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135 lines
4.1 KiB
Diff
135 lines
4.1 KiB
Diff
Subject: [PATCH 2/3] I2C: at24: add kernel interface for reading/writing EEPROM
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Date: Monday 25 August 2008
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From: Kevin Hilman <khilman@deeprootsystems.com>
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To: davinci-linux-open-source@linux.davincidsp.com
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This patch adds an interface by which other kernel code can read/write
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detected EEPROM.
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The platform code registers a 'setup' callback with the
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at24_platform_data. When the at24 driver detects an EEPROM, it fills
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out the read and write functions of at24_iface and calls the setup
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callback. The platform code can then use the read/write functions in
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the at24_iface struct for reading and writing the EEPROM.
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Original idea, review and updates by David Brownell <david-b@pacbell.net>
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Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
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---
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drivers/i2c/chips/at24.c | 42 +++++++++++++++++++++++++++++++++++-------
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include/linux/i2c/at24.h | 10 ++++++++++
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2 files changed, 45 insertions(+), 7 deletions(-)
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--- a/drivers/i2c/chips/at24.c
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+++ b/drivers/i2c/chips/at24.c
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@@ -53,6 +53,7 @@
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struct at24_data {
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struct at24_platform_data chip;
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+ struct at24_iface iface;
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bool use_smbus;
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/*
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@@ -264,13 +265,6 @@ static ssize_t at24_bin_read(struct kobj
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/*
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- * REVISIT: export at24_bin{read,write}() to let other kernel code use
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- * eeprom data. For example, it might hold a board's Ethernet address, or
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- * board-specific calibration data generated on the manufacturing floor.
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- */
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-
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-
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-/*
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* Note that if the hardware write-protect pin is pulled high, the whole
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* chip is normally write protected. But there are plenty of product
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* variants here, including OTP fuses and partial chip protect.
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@@ -386,6 +380,30 @@ static ssize_t at24_bin_write(struct kob
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/*-------------------------------------------------------------------------*/
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+/*
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+ * This lets other kernel code access the eeprom data. For example, it
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+ * might hold a board's Ethernet address, or board-specific calibration
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+ * data generated on the manufacturing floor.
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+ */
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+
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+static ssize_t at24_iface_read(struct at24_iface *iface, char *buf,
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+ off_t offset, size_t count)
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+{
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+ struct at24_data *at24 = container_of(iface, struct at24_data, iface);
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+
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+ return at24_eeprom_read(at24, buf, offset, count);
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+}
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+
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+static ssize_t at24_iface_write(struct at24_iface *iface, char *buf,
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+ off_t offset, size_t count)
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+{
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+ struct at24_data *at24 = container_of(iface, struct at24_data, iface);
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+
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+ return at24_eeprom_write(at24, buf, offset, count);
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+}
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+
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+/*-------------------------------------------------------------------------*/
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+
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static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
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{
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struct at24_platform_data chip;
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@@ -413,6 +431,9 @@ static int at24_probe(struct i2c_client
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* is recommended anyhow.
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*/
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chip.page_size = 1;
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+
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+ chip.setup = NULL;
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+ chip.context = NULL;
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}
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if (!is_power_of_2(chip.byte_len))
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@@ -449,6 +470,9 @@ static int at24_probe(struct i2c_client
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goto err_out;
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}
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+ at24->iface.read = at24_iface_read;
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+ at24->iface.write = at24_iface_write;
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+
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mutex_init(&at24->lock);
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at24->use_smbus = use_smbus;
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at24->chip = chip;
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@@ -521,6 +545,10 @@ static int at24_probe(struct i2c_client
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at24->write_max,
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use_smbus ? ", use_smbus" : "");
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+ /* export data to kernel code */
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+ if (chip.setup)
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+ chip.setup(&at24->iface, chip.context);
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+
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return 0;
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err_clients:
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--- a/include/linux/i2c/at24.h
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+++ b/include/linux/i2c/at24.h
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@@ -15,6 +15,13 @@
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* is bigger than what the chip actually supports!
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*/
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+struct at24_iface {
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+ ssize_t (*read)(struct at24_iface *, char *buf, off_t offset,
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+ size_t count);
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+ ssize_t (*write)(struct at24_iface *, char *buf, off_t offset,
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+ size_t count);
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+};
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+
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struct at24_platform_data {
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u32 byte_len; /* size (sum of all addr) */
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u16 page_size; /* for writes */
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@@ -23,6 +30,9 @@ struct at24_platform_data {
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#define AT24_FLAG_READONLY 0x40 /* sysfs-entry will be read-only */
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#define AT24_FLAG_IRUGO 0x20 /* sysfs-entry will be world-readable */
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#define AT24_FLAG_TAKE8ADDR 0x10 /* take always 8 addresses (24c00) */
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+
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+ int (*setup)(struct at24_iface *, void *context);
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+ void *context;
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};
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#endif /* _LINUX_AT24_H */
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