1 files changed, 233 insertions, 162 deletions

diff --git a/drivers/misc/eeprom/ee1004.c b/drivers/misc/eeprom/ee1004.c
index 276c1690ea1b..e13f9fdd9d7b 100644
--- a/drivers/misc/eeprom/ee1004.c
+++ b/drivers/misc/eeprom/ee1004.c
@@ -1,24 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * ee1004 - driver for DDR4 SPD EEPROMs
  *
- * Copyright (C) 2017 Jean Delvare
+ * Copyright (C) 2017-2019 Jean Delvare
  *
  * Based on the at24 driver:
  * Copyright (C) 2005-2007 David Brownell
  * Copyright (C) 2008 Wolfram Sang, Pengutronix
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
  */
 
+#include <linux/device.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/nvmem-provider.h>
 
 /*
  * DDR4 memory modules use special EEPROMs following the Jedec EE1004
@@ -35,62 +33,130 @@
  * over performance.
  */
 
+#define EE1004_MAX_BUSSES		8
 #define EE1004_ADDR_SET_PAGE		0x36
-#define EE1004_EEPROM_SIZE		512
+#define EE1004_NUM_PAGES		2
 #define EE1004_PAGE_SIZE		256
 #define EE1004_PAGE_SHIFT		8
+#define EE1004_EEPROM_SIZE		(EE1004_PAGE_SIZE * EE1004_NUM_PAGES)
 
 /*
  * Mutex protects ee1004_set_page and ee1004_dev_count, and must be held
  * from page selection to end of read.
  */
 static DEFINE_MUTEX(ee1004_bus_lock);
-static struct i2c_client *ee1004_set_page[2];
-static unsigned int ee1004_dev_count;
-static int ee1004_current_page;
+
+static struct ee1004_bus_data {
+	struct i2c_adapter *adap;
+	struct i2c_client *set_page[EE1004_NUM_PAGES];
+	unsigned int dev_count;
+	int current_page;
+} ee1004_bus_data[EE1004_MAX_BUSSES];
 
 static const struct i2c_device_id ee1004_ids[] = {
-	{ "ee1004", 0 },
+	{ "ee1004" },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, ee1004_ids);
 
 /*-------------------------------------------------------------------------*/
 
+static struct ee1004_bus_data *ee1004_get_bus_data(struct i2c_adapter *adap)
+{
+	int i;
+
+	for (i = 0; i < EE1004_MAX_BUSSES; i++)
+		if (ee1004_bus_data[i].adap == adap)
+			return ee1004_bus_data + i;
+
+	/* If not existent yet, create new entry */
+	for (i = 0; i < EE1004_MAX_BUSSES; i++)
+		if (!ee1004_bus_data[i].adap) {
+			ee1004_bus_data[i].adap = adap;
+			return ee1004_bus_data + i;
+		}
+
+	return NULL;
+}
+
+static int ee1004_get_current_page(struct ee1004_bus_data *bd)
+{
+	int err;
+
+	err = i2c_smbus_read_byte(bd->set_page[0]);
+	if (err == -ENXIO) {
+		/* Nack means page 1 is selected */
+		return 1;
+	}
+	if (err < 0) {
+		/* Anything else is a real error, bail out */
+		return err;
+	}
+
+	/* Ack means page 0 is selected, returned value meaningless */
+	return 0;
+}
+
+static int ee1004_set_current_page(struct i2c_client *client, int page)
+{
+	struct ee1004_bus_data *bd = i2c_get_clientdata(client);
+	int ret;
+
+	if (page == bd->current_page)
+		return 0;
+
+	/* Data is ignored */
+	ret = i2c_smbus_write_byte(bd->set_page[page], 0x00);
+	/*
+	 * Don't give up just yet. Some memory modules will select the page
+	 * but not ack the command. Check which page is selected now.
+	 */
+	if (ret == -ENXIO && ee1004_get_current_page(bd) == page)
+		ret = 0;
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to select page %d (%d)\n", page, ret);
+		return ret;
+	}
+
+	dev_dbg(&client->dev, "Selected page %d\n", page);
+	bd->current_page = page;
+
+	return 0;
+}
+
 static ssize_t ee1004_eeprom_read(struct i2c_client *client, char *buf,
 				  unsigned int offset, size_t count)
 {
-	int status;
+	int status, page;
+
+	page = offset >> EE1004_PAGE_SHIFT;
+	offset &= (1 << EE1004_PAGE_SHIFT) - 1;
+
+	status = ee1004_set_current_page(client, page);
+	if (status)
+		return status;
 
