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>
This commit is contained in:
Jiri Prchal
Greg Kroah-Hartman
parent
989f77e3fd
commit
fd307a4ad3
19
Documentation/ABI/testing/sysfs-class-spi-eeprom
Normal file
19
Documentation/ABI/testing/sysfs-class-spi-eeprom
Normal file
@ -0,0 +1,19 @@
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What: /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/fram
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Date: June 2021
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KernelVersion: 5.14
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Contact: Jiri Prchal <jiri.prchal@aksignal.cz>
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Description:
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Contains the FRAM binary data. Same as EEPROM, just another file
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name to indicate that it employs ferroelectric process.
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It performs write operations at bus speed - no write delays.
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What: /sys/class/spi_master/spi<bus>/spi<bus>.<dev>/sernum
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Date: May 2021
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KernelVersion: 5.14
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Contact: Jiri Prchal <jiri.prchal@aksignal.cz>
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Description:
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Contains the serial number of the Cypress FRAM (FM25VN) if it is
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present. It will be displayed as a 8 byte hex string, as read
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from the device.
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This is a read-only attribute.
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@ -4,14 +4,16 @@
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$id: "http://devicetree.org/schemas/eeprom/at25.yaml#"
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$schema: "http://devicetree.org/meta-schemas/core.yaml#"
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title: SPI EEPROMs compatible with Atmel's AT25
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title: SPI EEPROMs or FRAMs compatible with Atmel's AT25
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maintainers:
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- Christian Eggers <ceggers@arri.de>
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properties:
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$nodename:
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pattern: "^eeprom@[0-9a-f]{1,2}$"
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anyOf:
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- pattern: "^eeprom@[0-9a-f]{1,2}$"
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- pattern: "^fram@[0-9a-f]{1,2}$"
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# There are multiple known vendors who manufacture EEPROM chips compatible
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# with Atmel's AT25. The compatible string requires two items where the
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@ -31,6 +33,7 @@ properties:
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- microchip,25lc040
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- st,m95m02
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- st,m95256
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- cypress,fm25
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- const: atmel,at25
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@ -47,7 +50,7 @@ properties:
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$ref: /schemas/types.yaml#/definitions/uint32
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enum: [1, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072]
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description:
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Size of the eeprom page.
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Size of the eeprom page. FRAMs don't have pages.
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size:
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$ref: /schemas/types.yaml#/definitions/uint32
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@ -100,9 +103,19 @@ required:
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- compatible
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- reg
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- spi-max-frequency
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- pagesize
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- size
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- address-width
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allOf:
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- if:
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properties:
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compatible:
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not:
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contains:
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const: cypress,fm25
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then:
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required:
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- pagesize
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- size
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- address-width
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additionalProperties: false
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@ -125,4 +138,10 @@ examples:
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size = <32768>;
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address-width = <16>;
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};
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fram@1 {
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compatible = "cypress,fm25", "atmel,at25";
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reg = <1>;
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spi-max-frequency = <40000000>;
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};
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};
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@ -32,12 +32,13 @@ config EEPROM_AT24
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will be called at24.
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config EEPROM_AT25
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tristate "SPI EEPROMs from most vendors"
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tristate "SPI EEPROMs (FRAMs) from most vendors"
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depends on SPI && SYSFS
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select NVMEM
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select NVMEM_SYSFS
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help
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Enable this driver to get read/write support to most SPI EEPROMs,
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Enable this driver to get read/write support to most SPI EEPROMs
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and Cypress FRAMs,
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after you configure the board init code to know about each eeprom
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on your target board.
