From mboxrd@z Thu Jan 1 00:00:00 1970 From: Herbert Poetzl Subject: [PATCH] i2c: Floppy controller bus driver (V0.2) Date: Mon, 18 Aug 2008 05:10:46 +0200 Message-ID: <20080818031046.GE8052@MAIL.13thfloor.at> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: i2c-bounces-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org Errors-To: i2c-bounces-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org To: I2C ML List-Id: linux-i2c@vger.kernel.org here is the updated version of the floppy controller to I2C adapter driver, which uses the Motor Control and Disk Changed lines to interface to an I2C bus. I hope I fixed the style issues (except for the access to global var from "remove" function - to keep it similar to the i2c-parport-light for now) of course the patch is compile and run tested on PC style hardware with my test circuit connecting to an LM75 and LM85 (temp/fan/pwm) please consider for (mainline) inclusion! TIA, Herbert Signed-off-by: Herbert Poetzl diff -NurpP --minimal linux-2.6.27-rc3/Documentation/i2c/busses/i2c-floppy linux-2.6.27-rc3-fi2c-v0.2/Documentation/i2c/busses/i2c-floppy --- linux-2.6.27-rc3/Documentation/i2c/busses/i2c-floppy 1970-01-01 01:00:00.000000000 +0100 +++ linux-2.6.27-rc3-fi2c-v0.2/Documentation/i2c/busses/i2c-floppy 2008-08-18 04:34:53.000000000 +0200 @@ -0,0 +1,38 @@ +Kernel driver i2c-floppy + +Author: Herbert Poetzl + +This driver is for a simple do-it-yourself floppy controller to +I2C adapters which uses direct I/O access to control both Motor +Enable lines (A/B) and read back data via the Disk Changed line. + +The following circuit is not suited to be used together with +a Floppy drive (which would need some logic to work properly) +but as replacement. + + +---+ + | F | Motor Enable A [/MOTEA,10] -------------- SCL + | L | + | O | Motor Enable B [/MOTEB,16] ------+------- SDA + | P | | + | P | | + | Y | Disk Change [/DSKCHG,34] ------+ +-- GND + +-+-+ | + | | + GND GND + +the Motor Enable output of Floppy Disk Controllers is an open +drain output (48mA), usually pulled up to +5V via 1k or higher, +and the Disk Change is a Schmitt Trigger (0.8V/2.2V) input with +max 150uA input current (data taken from the WD/FDC 37C6xx +Floppy Disk Subsystem Controller datasheets, which basically +combine all the necessary parts of the PC Floppy Circuit) + +so it should be fine to connect it to all 5V i2c devices, and +most 3.3V devices (which are usually capable of handling 5V +i2c bus voltages) + +power for those devices can be drawn from either the Floppy +power connector (+5V/+12V) or from the SATA 3.3V lines +(or if you prefer from some external source) + diff -NurpP --minimal linux-2.6.27-rc3/drivers/i2c/busses/i2c-floppy.c linux-2.6.27-rc3-fi2c-v0.2/drivers/i2c/busses/i2c-floppy.c --- linux-2.6.27-rc3/drivers/i2c/busses/i2c-floppy.c 1970-01-01 01:00:00.000000000 +0100 +++ linux-2.6.27-rc3-fi2c-v0.2/drivers/i2c/busses/i2c-floppy.c 2008-08-18 03:35:34.000000000 +0200 @@ -0,0 +1,261 @@ +/* ------------------------------------------------------------------------ * + * i2c-floppy.c I2C bus over floppy controller * + * ------------------------------------------------------------------------ * + Copyright (C) 2008 Herbert Poetzl + + Somewhat based on i2c-parport-light.c driver + Copyright (C) 2003-2007 Jean Delvare + + 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. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + * ------------------------------------------------------------------------ */ + +#include +#include +#include +#include +#include +#include +#include +#include + +static struct platform_device *pdev; +static unsigned char dor; + +static u16 base; +module_param(base, ushort, 0); +MODULE_PARM_DESC(base, "Base I/O address"); + + +#define DEFAULT_BASE 0x3F0 /* for PC style hardware */ +#define DRVNAME "i2c-floppy" + + +#define FOFF_DOR 0x02 +#define FOFF_DIR 0x07 + +#define FDOR_MOTEA 0x10 +#define FDOR_MOTEB 0x20 + +#define FDIR_DCHNG 0x80 + +#define SCL FDOR_MOTEA +#define SDA FDOR_MOTEB +#define SDA_IN FDIR_DCHNG + +#define LO_INV (SDA|SCL) +#define LI_INV (SDA_IN) + + +/* ----- Device list ------------------------------------------------------ */ + +#if 0 +struct i2c_floppy_data { + unsigned char dor; +}; + +struct i2c_floppy { + struct i2c_adapter adapter; + struct i2c_algo_bit_data algo_data; + struct i2c_floppy_data data; + struct i2c_floppy *next; +}; +#endif + + +/* ----- Low-level floppy access ------------------------------------------ */ + +static inline void port_dor_out(unsigned char d) +{ + outb(d ^ LO_INV, base + FOFF_DOR); +} + +static inline unsigned char port_dir_in(void) +{ + return inb(base + FOFF_DIR) ^ LI_INV; +} + + +/* ----- I2C algorithm call-back functions and structures ----------------- */ + +static void floppy_setscl(void *data, int state) +{ + if (state) + dor |= SCL; + else + dor &= ~SCL; + + port_dor_out(dor); +} + +static void floppy_setsda(void *data, int state) +{ + if (state) + dor |= SDA; + else + dor &= ~SDA; + + port_dor_out(dor); +} + +static int floppy_getsda(void *data) +{ + return port_dir_in() & SDA_IN; +} + +/* Encapsulate the functions above in the correct structure + Note that getscl is set to NULL because SCL cannot be read + back with the current driver */ +static struct i2c_algo_bit_data floppy_algo_data = { + .setsda = floppy_setsda, + .setscl = floppy_setscl, + .getsda = floppy_getsda, + .udelay = 50, + .timeout = HZ, +}; + + +/* ----- Driver registration ---------------------------------------------- */ + +static struct i2c_adapter floppy_adapter = { + .owner = THIS_MODULE, + .class = I2C_CLASS_HWMON, + .algo_data = &floppy_algo_data, + .name = "Floppy controller adapter", +}; + +static int __devinit i2c_floppy_probe(struct platform_device *pdev) +{ + int err; + struct resource *res; + + res = platform_get_resource(pdev, IORESOURCE_IO, 0); + if (!request_region(res->start, res->end - res->start + 1, DRVNAME)) + return -EBUSY; + + /* Reset hardware to a sane state (SCL and SDA high) */ + floppy_setsda(NULL, 1); + floppy_setscl(NULL, 1); + + floppy_adapter.dev.parent = &pdev->dev; + err = i2c_bit_add_bus(&floppy_adapter); + if (err) { + dev_err(&pdev->dev, "Unable to register with I2C\n"); + goto exit_region; + } + return 0; + +exit_region: + release_region(res->start, res->end - res->start + 1); + return err; +} + +static int __devexit i2c_floppy_remove(struct platform_device *pdev) +{ + struct resource *res; + + i2c_del_adapter(&floppy_adapter); + + res = platform_get_resource(pdev, IORESOURCE_IO, 0); + release_region(res->start, res->end - res->start + 1); + return 0; +} + +static struct platform_driver i2c_floppy_driver = { + .driver = { + .owner = THIS_MODULE, + .name = DRVNAME, + }, + .probe = i2c_floppy_probe, + .remove = __devexit_p(i2c_floppy_remove), +}; + +static int __init i2c_floppy_device_add(u16 address) +{ + struct resource res = { + .start = address, + .end = address + 7, + .name = DRVNAME, + .flags = IORESOURCE_IO, + }; + int err; + + pdev = platform_device_alloc(DRVNAME, -1); + if (!pdev) { + err = -ENOMEM; + printk(KERN_ERR DRVNAME ": Device allocation failed\n"); + goto exit; + } + + err = platform_device_add_resources(pdev, &res, 1); + if (err) { + printk(KERN_ERR DRVNAME ": Device resource addition failed " + "(%d)\n", err); + goto exit_device_put; + } + + err = platform_device_add(pdev); + if (err) { + printk(KERN_ERR DRVNAME ": Device addition failed (%d)\n", + err); + goto exit_device_put; + } + + return 0; + +exit_device_put: + platform_device_put(pdev); +exit: + return err; +} + +static int __init i2c_floppy_init(void) +{ + int err; + + if (base == 0) { + pr_info(DRVNAME ": using default base 0x%x\n", DEFAULT_BASE); + base = DEFAULT_BASE; + } + + /* Sets global pdev as a side effect */ + err = i2c_floppy_device_add(base); + if (err) + goto exit; + + err = platform_driver_register(&i2c_floppy_driver); + if (err) + goto exit_device; + + return 0; + +exit_device: + platform_device_unregister(pdev); +exit: + return err; +} + +static void __exit i2c_floppy_exit(void) +{ + platform_driver_unregister(&i2c_floppy_driver); + platform_device_unregister(pdev); +} + + +MODULE_AUTHOR("Herbert Poetzl "); +MODULE_DESCRIPTION("I2C bus over floppy controller"); +MODULE_LICENSE("GPL"); + +module_init(i2c_floppy_init); +module_exit(i2c_floppy_exit); diff -NurpP --minimal linux-2.6.27-rc3/drivers/i2c/busses/Kconfig linux-2.6.27-rc3-fi2c-v0.2/drivers/i2c/busses/Kconfig --- linux-2.6.27-rc3/drivers/i2c/busses/Kconfig 2008-08-15 21:19:24.000000000 +0200 +++ linux-2.6.27-rc3-fi2c-v0.2/drivers/i2c/busses/Kconfig 2008-08-18 03:46:31.000000000 +0200 @@ -490,6 +490,22 @@ config I2C_VERSATILE comment "External I2C/SMBus adapter drivers" +config I2C_FLOPPY + tristate "Floppy controller adapter" + select I2C_ALGOBIT + default n + help + This supports a simple do-it-yourself floppy controller to + I2C adapters using the motor control lines for SDA and SCL, + and the drive change input for SDA readback. + + This support is also available as a module. If so, the module + will be called i2c-floppy. + + If you do not have such a device, and do not plan to build one, + it's safe to say N here. Do not say Y here and to the floppy + driver unless you know exactly what you are doing. + config I2C_PARPORT tristate "Parallel port adapter" depends on PARPORT diff -NurpP --minimal linux-2.6.27-rc3/drivers/i2c/busses/Makefile linux-2.6.27-rc3-fi2c-v0.2/drivers/i2c/busses/Makefile --- linux-2.6.27-rc3/drivers/i2c/busses/Makefile 2008-08-15 21:19:24.000000000 +0200 +++ linux-2.6.27-rc3-fi2c-v0.2/drivers/i2c/busses/Makefile 2008-08-18 03:46:42.000000000 +0200 @@ -48,6 +48,7 @@ obj-$(CONFIG_I2C_SIMTEC) += i2c-simtec.o obj-$(CONFIG_I2C_VERSATILE) += i2c-versatile.o # External I2C/SMBus adapter drivers +obj-$(CONFIG_I2C_FLOPPY) += i2c-floppy.o obj-$(CONFIG_I2C_PARPORT) += i2c-parport.o obj-$(CONFIG_I2C_PARPORT_LIGHT) += i2c-parport-light.o obj-$(CONFIG_I2C_TAOS_EVM) += i2c-taos-evm.o _______________________________________________ i2c mailing list i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org http://lists.lm-sensors.org/mailman/listinfo/i2c