diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
| commit | f4cdf7ca9a1fdcca413157df19753f388a5a224e (patch) | |
| tree | 60a31895b2446cd7fa27514e8c2843534a0de0da /drivers/misc/eeprom/ee1004.c | |
| download | linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.tar.gz linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.zip | |
Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediagrafted
Pull media updates from Mauro Carvalho Chehab:
- v4l2-core: added ISP statistics support and per-block validation
- v4l2-core: Allow unknown HDR10 white point and luminance
- New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor
- New codec: Milos: VPU v2.0 codec support
- isp driver: gained support for Dreamchip RPPX1 ISP framework
- vsp1 driver: gained support for RZ/T2H and RZ/N2H
- Novalake driver: gained CVS support for new NVL hardware
- dvb-core: fix feed leak on failed DMX_ADD_PID
- several driver fixes, cleanups and minor improvements
* tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits)
media: ipu-bridge: check all DMI entries when overriding sensor rotation
media: v4l2-async: avoid deleting unlinked ASC entry on link error
media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement
media: intel/ipu6: fix async notifier cleanup leak on parse error
media: staging/ipu7: fix async notifier UAF on probe error path
media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path
media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem()
media: rcar-isp: Fix VSPX reference leaks
media: rcar-isp: Release ISPCORE resources
media: i2c: imx415: Release runtime PM reference on VBLANK error
media: i2c: imx415: Return test pattern write errors
media: renesas: vsp1: Declare index variables in for loop statement
media: renesas: vsp1: Make reset control optional to support platforms without a reset line
media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs
media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs
media: nxp: imx8-isi: Add additional 32-bit RGB format support
media: nxp: imx8-isi: Add 16-bit raw Bayer format support
media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams
media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks
media: nxp: imx8-isi: Correct color map between V4L2 and ISI
...
Diffstat (limited to 'drivers/misc/eeprom/ee1004.c')
| -rw-r--r-- | drivers/misc/eeprom/ee1004.c | 351 |
1 files changed, 351 insertions, 0 deletions
diff --git a/drivers/misc/eeprom/ee1004.c b/drivers/misc/eeprom/ee1004.c new file mode 100644 index 000000000..923f404a4 --- /dev/null +++ b/drivers/misc/eeprom/ee1004.c @@ -0,0 +1,351 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * ee1004 - driver for DDR4 SPD EEPROMs + * + * Copyright (C) 2017-2019 Jean Delvare + * + * Based on the at24 driver: + * Copyright (C) 2005-2007 David Brownell + * Copyright (C) 2008 Wolfram Sang, Pengutronix + */ + +#include <linux/device.h> +#include <linux/i2c.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/nvmem-provider.h> + +/* + * DDR4 memory modules use special EEPROMs following the Jedec EE1004 + * specification. These are 512-byte EEPROMs using a single I2C address + * in the 0x50-0x57 range for data. One of two 256-byte page is selected + * by writing a command to I2C address 0x36 or 0x37 on the same I2C bus. + * + * Therefore we need to request these 2 additional addresses, and serialize + * access to all such EEPROMs with a single mutex. + * + * We assume it is safe to read up to 32 bytes at once from these EEPROMs. + * We use SMBus access even if I2C is available, these EEPROMs are small + * enough, and reading from them infrequent enough, that we favor simplicity + * over performance. + */ + +#define EE1004_MAX_BUSSES 8 +#define EE1004_ADDR_SET_PAGE 0x36 +#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 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" }, + { } +}; +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, page; + + page = offset >> EE1004_PAGE_SHIFT; + offset &= (1 << EE1004_PAGE_SHIFT) - 1; + + status = ee1004_set_current_page(client, page); + if (status) + return status; + + /* Can't cross page boundaries */ + if (offset + count > EE1004_PAGE_SIZE) + count = EE1004_PAGE_SIZE - offset; + + if (count > I2C_SMBUS_BLOCK_MAX) + count = I2C_SMBUS_BLOCK_MAX; + + return i2c_smbus_read_i2c_block_data_or_emulated(client, offset, count, buf); +} + +static int ee1004_read(void *priv, unsigned int off, void *val, size_t count) +{ + struct i2c_client *client = priv; + char *buf = val; + int ret; + + if (unlikely(!count)) + return count; + + if (off + count > EE1004_EEPROM_SIZE) + return -EINVAL; + + /* + * Read data from chip, protecting against concurrent access to + * other EE1004 SPD EEPROMs on the same adapter. + */ + mutex_lock(&ee1004_bus_lock); + + while (count) { + ret = ee1004_eeprom_read(client, buf, off, count); + if (ret < 0) { + mutex_unlock(&ee1004_bus_lock); + return ret; + } + + buf += ret; + off += ret; + count -= ret; + } + + mutex_unlock(&ee1004_bus_lock); + + return 0; +} + +static void ee1004_probe_temp_sensor(struct i2c_client *client) +{ + 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); +} + +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)); + } +} + +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); +} + +static int ee1004_init_bus_data(struct i2c_client *client) +{ + struct ee1004_bus_data *bd; + int err, cnr = 0; + + bd = ee1004_get_bus_data(client->adapter); + if (!bd) + return dev_err_probe(&client->dev, -ENOSPC, "Only %d busses supported", + EE1004_MAX_BUSSES); + + i2c_set_clientdata(client, bd); + + 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; + } + + return 0; + +err_out: + ee1004_cleanup(cnr, bd); + + return err; +} + +static int ee1004_probe(struct i2c_client *client) +{ + 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; + + /* 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; + + mutex_lock(&ee1004_bus_lock); + + 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; +} + +/*-------------------------------------------------------------------------*/ + +static struct i2c_driver ee1004_driver = { + .driver = { + .name = "ee1004", + }, + .probe = ee1004_probe, + .id_table = ee1004_ids, +}; +module_i2c_driver(ee1004_driver); + +MODULE_DESCRIPTION("Driver for EE1004-compliant DDR4 SPD EEPROMs"); +MODULE_AUTHOR("Jean Delvare"); +MODULE_LICENSE("GPL"); |
