From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: Re: [PATCH] i2c: Floppy controller bus driver (V0.2) Date: Mon, 18 Aug 2008 10:45:39 +0200 Message-ID: <20080818104539.480ba532@hyperion.delvare> References: <20080818031046.GE8052@MAIL.13thfloor.at> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20080818031046.GE8052-ZD0Mn47LIGX0Pe/G4T7+5F6hYfS7NtTn@public.gmane.org> 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: Herbert Poetzl Cc: I2C ML List-Id: linux-i2c@vger.kernel.org On Mon, 18 Aug 2008 05:10:46 +0200, Herbert Poetzl wrote: > > 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 Typo: adapter. > +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 "floppy disk controllers" (capitals not needed.) > +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) "PC floppy circuit" (again capitals not needed.) > + > +so it should be fine to connect it to all 5V i2c devices, and "I2C". Technically, you connect the devices to the bus, rather than the other way around. > +most 3.3V devices (which are usually capable of handling 5V > +i2c bus voltages) "I2C". > + > +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) These last 3 paragraphs lack leading capitals and ending dots. > + Unneeded trailing blank line. > 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 > + > + Please just discard the whole section. It can always be added later if you ever rework the driver (but I doubt it will ever happen...) > +/* ----- 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. Good point. In fact it would be safer to depend on !BLK_DEV_FD. There's no "if you know exactly what you are doing" that holds: if any of these drivers is built in, the other one _must_ be excluded. > + > 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 All the rest looks OK to me. Your driver is almost ready to merge. -- Jean Delvare _______________________________________________ i2c mailing list i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org http://lists.lm-sensors.org/mailman/listinfo/i2c