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Subject[RFC v2 3/3] pinctrl: imx: add of_notifier for dynamic pinctrl changes
Date
Currently the implementation is limited:
- can only add a new function
- if function already exists, it is discarded
- requires the dtso to know about this architecture

Another option would be to do like the pinctrl-single where each
group has its own function. Therefore it is easy to manage them.

Currently there's no easy way to add/remove groups to an existing
function.

Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
---
Hi all,

This implementation is far from ideal. It must be seen as a starting
point more than anything else.

The goal was to have the simplest patch possible. Here a group cannot
be added to an existing function. But a new function can be created.

There's currently no way to remove the group that has been added.

Regards,
Gary
---
drivers/pinctrl/freescale/pinctrl-imx.c | 103 ++++++++++++++++++++++++++++++++
1 file changed, 103 insertions(+)

diff --git a/drivers/pinctrl/freescale/pinctrl-imx.c b/drivers/pinctrl/freescale/pinctrl-imx.c
index e832a2c..5951a31 100644
--- a/drivers/pinctrl/freescale/pinctrl-imx.c
+++ b/drivers/pinctrl/freescale/pinctrl-imx.c
@@ -811,6 +811,106 @@ static void imx_free_resources(struct imx_pinctrl *ipctl)
imx_free_pingroups(ipctl->info);
}

+#if IS_ENABLED(CONFIG_OF_DYNAMIC)
+static int imx_pinctrl_add_function(struct device_node *np,
+ struct imx_pinctrl_soc_info *info)
+{
+ struct imx_pmx_func *func;
+ u32 i = 0;
+
+ for (i = 0; i < info->nfunctions; i++) {
+ struct imx_pmx_func *func;
+
+ func = radix_tree_lookup(&info->ftree, i);
+ if (!func)
+ continue;
+
+ if (!strcmp(func->name, np->name)) {
+ dev_err(info->dev, "function %s already exists!\n",
+ np->name);
+ return -EINVAL;
+ }
+ }
+
+ /* Create a new function */
+ func = devm_kzalloc(info->dev, sizeof(*func), GFP_KERNEL);
+ if (!func)
+ return -ENOMEM;
+
+ mutex_lock(&info->mutex);
+ radix_tree_insert(&info->ftree, info->nfunctions, func);
+ info->ngroups += of_get_child_count(np);
+ mutex_unlock(&info->mutex);
+
+ imx_pinctrl_parse_functions(np, info, info->nfunctions);
+
+ mutex_lock(&info->mutex);
+ info->nfunctions++;
+ mutex_unlock(&info->mutex);
+
+ return 0;
+}
+
+static inline struct platform_device *imx_get_device(struct device_node *np)
+{
+ struct platform_device *pdev = of_find_device_by_node(np->parent);
+
+ if (!pdev)
+ pdev = of_find_device_by_node(np->parent->parent);
+
+ return pdev;
+}
+
+static int of_pinctrl_notify(struct notifier_block *nb, unsigned long action,
+ void *arg)
+{
+ struct of_reconfig_data *rd = arg;
+ struct platform_device *pdev;
+ struct imx_pinctrl *ipctl;
+ int ret;
+
+ /* Looking for a pinctrl group node */
+ if (!of_property_read_bool(rd->dn, "fsl,pins"))
+ return NOTIFY_OK; /* not for us */
+
+ switch (of_reconfig_get_state_change(action, rd)) {
+ case OF_RECONFIG_CHANGE_ADD:
+ pdev = imx_get_device(rd->dn);
+ if (!pdev) {
+ pr_err("%s: couldn't find device\n", __func__);
+ return NOTIFY_OK;
+ }
+
+ ipctl = dev_get_drvdata(&pdev->dev);
+ if (!pdev) {
+ dev_err(&pdev->dev, "driver data not found\n");
+ return NOTIFY_OK;
+ }
+
+ ret = imx_pinctrl_add_function(rd->dn->parent, ipctl->info);
+ if (ret < 0)
+ dev_err(&pdev->dev, "couldn't add function: %d\n", ret);
+
+ break;
+ case OF_RECONFIG_CHANGE_REMOVE:
+ pdev = imx_get_device(rd->dn);
+ if (!pdev) {
+ pr_err("%s: couldn't find device\n", __func__);
+ return NOTIFY_OK;
+ }
+ dev_err(&pdev->dev, "removing a function isn't supported\n");
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+static struct notifier_block pinctrl_of_notifier = {
+ .notifier_call = of_pinctrl_notify,
+};
+#else
+extern struct notifier_block pinctrl_of_notifier;
+#endif /* CONFIG_OF_DYNAMIC */
+
int imx_pinctrl_probe(struct platform_device *pdev,
struct imx_pinctrl_soc_info *info)
{
@@ -906,6 +1006,9 @@ int imx_pinctrl_probe(struct platform_device *pdev,
goto free;
}

+ if (IS_ENABLED(CONFIG_OF_DYNAMIC))
+ WARN_ON(of_reconfig_notifier_register(&pinctrl_of_notifier));
+
dev_info(&pdev->dev, "initialized IMX pinctrl driver\n");

return 0;
--
2.9.3
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