diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-pca-isa.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-pca-isa.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-pca-isa.c b/drivers/i2c/busses/i2c-pca-isa.c new file mode 100644 index 0000000..9eb7626 --- /dev/null +++ b/drivers/i2c/busses/i2c-pca-isa.c @@ -0,0 +1,211 @@ +/* + * i2c-pca-isa.c driver for PCA9564 on ISA boards + * Copyright (C) 2004 Arcom Control Systems + * Copyright (C) 2008 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. + * + * 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 <linux/kernel.h> +#include <linux/ioport.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/wait.h> +#include <linux/isa.h> +#include <linux/i2c.h> +#include <linux/i2c-algo-pca.h> + +#include <asm/io.h> +#include <asm/irq.h> + +#define DRIVER "i2c-pca-isa" +#define IO_SIZE 4 + +static unsigned long base; +static int irq = -1; + +/* Data sheet recommends 59kHz for 100kHz operation due to variation + * in the actual clock rate */ +static int clock = I2C_PCA_CON_59kHz; + +static wait_queue_head_t pca_wait; + +static void pca_isa_writebyte(void *pd, int reg, int val) +{ +#ifdef DEBUG_IO + static char *names[] = { "T/O", "DAT", "ADR", "CON" }; + printk("*** write %s at %#lx <= %#04x\n", names[reg], base+reg, val); +#endif + outb(val, base+reg); +} + +static int pca_isa_readbyte(void *pd, int reg) +{ + int res = inb(base+reg); +#ifdef DEBUG_IO + { + static char *names[] = { "STA", "DAT", "ADR", "CON" }; + printk("*** read %s => %#04x\n", names[reg], res); + } +#endif + return res; +} + +static int pca_isa_waitforcompletion(void *pd) +{ + int ret = 0; + + if (irq > -1) { + ret = wait_event_interruptible(pca_wait, + pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI); + } else { + while ((pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0) + udelay(100); + } + return ret; +} + +static void pca_isa_resetchip(void *pd) +{ + /* apparently only an external reset will do it. not a lot can be done */ + printk(KERN_WARNING DRIVER ": Haven't figured out how to do a reset yet\n"); +} + +static irqreturn_t pca_handler(int this_irq, void *dev_id) { + wake_up_interruptible(&pca_wait); + return IRQ_HANDLED; +} + +static struct i2c_algo_pca_data pca_isa_data = { + /* .data intentionally left NULL, not needed with ISA */ + .write_byte = pca_isa_writebyte, + .read_byte = pca_isa_readbyte, + .wait_for_completion = pca_isa_waitforcompletion, + .reset_chip = pca_isa_resetchip, +}; + +static struct i2c_adapter pca_isa_ops = { + .owner = THIS_MODULE, + .id = I2C_HW_A_ISA, + .algo_data = &pca_isa_data, + .name = "PCA9564 ISA Adapter", + .timeout = 100, +}; + +static int __devinit pca_isa_match(struct device *dev, unsigned int id) +{ + int match = base != 0; + + if (match) { + if (irq <= -1) + dev_warn(dev, "Using polling mode (specify irq)\n"); + } else + dev_err(dev, "Please specify I/O base\n"); + + return match; +} + +static int __devinit pca_isa_probe(struct device *dev, unsigned int id) +{ + init_waitqueue_head(&pca_wait); + + dev_info(dev, "i/o base %#08lx. irq %d\n", base, irq); + +#ifdef CONFIG_PPC + if (check_legacy_ioport(base)) { + dev_err(dev, "I/O address %#08lx is not available\n", base); + goto out; + } +#endif + + if (!request_region(base, IO_SIZE, "i2c-pca-isa")) { + dev_err(dev, "I/O address %#08lx is in use\n", base); + goto out; + } + + if (irq > -1) { + if (request_irq(irq, pca_handler, 0, "i2c-pca-isa", &pca_isa_ops) < 0) { + dev_err(dev, "Request irq%d failed\n", irq); + goto out_region; + } + } + + pca_isa_data.i2c_clock = clock; + if (i2c_pca_add_bus(&pca_isa_ops) < 0) { + dev_err(dev, "Failed to add i2c bus\n"); + goto out_irq; + } + + return 0; + + out_irq: + if (irq > -1) + free_irq(irq, &pca_isa_ops); + out_region: + release_region(base, IO_SIZE); + out: + return -ENODEV; +} + +static int __devexit pca_isa_remove(struct device *dev, unsigned int id) +{ + i2c_del_adapter(&pca_isa_ops); + + if (irq > -1) { + disable_irq(irq); + free_irq(irq, &pca_isa_ops); + } + release_region(base, IO_SIZE); + + return 0; +} + +static struct isa_driver pca_isa_driver = { + .match = pca_isa_match, + .probe = pca_isa_probe, + .remove = __devexit_p(pca_isa_remove), + .driver = { + .owner = THIS_MODULE, + .name = DRIVER, + } +}; + +static int __init pca_isa_init(void) +{ + return isa_register_driver(&pca_isa_driver, 1); +} + +static void __exit pca_isa_exit(void) +{ + isa_unregister_driver(&pca_isa_driver); +} + +MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>"); +MODULE_DESCRIPTION("ISA base PCA9564 driver"); +MODULE_LICENSE("GPL"); + +module_param(base, ulong, 0); +MODULE_PARM_DESC(base, "I/O base address"); + +module_param(irq, int, 0); +MODULE_PARM_DESC(irq, "IRQ"); +module_param(clock, int, 0); +MODULE_PARM_DESC(clock, "Clock rate as described in table 1 of PCA9564 datasheet"); + +module_init(pca_isa_init); +module_exit(pca_isa_exit); |
