memory_accessor: implement the new memory_accessor interfaces for SPI EEPROMs
- Define new setup() hook to export the accessor - Implement accessor methods Moves some error checking out of the sysfs interface code into the layer below it, which is now shared by both sysfs and memory access code. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com> Cc: Jean Delvare <khali@linux-fr.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -30,6 +30,7 @@
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struct at25_data {
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struct at25_data {
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struct spi_device *spi;
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struct spi_device *spi;
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struct memory_accessor mem;
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struct mutex lock;
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struct mutex lock;
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struct spi_eeprom chip;
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struct spi_eeprom chip;
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struct bin_attribute bin;
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struct bin_attribute bin;
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@ -75,6 +76,13 @@ at25_ee_read(
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struct spi_transfer t[2];
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struct spi_transfer t[2];
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struct spi_message m;
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struct spi_message m;
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if (unlikely(offset >= at25->bin.size))
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return 0;
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if ((offset + count) > at25->bin.size)
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count = at25->bin.size - offset;
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if (unlikely(!count))
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return count;
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cp = command;
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cp = command;
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*cp++ = AT25_READ;
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*cp++ = AT25_READ;
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@ -127,13 +135,6 @@ at25_bin_read(struct kobject *kobj, struct bin_attribute *bin_attr,
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dev = container_of(kobj, struct device, kobj);
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dev = container_of(kobj, struct device, kobj);
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at25 = dev_get_drvdata(dev);
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at25 = dev_get_drvdata(dev);
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if (unlikely(off >= at25->bin.size))
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return 0;
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if ((off + count) > at25->bin.size)
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count = at25->bin.size - off;
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if (unlikely(!count))
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return count;
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return at25_ee_read(at25, buf, off, count);
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return at25_ee_read(at25, buf, off, count);
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}
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}
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@ -146,6 +147,13 @@ at25_ee_write(struct at25_data *at25, char *buf, loff_t off, size_t count)
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unsigned buf_size;
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unsigned buf_size;
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u8 *bounce;
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u8 *bounce;
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if (unlikely(off >= at25->bin.size))
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return -EFBIG;
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if ((off + count) > at25->bin.size)
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count = at25->bin.size - off;
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if (unlikely(!count))
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return count;
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/* Temp buffer starts with command and address */
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/* Temp buffer starts with command and address */
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buf_size = at25->chip.page_size;
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buf_size = at25->chip.page_size;
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if (buf_size > io_limit)
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if (buf_size > io_limit)
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@ -253,18 +261,31 @@ at25_bin_write(struct kobject *kobj, struct bin_attribute *bin_attr,
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dev = container_of(kobj, struct device, kobj);
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dev = container_of(kobj, struct device, kobj);
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at25 = dev_get_drvdata(dev);
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at25 = dev_get_drvdata(dev);
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if (unlikely(off >= at25->bin.size))
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return -EFBIG;
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if ((off + count) > at25->bin.size)
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count = at25->bin.size - off;
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if (unlikely(!count))
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return count;
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return at25_ee_write(at25, buf, off, count);
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return at25_ee_write(at25, buf, off, count);
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}
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}
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/*-------------------------------------------------------------------------*/
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/*-------------------------------------------------------------------------*/
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/* Let in-kernel code access the eeprom data. */
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static ssize_t at25_mem_read(struct memory_accessor *mem, char *buf,
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off_t offset, size_t count)
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{
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struct at25_data *at25 = container_of(mem, struct at25_data, mem);
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return at25_ee_read(at25, buf, offset, count);
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}
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static ssize_t at25_mem_write(struct memory_accessor *mem, char *buf,
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off_t offset, size_t count)
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{
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struct at25_data *at25 = container_of(mem, struct at25_data, mem);
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return at25_ee_write(at25, buf, offset, count);
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}
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/*-------------------------------------------------------------------------*/
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static int at25_probe(struct spi_device *spi)
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static int at25_probe(struct spi_device *spi)
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{
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{
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struct at25_data *at25 = NULL;
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struct at25_data *at25 = NULL;
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@ -317,6 +338,10 @@ static int at25_probe(struct spi_device *spi)
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at25->addrlen = addrlen;
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at25->addrlen = addrlen;
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/* Export the EEPROM bytes through sysfs, since that's convenient.
