.\" .\" Copyright (c) 2019 Ian Lepore .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES .\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. .\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, .\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, .\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY .\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" .\" $FreeBSD$ .\" .Dd March 2, 2019 .Dt AT45D 4 .Os .Sh NAME .Nm at45d .Nd driver for DataFlash(tm) non-volatile storage devices .Sh SYNOPSIS To compile this driver into the kernel, place the following line in your kernel configuration file: .Bd -ragged -offset indent .Cd "device at45d" .Ed .Pp Alternatively, to load the driver as a module at boot time, place the following line in .Xr loader.conf 5 : .Bd -literal -offset indent at45d_load="YES" .Ed .Sh DESCRIPTION The .Nm driver provides support for the family of non-volatile storage devices known collectively as DataFlash(tm). DataFlash chips typically have part numbers beginning with AT45DB. The .Nm driver supports only the SPI bus versions of each AT45DB device, indicated by the last digit of the part number being 1 or 2. .Pp The .Nm driver uses opcode 0x9f to read the manufacturer and device ID data to determine whether the device is supported. The device ID is looked up using a table of data within the driver which describes the attributes of each supported device, such as block size, sector size, and device capacity. When a supported device is found, the .Nm driver creates a disk device and makes it accessible at .Pa /dev/flash/at45d? . The new disk device is then tasted by the available .Xr geom 4 modules as with any disk device. .Sh HARDWARE The .Nm driver provides support for the following devices: .Pp .Bl -bullet -compact .It AT45DB011B .It AT45DB021B .It AT45DB041x .It AT45DB081B .It AT45DB161x .It AT45DB321x .It AT45DB321x .It AT45DB641E .It AT45DB642x .El .Sh FDT CONFIGURATION On an .Xr fdt 4 based system, the .Nm device is defined as a slave device subnode of the SPI bus controller node. All properties documented in the .Va spibus.txt bindings document can be used with the .Nm device. The most commonly-used ones are documented below. .Pp The following properties are required in the .Nm device subnode: .Bl -tag -width indent .It Va compatible Must be the string "atmel,at45". .It Va reg Chip select address of device. .It Va spi-max-frequency The maximum bus frequency to use when communicating with this slave device. Actual bus speed may be lower, depending on the capabilities of the SPI bus controller hardware. .El .Pp The following properties are optional for the .Nm device subnode: .Bl -tag -width indent .It Va freebsd,sectorsize The sector size of the disk created for this storage device. It must be a multiple of the device's page size. The default is the device page size. .It Va spi-cpha Empty property indicating the slave device requires shifted clock phase (CPHA) mode. .It Va spi-cpol Empty property indicating the slave device requires inverse clock polarity (CPOL) mode. .It Va spi-cs-high Empty property indicating the slave device requires chip select active high. .El .Sh HINTS CONFIGURATION On a .Xr device.hints 5 based system, such as .Li MIPS , these values are configurable for .Nm : .Bl -tag -width indent .It Va hint.at45d.%d.at The spibus the .Nm instance is attached to. .It Va hint.at45d.%d.clock The maximum bus frequency to use when communicating with this device. Actual bus speed may be lower, depending on the capabilities of the SPI bus controller hardware. .It Va hint.at45d.%d.cs The chip-select number to assert when performing I/O for this device. Set the high bit (1 << 31) to invert the logic level of the chip select line. .It Va hint.at45d.%d.mode The SPI mode (0-3) to use when communicating with this device. .It Va hint.at45d.%d.sectorsize The sector size of the disk created for this storage device. It must be a multiple of the device's page size. The default is the device page size. .El .Sh FILES .Bl -tag -width /dev/flash/at45d? .It Pa /dev/flash/at45d? Provides read/write access to the storage device. .It Pa /dev/flash/spi? An alias for the .Pa /dev/at45d? device, for backwards compatibility with older versions of the driver. .El .Sh SEE ALSO .Xr fdt 4 , .Xr geom 4 .Sh HISTORY The .Nm driver first appeared in .Fx 6.0 .