Adds support for Cypress FRAMs.
Jiri Prchal (5):
nvmem: prepare basics for FRAM support
nvmem: eeprom: at25: add support for FRAM
dt-bindings: nvmem: at25: add for FRAM support
nvmem: eeprom: at25: export FRAM serial num
nvmem: eeprom: add documentation of sysfs fram and sernum file
.../ABI/testing/sysfs-class-spi-eeprom | 20 +++
.../devicetree/bindings/eeprom/at25.yaml | 31 +++-
drivers/misc/eeprom/Kconfig | 5 +-
drivers/misc/eeprom/at25.c | 161 ++++++++++++++----
drivers/nvmem/core.c | 4 +
include/linux/nvmem-provider.h | 1 +
6 files changed, 184 insertions(+), 38 deletions(-)
create mode 100644 Documentation/ABI/testing/sysfs-class-spi-eeprom
--
2.25.1
Added support for Cypress FRAMs.
These frams have ID and some of them have serial number too.
Size of them is recognized by ID. They don't have pages, it could
be read or written at once, but it's limited in this driver to
io limit 4096.
Signed-off-by: Jiri Prchal <[email protected]>
---
v2: fixed warning at %zd at int
Reported-by: kernel test robot <[email protected]>
v3: resend and added more recipients
v4: resend
v5: used in-kernel function int_pow
v6: no change here
v7: moved definition of sernum size to patch 4
v8: changed buffer type to u8
v9: removed needless has_sernum
---
drivers/misc/eeprom/Kconfig | 5 +-
drivers/misc/eeprom/at25.c | 134 ++++++++++++++++++++++++++++--------
2 files changed, 107 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..e59b6852816d 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
@@ -42,6 +46,9 @@ 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 +58,8 @@ 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 +67,9 @@ struct at25_data {
*/
#define EE_TIMEOUT 25
+#define IS_EEPROM 0
+#define IS_FRAM 1
+
/*-------------------------------------------------------------------------*/
#define io_limit PAGE_SIZE /* bytes */
@@ -129,6 +141,36 @@ 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 int at25_ee_write(void *priv, unsigned int off, void *val, size_t count)
{
struct at25_data *at25 = priv;
@@ -303,34 +345,37 @@ 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];
+ 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)(uintptr_t)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 +394,44 @@ 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;
+
+ 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;
@@ -370,23 +450,17 @@ 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",
--
2.25.1
Added sysfs fram and sernum file documentation.
Signed-off-by: Jiri Prchal <[email protected]>
---
v5: new
v6: no change here
v7: no change here
v8: added fram file doc
v9: rewritten description
---
.../ABI/testing/sysfs-class-spi-eeprom | 20 +++++++++++++++++++
1 file changed, 20 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-class-spi-eeprom
diff --git a/Documentation/ABI/testing/sysfs-class-spi-eeprom b/Documentation/ABI/testing/sysfs-class-spi-eeprom
new file mode 100644
index 000000000000..4e69c78f9f65
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-spi-eeprom
@@ -0,0 +1,20 @@
+What: /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/sernum
+Date: May 2021
+KernelVersion: 5.14
+Contact: Jiri Prchal <[email protected]>
+Description:
+ Contains the serial number of the Cypress FRAM (FM25VN) if it is
+ present. It will be displayed as a 8 byte hex string, as read
+ from the device.
+
+ This is a read-only attribute.
+
+What: /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fram
+Date: June 2021
+KernelVersion: 5.14
+Contact: Jiri Prchal <[email protected]>
+Description:
+ Contains the FRAM binary data. Same as EEPROM, just another file
+ name to indicate that it employs ferroelectric process.
+ It performs write operations at bus speed - no write delays, capable
+ of 10^14 read/write cycles and 151 years data retention.
--
2.25.1
This exports serial number of FRAM in sysfs file named "sernum".
Formatted in hex, each byte separated by space.
Example:
$ cat /sys/class/spi_master/spi0/spi0.0/sernum
ef cd ab 89 67 45 23 01
Signed-off-by: Jiri Prchal <[email protected]>
---
v2: no change here
v3: resend and added more recipients
v4: resend
v5: reworked up on Greg comments: no spaces in string, sysfs done correctly
v6: no change here
v7: moved FM25_SN_LEN, static array, used sysfs_emit, DEVICE_ATTR_RO
v8: clarify sysfs_emit format
v9: sizeof parentheses, export with spaces MSB first
---
drivers/misc/eeprom/at25.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/drivers/misc/eeprom/at25.c b/drivers/misc/eeprom/at25.c
index e59b6852816d..19280e9f118d 100644
--- a/drivers/misc/eeprom/at25.c
+++ b/drivers/misc/eeprom/at25.c
@@ -31,6 +31,7 @@
* AT25M02, AT25128B
*/
+#define FM25_SN_LEN 8 /* serial number length */
struct at25_data {
struct spi_device *spi;
struct mutex lock;
@@ -38,6 +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 */
@@ -171,6 +173,21 @@ static int fm25_aux_read(struct at25_data *at25, u8 *buf, uint8_t command,
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;
@@ -359,6 +376,8 @@ static int at25_probe(struct spi_device *spi)
int err;
int sr;
u8 id[FM25_ID_LEN];
+ u8 sernum[FM25_SN_LEN];
+ int i;
const struct of_device_id *match;
int is_fram = 0;
@@ -415,6 +434,13 @@ static int at25_probe(struct spi_device *spi)
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));
}
@@ -465,6 +491,7 @@ static struct spi_driver at25_driver = {
.driver = {
.name = "at25",
.of_match_table = at25_of_match,
+ .dev_groups = sernum_groups,
},
.probe = at25_probe,
};
--
2.25.1
On Fri, Jun 11, 2021 at 07:26:49AM +0200, Jiri Prchal wrote:
> Added support for Cypress FRAMs.
