Hi Bartosz, > On Sep 17, 2015, at 17:42 , Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx> wrote: > > 2015-09-16 18:11 GMT+02:00 Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>: >> For DT and in-kernel users there is no interface to the >> at24 EEPROMs so provide an NVMEM framework interface. >> >> This allows us to use AT24 based EEPROMs and reference them >> from within the DT tree. >> >> Signed-off-by: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx> >> --- >> drivers/misc/eeprom/at24.c | 219 +++++++++++++++++++++++++++++++++++---------- >> 1 file changed, 174 insertions(+), 45 deletions(-) >> >> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c >> index c6cb7f8..195a45e 100644 >> --- a/drivers/misc/eeprom/at24.c >> +++ b/drivers/misc/eeprom/at24.c >> @@ -3,6 +3,7 @@ >> * >> * Copyright (C) 2005-2007 David Brownell >> * Copyright (C) 2008 Wolfram Sang, Pengutronix >> + * Copyright (C) 2015 Pantelis Antoniou, Konsulko Group >> * >> * This program is free software; you can redistribute it and/or modify >> * it under the terms of the GNU General Public License as published by >> @@ -23,6 +24,9 @@ >> #include <linux/of.h> >> #include <linux/i2c.h> >> #include <linux/platform_data/at24.h> >> +#include <linux/regmap.h> >> +#include <linux/nvmem-provider.h> >> +#include <linux/io.h> >> >> /* >> * I2C EEPROMs from most vendors are inexpensive and mostly interchangeable. >> @@ -63,12 +67,16 @@ struct at24_data { >> * but not from changes by other I2C masters. >> */ >> struct mutex lock; >> - struct bin_attribute bin; >> >> u8 *writebuf; >> unsigned write_max; >> unsigned num_addresses; >> >> + struct regmap_config *regmap_config; >> + struct regmap *regmap; >> + struct nvmem_config *nvmem_config; >> + struct nvmem_device *nvmem_dev; >> + >> /* >> * Some chips tie up multiple I2C addresses; dummy devices reserve >> * them for us, and we'll use them with SMBus calls. >> @@ -131,6 +139,8 @@ static const struct i2c_device_id at24_ids[] = { >> }; >> MODULE_DEVICE_TABLE(i2c, at24_ids); >> >> +static DEFINE_IDA(at24_ida); >> + >> /*-------------------------------------------------------------------------*/ >> >> /* >> @@ -276,17 +286,6 @@ static ssize_t at24_read(struct at24_data *at24, >> return retval; >> } >> >> -static ssize_t at24_bin_read(struct file *filp, struct kobject *kobj, >> - struct bin_attribute *attr, >> - char *buf, loff_t off, size_t count) >> -{ >> - struct at24_data *at24; >> - >> - at24 = dev_get_drvdata(container_of(kobj, struct device, kobj)); >> - return at24_read(at24, buf, off, count); >> -} >> - >> - >> /* >> * Note that if the hardware write-protect pin is pulled high, the whole >> * chip is normally write protected. But there are plenty of product >> @@ -407,18 +406,10 @@ static ssize_t at24_write(struct at24_data *at24, const char *buf, loff_t off, >> return retval; >> } >> >> -static ssize_t at24_bin_write(struct file *filp, struct kobject *kobj, >> - struct bin_attribute *attr, >> - char *buf, loff_t off, size_t count) >> -{ >> - struct at24_data *at24; >> - >> - at24 = dev_get_drvdata(container_of(kobj, struct device, kobj)); >> - return