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@ -1,6 +1,7 @@
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// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* at25.c -- support most SPI EEPROMs, such as Atmel AT25 models
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* and Cypress FRAMs FM25 models
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*
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* Copyright (C) 2006 David Brownell
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*/
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@ -16,6 +17,9 @@
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#include <linux/spi/spi.h>
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#include <linux/spi/eeprom.h>
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#include <linux/property.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/math.h>
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/*
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* NOTE: this is an *EEPROM* driver. The vagaries of product naming
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@ -27,6 +31,7 @@
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* AT25M02, AT25128B
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*/
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#define FM25_SN_LEN 8 /* serial number length */
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struct at25_data {
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struct spi_device *spi;
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struct mutex lock;
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@ -34,6 +39,7 @@ struct at25_data {
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unsigned addrlen;
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struct nvmem_config nvmem_config;
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struct nvmem_device *nvmem;
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u8 sernum[FM25_SN_LEN];
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};
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#define AT25_WREN 0x06 /* latch the write enable */
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@ -42,6 +48,9 @@ struct at25_data {
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#define AT25_WRSR 0x01 /* write status register */
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#define AT25_READ 0x03 /* read byte(s) */
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#define AT25_WRITE 0x02 /* write byte(s)/sector */
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#define FM25_SLEEP 0xb9 /* enter sleep mode */
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#define FM25_RDID 0x9f /* read device ID */
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#define FM25_RDSN 0xc3 /* read S/N */
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#define AT25_SR_nRDY 0x01 /* nRDY = write-in-progress */
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#define AT25_SR_WEN 0x02 /* write enable (latched) */
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@ -51,6 +60,8 @@ struct at25_data {
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#define AT25_INSTR_BIT3 0x08 /* Additional address bit in instr */
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#define FM25_ID_LEN 9 /* ID length */
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#define EE_MAXADDRLEN 3 /* 24 bit addresses, up to 2 MBytes */
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/* Specs often allow 5 msec for a page write, sometimes 20 msec;
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@ -58,6 +69,9 @@ struct at25_data {
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*/
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#define EE_TIMEOUT 25
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#define IS_EEPROM 0
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#define IS_FRAM 1
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/*-------------------------------------------------------------------------*/
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#define io_limit PAGE_SIZE /* bytes */
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@ -129,6 +143,51 @@ static int at25_ee_read(void *priv, unsigned int offset,
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return status;
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}
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/*
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* read extra registers as ID or serial number
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*/
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static int fm25_aux_read(struct at25_data *at25, u8 *buf, uint8_t command,
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int len)
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{
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int status;
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struct spi_transfer t[2];
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struct spi_message m;
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spi_message_init(&m);
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memset(t, 0, sizeof(t));
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t[0].tx_buf = &command;
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t[0].len = 1;
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spi_message_add_tail(&t[0], &m);
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t[1].rx_buf = buf;
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t[1].len = len;
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spi_message_add_tail(&t[1], &m);
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mutex_lock(&at25->lock);
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status = spi_sync(at25->spi, &m);
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dev_dbg(&at25->spi->dev, "read %d aux bytes --> %d\n", len, status);
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mutex_unlock(&at25->lock);
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return status;
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}
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static ssize_t sernum_show(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct at25_data *at25;
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at25 = dev_get_drvdata(dev);
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return sysfs_emit(buf, "%*ph\n", sizeof(at25->sernum), at25->sernum);
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}
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static DEVICE_ATTR_RO(sernum);
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static struct attribute *sernum_attrs[] = {
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&dev_attr_sernum.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(sernum);
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static int at25_ee_write(void *priv, unsigned int off, void *val, size_t count)
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{
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struct at25_data *at25 = priv;
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@ -303,34 +362,39 @@ static int at25_fw_to_chip(struct device *dev, struct spi_eeprom *chip)
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return 0;
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}
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static const struct of_device_id at25_of_match[] = {
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{ .compatible = "atmel,at25", .data = (const void *)IS_EEPROM },
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{ .compatible = "cypress,fm25", .data = (const void *)IS_FRAM },
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{ }
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};
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MODULE_DEVICE_TABLE(of, at25_of_match);
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static int at25_probe(struct spi_device *spi)
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{
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struct at25_data *at25 = NULL;
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struct spi_eeprom chip;
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int err;
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int sr;
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int addrlen;
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u8 id[FM25_ID_LEN];
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u8 sernum[FM25_SN_LEN];
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int i;
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const struct of_device_id *match;
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int is_fram = 0;
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match = of_match_device(of_match_ptr(at25_of_match), &spi->dev);
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if (match)
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is_fram = (int)match->data;
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/* Chip description */
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if (!spi->dev.platform_data) {
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err = at25_fw_to_chip(&spi->dev, &chip);
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if (err)
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return err;
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if (!is_fram) {
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err = at25_fw_to_chip(&spi->dev, &chip);
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if (err)
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return err;
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}
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} else
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chip = *(struct spi_eeprom *)spi->dev.platform_data;
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/* For now we only support 8/16/24 bit addressing */
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if (chip.flags & EE_ADDR1)
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addrlen = 1;
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else if (chip.flags & EE_ADDR2)
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addrlen = 2;
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else if (chip.flags & EE_ADDR3)
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addrlen = 3;
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else {
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dev_dbg(&spi->dev, "unsupported address type\n");
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return -EINVAL;
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}
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/* Ping the chip ... the status register is pretty portable,
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* unlike probing manufacturer IDs. We do expect that system
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* firmware didn't write it in the past few milliseconds!
