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Subject[PATCH 2/2] w1: add DS2501, DS2502, DS2505 EPROM device driver
Date
Add a 1-Wire slave driver to support DS250x EPROM deivces. This
slave driver attaches the devices to the NVMEM subsystem for
an easy in-kernel usage.

Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/w1/slaves/Kconfig | 6 +
drivers/w1/slaves/Makefile | 1 +
drivers/w1/slaves/w1_ds250x.c | 293 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 300 insertions(+)
create mode 100644 drivers/w1/slaves/w1_ds250x.c

diff --git a/drivers/w1/slaves/Kconfig b/drivers/w1/slaves/Kconfig
index 37aaad26b373..ebed495b9e69 100644
--- a/drivers/w1/slaves/Kconfig
+++ b/drivers/w1/slaves/Kconfig
@@ -101,6 +101,12 @@ config W1_SLAVE_DS2438
Say Y here if you want to use a 1-wire
DS2438 Smart Battery Monitor device support

+config W1_SLAVE_DS250X
+ tristate "512b/1kb/16kb EPROM family support"
+ help
+ Say Y here if you want to use a 1-wire
+ 512b/1kb/16kb EPROM family device (DS250x).
+
config W1_SLAVE_DS2780
tristate "Dallas 2780 battery monitor chip"
help
diff --git a/drivers/w1/slaves/Makefile b/drivers/w1/slaves/Makefile
index eab29f151413..8e9655eaa478 100644
--- a/drivers/w1/slaves/Makefile
+++ b/drivers/w1/slaves/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_W1_SLAVE_DS2431) += w1_ds2431.o
obj-$(CONFIG_W1_SLAVE_DS2805) += w1_ds2805.o
obj-$(CONFIG_W1_SLAVE_DS2433) += w1_ds2433.o
obj-$(CONFIG_W1_SLAVE_DS2438) += w1_ds2438.o
+obj-$(CONFIG_W1_SLAVE_DS250X) += w1_ds250x.o
obj-$(CONFIG_W1_SLAVE_DS2780) += w1_ds2780.o
obj-$(CONFIG_W1_SLAVE_DS2781) += w1_ds2781.o
obj-$(CONFIG_W1_SLAVE_DS28E04) += w1_ds28e04.o
diff --git a/drivers/w1/slaves/w1_ds250x.c b/drivers/w1/slaves/w1_ds250x.c
new file mode 100644
index 000000000000..78da3774bbbe
--- /dev/null
+++ b/drivers/w1/slaves/w1_ds250x.c
@@ -0,0 +1,293 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * w1_ds250x.c - w1 family 09/0b/89/91 (DS250x) driver
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/crc16.h>
+
+#include <linux/w1.h>
+#include <linux/nvmem-provider.h>
+
+#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);
+ if (IS_ERR(nvmem))
+ return PTR_ERR(nvmem);
+
+ return 0;
+}
+
+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 <tbogendoerfe@suse.de>");
+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));
--
2.13.7
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