// SPDX-License-Identifier: GPL-2.0 /* * w1_ds250x.c - w1 family 09/0b/89/91 (DS250x) driver */ #include #include #include #include #include #include #include #include #include #include #define W1_DS2501_UNW_FAMILY 0x91 #define W1_DS2501_SIZE 64 #define W1_DS2502_FAMILY 0x09 #define W1_DS2502_UNW_FAMILY 0x89 #define W1_DS2502_SIZE 128 #define W1_DS2505_FAMILY 0x0b #define W1_DS2505_SIZE 2048 #define W1_PAGE_SIZE 32 #define W1_EXT_READ_MEMORY 0xA5 #define W1_READ_DATA_CRC 0xC3 #define OFF2PG(off) ((off) / W1_PAGE_SIZE) #define CRC16_INIT 0 #define CRC16_VALID 0xb001 struct w1_eprom_data { size_t size; int (*read)(struct w1_slave *sl, int pageno); u8 eprom[W1_DS2505_SIZE]; DECLARE_BITMAP(page_present, W1_DS2505_SIZE / W1_PAGE_SIZE); char nvmem_name[64]; }; static int w1_ds2502_read_page(struct w1_slave *sl, int pageno) { struct w1_eprom_data *data = sl->family_data; int pgoff = pageno * W1_PAGE_SIZE; int ret = -EIO; u8 buf[3]; u8 crc8; if (test_bit(pageno, data->page_present)) return 0; /* page already present */ mutex_lock(&sl->master->bus_mutex); if (w1_reset_select_slave(sl)) goto err; buf[0] = W1_READ_DATA_CRC; buf[1] = pgoff & 0xff; buf[2] = pgoff >> 8; w1_write_block(sl->master, buf, 3); crc8 = w1_read_8(sl->master); if (w1_calc_crc8(buf, 3) != crc8) goto err; w1_read_block(sl->master, &data->eprom[pgoff], W1_PAGE_SIZE); crc8 = w1_read_8(sl->master); if (w1_calc_crc8(&data->eprom[pgoff], W1_PAGE_SIZE) != crc8) goto err; set_bit(pageno, data->page_present); /* mark page present */ ret = 0; err: mutex_unlock(&sl->master->bus_mutex); return ret; } static int w1_ds2505_read_page(struct w1_slave *sl, int pageno) { struct w1_eprom_data *data = sl->family_data; int redir_retries = 16; int pgoff, epoff; int ret = -EIO; u8 buf[6]; u8 redir; u16 crc; if (test_bit(pageno, data->page_present)) return 0; /* page already present */ epoff = pgoff = pageno * W1_PAGE_SIZE; mutex_lock(&sl->master->bus_mutex); retry: if (w1_reset_select_slave(sl)) goto err; buf[0] = W1_EXT_READ_MEMORY; buf[1] = pgoff & 0xff; buf[2] = pgoff >> 8; w1_write_block(sl->master, buf, 3); w1_read_block(sl->master, buf + 3, 3); /* redir, crc16 */ redir = buf[3]; crc = crc16(CRC16_INIT, buf, 6); if (crc != CRC16_VALID) goto err; if (redir != 0xff) { redir_retries--; if (redir_retries < 0) goto err; pgoff = (redir ^ 0xff) * W1_PAGE_SIZE; goto retry; } w1_read_block(sl->master, &data->eprom[epoff], W1_PAGE_SIZE); w1_read_block(sl->master, buf, 2); /* crc16 */ crc = crc16(CRC16_INIT, &data->eprom[epoff], W1_PAGE_SIZE); crc = crc16(crc, buf, 2); if (crc != CRC16_VALID) goto err; set_bit(pageno, data->page_present); ret = 0; err: mutex_unlock(&sl->master->bus_mutex); return ret; } static int w1_nvmem_read(void *priv, unsigned int off, void *buf, size_t count) { struct w1_slave *sl = priv; struct w1_eprom_data *data = sl->family_data; size_t eprom_size = data->size; int ret; int i; if (off > eprom_size) return -EINVAL; if ((off + count) > eprom_size) count = eprom_size - off; i = OFF2PG(off); do { ret = data->read(sl, i++); if (ret < 0) return ret; } while (i < OFF2PG(off + count)); memcpy(buf, &data->eprom[off], count); return 0; } static int w1_eprom_add_slave(struct w1_slave *sl) { struct w1_eprom_data *data; struct nvmem_device *nvmem; struct nvmem_config nvmem_cfg = { .dev = &sl->dev, .reg_read = w1_nvmem_read, .type = NVMEM_TYPE_OTP, .read_only = true, .word_size = 1, .priv = sl, .id = -1 }; data = devm_kzalloc(&sl->dev, sizeof(struct w1_eprom_data), GFP_KERNEL); if (!data) return -ENOMEM; sl->family_data = data; switch (sl->family->fid) { case W1_DS2501_UNW_FAMILY: data->size = W1_DS2501_SIZE; data->read = w1_ds2502_read_page; break; case W1_DS2502_FAMILY: case W1_DS2502_UNW_FAMILY: data->size = W1_DS2502_SIZE; data->read = w1_ds2502_read_page; break; case W1_DS2505_FAMILY: data->size = W1_DS2505_SIZE; data->read = w1_ds2505_read_page; break; } if (sl->master->bus_master->dev_id) snprintf(data->nvmem_name, sizeof(data->nvmem_name), "%s-%02x-%012llx", sl->master->bus_master->dev_id, sl->reg_num.family, (unsigned long long)sl->reg_num.id); else snprintf(data->nvmem_name, sizeof(data->nvmem_name), "%02x-%012llx", sl->reg_num.family, (unsigned long long)sl->reg_num.id); nvmem_cfg.name = data->nvmem_name; nvmem_cfg.size = data->size; nvmem = devm_nvmem_register(&sl->dev, &nvmem_cfg); return PTR_ERR_OR_ZERO(nvmem); } static struct w1_family_ops w1_eprom_fops = { .add_slave = w1_eprom_add_slave, }; static struct w1_family w1_family_09 = { .fid = W1_DS2502_FAMILY, .fops = &w1_eprom_fops, }; static struct w1_family w1_family_0b = { .fid = W1_DS2505_FAMILY, .fops = &w1_eprom_fops, }; static struct w1_family w1_family_89 = { .fid = W1_DS2502_UNW_FAMILY, .fops = &w1_eprom_fops, }; static struct w1_family w1_family_91 = { .fid = W1_DS2501_UNW_FAMILY, .fops = &w1_eprom_fops, }; static int __init w1_ds250x_init(void) { int err; err = w1_register_family(&w1_family_09); if (err) return err; err = w1_register_family(&w1_family_0b); if (err) goto err_0b; err = w1_register_family(&w1_family_89); if (err) goto err_89; err = w1_register_family(&w1_family_91); if (err) goto err_91; return 0; err_91: w1_unregister_family(&w1_family_89); err_89: w1_unregister_family(&w1_family_0b); err_0b: w1_unregister_family(&w1_family_09); return err; } static void __exit w1_ds250x_exit(void) { w1_unregister_family(&w1_family_09); w1_unregister_family(&w1_family_0b); w1_unregister_family(&w1_family_89); w1_unregister_family(&w1_family_91); } module_init(w1_ds250x_init); module_exit(w1_ds250x_exit); MODULE_AUTHOR("Thomas Bogendoerfer "); MODULE_DESCRIPTION("w1 family driver for DS250x Add Only Memory"); MODULE_LICENSE("GPL"); MODULE_ALIAS("w1-family-" __stringify(W1_DS2502_FAMILY)); MODULE_ALIAS("w1-family-" __stringify(W1_DS2505_FAMILY)); MODULE_ALIAS("w1-family-" __stringify(W1_DS2501_UNW_FAMILY)); MODULE_ALIAS("w1-family-" __stringify(W1_DS2502_UNW_FAMILY));