Which devices exactly are you adding support for?
> These frams have ID and some of them have serial number too.
> Size of them is recognized by ID. They don't have pages, it could
> be read or written at once, but it's limited in this driver to
> io limit 4096.
>
> Signed-off-by: Jiri Prchal <[email protected]>
> ---
> v2: fixed warning at %zd at int
> Reported-by: kernel test robot <[email protected]>
> v3: resend and added more recipients
> v4: resend
> v5: used in-kernel function int_pow
> v6: no change here
> v7: moved definition of sernum size to patch 4
> v8: changed buffer type to u8
> v9: removed needless has_sernum
> ---
> drivers/misc/eeprom/Kconfig | 5 +-
> drivers/misc/eeprom/at25.c | 134 ++++++++++++++++++++++++++++--------
> 2 files changed, 107 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..e59b6852816d 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
> @@ -42,6 +46,9 @@ 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 +58,8 @@ 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 +67,9 @@ struct at25_data {
> */
> #define EE_TIMEOUT 25
>
> +#define IS_EEPROM 0
> +#define IS_FRAM 1
> +
> /*-------------------------------------------------------------------------*/
>
> #define io_limit PAGE_SIZE /* bytes */
> @@ -129,6 +141,36 @@ 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 int at25_ee_write(void *priv, unsigned int off, void *val, size_t count)
> {
> struct at25_data *at25 = priv;
> @@ -303,34 +345,37 @@ 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];
> + 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)(uintptr_t)match->data;
Why the double cast?
And "uintptr_t" is not a kernel type. This originally is just a void *,
so no need to "double cast" it here, right?
thanks,
greg k-h
On Fri, Jun 11, 2021 at 07:26:51AM +0200, Jiri Prchal wrote:
> This exports serial number of FRAM in sysfs file named "sernum".
> Formatted in hex, each byte separated by space.
> Example:
> $ cat /sys/class/spi_master/spi0/spi0.0/sernum
> ef cd ab 89 67 45 23 01
Again, add the Documentation update to this commit so it can be reviewed
easier.
thanks,
greg k-h
On Fri, Jun 11, 2021 at 07:26:52AM +0200, Jiri Prchal wrote:
> Added sysfs fram and sernum file documentation.
>
> Signed-off-by: Jiri Prchal <[email protected]>
> ---
> v5: new
> v6: no change here
> v7: no change here
> v8: added fram file doc
> v9: rewritten description
> ---
> .../ABI/testing/sysfs-class-spi-eeprom | 20 +++++++++++++++++++
> 1 file changed, 20 insertions(+)
> create mode 100644 Documentation/ABI/testing/sysfs-class-spi-eeprom
>
> diff --git a/Documentation/ABI/testing/sysfs-class-spi-eeprom b/Documentation/ABI/testing/sysfs-class-spi-eeprom
> new file mode 100644
> index 000000000000..4e69c78f9f65
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-spi-eeprom
> @@ -0,0 +1,20 @@
> +What: /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/sernum
> +Date: May 2021
> +KernelVersion: 5.14
> +Contact: Jiri Prchal <[email protected]>
> +Description:
> + Contains the serial number of the Cypress FRAM (FM25VN) if it is
> + present. It will be displayed as a 8 byte hex string, as read
> + from the device.
> +
> + This is a read-only attribute.
> +
> +What: /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fram
> +Date: June 2021
> +KernelVersion: 5.14
> +Contact: Jiri Prchal <[email protected]>
> +Description:
> + Contains the FRAM binary data. Same as EEPROM, just another file
> + name to indicate that it employs ferroelectric process.
> + It performs write operations at bus speed - no write delays, capable
> + of 10^14 read/write cycles and 151 years data retention.
Are you sure of these statistics? Don't promise something here that
might not be true, this is not a marketing document :)
thanks,
greg k-h
On 11. 06. 21 10:53, Greg Kroah-Hartman wrote:
> On Fri, Jun 11, 2021 at 07:26:52AM +0200, Jiri Prchal wrote:
>> +Description:
>> + Contains the FRAM binary data. Same as EEPROM, just another file
>> + name to indicate that it employs ferroelectric process.
>> + It performs write operations at bus speed - no write delays, capable
>> + of 10^14 read/write cycles and 151 years data retention.
>
> Are you sure of these statistics? Don't promise something here that
> might not be true, this is not a marketing document :)
Just copied from datasheet. Is write at bus speed OK? And about others:
much more then EEPROM would be OK? Or don't write about it?
On Fri, Jun 11, 2021 at 11:01:57AM +0200, Jiří Prchal wrote:
>
>
> On 11. 06. 21 10:53, Greg Kroah-Hartman wrote:
> > On Fri, Jun 11, 2021 at 07:26:52AM +0200, Jiri Prchal wrote:
> > > +Description:
> > > + Contains the FRAM binary data. Same as EEPROM, just another file
> > > + name to indicate that it employs ferroelectric process.
> > > + It performs write operations at bus speed - no write delays, capable
> > > + of 10^14 read/write cycles and 151 years data retention.
> >
> > Are you sure of these statistics? Don't promise something here that
> > might not be true, this is not a marketing document :)
>
> Just copied from datasheet. Is write at bus speed OK? And about others: much
> more then EEPROM would be OK? Or don't write about it?
I would not even mention it :)