param: Add integer and boolean parameter helpers

This adds convenience functions for directly registering integers
and bools as device parameter. This way driver no longer have to
fiddle with string handling. The format used to print the parameter
is passed to the functions to be able to print parameters in a
flexible way.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 161 insertions, 0 deletions

diff --git a/lib/parameter.c b/lib/parameter.c
index 70f035aab3..3e78c96728 100644
--- a/lib/parameter.c
+++ b/lib/parameter.c
@@ -27,6 +27,7 @@
 #include <net.h>
 #include <malloc.h>
 #include <driver.h>
+#include <linux/err.h>
 
 struct param_d *get_param_by_name(struct device_d *dev, const char *name)
 {
@@ -218,6 +219,166 @@ int dev_add_param_fixed(struct device_d *dev, char *name, char *value)
 	return 0;
 }
 
+struct param_int {
+	struct param_d param;
+	int *value;
+	const char *format;
+#define PARAM_INT_FLAG_BOOL (1 << 0)
+	unsigned flags;
+	int (*set)(struct param_d *p, void *priv);
+	int (*get)(struct param_d *p, void *priv);
+};
+
+static inline struct param_int *to_param_int(struct param_d *p)
+{
+	return container_of(p, struct param_int, param);
+}
+
+static int param_int_set(struct device_d *dev, struct param_d *p, const char *val)
+{
+	struct param_int *pi = to_param_int(p);
+	int value_save = *pi->value;
+	int ret;
+
+	if (!val)
+		return -EINVAL;
+
+	*pi->value = simple_strtol(val, NULL, 0);
+	if (pi->flags & PARAM_INT_FLAG_BOOL)
+		*pi->value = !!*pi->value;
+
+	if (pi->set) {
+		ret = pi->set(p, p->driver_priv);
+		if (ret) {
+			*pi->value = value_save;
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static const char *param_int_get(struct device_d *dev, struct param_d *p)
+{
+	struct param_int *pi = to_param_int(p);
+	int ret;
+
+	if (pi->get) {
+		ret = pi->get(p, p->driver_priv);
+		if (ret)
+			return NULL;
+	}
+
+	free(p->value);
+	p->value = asprintf(pi->format, *pi->value);
+
+	return p->value;
+}
+
+/**
+ * dev_add_param_int - add an integer parameter to a device
+ * @param dev	The device
+ * @param name	The name of the parameter
+ * @param set	set function
+ * @param get	get function
+ * @param value	pointer to the integer containing the value of the parameter
+ * @param format the printf format used to print the value
+ * @param priv	user private data, will be passed to get/set
+ *
+ * The get function can be used as a notifier when the variable is about
+ * to be read.
+ * The set function can be used as a notifer when the variable is about
+ * to be written. Can also be used to limit the value.
+ */
+struct param_d *dev_add_param_int(struct device_d *dev, const char *name,
+		int (*set)(struct param_d *p, void *priv),
+		int (*get)(struct param_d *p, void *priv),
+		int *value, const char *format, void *priv)
+{
+	struct param_int *pi;
+	struct param_d *p;
+	int ret;
+
+	pi = xzalloc(sizeof(*pi));
+	pi->value = value;
+	pi->format = format;
+	pi->set = set;
+	pi->get = get;
+	p = &pi->param;
+	p->driver_priv = priv;
+
+	ret = __dev_add_param(p, dev, name, param_int_set, param_int_get, 0);
+	if (ret) {
+		free(pi);
+		return ERR_PTR(ret);
+	}
+
+	return &pi->param;
+}
+
+/**
+ * dev_add_param_bool - add an boolean parameter to a device
+ * @param dev	The device
+ * @param name	The name of the parameter
+ * @param set	set function
+ * @param get	get function
+ * @param value	pointer to the integer containing the value of the parameter
+ * @param priv	user private data, will be passed to get/set
+ *
+ * The get function can be used as a notifier when the variable is about
+ * to be read.
+ * The set function can be used as a notifer when the variable is about
+ * to be written. Can also be used to limit the value.
+ */
+struct param_d *dev_add_param_bool(struct device_d *dev, const char *name,
+		int (*set)(struct param_d *p, void *priv),
+		int (*get)(struct param_d *p, void *priv),
+		int *value, void *priv)
+{
+	struct param_int *pi;
+	struct param_d *p;
+
+	p = dev_add_param_int(dev, name, set, get, value, "%d", priv);
+	if (IS_ERR(p))
+		return p;
+
+	pi = to_param_int(p);
+	pi->flags |= PARAM_INT_FLAG_BOOL;
+
+	return p;
+}
+
+struct param_int_ro {
+	struct param_d param;
+	char *value;
+};
+
+/**
+ * dev_add_param_int_ro - add a read only integer parameter to a device
+ * @param dev	The device
+ * @param name	The name of the parameter
+ * @param value	The value of the parameter
+ * @param format the printf format used to print the value
+ */
+struct param_d *dev_add_param_int_ro(struct device_d *dev, const char *name,
+		int value, const char *format)
+{
+	struct param_int *piro;
+	int ret;
+
+	piro = xzalloc(sizeof(*piro));
+
+	ret = __dev_add_param(&piro->param, dev, name, NULL, NULL, 0);
+	if (ret) {
+		free(piro);
+		return ERR_PTR(ret);
+	}
+
+	piro->param.value = asprintf(format, value);
+
+	return &piro->param;
+}
+
 /**
  * dev_remove_param - remove a parameter from a device and free its
  * memory