regmap: add configurable downshift for addresses

Add an additional reg_downshift to be applied to register addresses before
any register accesses. An example of a device that uses this is a VSC7514
chip, which require each register address to be downshifted by two if the
access is performed over a SPI bus.

Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
Link: https://lore.kernel.org/r/20220313224524.399947-2-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 b190591..88f710e 100644 (file)
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -31,6 +31,7 @@ struct regmap_format {
        size_t buf_size;
        size_t reg_bytes;
        size_t pad_bytes;
+       size_t reg_downshift;
        size_t val_bytes;
        void (*format_write)(struct regmap *map,
                             unsigned int reg, unsigned int val);

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 8f9fe5f..1c7c6d6 100644 (file)
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -823,6 +823,7 @@ struct regmap *__regmap_init(struct device *dev,
 
        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;
        map->format.val_bytes = DIV_ROUND_UP(config->val_bits, 8);
        map->format.buf_size = DIV_ROUND_UP(config->reg_bits +
                        config->val_bits + config->pad_bits, 8);
@@ -1735,6 +1736,7 @@ static int _regmap_raw_write_impl(struct regmap *map, unsigned int reg,
                        return ret;
        }
 
+       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,
                                      map->write_flag_mask);
@@ -1905,6 +1907,7 @@ static int _regmap_bus_formatted_write(void *context, unsigned int reg,
                        return ret;
        }
 
+       reg >>= map->format.reg_downshift;
        map->format.format_write(map, reg, val);
 
        trace_regmap_hw_write_start(map, reg, 1);
@@ -2346,6 +2349,7 @@ 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->format.reg_downshift;
                map->format.format_reg(u8, reg, map->reg_shift);
                u8 += reg_bytes + pad_bytes;
                map->format.format_val(u8, val, 0);
@@ -2673,6 +2677,7 @@ static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
                        return ret;
        }
 
+       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,
                                      map->read_flag_mask);

diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 22652e5..40fb939 100644 (file)
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -237,6 +237,8 @@ typedef void (*regmap_unlock)(void *);
  * @reg_stride: The register address stride. Valid register addresses are a
  *              multiple of this value. If set to 0, a value of 1 will be
  *              used.
+ * @reg_downshift: The number of bits to downshift the register before
+ *                performing any operations.
  * @pad_bits: Number of bits of padding between register and value.
  * @val_bits: Number of bits in a register value, mandatory.
  *
@@ -360,6 +362,7 @@ struct regmap_config {
 
        int reg_bits;
        int reg_stride;
+       int reg_downshift;
        int pad_bits;
        int val_bits;