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Date: Wed, 22 Aug 2012 12:03:57 -0700
From: David Daney <ddaney.cavm@...il.com>
To: devicetree-discuss@...ts.ozlabs.org,
Grant Likely <grant.likely@...retlab.ca>,
Rob Herring <rob.herring@...xeda.com>
Cc: linux-kernel@...r.kernel.org, David Daney <david.daney@...ium.com>,
Alexandre Pereira da Silva <aletes.xgr@...il.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Michael Hennerich <michael.hennerich@...log.com>,
Axel Lin <axel.lin@...il.com>
Subject: [PATCH 1/2] misc/at25, dt: Improve at25 SPI eeprom device tree bindings.
From: David Daney <david.daney@...ium.com>
Commit 002176db (misc: at25: Parse dt settings) added device tree
bindings the differ significantly in style from the I2C EEPROM
bindings and don't seem well vetted. Here I deprecate (but still
support) the "at25,*" properties, and add what I hope is a better
alternative. These new bindings also happen to be deployed in the
field and were previously submitted for consideration here:
https://lists.ozlabs.org/pipermail/devicetree-discuss/2012-May/015556.html
The advantages of the new bindings are that they are similar to the
I2C EEPROMs and they don't conflate read-only and the address width
modes in a binary encoded blob.
Signed-off-by: David Daney <david.daney@...ium.com>
Cc: Alexandre Pereira da Silva <aletes.xgr@...il.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Michael Hennerich <michael.hennerich@...log.com>
Cc: Axel Lin <axel.lin@...il.com>
---
Documentation/devicetree/bindings/misc/at25.txt | 34 +++++++---
drivers/misc/eeprom/at25.c | 83 +++++++++++++++++--------
2 files changed, 82 insertions(+), 35 deletions(-)
diff --git a/Documentation/devicetree/bindings/misc/at25.txt b/Documentation/devicetree/bindings/misc/at25.txt
index ab3c327..1d34471 100644
--- a/Documentation/devicetree/bindings/misc/at25.txt
+++ b/Documentation/devicetree/bindings/misc/at25.txt
@@ -1,21 +1,35 @@
-Atmel AT25 eeprom
+EEPROMs (SPI) compatible with Atmel at25.
Required properties:
- compatible : "atmel,at25".
- reg : chip select number
- spi-max-frequency : max spi frequency to use
+- pagesize : size of the eeprom page
+- size : total eeprom size in bytes
+- address-width : number of address bits (one of 8, 16, or 24)
+Optional properties:
+- spi-cpha : SPI shifted clock phase, as per spi-bus bindings.
+- spi-cpol : SPI inverse clock polarity, as per spi-bus bindings.
+- read-only : this parameter-less property disables writes to the eeprom
+
+Obsolete legacy properties are can be used in place of "size", "pagesize",
+"address-width", and "read-only":
- at25,byte-len : total eeprom size in bytes
- at25,addr-mode : addr-mode flags, as defined in include/linux/spi/eeprom.h
- at25,page-size : size of the eeprom page
-Examples:
-at25@0 {
- compatible = "atmel,at25";
- reg = <0>
- spi-max-frequency = <5000000>;
+Additional compatible properties are also allowed.
+
+Example:
+ at25@0 {
+ compatible = "atmel,at25", "st,m95256";
+ reg = <0>
+ spi-max-frequency = <5000000>;
+ spi-cpha;
+ spi-cpol;
- at25,byte-len = <0x8000>;
- at25,addr-mode = <2>;
- at25,page-size = <64>;
-};
+ pagesize = <64>;
+ size = <32768>;
+ address-width = <16>;
+ };
diff --git a/drivers/misc/eeprom/at25.c b/drivers/misc/eeprom/at25.c
index 25003d6..4ed93dd 100644
--- a/drivers/misc/eeprom/at25.c
+++ b/drivers/misc/eeprom/at25.c
@@ -302,6 +302,61 @@ static ssize_t at25_mem_write(struct memory_accessor *mem, const char *buf,
/*-------------------------------------------------------------------------*/
+static int at25_np_to_chip(struct device *dev,
+ struct device_node *np,
+ struct spi_eeprom *chip)
+{
+ u32 val;
+
+ memset(chip, 0, sizeof(*chip));
+ strncpy(chip->name, np->name, sizeof(chip->name));
+
+ if (of_property_read_u32(np, "size", &val) == 0 ||
+ of_property_read_u32(np, "at25,byte-len", &val) == 0) {
+ chip->byte_len = val;
+ } else {
+ dev_err(dev, "Error: missing \"size\" property\n");
+ return -ENODEV;
+ }
+
+ if (of_property_read_u32(np, "pagesize", &val) == 0 ||
+ of_property_read_u32(np, "at25,page-size", &val) == 0) {
+ chip->page_size = (u16)val;
+ } else {
+ dev_err(dev, "Error: missing \"pagesize\" property\n");
+ return -ENODEV;
+ }
+
+ if (of_property_read_u32(np, "at25,addr-mode", &val) == 0) {
+ chip->flags = (u16)val;
+ } else {
+ if (of_property_read_u32(np, "address-width", &val)) {
+ dev_err(dev,
+ "Error: missing \"address-width\" property\n");
+ return -ENODEV;
+ }
+ switch (val) {
+ case 8:
+ chip->flags |= EE_ADDR1;
+ break;
+ case 16:
+ chip->flags |= EE_ADDR2;
+ break;
+ case 24:
+ chip->flags |= EE_ADDR3;
+ break;
+ default:
+ dev_err(dev,
+ "Error: bad \"address-width\" property: %u\n",
+ val);
+ return -ENODEV;
+ }
+ if (of_find_property(np, "read-only", NULL))
+ chip->flags |= EE_READONLY;
+ }
+ return 0;
+}
+
static int at25_probe(struct spi_device *spi)
{
struct at25_data *at25 = NULL;
@@ -314,33 +369,11 @@ static int at25_probe(struct spi_device *spi)
/* Chip description */
if (!spi->dev.platform_data) {
if (np) {
- u32 val;
-
- memset(&chip, 0, sizeof(chip));
- strncpy(chip.name, np->name, 10);
-
- err = of_property_read_u32(np, "at25,byte-len", &val);
- if (err) {
- dev_dbg(&spi->dev, "invalid chip dt description\n");
- goto fail;
- }
- chip.byte_len = val;
-
- err = of_property_read_u32(np, "at25,addr-mode", &val);
- if (err) {
- dev_dbg(&spi->dev, "invalid chip dt description\n");
- goto fail;
- }
- chip.flags = (u16)val;
-
- err = of_property_read_u32(np, "at25,page-size", &val);
- if (err) {
- dev_dbg(&spi->dev, "invalid chip dt description\n");
+ err = at25_np_to_chip(&spi->dev, np, &chip);
+ if (err)
goto fail;
- }
- chip.page_size = (u16)val;
} else {
- dev_dbg(&spi->dev, "no chip description\n");
+ dev_err(&spi->dev, "Error: no chip description\n");
err = -ENODEV;
goto fail;
}
--
1.7.11.4
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