-	if (count > I2C_SMBUS_BLOCK_MAX)
-		count = I2C_SMBUS_BLOCK_MAX;
 	/* Can't cross page boundaries */
-	if (unlikely(offset + count > EE1004_PAGE_SIZE))
+	if (offset + count > EE1004_PAGE_SIZE)
 		count = EE1004_PAGE_SIZE - offset;
 
-	status = i2c_smbus_read_i2c_block_data_or_emulated(client, offset,
-							   count, buf);
-	dev_dbg(&client->dev, "read %zu@%d --> %d\n", count, offset, status);
+	if (count > I2C_SMBUS_BLOCK_MAX)
+		count = I2C_SMBUS_BLOCK_MAX;
 
-	return status;
+	return i2c_smbus_read_i2c_block_data_or_emulated(client, offset, count, buf);
 }
 
-static ssize_t ee1004_read(struct file *filp, struct kobject *kobj,
-			   struct bin_attribute *bin_attr,
-			   char *buf, loff_t off, size_t count)
+static int ee1004_read(void *priv, unsigned int off, void *val, size_t count)
 {
-	struct device *dev = kobj_to_dev(kobj);
-	struct i2c_client *client = to_i2c_client(dev);
-	size_t requested = count;
-	int page;
+	struct i2c_client *client = priv;
+	char *buf = val;
+	int ret;
 
 	if (unlikely(!count))
 		return count;
 
-	page = off >> EE1004_PAGE_SHIFT;
-	if (unlikely(page > 1))
-		return 0;
-	off &= (1 << EE1004_PAGE_SHIFT) - 1;
+	if (off + count > EE1004_EEPROM_SIZE)
+		return -EINVAL;
 
 	/*
 	 * Read data from chip, protecting against concurrent access to
@@ -99,157 +165,174 @@ static ssize_t ee1004_read(struct file *filp, struct kobject *kobj,
 	mutex_lock(&ee1004_bus_lock);
 
 	while (count) {
-		int status;
-
-		/* Select page */
-		if (page != ee1004_current_page) {
-			/* Data is ignored */
-			status = i2c_smbus_write_byte(ee1004_set_page[page],
-						      0x00);
-			if (status < 0) {
-				dev_err(dev, "Failed to select page %d (%d)\n",
-					page, status);
-				mutex_unlock(&ee1004_bus_lock);
-				return status;
-			}
-			dev_dbg(dev, "Selected page %d\n", page);
-			ee1004_current_page = page;
-		}
-
-		status = ee1004_eeprom_read(client, buf, off, count);
-		if (status < 0) {
+		ret = ee1004_eeprom_read(client, buf, off, count);
+		if (ret < 0) {
 			mutex_unlock(&ee1004_bus_lock);
-			return status;
+			return ret;
 		}
-		buf += status;
-		off += status;
-		count -= status;
 
-		if (off == EE1004_PAGE_SIZE) {
-			page++;
-			off = 0;
-		}
+		buf += ret;
+		off += ret;
+		count -= ret;
 	}
 
 	mutex_unlock(&ee1004_bus_lock);
 
