From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sun, 7 Apr 2024 20:49:45 +0200
Subject: Adding upstream version 6.1.76.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 drivers/i2c/busses/i2c-acorn.c | 96 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-acorn.c

(limited to 'drivers/i2c/busses/i2c-acorn.c')

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");
-- 
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