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Date: Tue, 8 Jun 2021 11:07:50 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: Jiri Prchal <jiri.prchal@...ignal.cz>
Cc: devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
Rob Herring <robh+dt@...nel.org>,
Christian Eggers <ceggers@...i.de>,
Arnd Bergmann <arnd@...db.de>,
kernel test robot <lkp@...el.com>
Subject: Re: [PATCH v8 2/5] nvmem: eeprom: at25: add support for FRAM
On Mon, Jun 07, 2021 at 06:11:58PM +0200, Jiri Prchal wrote:
> 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 <jiri.prchal@...ignal.cz>
> ---
> v2: fixed warning at %zd at int
> Reported-by: kernel test robot <lkp@...el.com>
> 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
> ---
> drivers/misc/eeprom/Kconfig | 5 +-
> drivers/misc/eeprom/at25.c | 140 ++++++++++++++++++++++++++++--------
> 2 files changed, 113 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..e25cec7c474b 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
> @@ -34,6 +38,7 @@ struct at25_data {
> unsigned addrlen;
> struct nvmem_config nvmem_config;
> struct nvmem_device *nvmem;
> + int has_sernum;
bool?
> };
>
> #define AT25_WREN 0x06 /* latch the write enable */
> @@ -42,6 +47,9 @@ 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 +59,8 @@ 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 +68,9 @@ struct at25_data {
> */
> #define EE_TIMEOUT 25
>
> +#define IS_EEPROM 0
> +#define IS_FRAM 1
> +
> /*-------------------------------------------------------------------------*/
>
> #define io_limit PAGE_SIZE /* bytes */
> @@ -129,6 +142,36 @@ 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));
Are you allowed to send spi messages off of the stack?
> +
> + 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 +346,37 @@ 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 +395,49 @@ 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])
> + at25->has_sernum = 1;
> + else
> + at25->has_sernum = 0;
> +
> + 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 +456,17 @@ 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);
When drivers work properly, they should be quiet. This whole dev_info()
should be removed in a later patch.
thanks,
greg k-h
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