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author | Jiri Prchal <jiri.prchal@aksignal.cz> | 2021-06-11 11:45:58 +0200 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-06-11 12:23:10 +0200 |
commit | fd307a4ad332ef50be5569c92490219e7cd84ce5 (patch) | |
tree | 6683353455acad103535cdbceb9af084ff50531a /drivers/misc | |
parent | 989f77e3fdee2e8f414dd1da9b6397d8763d414e (diff) | |
download | linux-stable-fd307a4ad332ef50be5569c92490219e7cd84ce5.tar.gz linux-stable-fd307a4ad332ef50be5569c92490219e7cd84ce5.tar.bz2 linux-stable-fd307a4ad332ef50be5569c92490219e7cd84ce5.zip |
nvmem: prepare basics for FRAM support
Added enum and string for FRAM (ferroelectric RAM) to expose it as file
named "fram".
Added documentation of sysfs file.
Signed-off-by: Jiri Prchal <jiri.prchal@aksignal.cz>
Link: https://lore.kernel.org/r/20210611094601.95131-2-jiri.prchal@aksignal.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/misc')
-rw-r--r-- | drivers/misc/eeprom/Kconfig | 5 | ||||
-rw-r--r-- | drivers/misc/eeprom/at25.c | 161 |
2 files changed, 134 insertions, 32 deletions
diff --git a/drivers/misc/eeprom/Kconfig b/drivers/misc/eeprom/Kconfig index 0f791bfdc1f5..f0a7531f354c 100644 --- a/drivers/misc/eeprom/Kconfig +++ b/drivers/misc/eeprom/Kconfig @@ -32,12 +32,13 @@ config EEPROM_AT24 will be called at24. config EEPROM_AT25 - tristate "SPI EEPROMs from most vendors" + tristate "SPI EEPROMs (FRAMs) from most vendors" depends on SPI && SYSFS select NVMEM select NVMEM_SYSFS help - Enable this driver to get read/write support to most SPI EEPROMs, + Enable this driver to get read/write support to most SPI EEPROMs + and Cypress FRAMs, after you configure the board init code to know about each eeprom on your target board. diff --git a/drivers/misc/eeprom/at25.c b/drivers/misc/eeprom/at25.c index b76e4901b4a4..6e26de68a001 100644 --- a/drivers/misc/eeprom/at25.c +++ b/drivers/misc/eeprom/at25.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0-or-later /* * at25.c -- support most SPI EEPROMs, such as Atmel AT25 models + * and Cypress FRAMs FM25 models * * Copyright (C) 2006 David Brownell */ @@ -16,6 +17,9 @@ #include <linux/spi/spi.h> #include <linux/spi/eeprom.h> #include <linux/property.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/math.h> /* * NOTE: this is an *EEPROM* driver. The vagaries of product naming @@ -27,6 +31,7 @@ * AT25M02, AT25128B */ +#define FM25_SN_LEN 8 /* serial number length */ struct at25_data { struct spi_device *spi; struct mutex lock; @@ -34,6 +39,7 @@ struct at25_data { unsigned addrlen; struct nvmem_config nvmem_config; struct nvmem_device *nvmem; + u8 sernum[FM25_SN_LEN]; }; #define AT25_WREN 0x06 /* latch the write enable */ @@ -42,6 +48,9 @@ struct at25_data { #define AT25_WRSR 0x01 /* write status register */ #define AT25_READ 0x03 /* read byte(s) */ #define AT25_WRITE 0x02 /* write byte(s)/sector */ +#define FM25_SLEEP 0xb9 /* enter sleep mode */ +#define FM25_RDID 0x9f /* read device ID */ +#define FM25_RDSN 0xc3 /* read S/N */ #define AT25_SR_nRDY 0x01 /* nRDY = write-in-progress */ #define AT25_SR_WEN 0x02 /* write enable (latched) */ @@ -51,6 +60,8 @@ struct at25_data { #define AT25_INSTR_BIT3 0x08 /* Additional address bit in instr */ +#define FM25_ID_LEN 9 /* ID length */ + #define EE_MAXADDRLEN 3 /* 24 bit addresses, up to 2 MBytes */ /* Specs often allow 5 msec for a page write, sometimes 20 msec; @@ -58,6 +69,9 @@ struct at25_data { */ #define EE_TIMEOUT 25 +#define IS_EEPROM 0 +#define IS_FRAM 1 + /*-------------------------------------------------------------------------*/ #define io_limit PAGE_SIZE /* bytes */ @@ -129,6 +143,51 @@ static int at25_ee_read(void *priv, unsigned int offset, return status; } +/* + * read extra registers as ID or serial number + */ +static int fm25_aux_read(struct at25_data *at25, u8 *buf, uint8_t command, + int len) +{ + int status; + struct spi_transfer t[2]; + struct spi_message m; + + spi_message_init(&m); + memset(t, 0, sizeof(t)); + + t[0].tx_buf = &command; + t[0].len = 1; + spi_message_add_tail(&t[0], &m); + + t[1].rx_buf = buf; + t[1].len = len; + spi_message_add_tail(&t[1], &m); + + mutex_lock(&at25->lock); + + status = spi_sync(at25->spi, &m); + dev_dbg(&at25->spi->dev, "read %d aux bytes --> %d\n", len, status); + + mutex_unlock(&at25->lock); + return status; +} + +static ssize_t sernum_show(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct at25_data *at25; + + at25 = dev_get_drvdata(dev); + return sysfs_emit(buf, "%*ph\n", sizeof(at25->sernum), at25->sernum); +} +static DEVICE_ATTR_RO(sernum); + +static struct attribute *sernum_attrs[] = { + &dev_attr_sernum.attr, + NULL, +}; +ATTRIBUTE_GROUPS(sernum); + static int at25_ee_write(void *priv, unsigned int off, void *val, size_t count) { struct at25_data *at25 = priv; @@ -303,34 +362,39 @@ static int at25_fw_to_chip(struct device *dev, struct spi_eeprom *chip) return 0; } +static const struct of_device_id at25_of_match[] = { + { .compatible = "atmel,at25", .data = (const void *)IS_EEPROM }, + { .compatible = "cypress,fm25", .data = (const void *)IS_FRAM }, + { } +}; +MODULE_DEVICE_TABLE(of, at25_of_match); + static int at25_probe(struct spi_device *spi) { struct at25_data *at25 = NULL; struct spi_eeprom chip; int err; int sr; - int addrlen; + u8 id[FM25_ID_LEN]; + u8 sernum[FM25_SN_LEN]; + int i; + const struct of_device_id *match; + int is_fram = 0; + + match = of_match_device(of_match_ptr(at25_of_match), &spi->dev); + if (match) + is_fram = (int)match->data; /* Chip description */ if (!spi->dev.platform_data) { - err = at25_fw_to_chip(&spi->dev, &chip); - if (err) - return err; + if (!is_fram) { + err = at25_fw_to_chip(&spi->dev, &chip); + if (err) + return err; + } } else chip = *(struct spi_eeprom *)spi->dev.platform_data; - /* For now we only support 8/16/24 bit addressing */ - if (chip.flags & EE_ADDR1) - addrlen = 1; - else if (chip.flags & EE_ADDR2) - addrlen = 2; - else if (chip.flags & EE_ADDR3) - addrlen = 3; - else { - dev_dbg(&spi->dev, "unsupported address type\n"); - return -EINVAL; - } - /* Ping the chip ... the status register is pretty portable, * unlike probing manufacturer IDs. We do expect that system * firmware didn't write it in the past few milliseconds! @@ -349,9 +413,51 @@ static int at25_probe(struct spi_device *spi) at25->chip = chip; at25->spi = spi; spi_set_drvdata(spi, at25); - at25->addrlen = addrlen; - at25->nvmem_config.type = NVMEM_TYPE_EEPROM; + if (is_fram) { + /* Get ID of chip */ + fm25_aux_read(at25, id, FM25_RDID, FM25_ID_LEN); + if (id[6] != 0xc2) { + dev_err(&spi->dev, + "Error: no Cypress FRAM (id %02x)\n", id[6]); + return -ENODEV; + } + /* set size found in ID */ + if (id[7] < 0x21 || id[7] > 0x26) { + dev_err(&spi->dev, "Error: unsupported size (id %02x)\n", id[7]); + return -ENODEV; + } + chip.byte_len = int_pow(2, id[7] - 0x21 + 4) * 1024; + + if (at25->chip.byte_len > 64 * 1024) + at25->chip.flags |= EE_ADDR3; + else + at25->chip.flags |= EE_ADDR2; + + if (id[8]) { + fm25_aux_read(at25, sernum, FM25_RDSN, FM25_SN_LEN); + /* swap byte order */ + for (i = 0; i < FM25_SN_LEN; i++) + at25->sernum[i] = sernum[FM25_SN_LEN - 1 - i]; + } + + at25->chip.page_size = PAGE_SIZE; + strncpy(at25->chip.name, "fm25", sizeof(at25->chip.name)); + } + + /* For now we only support 8/16/24 bit addressing */ + if (at25->chip.flags & EE_ADDR1) + at25->addrlen = 1; + else if (at25->chip.flags & EE_ADDR2) + at25->addrlen = 2; + else if (at25->chip.flags & EE_ADDR3) + at25->addrlen = 3; + else { + dev_dbg(&spi->dev, "unsupported address type\n"); + return -EINVAL; + } + + at25->nvmem_config.type = is_fram ? NVMEM_TYPE_FRAM : NVMEM_TYPE_EEPROM; at25->nvmem_config.name = dev_name(&spi->dev); at25->nvmem_config.dev = &spi->dev; at25->nvmem_config.read_only = chip.flags & EE_READONLY; @@ -370,27 +476,22 @@ static int at25_probe(struct spi_device *spi) if (IS_ERR(at25->nvmem)) return PTR_ERR(at25->nvmem); - dev_info(&spi->dev, "%d %s %s eeprom%s, pagesize %u\n", - (chip.byte_len < 1024) ? chip.byte_len : (chip.byte_len / 1024), - (chip.byte_len < 1024) ? "Byte" : "KByte", - at25->chip.name, - (chip.flags & EE_READONLY) ? " (readonly)" : "", - at25->chip.page_size); + dev_info(&spi->dev, "%d %s %s %s%s, pagesize %u\n", + (chip.byte_len < 1024) ? chip.byte_len : (chip.byte_len / 1024), + (chip.byte_len < 1024) ? "Byte" : "KByte", + at25->chip.name, is_fram ? "fram" : "eeprom", + (chip.flags & EE_READONLY) ? " (readonly)" : "", + at25->chip.page_size); return 0; } /*-------------------------------------------------------------------------*/ -static const struct of_device_id at25_of_match[] = { - { .compatible = "atmel,at25", }, - { } -}; -MODULE_DEVICE_TABLE(of, at25_of_match); - static struct spi_driver at25_driver = { .driver = { .name = "at25", .of_match_table = at25_of_match, + .dev_groups = sernum_groups, }, .probe = at25_probe, }; |