-	return requested;
+	return 0;
 }
 
-static const struct bin_attribute eeprom_attr = {
-	.attr = {
-		.name = "eeprom",
-		.mode = 0444,
-	},
-	.size = EE1004_EEPROM_SIZE,
-	.read = ee1004_read,
-};
-
-static int ee1004_probe(struct i2c_client *client,
-			const struct i2c_device_id *id)
+static void ee1004_probe_temp_sensor(struct i2c_client *client)
 {
-	int err, cnr = 0;
-	const char *slow = NULL;
-
-	/* Make sure we can operate on this adapter */
-	if (!i2c_check_functionality(client->adapter,
-				     I2C_FUNC_SMBUS_READ_BYTE |
-				     I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
-		if (i2c_check_functionality(client->adapter,
-				     I2C_FUNC_SMBUS_READ_BYTE |
-				     I2C_FUNC_SMBUS_READ_WORD_DATA))
-			slow = "word";
-		else if (i2c_check_functionality(client->adapter,
-				     I2C_FUNC_SMBUS_READ_BYTE |
-				     I2C_FUNC_SMBUS_READ_BYTE_DATA))
-			slow = "byte";
-		else
-			return -EPFNOSUPPORT;
+	struct i2c_board_info info = { .type = "jc42" };
+	unsigned short addr = 0x18 | (client->addr & 7);
+	unsigned short addr_list[] = { addr, I2C_CLIENT_END };
+	u8 data[2];
+	int ret;
+
+	/* byte 14, bit 7 is set if temp sensor is present */
+	ret = ee1004_eeprom_read(client, data, 14, 1);
+	if (ret != 1)
+		return;
+
+	if (!(data[0] & BIT(7))) {
+		/*
+		 * If the SPD data suggests that there is no temperature
+		 * sensor, it may still be there for SPD revision 1.0.
+		 * See SPD Annex L, Revision 1 and 2, for details.
+		 * Check DIMM type and SPD revision; if it is a DDR4
+		 * with SPD revision 1.0, check the thermal sensor address
+		 * and instantiate the jc42 driver if a chip is found at
+		 * that address.
+		 * It is not necessary to check if there is a chip at the
+		 * temperature sensor address since i2c_new_scanned_device()
+		 * will do that and return silently if no chip is found.
+		 */
+		ret = ee1004_eeprom_read(client, data, 1, 2);
+		if (ret != 2 || data[0] != 0x10 || data[1] != 0x0c)
+			return;
 	}
+	i2c_new_scanned_device(client->adapter, &info, addr_list, NULL);
+}
 
-	/* Use 2 dummy devices for page select command */
-	mutex_lock(&ee1004_bus_lock);
-	if (++ee1004_dev_count == 1) {
-		for (cnr = 0; cnr < 2; cnr++) {
-			ee1004_set_page[cnr] = i2c_new_dummy(client->adapter,
-						EE1004_ADDR_SET_PAGE + cnr);
-			if (!ee1004_set_page[cnr]) {
-				dev_err(&client->dev,
-					"address 0x%02x unavailable\n",
-					EE1004_ADDR_SET_PAGE + cnr);
-				err = -EADDRINUSE;
-				goto err_clients;
-			}
-		}
-	} else if (i2c_adapter_id(client->adapter) !=
-		   i2c_adapter_id(ee1004_set_page[0]->adapter)) {
-		dev_err(&client->dev,
-			"Driver only supports devices on a single I2C bus\n");
-		err = -EOPNOTSUPP;
-		goto err_clients;
+static void ee1004_cleanup(int idx, struct ee1004_bus_data *bd)
+{
+	if (--bd->dev_count == 0) {
+		while (--idx >= 0)
+			i2c_unregister_device(bd->set_page[idx]);
+		memset(bd, 0, sizeof(struct ee1004_bus_data));
 	}
+}
 
-	/* Remember current page to avoid unneeded page select */
-	err = i2c_smbus_read_byte(ee1004_set_page[0]);
-	if (err == -ENXIO) {
-		/* Nack means page 1 is selected */
-		ee1004_current_page = 1;
-	} else if (err < 0) {
-		/* Anything else is a real error, bail out */
-		goto err_clients;
-	} else {
-		/* Ack means page 0 is selected, returned value meaningless */
-		ee1004_current_page = 0;
-	}
-	dev_dbg(&client->dev, "Currently selected page: %d\n",
-		ee1004_current_page);
+static void ee1004_cleanup_bus_data(void *data)
+{
+	struct ee1004_bus_data *bd = data;
+
+	/* Remove page select clients if this is the last device */
+	mutex_lock(&ee1004_bus_lock);
+	ee1004_cleanup(EE1004_NUM_PAGES, bd);
 	mutex_unlock(&ee1004_bus_lock);
+}
 
-	/* Create the sysfs eeprom file */
-	err = sysfs_create_bin_file(&client->dev.kobj, &eeprom_attr);
-	if (err)
-		goto err_clients_lock;
+static int ee1004_init_bus_data(struct i2c_client *client)
+{
+	struct ee1004_bus_data *bd;
+	int err, cnr = 0;
 
-	dev_info(&client->dev,
-		 "%u byte EE1004-compliant SPD EEPROM, read-only\n",
-		 EE1004_EEPROM_SIZE);
-	if (slow)
-		dev_notice(&client->dev,
-			   "Falling back to %s reads, performance will suffer\n",
-			   slow);
+	bd = ee1004_get_bus_data(client->adapter);
+	if (!bd)
+		return dev_err_probe(&client->dev, -ENOSPC, "Only %d busses supported",
+				     EE1004_MAX_BUSSES);
 
