--- /dev/null
+/*
+ * w1_ds2805 - w1 family 0d (DS28E05) driver
+ *
+ * Copyright (c) 2016 Andrew Worsley amworsley@gmail.com
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
+ */
+
+#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/w1.h>
+
+#define W1_EEPROM_DS2805 0x0D
+
+#define W1_F0D_EEPROM_SIZE 128
+#define W1_F0D_PAGE_BITS 3
+#define W1_F0D_PAGE_SIZE (1<<W1_F0D_PAGE_BITS)
+#define W1_F0D_PAGE_MASK 0x0F
+
+#define W1_F0D_SCRATCH_BITS 1
+#define W1_F0D_SCRATCH_SIZE (1<<W1_F0D_SCRATCH_BITS)
+#define W1_F0D_SCRATCH_MASK (W1_F0D_SCRATCH_SIZE-1)
+
+#define W1_F0D_READ_EEPROM 0xF0
+#define W1_F0D_WRITE_EEPROM 0x55
+#define W1_F0D_RELEASE 0xFF
+
+#define W1_F0D_CS_OK 0xAA /* Chip Status Ok */
+
+#define W1_F0D_TPROG_MS 16
+
+#define W1_F0D_READ_RETRIES 10
+#define W1_F0D_READ_MAXLEN W1_F0D_EEPROM_SIZE
+
+/*
+ * Check the file size bounds and adjusts count as needed.
+ * This would not be needed if the file size didn't reset to 0 after a write.
+ */
+static inline size_t w1_f0d_fix_count(loff_t off, size_t count, size_t size)
+{
+ if (off > size)
+ return 0;
+
+ if ((off + count) > size)
+ return size - off;
+
+ return count;
+}
+
+/*
+ * Read a block from W1 ROM two times and compares the results.
+ * If they are equal they are returned, otherwise the read
+ * is repeated W1_F0D_READ_RETRIES times.
+ *
+ * count must not exceed W1_F0D_READ_MAXLEN.
+ */
+static int w1_f0d_readblock(struct w1_slave *sl, int off, int count, char *buf)
+{
+ u8 wrbuf[3];
+ u8 cmp[W1_F0D_READ_MAXLEN];
+ int tries = W1_F0D_READ_RETRIES;
+
+ do {
+ wrbuf[0] = W1_F0D_READ_EEPROM;
+ wrbuf[1] = off & 0x7f;
+ wrbuf[2] = 0;
+
+ if (w1_reset_select_slave(sl))
+ return -1;
+
+ w1_write_block(sl->master, wrbuf, sizeof(wrbuf));
+ w1_read_block(sl->master, buf, count);
+
+ if (w1_reset_select_slave(sl))
+ return -1;
+
+ w1_write_block(sl->master, wrbuf, sizeof(wrbuf));
+ w1_read_block(sl->master, cmp, count);
+
+ if (!memcmp(cmp, buf, count))
+ return 0;
+ } while (--tries);
+
+ dev_err(&sl->dev, "proof reading failed %d times\n",
+ W1_F0D_READ_RETRIES);
+
+ return -1;
+}
+
+static ssize_t w1_f0d_read_bin(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buf, loff_t off, size_t count)
+{
+ struct w1_slave *sl = kobj_to_w1_slave(kobj);
+ int todo = count;
+
+ count = w1_f0d_fix_count(off, count, W1_F0D_EEPROM_SIZE);
+ if (count == 0)
+ return 0;
+
+ mutex_lock(&sl->master->mutex);
+
+ /* read directly from the EEPROM in chunks of W1_F0D_READ_MAXLEN */
+ while (todo > 0) {
+ int block_read;
+
+ if (todo >= W1_F0D_READ_MAXLEN)
+ block_read = W1_F0D_READ_MAXLEN;
+ else
+ block_read = todo;
+
+ if (w1_f0d_readblock(sl, off, block_read, buf) < 0) {
+ count = -EIO;
+ break;
+ }
+
+ todo -= W1_F0D_READ_MAXLEN;
+ buf += W1_F0D_READ_MAXLEN;
+ off += W1_F0D_READ_MAXLEN;
+ }
+
+ mutex_unlock(&sl->master->mutex);
+
+ return count;
+}
+
+/*
+ * Writes to the scratchpad and reads it back for verification.
+ * Then copies the scratchpad to EEPROM.
+ * The data must be aligned at W1_F0D_SCRATCH_SIZE bytes and
+ * must be W1_F0D_SCRATCH_SIZE bytes long.
+ * The master must be locked.
