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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/i2c/busses/i2c-acorn.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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..34bbbb8c5 --- /dev/null +++ b/drivers/i2c/busses/i2c-acorn.c @@ -0,0 +1,96 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * ARM IOC/IOMD i2c driver. + * + * Copyright (C) 2000 Russell King + * + * 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, + .name = "ioc", + .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); + +MODULE_AUTHOR("Russell King <linux@armlinux.org.uk>"); +MODULE_DESCRIPTION("ARM IOC/IOMD i2c driver"); +MODULE_LICENSE("GPL v2"); |