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/* Export the EEPROM bytes through sysfs, since that's convenient.
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* And maybe to other kernel code; it might hold a board's Ethernet
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* address, or board-specific calibration data generated on the
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* manufacturing floor.
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*
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* Default to root-only access to the data; EEPROMs often hold data
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* Default to root-only access to the data; EEPROMs often hold data
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* that's sensitive for read and/or write, like ethernet addresses,
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* that's sensitive for read and/or write, like ethernet addresses,
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* security codes, board-specific manufacturing calibrations, etc.
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* security codes, board-specific manufacturing calibrations, etc.
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@ -324,17 +349,22 @@ static int at25_probe(struct spi_device *spi)
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at25->bin.attr.name = "eeprom";
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at25->bin.attr.name = "eeprom";
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at25->bin.attr.mode = S_IRUSR;
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at25->bin.attr.mode = S_IRUSR;
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at25->bin.read = at25_bin_read;
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at25->bin.read = at25_bin_read;
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at25->mem.read = at25_mem_read;
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at25->bin.size = at25->chip.byte_len;
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at25->bin.size = at25->chip.byte_len;
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if (!(chip->flags & EE_READONLY)) {
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if (!(chip->flags & EE_READONLY)) {
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at25->bin.write = at25_bin_write;
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at25->bin.write = at25_bin_write;
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at25->bin.attr.mode |= S_IWUSR;
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at25->bin.attr.mode |= S_IWUSR;
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at25->mem.write = at25_mem_write;
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}
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}
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err = sysfs_create_bin_file(&spi->dev.kobj, &at25->bin);
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err = sysfs_create_bin_file(&spi->dev.kobj, &at25->bin);
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if (err)
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if (err)
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goto fail;
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goto fail;
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if (chip->setup)
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chip->setup(&at25->mem, chip->context);
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dev_info(&spi->dev, "%Zd %s %s eeprom%s, pagesize %u\n",
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dev_info(&spi->dev, "%Zd %s %s eeprom%s, pagesize %u\n",
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(at25->bin.size < 1024)
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(at25->bin.size < 1024)
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? at25->bin.size
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? at25->bin.size
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@ -1,6 +1,8 @@
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#ifndef __LINUX_SPI_EEPROM_H
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#ifndef __LINUX_SPI_EEPROM_H
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#define __LINUX_SPI_EEPROM_H
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#define __LINUX_SPI_EEPROM_H
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#include <linux/memory.h>
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/*
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/*
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* Put one of these structures in platform_data for SPI EEPROMS handled
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* Put one of these structures in platform_data for SPI EEPROMS handled
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* by the "at25" driver. On SPI, most EEPROMS understand the same core
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* by the "at25" driver. On SPI, most EEPROMS understand the same core
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@ -17,6 +19,10 @@ struct spi_eeprom {
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#define EE_ADDR2 0x0002 /* 16 bit addrs */
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#define EE_ADDR2 0x0002 /* 16 bit addrs */
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#define EE_ADDR3 0x0004 /* 24 bit addrs */
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#define EE_ADDR3 0x0004 /* 24 bit addrs */
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#define EE_READONLY 0x0008 /* disallow writes */
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#define EE_READONLY 0x0008 /* disallow writes */
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/* for exporting this chip's data to other kernel code */
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void (*setup)(struct memory_accessor *mem, void *context);
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void *context;
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};
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};
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#endif /* __LINUX_SPI_EEPROM_H */
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#endif /* __LINUX_SPI_EEPROM_H */
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