+ *
+ * @param sl The slave structure
+ * @param addr Address for the write
+ * @param len length must be <= (W1_F0D_PAGE_SIZE - (addr & W1_F0D_PAGE_MASK))
+ * @param data The data to write
+ * @return 0=Success -1=failure
+ */
+static int w1_f0d_write(struct w1_slave *sl, int addr, int len, const u8 *data)
+{
+ int tries = W1_F0D_READ_RETRIES;
+ u8 wrbuf[3];
+ u8 rdbuf[W1_F0D_SCRATCH_SIZE];
+ u8 cs;
+
+ if ((addr & 1) || (len != 2)) {
+ dev_err(&sl->dev, "%s: bad addr/len - addr=%#x len=%d\n",
+ __func__, addr, len);
+ return -1;
+ }
+
+retry:
+
+ /* Write the data to the scratchpad */
+ if (w1_reset_select_slave(sl))
+ return -1;
+
+ wrbuf[0] = W1_F0D_WRITE_EEPROM;
+ wrbuf[1] = addr & 0xff;
+ wrbuf[2] = 0xff; /* ?? from Example */
+
+ w1_write_block(sl->master, wrbuf, sizeof(wrbuf));
+ w1_write_block(sl->master, data, len);
+
+ w1_read_block(sl->master, rdbuf, sizeof(rdbuf));
+ /* Compare what was read against the data written */
+ if ((rdbuf[0] != data[0]) || (rdbuf[1] != data[1])) {
+
+ if (--tries)
+ goto retry;
+
+ dev_err(&sl->dev,
+ "could not write to eeprom, scratchpad compare failed %d times\n",
+ W1_F0D_READ_RETRIES);
+ pr_info("%s: rdbuf = %#x %#x data = %#x %#x\n",
+ __func__, rdbuf[0], rdbuf[1], data[0], data[1]);
+
+ return -1;
+ }
+
+ /* Trigger write out to EEPROM */
+ w1_write_8(sl->master, W1_F0D_RELEASE);
+
+ /* Sleep for tprog ms to wait for the write to complete */
+ msleep(W1_F0D_TPROG_MS);
+
+ /* Check CS (Command Status) == 0xAA ? */
+ cs = w1_read_8(sl->master);
+ if (cs != W1_F0D_CS_OK) {
+ dev_err(&sl->dev, "save to eeprom failed = CS=%#x\n", cs);
+ return -1;
+ }
+
+ return 0;
+}
+
+static ssize_t w1_f0d_write_bin(struct file *filp, struct kobject *kobj,
+ struct bin_attribute *bin_attr,
+ char *buf, loff_t off, size_t count)
+{
+ struct w1_slave *sl = kobj_to_w1_slave(kobj);
+ int addr, len;
+ int copy;
+
+ count = w1_f0d_fix_count(off, count, W1_F0D_EEPROM_SIZE);
+ if (count == 0)
+ return 0;
+
+ mutex_lock(&sl->master->mutex);
+
+ /* Can only write data in blocks of the size of the scratchpad */
+ addr = off;
+ len = count;
+ while (len > 0) {
+
+ /* if len too short or addr not aligned */
+ if (len < W1_F0D_SCRATCH_SIZE || addr & W1_F0D_SCRATCH_MASK) {
+ char tmp[W1_F0D_SCRATCH_SIZE];
+
+ /* read the block and update the parts to be written */
+ if (w1_f0d_readblock(sl, addr & ~W1_F0D_SCRATCH_MASK,
+ W1_F0D_SCRATCH_SIZE, tmp)) {
+ count = -EIO;
+ goto out_up;
+ }
+
+ /* copy at most to the boundary of the PAGE or len */
+ copy = W1_F0D_SCRATCH_SIZE -
+ (addr & W1_F0D_SCRATCH_MASK);
+
+ if (copy > len)
+ copy = len;
+
+ memcpy(&tmp[addr & W1_F0D_SCRATCH_MASK], buf, copy);
+ if (w1_f0d_write(sl, addr & ~W1_F0D_SCRATCH_MASK,
+ W1_F0D_SCRATCH_SIZE, tmp) < 0) {
+ count = -EIO;
+ goto out_up;
+ }
+ } else {
+
+ copy = W1_F0D_SCRATCH_SIZE;
+ if (w1_f0d_write(sl, addr, copy, buf) < 0) {
+ count = -EIO;
+ goto out_up;
+ }
+ }
+ buf += copy;
+ addr += copy;
+ len -= copy;
+ }
+
+out_up:
+ mutex_unlock(&sl->master->mutex);
+
+ return count;
+}
+
+static struct bin_attribute w1_f0d_bin_attr = {
+ .attr = {
+ .name = "eeprom",
+ .mode = S_IRUGO | S_IWUSR,
+ },
+ .size = W1_F0D_EEPROM_SIZE,
+ .read = w1_f0d_read_bin,
+ .write = w1_f0d_write_bin,
+};
+
+static int w1_f0d_add_slave(struct w1_slave *sl)
+{
+ return sysfs_create_bin_file(&sl->dev.kobj, &w1_f0d_bin_attr);
+}
+
+static void w1_f0d_remove_slave(struct w1_slave *sl)
+{
+ sysfs_remove_bin_file(&sl->dev.kobj, &w1_f0d_bin_attr);
+}
+
+static struct w1_family_ops w1_f0d_fops = {
+ .add_slave = w1_f0d_add_slave,
+ .remove_slave = w1_f0d_remove_slave,
+};
+
+static struct w1_family w1_family_2d = {
+ .fid = W1_EEPROM_DS2805,
+ .fops = &w1_f0d_fops,
+};
+
+static int __init w1_f0d_init(void)
+{
+ pr_info("%s()\n", __func__);
+ return w1_register_family(&w1_family_2d);
+}
+
+static void __exit w1_f0d_fini(void)
+{
+ pr_info("%s()\n", __func__);
+ w1_unregister_family(&w1_family_2d);
+}
+
+module_init(w1_f0d_init);
+module_exit(w1_f0d_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Andrew Worsley amworsley@gmail.com");
+MODULE_DESCRIPTION("w1 family 0d driver for DS2805, 1kb EEPROM");
projects / GitHub / LineageOS / android_kernel_motorola_exynos9610.git / commitdiff