[PATCH 1/3] eeprom-93cx6: Add (read-only) support for 8-bit mode

From: Ondrej Zary
Date: Mon Nov 24 2014 - 07:12:22 EST


Add read-only support for EEPROMs configured in 8-bit mode (ORG pin connected
to GND).
This will be used by wd719x driver.

Signed-off-by: Ondrej Zary <linux@xxxxxxxxxxxxxxxxxxxx>
---
drivers/misc/eeprom/eeprom_93cx6.c | 62 +++++++++++++++++++++++++++++++++++-
include/linux/eeprom_93cx6.h | 4 +++
2 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/eeprom/eeprom_93cx6.c b/drivers/misc/eeprom/eeprom_93cx6.c
index 0ff4b02..0cf2c9d 100644
--- a/drivers/misc/eeprom/eeprom_93cx6.c
+++ b/drivers/misc/eeprom/eeprom_93cx6.c
@@ -170,7 +170,7 @@ static void eeprom_93cx6_read_bits(struct eeprom_93cx6 *eeprom,
}

/**
- * eeprom_93cx6_read - Read multiple words from eeprom
+ * eeprom_93cx6_read - Read a word from eeprom
* @eeprom: Pointer to eeprom structure
* @word: Word index from where we should start reading
* @data: target pointer where the information will have to be stored
@@ -235,6 +235,66 @@ void eeprom_93cx6_multiread(struct eeprom_93cx6 *eeprom, const u8 word,
EXPORT_SYMBOL_GPL(eeprom_93cx6_multiread);

/**
+ * eeprom_93cx6_readb - Read a byte from eeprom
+ * @eeprom: Pointer to eeprom structure
+ * @word: Byte index from where we should start reading
+ * @data: target pointer where the information will have to be stored
+ *
+ * This function will read a byte of the eeprom data
+ * into the given data pointer.
+ */
+void eeprom_93cx6_readb(struct eeprom_93cx6 *eeprom, const u8 byte,
+ u8 *data)
+{
+ u16 command;
+ u16 tmp;
+
+ /*
+ * Initialize the eeprom register
+ */
+ eeprom_93cx6_startup(eeprom);
+
+ /*
+ * Select the read opcode and the byte to be read.
+ */
+ command = (PCI_EEPROM_READ_OPCODE << (eeprom->width + 1)) | byte;
+ eeprom_93cx6_write_bits(eeprom, command,
+ PCI_EEPROM_WIDTH_OPCODE + eeprom->width + 1);
+
+ /*
+ * Read the requested 8 bits.
+ */
+ eeprom_93cx6_read_bits(eeprom, &tmp, 8);
+ *data = tmp & 0xff;
+
+ /*
+ * Cleanup eeprom register.
+ */
+ eeprom_93cx6_cleanup(eeprom);
+}
+EXPORT_SYMBOL_GPL(eeprom_93cx6_readb);
+
+/**
+ * eeprom_93cx6_multireadb - Read multiple bytes from eeprom
+ * @eeprom: Pointer to eeprom structure
+ * @byte: Index from where we should start reading
+ * @data: target pointer where the information will have to be stored
+ * @words: Number of bytes that should be read.
+ *
+ * This function will read all requested bytes from the eeprom,
+ * this is done by calling eeprom_93cx6_readb() multiple times.
+ */
+void eeprom_93cx6_multireadb(struct eeprom_93cx6 *eeprom, const u8 byte,
+ u8 *data, const u16 bytes)
+{
+ unsigned int i;
+
+ for (i = 0; i < bytes; i++)
+ eeprom_93cx6_readb(eeprom, byte + i, &data[i]);
+}
+EXPORT_SYMBOL_GPL(eeprom_93cx6_multireadb);
+
+/**
* eeprom_93cx6_wren - set the write enable state
* @eeprom: Pointer to eeprom structure
* @enable: true to enable writes, otherwise disable writes
diff --git a/include/linux/eeprom_93cx6.h b/include/linux/eeprom_93cx6.h
index e50f98b..eb0b198 100644
--- a/include/linux/eeprom_93cx6.h
+++ b/include/linux/eeprom_93cx6.h
@@ -75,6 +75,10 @@ extern void eeprom_93cx6_read(struct eeprom_93cx6 *eeprom,
const u8 word, u16 *data);
extern void eeprom_93cx6_multiread(struct eeprom_93cx6 *eeprom,
const u8 word, __le16 *data, const u16 words);
+extern void eeprom_93cx6_readb(struct eeprom_93cx6 *eeprom,
+ const u8 byte, u8 *data);
+extern void eeprom_93cx6_multireadb(struct eeprom_93cx6 *eeprom,
+ const u8 byte, u8 *data, const u16 bytes);

extern void eeprom_93cx6_wren(struct eeprom_93cx6 *eeprom, bool enable);

--
Ondrej Zary

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