^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * max6875.c - driver for MAX6874/MAX6875
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * Based on eeprom.c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) * The MAX6875 has a bank of registers and two banks of EEPROM.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) * Address ranges are defined as follows:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) * * 0x0000 - 0x0046 = configuration registers
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) * * 0x8000 - 0x8046 = configuration EEPROM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) * * 0x8100 - 0x82FF = user EEPROM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) * This driver makes the user EEPROM available for read.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) * The registers & config EEPROM should be accessed via i2c-dev.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) * The MAX6875 ignores the lowest address bit, so each chip responds to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) * two addresses - 0x50/0x51 and 0x52/0x53.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) * Note that the MAX6875 uses i2c_smbus_write_byte_data() to set the read
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) * address, so this driver is destructive if loaded for the wrong EEPROM chip.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) #include <linux/i2c.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) #include <linux/mutex.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) /* The MAX6875 can only read/write 16 bytes at a time */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) #define SLICE_SIZE 16
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) #define SLICE_BITS 4
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) /* USER EEPROM is at addresses 0x8100 - 0x82FF */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) #define USER_EEPROM_BASE 0x8100
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) #define USER_EEPROM_SIZE 0x0200
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) #define USER_EEPROM_SLICES 32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) /* MAX6875 commands */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) #define MAX6875_CMD_BLK_READ 0x84
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) /* Each client has this additional data */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) struct max6875_data {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) struct i2c_client *fake_client;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) struct mutex update_lock;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) u32 valid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) u8 data[USER_EEPROM_SIZE];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) unsigned long last_updated[USER_EEPROM_SLICES];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) static void max6875_update_slice(struct i2c_client *client, int slice)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) struct max6875_data *data = i2c_get_clientdata(client);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) int i, j, addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) u8 *buf;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) if (slice >= USER_EEPROM_SLICES)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) mutex_lock(&data->update_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) buf = &data->data[slice << SLICE_BITS];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) if (!(data->valid & (1 << slice)) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) time_after(jiffies, data->last_updated[slice])) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) dev_dbg(&client->dev, "Starting update of slice %u\n", slice);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) data->valid &= ~(1 << slice);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) addr = USER_EEPROM_BASE + (slice << SLICE_BITS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) /* select the eeprom address */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) if (i2c_smbus_write_byte_data(client, addr >> 8, addr & 0xFF)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) dev_err(&client->dev, "address set failed\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) goto exit_up;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) if (i2c_check_functionality(client->adapter,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) if (i2c_smbus_read_i2c_block_data(client,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) MAX6875_CMD_BLK_READ,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) SLICE_SIZE,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) buf) != SLICE_SIZE) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) goto exit_up;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) for (i = 0; i < SLICE_SIZE; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) j = i2c_smbus_read_byte(client);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) if (j < 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) goto exit_up;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) buf[i] = j;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) data->last_updated[slice] = jiffies;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) data->valid |= (1 << slice);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) exit_up:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) mutex_unlock(&data->update_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) static ssize_t max6875_read(struct file *filp, struct kobject *kobj,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) struct bin_attribute *bin_attr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) char *buf, loff_t off, size_t count)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) struct i2c_client *client = kobj_to_i2c_client(kobj);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) struct max6875_data *data = i2c_get_clientdata(client);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) int slice, max_slice;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) /* refresh slices which contain requested bytes */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) max_slice = (off + count - 1) >> SLICE_BITS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) for (slice = (off >> SLICE_BITS); slice <= max_slice; slice++)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) max6875_update_slice(client, slice);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) memcpy(buf, &data->data[off], count);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) return count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) static const struct bin_attribute user_eeprom_attr = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) .attr = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) .name = "eeprom",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) .mode = S_IRUGO,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) .size = USER_EEPROM_SIZE,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) .read = max6875_read,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) static int max6875_probe(struct i2c_client *client,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) const struct i2c_device_id *id)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) struct i2c_adapter *adapter = client->adapter;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) struct max6875_data *data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE_DATA
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) | I2C_FUNC_SMBUS_READ_BYTE))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) return -ENODEV;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) /* Only bind to even addresses */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) if (client->addr & 1)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) return -ENODEV;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) data = kzalloc(sizeof(struct max6875_data), GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) if (!data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) /* A fake client is created on the odd address */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) data->fake_client = i2c_new_dummy_device(client->adapter, client->addr + 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) if (IS_ERR(data->fake_client)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) err = PTR_ERR(data->fake_client);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) goto exit_kfree;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) /* Init real i2c_client */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) i2c_set_clientdata(client, data);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) mutex_init(&data->update_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) err = sysfs_create_bin_file(&client->dev.kobj, &user_eeprom_attr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) goto exit_remove_fake;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) exit_remove_fake:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) i2c_unregister_device(data->fake_client);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) exit_kfree:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) kfree(data);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) static int max6875_remove(struct i2c_client *client)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) struct max6875_data *data = i2c_get_clientdata(client);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) i2c_unregister_device(data->fake_client);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) sysfs_remove_bin_file(&client->dev.kobj, &user_eeprom_attr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) kfree(data);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) static const struct i2c_device_id max6875_id[] = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) { "max6875", 0 },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) { }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) MODULE_DEVICE_TABLE(i2c, max6875_id);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) static struct i2c_driver max6875_driver = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) .driver = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) .name = "max6875",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) .probe = max6875_probe,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) .remove = max6875_remove,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) .id_table = max6875_id,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) module_i2c_driver(max6875_driver);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) MODULE_DESCRIPTION("MAX6875 driver");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) MODULE_LICENSE("GPL");
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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