_resets;
--
2.34.1
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