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-rw-r--r--drivers/i2c/busses/Kconfig10
-rw-r--r--drivers/i2c/busses/Makefile1
-rw-r--r--drivers/i2c/busses/i2c-acorn.c97
3 files changed, 108 insertions, 0 deletions
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 4d44a2db29d..fb19dbb31e4 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -495,6 +495,16 @@ config I2C_VERSATILE
This driver can also be built as a module. If so, the module
will be called i2c-versatile.
+config I2C_ACORN
+ bool "Acorn IOC/IOMD I2C bus support"
+ depends on I2C && ARCH_ACORN
+ default y
+ select I2C_ALGOBIT
+ help
+ Say yes if you want to support the I2C bus on Acorn platforms.
+
+ If you don't know, say Y.
+
config I2C_VIA
tristate "VIA 82C586B"
depends on I2C && PCI && EXPERIMENTAL
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 03505aa44bb..290b5401835 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -42,6 +42,7 @@ obj-$(CONFIG_I2C_SIS630) += i2c-sis630.o
obj-$(CONFIG_I2C_SIS96X) += i2c-sis96x.o
obj-$(CONFIG_I2C_STUB) += i2c-stub.o
obj-$(CONFIG_I2C_VERSATILE) += i2c-versatile.o
+obj-$(CONFIG_I2C_ACORN) += i2c-acorn.o
obj-$(CONFIG_I2C_VIA) += i2c-via.o
obj-$(CONFIG_I2C_VIAPRO) += i2c-viapro.o
obj-$(CONFIG_I2C_VOODOO3) += i2c-voodoo3.o
diff --git a/drivers/i2c/busses/i2c-acorn.c b/drivers/i2c/busses/i2c-acorn.c
new file mode 100644
index 00000000000..09bd7f40b90
--- /dev/null
+++ b/drivers/i2c/busses/i2c-acorn.c
@@ -0,0 +1,97 @@
+/*
+ * 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/init.h>
+#include <linux/i2c.h>
+#include <linux/i2c-algo-bit.h>
+
+#include <asm/hardware.h>
+#include <asm/io.h>
+#include <asm/hardware/ioc.h>
+#include <asm/system.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 = 100
+};
+
+static struct i2c_adapter ioc_ops = {
+ .id = I2C_HW_B_IOC,
+ .algo_data = &ioc_data,
+};
+
+static int __init i2c_ioc_init(void)
+{
+ force_ones = FORCE_ONES | SCL | SDA;
+
+ return i2c_bit_add_bus(&ioc_ops);
+}
+
+__initcall(i2c_ioc_init);