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SubjectRe: [PATCH V2 3/6] pinctrl: core device tree mapping table parsing support
On Wed, Mar 21, 2012 at 01:44:36AM +0800, Stephen Warren wrote:
> During pinctrl_get(), if the client device has a device tree node, look
> for the common pinctrl properties there. If found, parse the referenced
> device tree nodes, with the help of the pinctrl drivers, and generate
> mapping table entries from them.
>
> During pinctrl_put(), free any results of device tree parsing.
>
> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
> ---
> v2: Place most code into new file devicetree.c
Much clearer.:)

> + * struct pinctrl_dt_map - mapping table chunk parsed from device tree
> + * @node: list node for struct pinctrl's @dt_maps field
> + * @pctldev: the pin controller that allocated this struct, and will free it
> + * @maps: the mapping table entries
> + */
> +struct pinctrl_dt_map {
> + struct list_head node;
> + struct pinctrl_dev *pctldev;
> + struct pinctrl_map *map;
> + unsigned num_maps;
> +};
> +
> +static void dt_free_map(struct pinctrl_dev *pctldev,
> + struct pinctrl_map *map, unsigned num_maps)
> +{
> + if (pctldev) {
> + struct pinctrl_ops *ops = pctldev->desc->pctlops;
> + ops->dt_free_map(pctldev, map, num_maps);
> + } else {
I remember for hog on functions the pctldev becomes pinctrl devices itself,
so in which case pctldev can be NULL?

> +static struct pinctrl_dev *find_pinctrl_by_of_node(struct device_node *np)
> +{
> + struct pinctrl_dev *pctldev;
> +
> + list_for_each_entry(pctldev, &pinctrldev_list, node)
> + if (pctldev->dev->of_node == np)
> + return pctldev;
> +
> + return NULL;
> +}
> +
> +static int dt_to_map_one_config(struct pinctrl *p, const char *statename,
> + struct device_node *np_config)
> +{
> + struct device_node *np_pctldev;
> + struct pinctrl_dev *pctldev;
> + struct pinctrl_ops *ops;
> + int ret;
> + struct pinctrl_map *map;
> + unsigned num_maps;
> +
> + /* Find the pin controller containing np_config */
> + np_pctldev = of_node_get(np_config);
It seems the np_config node is already got when call of_find_node_by_phandle.
So do we still need this line?

> +int pinctrl_dt_to_map(struct pinctrl *p)
> +{
> + struct device_node *np = p->dev->of_node;
> + int state, ret;
> + char *propname;
> + struct property *prop;
> + const char *statename;
> + const __be32 *list;
> + int size, config;
> + phandle phandle;
> + struct device_node *np_config;
> + struct pinctrl_dt_map *dt_map;
> +
Add NULL np checking?

> + /* We may store pointers to property names within the node */
> + of_node_get(np);
> +
> + /* For each defined state ID */
> + for (state = 0; ; state++) {
> + /* Retrieve the pinctrl-* property */
> + propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state);
> + prop = of_find_property(np, propname, &size);
> + kfree(propname);
> + if (!prop)
> + break;
> + list = prop->value;
> + size /= sizeof(*list);
> +
> + /* Determine whether pinctrl-names property names the state */
> + ret = of_property_read_string_index(np, "pinctrl-names",
> + state, &statename);
> + /*
> + * If not, statename is just the integer state ID. But rather
> + * than dynamically allocate it and have to free it later,
> + * just point part way into the property name for the string.
> + */
> + if (ret < 0) {
> + /* strlen("pinctrl-") == 8 */
> + if (strlen(prop->name) < 8) {
Do we really need this extra checking?
It seems the prop->name is the "pinctrl-%d" you searched above, so the
strlen(prop->name) must not < 8, right?

> + dev_err(p->dev, "prop %s inconsistent length\n",
> + prop->name);
> + ret = -EINVAL;
> + goto err;
> + }
> + statename = prop->name + 8;
From this code, it seems actually we provide user the option by chance to define
state as pinctrl-syspend which is out of our binding doc.

> + }
> +
> + /* For every referenced pin configuration node in it */
> + for (config = 0; config < size; config++) {
> + phandle = be32_to_cpup(list++);
> +
> + /* Look up the pin configuration node */
> + np_config = of_find_node_by_phandle(phandle);
One option is using of_parse_phandle, then we do not need calculate
the phandle offset by ourselves.
Like:
np_config = of_parse_phandle(propname , config);

> + if (!np_config) {
> + dev_err(p->dev,
> + "prop %s index %i invalid phandle\n",
> + prop->name, config);
> + ret = -EINVAL;
> + goto err;
> + }
> +
> + /* Parse the node */
> + ret = dt_to_map_one_config(p, statename, np_config);
> + of_node_put(np_config);
> + if (ret < 0)
> + goto err;
> + }
> +
> + /* No entries in DT? Generate a dummy state table entry */
> + if (!size) {
> + ret = dt_remember_dummy_state(p, statename);
> + if (ret < 0)
> + goto err;
> + }
> + }
> +
> + list_for_each_entry(dt_map, &p->dt_maps, node) {
> + ret = pinctrl_register_map(dt_map->map, dt_map->num_maps,
> + false, true);
> + if (ret < 0)
> + goto err;
> + }
What's main purpose of differing the map registration and introduce a
intermediate pinctrl_dt_map(dt_remember_or_free_map)?
What about directly register maps once it's parsed?

Regards
Dong Aisheng



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