regmap: allow a defined reg_base to be added to every address

There's an inconsistency that arises when a register set can be accessed
internally via MMIO, or externally via SPI. The VSC7514 chip allows both
modes of operation. When internally accessed, the system utilizes __iomem,
devm_ioremap_resource, and devm_regmap_init_mmio.

For SPI it isn't possible to utilize memory-mapped IO. To properly operate,
the resource base must be added to the register before every operation.

Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
Link: https://lore.kernel.org/r/20220313224524.399947-3-colin.foster@in-advantage.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 88f710e..b4df36c 100644 (file)
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -63,6 +63,7 @@ struct regmap {
        regmap_unlock unlock;
        void *lock_arg; /* This is passed to lock/unlock functions */
        gfp_t alloc_flags;
+       unsigned int reg_base;
 
        struct device *dev; /* Device we do I/O on */
        void *work_buf;     /* Scratch buffer used to format I/O */

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 1c7c6d6..5e12f7c 100644 (file)
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -821,6 +821,8 @@ struct regmap *__regmap_init(struct device *dev,
        else
                map->alloc_flags = GFP_KERNEL;
 
+       map->reg_base = config->reg_base;
+
        map->format.reg_bytes = DIV_ROUND_UP(config->reg_bits, 8);
        map->format.pad_bytes = config->pad_bits / 8;
        map->format.reg_downshift = config->reg_downshift;
@@ -1736,6 +1738,7 @@ static int _regmap_raw_write_impl(struct regmap *map, unsigned int reg,
                        return ret;
        }
 
+       reg += map->reg_base;
        reg >>= map->format.reg_downshift;
        map->format.format_reg(map->work_buf, reg, map->reg_shift);
        regmap_set_work_buf_flag_mask(map, map->format.reg_bytes,
@@ -1907,6 +1910,7 @@ static int _regmap_bus_formatted_write(void *context, unsigned int reg,
                        return ret;
        }
 
+       reg += map->reg_base;
        reg >>= map->format.reg_downshift;
        map->format.format_write(map, reg, val);
 
@@ -2349,6 +2353,7 @@ static int _regmap_raw_multi_reg_write(struct regmap *map,
                unsigned int reg = regs[i].reg;
                unsigned int val = regs[i].def;
                trace_regmap_hw_write_start(map, reg, 1);
+               reg += map->reg_base;
                reg >>= map->format.reg_downshift;
                map->format.format_reg(u8, reg, map->reg_shift);
                u8 += reg_bytes + pad_bytes;
@@ -2677,6 +2682,7 @@ static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
                        return ret;
        }
 
+       reg += map->reg_base;
        reg >>= map->format.reg_downshift;
        map->format.format_reg(map->work_buf, reg, map->reg_shift);
        regmap_set_work_buf_flag_mask(map, map->format.reg_bytes,

diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 40fb939..de81a94 100644 (file)
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -239,6 +239,8 @@ typedef void (*regmap_unlock)(void *);
  *              used.
  * @reg_downshift: The number of bits to downshift the register before
  *                performing any operations.
+ * @reg_base: Value to be added to every register address before performing any
+ *           operation.
  * @pad_bits: Number of bits of padding between register and value.
  * @val_bits: Number of bits in a register value, mandatory.
  *
@@ -363,6 +365,7 @@ struct regmap_config {
        int reg_bits;
        int reg_stride;
        int reg_downshift;
+       unsigned int reg_base;
        int pad_bits;
        int val_bits;