at24_write(at24, buf, off, count); >> -} >> - >> /*-------------------------------------------------------------------------*/ >> >> +/* panto: using the EEPROM framework macc is superfluous */ >> + >> /* >> * This lets other kernel code access the eeprom data. For example, it >> * might hold a board's Ethernet address, or board-specific calibration >> @@ -464,6 +455,91 @@ static void at24_get_ofdata(struct i2c_client *client, >> { } >> #endif /* CONFIG_OF */ >> >> +static int regmap_at24_read(void *context, >> + const void *reg, size_t reg_size, >> + void *val, size_t val_size) >> +{ >> + struct i2c_client *client = context; >> + struct at24_data *at24; >> + unsigned int offset; >> + int ret; >> + >> + /* reg bits is hardcoded to 32 bits */ >> + BUG_ON(reg_size != 4); >> + offset = __raw_readl(reg); >> + >> + at24 = i2c_get_clientdata(client); >> + if (at24 == NULL) >> + return -ENODEV; >> + >> + /* val bytes is always 1 */ >> + BUG_ON(at24->regmap_config->val_bits != 8); >> + >> + ret = at24_read(at24, val, offset, val_size); >> + if (ret < 0) >> + return ret; >> + if (ret != val_size) >> + return -EINVAL; >> + >> + return 0; >> +} >> + >> +static int regmap_at24_gather_write(void *context, >> + const void *reg, size_t reg_size, >> + const void *val, size_t val_size) >> +{ >> + struct i2c_client *client = context; >> + struct at24_data *at24; >> + unsigned int offset; >> + int ret; >> + >> + at24 = i2c_get_clientdata(client); >> + if (at24 == NULL) >> + return -ENODEV; >> + >> + BUG_ON(reg_size != 4); >> + offset = __raw_readl(reg); >> + >> + /* val bytes is always 1 */ >> + BUG_ON(at24->regmap_config->val_bits != 8); >> + >> + ret = at24_write(at24, val, offset, val_size); >> + if (ret < 0) >> + return ret; >> + if (ret != val_size) >> + return -EINVAL; >> + >> + return 0; >> +} >> + >> +static int regmap_at24_write(void *context, const void *data, size_t count) >> +{ >> + struct i2c_client *client = context; >> + struct at24_data *at24; >> + unsigned int reg_bytes, offset; >> + >> + at24 = i2c_get_clientdata(client); >> + if (at24 == NULL) >> + return -ENODEV; >> + >> + reg_bytes = at24->regmap_config->reg_bits / 8; >> + offset = reg_bytes; >> + >> + BUG_ON(reg_bytes != 4); >> + BUG_ON(count <= offset); >> + >> + return regmap_at24_gather_write(context, data, reg_bytes, >> + data + offset, count - offset); >> +} >> + >> +static struct regmap_bus regmap_at24_bus = { >> + .read = regmap_at24_read, >> + .write = regmap_at24_write, >> + .gather_write = regmap_at24_gather_write, >> + .reg_format_endian_default = REGMAP_ENDIAN_NATIVE, >> + .val_format_endian_default = REGMAP_ENDIAN_NATIVE, >> +}; >> + >> static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) >> { >> struct at24_platform_data chip; >> @@ -474,6 +550,10 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) >> int err; >> unsigned i, num_addresses; >> kernel_ulong_t magic; >> + struct regmap_config *regmap_config; >> + struct regmap *regmap; >> + struct nvmem_config *nvmem_config; >> + struct nvmem_device *nvmem_dev; >> >> if (client->dev.platform_data) { >> chip = *(struct at24_platform_data *)client->dev.platform_data; >> @@ -541,16 +621,75 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) >> } >> } >> >> + regmap_config = devm_kzalloc(&client->dev, sizeof(*regmap_config), >> + GFP_KERNEL); >> + if (IS_ERR(regmap_config)) { >> + err = PTR_ERR(regmap_config); >> + dev_err(&client->dev, "%s: regmap_config allocation failed (%d)\n", >> + __func__, err); >> + return err; >> + } >> + >> + /* use 32 bits as registers, they don't appear on the wire anyway */ >> + regmap_config->reg_bits = 32; >> + regmap_config->val_bits = 8; >> + regmap_config->cache_type = REGCACHE_NONE; >> + regmap_config->max_register = chip.byte_len; >> + >> if (chip.flags & AT24_FLAG_TAKE8ADDR) >> num_addresses = 8; >> else >> num_addresses = DIV_ROUND_UP(chip.byte_len, >> (chip.flags & AT24_FLAG_ADDR16) ? 65536 : 256); >> >> + /* we can't use devm_regmap_init_i2c due to the many i2c clients */ >> + regmap = devm_regmap_init(&client->dev, ®map_at24_bus, >> + client, regmap_config); >> + if (IS_ERR(regmap)) { >> + err = PTR_ERR(regmap); >> + dev_err(&client->dev, "%s: regmap allocation failed (%d)\n", >> + __func__, err); >> + return err; >> + } >> + >> + nvmem_config = devm_kzalloc(&client->dev, sizeof(*nvmem_config), >> + GFP_KERNEL); >> + if (IS_ERR(nvmem_config)) { >> + err = PTR_ERR(nvmem_config); >> + dev_err(&client->dev, "%s: nvmem_config allocation failed (%d)\n", >> + __func__, err); >> + return err; >> + } >> + nvmem_config->dev = &client->dev; >> + nvmem_config->name = "at24-"; >> + nvmem_config->id = ida_simple_get(&at24_ida, 0, 0, GFP_KERNEL); >> + nvmem_config->owner = THIS_MODULE; >> + if (nvmem_config->id < 0) { >> + err = nvmem_config->id; >> + dev_err(&client->dev, "%s: eeprom id allocation failed (%d)\n", >> + __func__, err); >> + return err; >> + } >> + >> + nvmem_dev = nvmem_register(nvmem_config); >> + if (IS_ERR(nvmem_dev)) { >> + err = PTR_ERR(nvmem_dev); >> + dev_err(&client->dev, "%s: nvmem_register failed (%d)\n", >> + __func__, err); >> + goto err_out; >> + } >> + >> at24 = devm_kzalloc(&client->dev, sizeof(struct at24_data) + >> num_addresses * sizeof(struct i2c_client *), GFP_KERNEL); >> - if (!at24) >> - return -ENOMEM; >> + if (!at24) { >> + err = -ENOMEM; >> + goto err_out; >> + } >> + >> + at24->regmap = regmap; >> + at24->regmap_config = regmap_config; >> + at24->nvmem_config = nvmem_config; >> + at24->nvmem_dev = nvmem_dev; >> >> mutex_init(&at24->lock); >> at24->use_smbus = use_smbus; >> @@ -558,16 +697,6 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) >> at24->chip = chip; >> at24->num_addresses = num_addresses; >> >> - /* >> - * Export the EEPROM bytes through sysfs, since that's convenient. >> - * By default, only root should see the data (maybe passwords etc) >> - */ >> - sysfs_bin_attr_init(&at24->bin); >> - at24->bin.attr.name = "eeprom"; >> - at24->bin.attr.mode = chip.flags & AT24_FLAG_IRUGO ? S_IRUGO : S_IRUSR; >> - at24->bin.read = at24_bin_read; >> - at24->bin.size = chip.byte_len; > > Hi Pantelis, > > this breaks the ABI. > > Additionally: the nvmem file is 0 in size with this patch and reading > it produces the following NULL pointer dereference on BeagleBone > Black: > > I'm using an at24cs02 chip, that works with mainline. > > [ 147.023405] Unable to handle kernel NULL pointer dereference at > virtual address 00000002 > [ 147.041713] pgd = de6f8000 > [ 147.053787] [00000002] *pgd=9e6eb831, *pte=00000000, *ppte=00000000 > [ 147.070152] Internal error: Oops: 17 [#1] SMP ARM > [ 147.084543] Modules linked in: gpio_pca953x ina2xx ipv6 omap_rng > rng_core rtc_omap omap_wdt at24 cpufreq_dt leds_gpio thermal_sys > led_class hwmon > [ 147.109168] CPU: 0 PID: 177 Comm: dd Not tainted 4.3.0-rc1-acme+ #18 > [ 147.126126] Hardware name: Generic AM33XX (Flattened Device Tree) > [ 147.142765] task: de68c380 ti: de672000 task.ti: de672000 > [ 147.158659] PC is at at24_read+0x1c4/0x200 [at24] > [ 147.173739] LR is at at24_read+0x54/0x200 [at24] > [ 147.188538] pc : [<bf02a20c>] lr : [<bf02a09c>] psr: 60080013 > [ 147.188538] sp : de673d88 ip : bf02b17c fp : ffffc440 > [ 147.220290] r10: de673da4 r9 : c09c6100 r8 : de6f3300 > [ 147.235487] r7 : de77c1d0 r6 : 00000000 r5 : 00000000 r4 : 00000001 > [ 147.251957] r3 : 00000001 r2 : de673dc0 r1 : de673dc0 r0 : 00000001 > [ 147.268442] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none > [ 147.285639] Control: 10c5387d Table: 9e6f8019 DAC: 00000051 > [ 147.301332] Process dd (pid: 177, stack limit = 0xde672218) > [ 147.316864] Stack: (0xde673d88 to 0xde674000) > [ 147.331094] 3d80: 00000080 00000080 00000100 > 00000000 00000100 de77c1f0 > [ 147.349553] 3da0: 00000001 00000000 00000000 00000000 00000000 > 00000000 00000000 00000100 > [ 147.368085] 3dc0: de68c380 00000101 00000101 de6c2e00 c0a7f4ac > c0a7f4e4 00000101 00000000 > [ 147.386542] 3de0: de6f3200 bf02a290 00000001 c06b5d3c de617800 > c04707a8 00000101 00000020 > [ 147.404852] 3e00: 00000000 00000000 60080013 c0a7d784 00000000 > c0093c74 00000001 de617800 > [ 147.423274] 3e20: 00000000 00000001 00000101 de6f3200 00000101 > 00000101 00000000 c04709c0 > [ 147.441694] 3e40: 00000001 c0093c74 00000001 00000101 00000000 > 00000000 00000000 00000000 > [ 147.460163] 3e60: 00000000 dba5a94c 00000000 c05a15ac c0a6e5dc > de641980 00000000 de6f3200 > [ 147.478710] 3e80: 00000000 c01f0fb8 00000000 00000000 00000200 > c008da64 dba5a940 de673f80 > [ 147.497227] 3ea0: 00000200 00000000 00000000 dba5a94c 00000000 > c01f08ac 00000000 00000000 > [ 147.515693] 3ec0: 00000256 000af008 de673f04 de641980 c06d16bc > 00000200 000af008 de673f80 > [ 147.534153] 3ee0: 00000000 00000000 00000000 c0176af8 de641988 > ddcf1868 de641980 00000000 > [ 147.552575] 3f00: 00000000 00000000 00000000 c0326588 00000000 > 00000000 00000001 de641980 > [ 147.570949] 3f20: 00000200 00000000 00000000 c0176c04 60080013 > de6afc00 de641980 00000200 > [ 147.589215] 3f40: 000af008 de673f80 00000000 00000000 00000000 > c0177acc de6afc00 de6afe80 > [ 147.607452] 3f60: de641980 de641980 de641980 00000200 000af008 > 00000000 00000000 c0177c00 > [ 147.625712] 3f80: 00000000 00000000 000aea10 000aea10 00000000 > 000af008 00000003 c000ff44 > [ 147.643928] 3fa0: de672000 c000fda0 000aea10 00000000 00000000 > 000af008 00000200 00000000 > [ 147.662047] 3fc0: 000aea10 00000000 000af008 00000003 000af008 > 00000000 000af008 00000000 > [ 147.680078] 3fe0: 00000000 beec7aac 0000fc00 b6f2c07c 60080010 > 00000000 00000000 00000000 > [ 147.698148] [<bf02a20c>] (at24_read [at24]) from [<bf02a290>] > (regmap_at24_read+0x48/0x78 [at24]) > [ 147.717080] [<bf02a290>] (regmap_at24_read [at24]) from > [<c04707a8>] (_regmap_raw_read+0xdc/0x1f4) > [ 147.736127] [<c04707a8>] (_regmap_raw_read) from [<c04709c0>] > (regmap_raw_read+0x100/0x160) > [ 147.754515] [<c04709c0>] (regmap_raw_read) from [<c05a15ac>] > (bin_attr_nvmem_read+0x54/0x8c) > [ 147.773017] [<c05a15ac>] (bin_attr_nvmem_read) from [<c01f0fb8>] > (sysfs_kf_bin_read+0xa0/0xac) > [ 147.791728] [<c01f0fb8>] (sysfs_kf_bin_read) from [<c01f08ac>] > (kernfs_fop_read+0xb8/0x180) > [ 147.810159] [<c01f08ac>] (kernfs_fop_read) from [<c0176af8>] > (__vfs_read+0x2c/0xe0) > [ 147.827787] [<c0176af8>] (__vfs_read) from [<c0177acc>] (vfs_read+0x90/0xf0) > [ 147.844732] [<c0177acc>] (vfs_read) from [<c0177c00>] (SyS_read+0x44/0x88) > [ 147.861535] [<c0177c00>] (SyS_read) from [<c000fda0>] > (ret_fast_syscall+0x0/0x1c) > [ 147.878728] Code: e28d1038 e0812002 a3a03001 e5425004 (e1d620b2) > [ 147.894527] ---[ end trace 4f2f3a675fee7446 ]--- > > Best regards, > Bartosz Golaszewski > >> at24->macc.read = at24_macc_read; >> >> writable = !(chip.flags & AT24_FLAG_READONLY); >> @@ -578,9 +707,6 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) >> >> at24->macc.write = at24_macc_write; >> >> - at24->bin.write = at24_bin_write; >> - at24->bin.attr.mode |= S_IWUSR; >> - >> if (write_max > io_limit) >> write_max = io_limit; >> if (use_smbus && write_max > I2C_SMBUS_BLOCK_MAX) >> @@ -590,8 +716,10 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) >> /* buffer (data + address at the beginning) */ >> at24->writebuf = devm_kzalloc(&client->dev, >> write_max + 2, GFP_KERNEL); >> - if (!at24->writebuf) >> - return -ENOMEM; >> + if (!at24->writebuf) { >> + err = -ENOMEM; >> + goto err_out; >> + } >> } else { >> dev_warn(&client->dev, >> "cannot write due to controller restrictions."); >> @@ -612,14 +740,10 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) >> } >> } >> >> - err = sysfs_create_bin_file(&client->dev.kobj, &at24->bin); >> - if (err) >> - goto err_clients; >> - >> i2c_set_clientdata(client, at24); >> >> dev_info(&client->dev, "%zu byte %s EEPROM, %s, %u bytes/write\n", >> - at24->bin.size, client->name, >> + at24->chip.byte_len, client->name, >> writable ? "writable" : "read-only", at24->write_max); >> if (use_smbus == I2C_SMBUS_WORD_DATA || >> use_smbus == I2C_SMBUS_BYTE_DATA) { >> @@ -635,10 +759,14 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) >> return 0; >> >> err_clients: >> + >> for (i = 1; i < num_addresses; i++) >> if (at24->client[i]) >> i2c_unregister_device(at24->client[i]); >> >> +err_out: >> + ida_simple_remove(&at24_ida, nvmem_config->id); >> + >> return err; >> } >> >> @@ -648,11 +776,12 @@ static int at24_remove(struct i2c_client *client) >> int i; >> >> at24 = i2c_get_clientdata(client); >> - sysfs_remove_bin_file(&client->dev.kobj, &at24->bin); >> >> for (i = 1; i < at24->num_addresses; i++) >> i2c_unregister_device(at24->client[i]); >> >> + nvmem_unregister(at24->nvmem_dev); >> + >> return 0; >> } >> >> >> 1.7.12 Thanks for the bug report. Are you using the user-space API to read from the device? Regards — Pantelis -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html