On 10/14/2014 02:53 PM, Jiri Prchal wrote:
This patch adds driver for Cypress FRAMs on SPI bus, such as FM25V05, FM25V10
etc.
Reworked from at25 driver:
- simplified writing since data are written without erasing and waiting to
finish write cycle
- add reading device ID and choose size and addr len from it
- add serial number reading and exporting it to sysfs
(...)
+static int fm25_probe(struct spi_device *spi)
+{
+ struct fm25_data *fm25 = NULL;
+ struct spi_eeprom chip;
+ struct device_node *np = spi->dev.of_node;
+ int err;
+ char id[FM25_ID_LEN];
+
+ /* Chip description */
+ if (!spi->dev.platform_data) {
+ if (np) {
+ err = fm25_np_to_chip(&spi->dev, np, &chip);
+ if (err)
+ return err;
+ } else {
+ dev_err(&spi->dev, "Error: no chip description\n");
+ return -ENODEV;
+ }
+ } else
+ chip = *(struct spi_eeprom *)spi->dev.platform_data;
+
+ fm25 = devm_kzalloc(&spi->dev, sizeof(struct fm25_data), GFP_KERNEL);
+ if (!fm25)
+ return -ENOMEM;
sizeof(*fm25)..?
+
+ mutex_init(&fm25->lock);
+ fm25->chip = chip;
+ fm25->spi = spi_dev_get(spi);
+ spi_set_drvdata(spi, fm25);
+
+ /* Get ID of chip */
+ fm25_id_read(fm25, id);
+ if (id[6] != 0xc2) {
+ dev_err(&spi->dev, "Error: no Cypress FRAM (id %02x)\n", id[6]);
+ return -ENODEV;
+ }
+ /* set size found in ID */
+ switch (id[7]) {
+ case 0x21:
+ fm25->chip.byte_len = 16 * 1024;
+ break;
+ case 0x22:
+ fm25->chip.byte_len = 32 * 1024;
+ break;
+ case 0x23:
+ fm25->chip.byte_len = 64 * 1024;
+ break;
+ case 0x24:
+ fm25->chip.byte_len = 128 * 1024;
+ break;
+ case 0x25:
+ fm25->chip.byte_len = 256 * 1024;
+ break;
+ default:
+ dev_err(&spi->dev,
+ "Error: unsupported size (id %02x)\n", id[7]);
+ return -ENODEV;
+ break;
+ }
The preferred way of using
switchhttp://lxr.free-electrons.com/source/Documentation/CodingStyle#L38
+
+ if (fm25->chip.byte_len > 64 * 1024) {
+ fm25->addrlen = 3;
+ fm25->chip.flags |= EE_ADDR3;
+ }
+ else {
+ fm25->addrlen = 2;
+ fm25->chip.flags |= EE_ADDR2;
+ }
+
+ if (id[8])
+ fm25->has_sernum = 1;
+ else
+ fm25->has_sernum = 0;
+
+ /* Export the EEPROM bytes through sysfs, since that's convenient.
+ * And maybe to other kernel code; it might hold a board's Ethernet
+ * address, or board-specific calibration data generated on the
+ * manufacturing floor.
+ *
+ * Default to root-only access to the data; EEPROMs often hold data
+ * that's sensitive for read and/or write, like ethernet addresses,
+ * security codes, board-specific manufacturing calibrations, etc.
+ */
+ sysfs_bin_attr_init(&fm25->bin);
+ fm25->bin.attr.name = "fram";
+ fm25->bin.attr.mode = S_IRUGO;
+ fm25->bin.read = fm25_bin_read;
+ fm25->mem.read = fm25_mem_read;
+
+ fm25->bin.size = fm25->chip.byte_len;
+ if (!(chip.flags & EE_READONLY)) {
+ fm25->bin.write = fm25_bin_write;
+ fm25->bin.attr.mode |= S_IWUSR | S_IWGRP;
+ fm25->mem.write = fm25_mem_write;
+ }
+
+ err = sysfs_create_bin_file(&spi->dev.kobj, &fm25->bin);
+ if (err)
+ return err;
+
+ /* Export the FM25 serial number */
+ if (fm25->has_sernum) {
+ err = device_create_file(&spi->dev, &dev_attr_sernum);
+ if (err)
+ return err;
+ }
+
+ if (chip.setup)
+ chip.setup(&fm25->mem, chip.context);
+
+ dev_info(&spi->dev, "%Zd %s %s fram%s\n",
+ (fm25->bin.size < 1024)
+ ? fm25->bin.size
+ : (fm25->bin.size / 1024),
+ (fm25->bin.size < 1024) ? "Byte" : "KByte",
+ fm25->chip.name,
+ (chip.flags & EE_READONLY) ? " (readonly)" : "");
+ return 0;
+}
+
+static int fm25_remove(struct spi_device *spi)
+{
+ struct fm25_data *fm25;
+
+ fm25 = spi_get_drvdata(spi);
Both statements can be combine.
struct fm25_datd *fm25 = spi_get_drvdata(spi);
+ sysfs_remove_bin_file(&spi->dev.kobj, &fm25->bin);
+ if (fm25->has_sernum)
+ device_remove_file(&spi->dev, &dev_attr_sernum);
+ return 0;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static const struct of_device_id fm25_of_match[] = {
+ { .compatible = "cypress,fm25", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, fm25_of_match);
+
+static struct spi_driver fm25_driver = {
+ .driver = {
+ .name = "fm25",
+ .owner = THIS_MODULE,
Can remove this filed. It will populate by module_spi_driver().
+ .of_match_table = fm25_of_match,
+ },
+ .probe = fm25_probe,
+ .remove = fm25_remove,
+};
+
+module_spi_driver(fm25_driver);
+
+MODULE_DESCRIPTION("Driver for Cypress SPI FRAMs");
+MODULE_AUTHOR("Jiri Prchal");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("spi:fram");
--
Regards,
Varka Bhadram.
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