-	return 0;
+	i2c_set_clientdata(client, bd);
 
- err_clients_lock:
-	mutex_lock(&ee1004_bus_lock);
- err_clients:
-	if (--ee1004_dev_count == 0) {
-		for (cnr--; cnr >= 0; cnr--) {
-			i2c_unregister_device(ee1004_set_page[cnr]);
-			ee1004_set_page[cnr] = NULL;
+	if (++bd->dev_count == 1) {
+		/* Use 2 dummy devices for page select command */
+		for (cnr = 0; cnr < EE1004_NUM_PAGES; cnr++) {
+			struct i2c_client *cl;
+
+			cl = i2c_new_dummy_device(client->adapter, EE1004_ADDR_SET_PAGE + cnr);
+			if (IS_ERR(cl)) {
+				err = PTR_ERR(cl);
+				goto err_out;
+			}
+
+			bd->set_page[cnr] = cl;
 		}
+
+		/* Remember current page to avoid unneeded page select */
+		err = ee1004_get_current_page(bd);
+		if (err < 0)
+			goto err_out;
+
+		dev_dbg(&client->dev, "Currently selected page: %d\n", err);
+		bd->current_page = err;
 	}
-	mutex_unlock(&ee1004_bus_lock);
+
+	return 0;
+
+err_out:
+	ee1004_cleanup(cnr, bd);
 
 	return err;
 }
 
-static int ee1004_remove(struct i2c_client *client)
+static int ee1004_probe(struct i2c_client *client)
 {
-	int i;
+	struct nvmem_config config = {
+		.dev = &client->dev,
+		.name = dev_name(&client->dev),
+		.id = NVMEM_DEVID_NONE,
+		.owner = THIS_MODULE,
+		.type = NVMEM_TYPE_EEPROM,
+		.read_only = true,
+		.root_only = false,
+		.reg_read = ee1004_read,
+		.size = EE1004_EEPROM_SIZE,
+		.word_size = 1,
+		.stride = 1,
+		.priv = client,
+		.compat = true,
+		.base_dev = &client->dev,
+	};
+	struct nvmem_device *ndev;
+	int err;
 
-	sysfs_remove_bin_file(&client->dev.kobj, &eeprom_attr);
+	/* Make sure we can operate on this adapter */
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_READ_I2C_BLOCK) &&
+	    !i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_READ_BYTE_DATA))
+		return -EPFNOSUPPORT;
+
+	err = i2c_smbus_read_byte(client);
+	if (err < 0)
+		return -ENODEV;
 
-	/* Remove page select clients if this is the last device */
 	mutex_lock(&ee1004_bus_lock);
-	if (--ee1004_dev_count == 0) {
-		for (i = 0; i < 2; i++) {
-			i2c_unregister_device(ee1004_set_page[i]);
-			ee1004_set_page[i] = NULL;
-		}
+
+	err = ee1004_init_bus_data(client);
+	if (err < 0) {
+		mutex_unlock(&ee1004_bus_lock);
+		return err;
 	}
+
+	ee1004_probe_temp_sensor(client);
+
 	mutex_unlock(&ee1004_bus_lock);
 
+	err = devm_add_action_or_reset(&client->dev, ee1004_cleanup_bus_data,
+				       i2c_get_clientdata(client));
+	if (err < 0)
+		return err;
+
+	ndev = devm_nvmem_register(&client->dev, &config);
+	if (IS_ERR(ndev))
+		return PTR_ERR(ndev);
+
+	dev_info(&client->dev,
+		 "%u byte EE1004-compliant SPD EEPROM, read-only\n",
+		 EE1004_EEPROM_SIZE);
+
 	return 0;
 }
 
@@ -260,21 +343,9 @@ static struct i2c_driver ee1004_driver = {
 		.name = "ee1004",
 	},
 	.probe = ee1004_probe,
-	.remove = ee1004_remove,
 	.id_table = ee1004_ids,
 };
-
-static int __init ee1004_init(void)
-{
-	return i2c_add_driver(&ee1004_driver);
-}
-module_init(ee1004_init);
-
-static void __exit ee1004_exit(void)
-{
-	i2c_del_driver(&ee1004_driver);
-}
-module_exit(ee1004_exit);
+module_i2c_driver(ee1004_driver);
 
 MODULE_DESCRIPTION("Driver for EE1004-compliant DDR4 SPD EEPROMs");
 MODULE_AUTHOR("Jean Delvare");