V4L/DVB (7134): tuner: create a macro for sharing state between hybrid tuner instances

Create a macro implementing a standard method to share state amongst
multiple instances of a hybrid tuner object.

Also, prepare tuner_foo printk macros for the removal of PREFIX

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 96 insertions, 16 deletions

diff --git a/drivers/media/video/tuner-i2c.h b/drivers/media/video/tuner-i2c.h
index de52e8ffd347..8ec5b41d459f 100644
--- a/drivers/media/video/tuner-i2c.h
+++ b/drivers/media/video/tuner-i2c.h
@@ -26,6 +26,10 @@
 struct tuner_i2c_props {
         u8 addr;
         struct i2c_adapter *adap;
+
+        /* used for tuner instance management */
+        int count;
+        char *name;
 };
 
 static inline int tuner_i2c_xfer_send(struct tuner_i2c_props *props, char *buf, int len)
@@ -59,29 +63,105 @@ static inline int tuner_i2c_xfer_send_recv(struct tuner_i2c_props *props,
         return (ret == 2) ? ilen : ret;
 }
 
-#define tuner_warn(fmt, arg...) do {                                    \
-        printk(KERN_WARNING "%s %d-%04x: " fmt, PREFIX,                 \
-                        i2c_adapter_id(priv->i2c_props.adap),           \
-                        priv->i2c_props.addr, ##arg);                   \
+/* Callers must declare as a global for the module:
+ *
+ * static LIST_HEAD(hybrid_tuner_instance_list);
+ *
+ * hybrid_tuner_instance_list should be the third argument
+ * passed into hybrid_tuner_request_state().
+ *
+ * state structure must contain the following:
+ *
+ *      struct list_head        hybrid_tuner_instance_list;
+ *      struct tuner_i2c_props  i2c_props;
+ *
+ * hybrid_tuner_instance_list (both within state structure and globally)
+ * is only required if the driver is using hybrid_tuner_request_state
+ * and hybrid_tuner_release_state to manage state sharing between
+ * multiple instances of hybrid tuners.
+ */
+
+#define tuner_printk(kernlvl, i2cprops, fmt, arg...) do {               \
+        printk(kernlvl "%s %d-%04x: " fmt, i2cprops.name,               \
+                        i2c_adapter_id(i2cprops.adap),                  \
+                        i2cprops.addr, ##arg);                          \
          } while (0)
 
-#define tuner_info(fmt, arg...) do {                                    \
-        printk(KERN_INFO "%s %d-%04x: " fmt, PREFIX,                    \
-                        i2c_adapter_id(priv->i2c_props.adap),           \
-                        priv->i2c_props.addr , ##arg);                  \
+/* TO DO: convert all callers of these macros to pass in
+ * struct tuner_i2c_props, then remove the macro wrappers */
+
+#define __tuner_warn(i2cprops, fmt, arg...) do {                        \
+        tuner_printk(KERN_WARNING, i2cprops, fmt, ##arg);               \
         } while (0)
 
-#define tuner_err(fmt, arg...) do {                                     \
-        printk(KERN_ERR "%s %d-%04x: " fmt, PREFIX,                     \
-                        i2c_adapter_id(priv->i2c_props.adap),           \
-                        priv->i2c_props.addr , ##arg);                  \
+#define __tuner_info(i2cprops, fmt, arg...) do {                        \
+        tuner_printk(KERN_INFO, i2cprops, fmt, ##arg);                  \
         } while (0)
 
-#define tuner_dbg(fmt, arg...) do {                                     \
+#define __tuner_err(i2cprops, fmt, arg...) do {                         \
+        tuner_printk(KERN_ERR, i2cprops, fmt, ##arg);                   \
+        } while (0)
+
+#define __tuner_dbg(i2cprops, fmt, arg...) do {                         \
         if ((debug))                                                    \
-                printk(KERN_DEBUG "%s %d-%04x: " fmt, PREFIX,           \
-                        i2c_adapter_id(priv->i2c_props.adap),           \
-                        priv->i2c_props.addr , ##arg);                  \
+                tuner_printk(KERN_DEBUG, i2cprops, fmt, ##arg);         \
         } while (0)
 
+#define tuner_warn(fmt, arg...) __tuner_warn(priv->i2c_props, fmt, ##arg)
+#define tuner_info(fmt, arg...) __tuner_info(priv->i2c_props, fmt, ##arg)
+#define tuner_err(fmt, arg...) __tuner_err(priv->i2c_props, fmt, ##arg)
+#define tuner_dbg(fmt, arg...) __tuner_dbg(priv->i2c_props, fmt, ##arg)
+
+/****************************************************************************/
+
+/* The return value of hybrid_tuner_request_state indicates the number of
+ * instances using this tuner object.
+ *
+ * 0 - no instances, indicates an error - kzalloc must have failed
+ *
+ * 1 - one instance, indicates that the tuner object was created successfully
+ *
+ * 2 (or more) instances, indicates that an existing tuner object was found
+ */
+
+#define hybrid_tuner_request_state(type, state, list, i2cadap, i2caddr, devname)\
+({                                                                      \
+        int __ret = 0;                                                  \
+        list_for_each_entry(state, &list, hybrid_tuner_instance_list) { \
+                if ((i2c_adapter_id(state->i2c_props.adap) ==           \
+                     i2c_adapter_id(i2cadap)) &&                        \
+                    (state->i2c_props.addr == i2caddr)) {               \
+                        __tuner_info(state->i2c_props,                  \
+                                     "attaching existing instance\n");  \
+                        state->i2c_props.count++;                       \
+                        __ret = state->i2c_props.count;                 \
+                        break;                                          \
+                }                                                       \
+        }                                                               \
+        if (0 == __ret) {                                               \
+                state = kzalloc(sizeof(type), GFP_KERNEL);              \
+                if (NULL == state)                                      \
+                        goto __fail;                                    \
+                state->i2c_props.addr = i2caddr;                        \
+                state->i2c_props.adap = i2cadap;                        \
+                state->i2c_props.name = devname;                        \
+                __tuner_info(state->i2c_props,                          \
+                             "creating new instance\n");                \
+                list_add_tail(&state->hybrid_tuner_instance_list, &list);\
+                state->i2c_props.count++;                               \
+                __ret = state->i2c_props.count;                         \
+        }                                                               \
+__fail:                                                                 \
+        __ret;                                                          \
+})
+
+#define hybrid_tuner_release_state(state) do {                          \
+        state->i2c_props.count--;                                       \
+        if (!state->i2c_props.count) {                                  \
+                __tuner_info(state->i2c_props, "destroying instance\n");\
+                list_del(&state->hybrid_tuner_instance_list);           \
+                kfree(state);                                           \
+        }                                                               \
+} while (0)
+
 #endif /* __TUNER_I2C_H__ */