regmap: Add support for register indirect addressing.

Devices with register paging or indirectly accessed registers can configure
register mapping to map those on virtual address range. During access to
virtually mapped register range, indirect addressing is processed
automatically, in following steps:
  1. selector for page or indirect register is updated (when needed);
  2. register in data window is accessed.

Configuration should provide minimum and maximum register for virtual range,
details of selector field for page selection, minimum and maximum register of
data window for indirect access.

Virtual range registers are managed by cache as well as direct access
registers. In order to make indirect access more efficient, selector register
should be declared as non-volatile, if possible.

struct regmap_config is extended with the following:
struct regmap_range_cfg	*ranges;
unsigned int		n_ranges;

[Also reordered debugfs init to later on since the cleanup code was
conflicting with the new cleanup code for ranges anyway -- broonie]

Signed-off-by: Krystian Garbaciak <krystian.garbaciak@diasemi.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 39 insertions, 0 deletions

diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 56af22ec9aba..5f69d4ad3eb1 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -14,12 +14,14 @@
  */
 
 #include <linux/list.h>
+#include <linux/rbtree.h>
 
 struct module;
 struct device;
 struct i2c_client;
 struct spi_device;
 struct regmap;
+struct regmap_range_cfg;
 
 /* An enum of all the supported cache types */
 enum regcache_type {
@@ -84,6 +86,9 @@ struct reg_default {
  * @reg_defaults_raw: Power on reset values for registers (for use with
  *                    register cache support).
  * @num_reg_defaults_raw: Number of elements in reg_defaults_raw.
+ *
+ * @ranges: Array of configuration entries for virtual address ranges.
+ * @num_ranges: Number of range configuration entries.
  */
 struct regmap_config {
         const char *name;
@@ -109,6 +114,40 @@ struct regmap_config {
         u8 write_flag_mask;
 
         bool use_single_rw;
+
+        const struct regmap_range_cfg *ranges;
+        unsigned int n_ranges;
+};
+
+/**
+ * Configuration for indirectly accessed or paged registers.
+ * Registers, mapped to this virtual range, are accessed in two steps:
+ *     1. page selector register update;
+ *     2. access through data window registers.
+ *
+ * @range_min: Address of the lowest register address in virtual range.
+ * @range_max: Address of the highest register in virtual range.
+ *
+ * @page_sel_reg: Register with selector field.
+ * @page_sel_mask: Bit shift for selector value.
+ * @page_sel_shift: Bit mask for selector value.
+ *
+ * @window_start: Address of first (lowest) register in data window.
+ * @window_len: Number of registers in data window.
+ */
+struct regmap_range_cfg {
+        /* Registers of virtual address range */
+        unsigned int range_min;
+        unsigned int range_max;
+
+        /* Page selector for indirect addressing */
+        unsigned int selector_reg;
+        unsigned int selector_mask;
+        int selector_shift;
+
+        /* Data window (per each page) */
+        unsigned int window_start;
+        unsigned int window_len;
 };
 
 typedef int (*regmap_hw_write)(void *context, const void *data,