[PATCH] Add erase interface for AT25 driver.

[PATCH] Add erase interface for AT25 driver.

[Joe Burmeister]

Signed-off-by: Joe Burmeister <joe.burmeister@devtank.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

Re: [PATCH] Add erase interface for AT25 driver.

[Greg Kroah-Hartman]

On Mon, Aug 05, 2019 at 11:21:26AM +0100, Joe Burmeister wrote:
> Signed-off-by: Joe Burmeister <joe.burmeister@devtank.co.uk>
> ---

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
as indicated below:

- You did not specify a description of why the patch is needed, or
  possibly, any description at all, in the email body.  Please read the
  section entitled "The canonical patch format" in the kernel file,
  Documentation/SubmittingPatches for what is needed in order to
  properly describe the change.

- You did not write a descriptive Subject: for the patch, allowing Greg,
  and everyone else, to know what this patch is all about.  Please read
  the section entitled "The canonical patch format" in the kernel file,
  Documentation/SubmittingPatches for what a proper Subject: line should
  look like.

If you wish to discuss this problem further, or you have questions about
how to resolve this issue, please feel free to respond to this email and
Greg will reply once he has dug out from the pending patches received
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thanks,

greg k-h's patch email bot