[PATCH 1/2] regmap: Allow a base register to be specified for the RAM regmap

To allow testing of register maps with very large register values add
support for specifying base address to the RAM regmap.

Signed-off-by: Mark Brown <[email protected]>
---
 drivers/base/regmap/internal.h   |  1 +
 drivers/base/regmap/regmap-ram.c | 26 ++++++++++++++++++++------
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 55273a6178f8..8176d91aacd1 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -322,6 +322,7 @@ static inline unsigned int regcache_get_index_by_order(const struct regmap *map,
 }
 
 struct regmap_ram_data {
+	unsigned int base_reg;
 	unsigned int *vals;  /* Allocatd by caller */
 	bool *read;
 	bool *written;
diff --git a/drivers/base/regmap/regmap-ram.c b/drivers/base/regmap/regmap-ram.c
index c7356b0d8c83..a666bfb4d667 100644
--- a/drivers/base/regmap/regmap-ram.c
+++ b/drivers/base/regmap/regmap-ram.c
@@ -20,8 +20,11 @@ static int regmap_ram_write(void *context, unsigned int reg, unsigned int val)
 {
 	struct regmap_ram_data *data = context;
 
-	data->vals[reg] = val;
-	data->written[reg] = true;
+	if (reg < data->base_reg)
+		return -EINVAL;
+
+	data->vals[reg - data->base_reg] = val;
+	data->written[reg - data->base_reg] = true;
 
 	return 0;
 }
@@ -30,8 +33,11 @@ static int regmap_ram_read(void *context, unsigned int reg, unsigned int *val)
 {
 	struct regmap_ram_data *data = context;
 
-	*val = data->vals[reg];
-	data->read[reg] = true;
+	if (reg < data->base_reg)
+		return -EINVAL;
+
+	*val = data->vals[reg - data->base_reg];
+	data->read[reg - data->base_reg] = true;
 
 	return 0;
 }
@@ -60,17 +66,25 @@ struct regmap *__regmap_init_ram(struct device *dev,
 				 const char *lock_name)
 {
 	struct regmap *map;
+	unsigned int num_regs;
 
 	if (!config->max_register) {
 		pr_crit("No max_register specified for RAM regmap\n");
 		return ERR_PTR(-EINVAL);
 	}
 
-	data->read = kzalloc_objs(bool, config->max_register + 1);
+	if (data->base_reg > config->max_register) {
+		pr_crit("base_reg above max_register for RAM regmap\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	num_regs = config->max_register - data->base_reg + 1;
+
+	data->read = kzalloc_objs(bool, num_regs);
 	if (!data->read)
 		return ERR_PTR(-ENOMEM);
 
-	data->written = kzalloc_objs(bool, config->max_register + 1);
+	data->written = kzalloc_objs(bool, num_regs);
 	if (!data->written) {
 		kfree(data->read);
 		return ERR_PTR(-ENOMEM);

-- 
2.47.3