2 * Register map access API - MMIO support
4 * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
19 #include <linux/err.h>
20 #include <linux/init.h>
22 #include <linux/module.h>
23 #include <linux/regmap.h>
24 #include <linux/slab.h>
26 struct regmap_mmio_context {
31 static int regmap_mmio_gather_write(void *context,
32 const void *reg, size_t reg_size,
33 const void *val, size_t val_size)
35 struct regmap_mmio_context *ctx = context;
38 BUG_ON(reg_size != 4);
43 switch (ctx->val_bytes) {
45 writeb(*(u8 *)val, ctx->regs + offset);
48 writew(*(u16 *)val, ctx->regs + offset);
51 writel(*(u32 *)val, ctx->regs + offset);
55 writeq(*(u64 *)val, ctx->regs + offset);
59 /* Should be caught by regmap_mmio_check_config */
62 val_size -= ctx->val_bytes;
63 val += ctx->val_bytes;
64 offset += ctx->val_bytes;
70 static int regmap_mmio_write(void *context, const void *data, size_t count)
74 return regmap_mmio_gather_write(context, data, 4, data + 4, count - 4);
77 static int regmap_mmio_read(void *context,
78 const void *reg, size_t reg_size,
79 void *val, size_t val_size)
81 struct regmap_mmio_context *ctx = context;
84 BUG_ON(reg_size != 4);
89 switch (ctx->val_bytes) {
91 *(u8 *)val = readb(ctx->regs + offset);
94 *(u16 *)val = readw(ctx->regs + offset);
97 *(u32 *)val = readl(ctx->regs + offset);
101 *(u64 *)val = readq(ctx->regs + offset);
105 /* Should be caught by regmap_mmio_check_config */
108 val_size -= ctx->val_bytes;
109 val += ctx->val_bytes;
110 offset += ctx->val_bytes;
116 static void regmap_mmio_free_context(void *context)
121 static struct regmap_bus regmap_mmio = {
123 .write = regmap_mmio_write,
124 .gather_write = regmap_mmio_gather_write,
125 .read = regmap_mmio_read,
126 .free_context = regmap_mmio_free_context,
127 .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
128 .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
131 static struct regmap_mmio_context *regmap_mmio_gen_context(void __iomem *regs,
132 const struct regmap_config *config)
134 struct regmap_mmio_context *ctx;
137 if (config->reg_bits != 32)
138 return ERR_PTR(-EINVAL);
140 if (config->pad_bits)
141 return ERR_PTR(-EINVAL);
143 switch (config->val_bits) {
145 /* The core treats 0 as 1 */
161 return ERR_PTR(-EINVAL);
164 if (config->reg_stride < min_stride)
165 return ERR_PTR(-EINVAL);
167 switch (config->reg_format_endian) {
168 case REGMAP_ENDIAN_DEFAULT:
169 case REGMAP_ENDIAN_NATIVE:
172 return ERR_PTR(-EINVAL);
175 ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
177 return ERR_PTR(-ENOMEM);
180 ctx->val_bytes = config->val_bits / 8;
186 * regmap_init_mmio(): Initialise register map
188 * @dev: Device that will be interacted with
189 * @regs: Pointer to memory-mapped IO region
190 * @config: Configuration for register map
192 * The return value will be an ERR_PTR() on error or a valid pointer to
195 struct regmap *regmap_init_mmio(struct device *dev,
197 const struct regmap_config *config)
199 struct regmap_mmio_context *ctx;
201 ctx = regmap_mmio_gen_context(regs, config);
203 return ERR_CAST(ctx);
205 return regmap_init(dev, ®map_mmio, ctx, config);
207 EXPORT_SYMBOL_GPL(regmap_init_mmio);
210 * devm_regmap_init_mmio(): Initialise managed register map
212 * @dev: Device that will be interacted with
213 * @regs: Pointer to memory-mapped IO region
214 * @config: Configuration for register map
216 * The return value will be an ERR_PTR() on error or a valid pointer
217 * to a struct regmap. The regmap will be automatically freed by the
218 * device management code.
220 struct regmap *devm_regmap_init_mmio(struct device *dev,
222 const struct regmap_config *config)
224 struct regmap_mmio_context *ctx;
226 ctx = regmap_mmio_gen_context(regs, config);
228 return ERR_CAST(ctx);
230 return devm_regmap_init(dev, ®map_mmio, ctx, config);
232 EXPORT_SYMBOL_GPL(devm_regmap_init_mmio);
234 MODULE_LICENSE("GPL v2");