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Date: Mon, 5 Aug 2019 11:21:26 +0100
From: Joe Burmeister <joe.burmeister@...tank.co.uk>
To: joe.burmeister@...tank.co.uk, Arnd Bergmann <arnd@...db.de>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
YueHaibing <yuehaibing@...wei.com>,
Bartosz Golaszewski <bgolaszewski@...libre.com>,
Geert Uytterhoeven <geert+renesas@...der.be>,
linux-kernel@...r.kernel.org
Subject: [PATCH] Add erase interface for AT25 driver.
Signed-off-by: Joe Burmeister <joe.burmeister@...tank.co.uk>
---
drivers/misc/eeprom/at25.c | 75 +++++++++++++++++++++++++++++++++++++-
1 file changed, 74 insertions(+), 1 deletion(-)
diff --git a/drivers/misc/eeprom/at25.c b/drivers/misc/eeprom/at25.c
index 99de6939cd5a..b1fb3bfd935d 100644
--- a/drivers/misc/eeprom/at25.c
+++ b/drivers/misc/eeprom/at25.c
@@ -43,6 +43,7 @@ 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 AT25_CHIP_ERASE 0x62 /* Erase whole chip */
#define AT25_SR_nRDY 0x01 /* nRDY = write-in-progress */
#define AT25_SR_WEN 0x02 /* write enable (latched) */
@@ -52,6 +53,7 @@ struct at25_data {
#define AT25_INSTR_BIT3 0x08 /* Additional address bit in instr */
+
#define EE_MAXADDRLEN 3 /* 24 bit addresses, up to 2 MBytes */
/* Specs often allow 5 msec for a page write, sometimes 20 msec;
@@ -59,6 +61,8 @@ struct at25_data {
*/
#define EE_TIMEOUT 25
+#define ERASE_TIMEOUT 2020
+
/*-------------------------------------------------------------------------*/
#define io_limit PAGE_SIZE /* bytes */
@@ -304,6 +308,71 @@ static int at25_fw_to_chip(struct device *dev, struct spi_eeprom *chip)
return 0;
}
+static void _eeprom_at25_store_erase_locked(struct at25_data *at25)
+{
+ unsigned long timeout, retries;
+ int sr, status;
+ u8 cp;
+
+ cp = AT25_WREN;
+ status = spi_write(at25->spi, &cp, 1);
+ if (status < 0) {
+ dev_dbg(&at25->spi->dev, "ERASE WREN --> %d\n", status);
+ return;
+ }
+ cp = AT25_CHIP_ERASE;
+ status = spi_write(at25->spi, &cp, 1);
+ if (status < 0) {
+ dev_dbg(&at25->spi->dev, "CHIP_ERASE --> %d\n", status);
+ return;
+ }
+ /* Wait for non-busy status */
+ timeout = jiffies + msecs_to_jiffies(ERASE_TIMEOUT);
+ retries = 0;
+ do {
+ sr = spi_w8r8(at25->spi, AT25_RDSR);
+ if (sr < 0 || (sr & AT25_SR_nRDY)) {
+ dev_dbg(&at25->spi->dev,
+ "rdsr --> %d (%02x)\n", sr, sr);
+ /* at HZ=100, this is sloooow */
+ msleep(1);
+ continue;
+ }
+ if (!(sr & AT25_SR_nRDY))
+ return;
+ } while (retries++ < 200 || time_before_eq(jiffies, timeout));
+
+ if ((sr < 0) || (sr & AT25_SR_nRDY)) {
+ dev_err(&at25->spi->dev,
+ "chip erase, timeout after %u msecs\n",
+ jiffies_to_msecs(jiffies -
+ (timeout - ERASE_TIMEOUT)));
+ status = -ETIMEDOUT;
+ return;
+ }
+}
+
+
+static ssize_t eeprom_at25_store_erase(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct at25_data *at25 = dev_get_drvdata(dev);
+ int erase = 0;
+
+ sscanf(buf, "%d", &erase);
+ if (erase) {
+ mutex_lock(&at25->lock);
+ _eeprom_at25_store_erase_locked(at25);
+ mutex_unlock(&at25->lock);
+ }
+
+ return count;
+}
+
+static DEVICE_ATTR(erase, S_IWUSR, NULL, eeprom_at25_store_erase);
+
+
static int at25_probe(struct spi_device *spi)
{
struct at25_data *at25 = NULL;
@@ -376,11 +445,15 @@ static int at25_probe(struct spi_device *spi)
at25->chip.name,
(chip.flags & EE_READONLY) ? " (readonly)" : "",
at25->chip.page_size);
+
+ if (!(chip.flags & EE_READONLY))
+ if (device_create_file(&spi->dev, &dev_attr_erase))
+ dev_err(&spi->dev, "can't create erase interface\n");
+
return 0;
}
/*-------------------------------------------------------------------------*/
-
static const struct of_device_id at25_of_match[] = {
{ .compatible = "atmel,at25", },
{ }
--
2.20.1
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