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Subject[PATCH] at25: DeviceTree support added
Date
From: Frederic Lambert <frdrc66@gmail.com>

Signed-off-by: Frederic Lambert <frdrc66@gmail.com>
Signed-off-by: Frederic LAMBERT <frdrc66@gmail.com>
---
Documentation/devicetree/bindings/spi/spi-bus.txt | 19 ++++++
drivers/misc/eeprom/at25.c | 62 ++++++++++++++++----
2 files changed, 68 insertions(+), 13 deletions(-)
diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt
index e782add..168ac87 100644
--- a/Documentation/devicetree/bindings/spi/spi-bus.txt
+++ b/Documentation/devicetree/bindings/spi/spi-bus.txt
@@ -33,6 +33,16 @@ contain the following properties.
shifted clock phase (CPHA) mode
- spi-cs-high - (optional) Empty property indicating device requires
chip select active high
+For SPI eeprom using driver 'at25', slave nodes shall also contain the
+following properties.
+- byte_len - device RAM size
+- dev_name - device name
+- pagesize - for writes (see at25.c)
+- flags - adressing mode and R/O flag
+ - bit 0: 8 bits addrs (EE_ADDR1)
+ - bit 1: 16 bits addrs (EE_ADDR2)
+ - bit 2: 24 bits addrs (EE_ADDR3)
+ - bit 3: disallow writes (EE_READONLY)

SPI example for an MPC5200 SPI bus:
spi@f00 {
@@ -54,4 +64,13 @@ SPI example for an MPC5200 SPI bus:
spi-max-frequency = <100000>;
reg = <1>;
};
+ at25@0 {
+ compatible = "eeprom,at25";
+ spi-max-frequency = <2500000>;
+ reg = <3>;
+ byte_len = <131072>;
+ dev_name = "CY14B101P";
+ pagesize = <128>;
+ flags = <4>; // EE_ADDR3
+ };
};
diff --git a/drivers/misc/eeprom/at25.c b/drivers/misc/eeprom/at25.c
index c627e41..b4dd9f0 100644
--- a/drivers/misc/eeprom/at25.c
+++ b/drivers/misc/eeprom/at25.c
@@ -16,11 +16,11 @@
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/sched.h>
+#include <linux/of.h>

#include <linux/spi/spi.h>
#include <linux/spi/eeprom.h>

-
/*
* NOTE: this is an *EEPROM* driver. The vagaries of product naming
* mean that some AT25 products are EEPROMs, and others are FLASH.
@@ -288,29 +288,65 @@ static ssize_t at25_mem_write(struct memory_accessor *mem, const char *buf,
}

/*-------------------------------------------------------------------------*/
-
static int at25_probe(struct spi_device *spi)
{
struct at25_data *at25 = NULL;
- const struct spi_eeprom *chip;
+ struct spi_eeprom chip;
int err;
int sr;
int addrlen;

/* Chip description */
- chip = spi->dev.platform_data;
- if (!chip) {
+ if (spi->dev.platform_data) {
+
+ chip = *(struct spi_eeprom *)spi->dev.platform_data;
+ } else {
+#ifdef CONFIG_OF
+ const char *dev_name;
+ int len;
+ u32 value;
+
+ /* get FLAGS property from device tree */
+ err = of_property_read_u32(spi->dev.of_node, "flags", &value);
+ if (err) {
+ dev_dbg(&spi->dev, "unsupported address type\n");
+ goto fail;
+ }
+ chip.flags = value;
+ err = of_property_read_u32(spi->dev.of_node, "byte_len",
+ &chip.byte_len);
+ if (err) {
+ dev_dbg(&spi->dev, "byte_len missing from devtree\n");
+ goto fail;
+ }
+ err = of_property_read_u32(spi->dev.of_node, "pagesize",
+ &value);
+ if (err) {
+ dev_dbg(&spi->dev, "pagesize missing from devtre\n");
+ goto fail;
+ }
+ chip.page_size = value;
+ dev_name = of_get_property(spi->dev.of_node, "dev_name", &len);
+ if (!dev_name || len > sizeof(chip.name)) {
+ err = -ENODEV;
+ dev_dbg(&spi->dev, "dev_name missing from devtree\n");
+ goto fail;
+ }
+ strcpy(chip.name, dev_name);
+ chip.setup = 0;
+#else
dev_dbg(&spi->dev, "no chip description\n");
err = -ENODEV;
goto fail;
+#endif
}

/* For now we only support 8/16/24 bit addressing */
- if (chip->flags & EE_ADDR1)
+ if (chip.flags & EE_ADDR1)
addrlen = 1;
- else if (chip->flags & EE_ADDR2)
+ else if (chip.flags & EE_ADDR2)
addrlen = 2;
- else if (chip->flags & EE_ADDR3)
+ else if (chip.flags & EE_ADDR3)
addrlen = 3;
else {
dev_dbg(&spi->dev, "unsupported address type\n");
@@ -335,7 +371,7 @@ static int at25_probe(struct spi_device *spi)
}

mutex_init(&at25->lock);
- at25->chip = *chip;
+ at25->chip = chip;
at25->spi = spi_dev_get(spi);
dev_set_drvdata(&spi->dev, at25);
at25->addrlen = addrlen;
@@ -356,7 +392,7 @@ static int at25_probe(struct spi_device *spi)
at25->mem.read = at25_mem_read;

at25->bin.size = at25->chip.byte_len;
- if (!(chip->flags & EE_READONLY)) {
+ if (!(chip.flags & EE_READONLY)) {
at25->bin.write = at25_bin_write;
at25->bin.attr.mode |= S_IWUSR;
at25->mem.write = at25_mem_write;
@@ -366,8 +402,8 @@ static int at25_probe(struct spi_device *spi)
if (err)
goto fail;

- if (chip->setup)
- chip->setup(&at25->mem, chip->context);
+ if (chip.setup)
+ chip.setup(&at25->mem, chip.context);

dev_info(&spi->dev, "%Zd %s %s eeprom%s, pagesize %u\n",
(at25->bin.size < 1024)
@@ -375,7 +411,7 @@ static int at25_probe(struct spi_device *spi)
: (at25->bin.size / 1024),
(at25->bin.size < 1024) ? "Byte" : "KByte",
at25->chip.name,
- (chip->flags & EE_READONLY) ? " (readonly)" : "",
+ (chip.flags & EE_READONLY) ? " (readonly)" : "",
at25->chip.page_size);
return 0;
fail:
--
1.7.4.1


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