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@ -349,9 +413,51 @@ static int at25_probe(struct spi_device *spi)
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at25->chip = chip;
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at25->spi = spi;
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spi_set_drvdata(spi, at25);
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at25->addrlen = addrlen;
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at25->nvmem_config.type = NVMEM_TYPE_EEPROM;
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if (is_fram) {
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/* Get ID of chip */
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fm25_aux_read(at25, id, FM25_RDID, FM25_ID_LEN);
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if (id[6] != 0xc2) {
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dev_err(&spi->dev,
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"Error: no Cypress FRAM (id %02x)\n", id[6]);
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return -ENODEV;
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}
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/* set size found in ID */
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if (id[7] < 0x21 || id[7] > 0x26) {
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dev_err(&spi->dev, "Error: unsupported size (id %02x)\n", id[7]);
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return -ENODEV;
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}
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chip.byte_len = int_pow(2, id[7] - 0x21 + 4) * 1024;
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if (at25->chip.byte_len > 64 * 1024)
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at25->chip.flags |= EE_ADDR3;
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else
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at25->chip.flags |= EE_ADDR2;
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if (id[8]) {
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fm25_aux_read(at25, sernum, FM25_RDSN, FM25_SN_LEN);
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/* swap byte order */
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for (i = 0; i < FM25_SN_LEN; i++)
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at25->sernum[i] = sernum[FM25_SN_LEN - 1 - i];
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}
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at25->chip.page_size = PAGE_SIZE;
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strncpy(at25->chip.name, "fm25", sizeof(at25->chip.name));
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}
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/* For now we only support 8/16/24 bit addressing */
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if (at25->chip.flags & EE_ADDR1)
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at25->addrlen = 1;
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else if (at25->chip.flags & EE_ADDR2)
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at25->addrlen = 2;
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else if (at25->chip.flags & EE_ADDR3)
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at25->addrlen = 3;
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else {
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dev_dbg(&spi->dev, "unsupported address type\n");
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return -EINVAL;
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}
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at25->nvmem_config.type = is_fram ? NVMEM_TYPE_FRAM : NVMEM_TYPE_EEPROM;
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at25->nvmem_config.name = dev_name(&spi->dev);
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at25->nvmem_config.dev = &spi->dev;
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at25->nvmem_config.read_only = chip.flags & EE_READONLY;
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@ -370,27 +476,22 @@ static int at25_probe(struct spi_device *spi)
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if (IS_ERR(at25->nvmem))
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return PTR_ERR(at25->nvmem);
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dev_info(&spi->dev, "%d %s %s eeprom%s, pagesize %u\n",
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(chip.byte_len < 1024) ? chip.byte_len : (chip.byte_len / 1024),
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(chip.byte_len < 1024) ? "Byte" : "KByte",
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at25->chip.name,
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(chip.flags & EE_READONLY) ? " (readonly)" : "",
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at25->chip.page_size);
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dev_info(&spi->dev, "%d %s %s %s%s, pagesize %u\n",
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(chip.byte_len < 1024) ? chip.byte_len : (chip.byte_len / 1024),
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(chip.byte_len < 1024) ? "Byte" : "KByte",
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at25->chip.name, is_fram ? "fram" : "eeprom",
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(chip.flags & EE_READONLY) ? " (readonly)" : "",
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at25->chip.page_size);
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return 0;
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}
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/*-------------------------------------------------------------------------*/
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static const struct of_device_id at25_of_match[] = {
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{ .compatible = "atmel,at25", },
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{ }
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};
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MODULE_DEVICE_TABLE(of, at25_of_match);
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static struct spi_driver at25_driver = {
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.driver = {
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.name = "at25",
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.of_match_table = at25_of_match,
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.dev_groups = sernum_groups,
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},
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.probe = at25_probe,
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};
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@ -180,6 +180,7 @@ static const char * const nvmem_type_str[] = {
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[NVMEM_TYPE_EEPROM] = "EEPROM",
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[NVMEM_TYPE_OTP] = "OTP",
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[NVMEM_TYPE_BATTERY_BACKED] = "Battery backed",
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[NVMEM_TYPE_FRAM] = "FRAM",
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};
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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@ -359,6 +360,9 @@ static int nvmem_sysfs_setup_compat(struct nvmem_device *nvmem,
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if (!config->base_dev)
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return -EINVAL;
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if (config->type == NVMEM_TYPE_FRAM)
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bin_attr_nvmem_eeprom_compat.attr.name = "fram";
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nvmem->eeprom = bin_attr_nvmem_eeprom_compat;
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nvmem->eeprom.attr.mode = nvmem_bin_attr_get_umode(nvmem);
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nvmem->eeprom.size = nvmem->size;
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@ -25,6 +25,7 @@ enum nvmem_type {
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NVMEM_TYPE_EEPROM,
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NVMEM_TYPE_OTP,
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NVMEM_TYPE_BATTERY_BACKED,
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NVMEM_TYPE_FRAM,
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};
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#define NVMEM_DEVID_NONE (-1)
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