diff options
author | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2015-08-05 17:04:01 -0300 |
---|---|---|
committer | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2015-08-05 17:04:01 -0300 |
commit | 57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch) | |
tree | 5e910f0e82173f4ef4f51111366a3f1299037a7b /drivers/i2c/busses/i2c-acorn.c |
Initial import
Diffstat (limited to 'drivers/i2c/busses/i2c-acorn.c')
-rw-r--r-- | drivers/i2c/busses/i2c-acorn.c | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-acorn.c b/drivers/i2c/busses/i2c-acorn.c new file mode 100644 index 000000000..9d7be5af2 --- /dev/null +++ b/drivers/i2c/busses/i2c-acorn.c @@ -0,0 +1,96 @@ +/* + * linux/drivers/acorn/char/i2c.c + * + * Copyright (C) 2000 Russell King + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * ARM IOC/IOMD i2c driver. + * + * On Acorn machines, the following i2c devices are on the bus: + * - PCF8583 real time clock & static RAM + */ +#include <linux/module.h> +#include <linux/i2c.h> +#include <linux/i2c-algo-bit.h> +#include <linux/io.h> + +#include <mach/hardware.h> +#include <asm/hardware/ioc.h> + +#define FORCE_ONES 0xdc +#define SCL 0x02 +#define SDA 0x01 + +/* + * We must preserve all non-i2c output bits in IOC_CONTROL. + * Note also that we need to preserve the value of SCL and + * SDA outputs as well (which may be different from the + * values read back from IOC_CONTROL). + */ +static u_int force_ones; + +static void ioc_setscl(void *data, int state) +{ + u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL | SDA); + u_int ones = force_ones; + + if (state) + ones |= SCL; + else + ones &= ~SCL; + + force_ones = ones; + + ioc_writeb(ioc_control | ones, IOC_CONTROL); +} + +static void ioc_setsda(void *data, int state) +{ + u_int ioc_control = ioc_readb(IOC_CONTROL) & ~(SCL | SDA); + u_int ones = force_ones; + + if (state) + ones |= SDA; + else + ones &= ~SDA; + + force_ones = ones; + + ioc_writeb(ioc_control | ones, IOC_CONTROL); +} + +static int ioc_getscl(void *data) +{ + return (ioc_readb(IOC_CONTROL) & SCL) != 0; +} + +static int ioc_getsda(void *data) +{ + return (ioc_readb(IOC_CONTROL) & SDA) != 0; +} + +static struct i2c_algo_bit_data ioc_data = { + .setsda = ioc_setsda, + .setscl = ioc_setscl, + .getsda = ioc_getsda, + .getscl = ioc_getscl, + .udelay = 80, + .timeout = HZ, +}; + +static struct i2c_adapter ioc_ops = { + .nr = 0, + .algo_data = &ioc_data, +}; + +static int __init i2c_ioc_init(void) +{ + force_ones = FORCE_ONES | SCL | SDA; + + return i2c_bit_add_numbered_bus(&ioc_ops); +} + +module_init(i2c_ioc_init); |