i2c: Add i2c-icy for I2C on m68k/Amiga
This is the i2c-icy driver for the ICY board for Amiga computers. It connects a PCF8584 I2C controller to the Zorro bus, providing I2C connectivity. The original documentation can be found on Aminet: https://aminet.net/package/docs/hard/icy IRQ support is currently not implemented, as i2c-algo-pcf is built for the ISA bus and a straight implementation of the same stack locks up a Zorro machine. Signed-off-by: Max Staudt <max@enpas.org> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> [wsa: added a missing newline reported by checkpatch] Signed-off-by: Wolfram Sang <wsa@the-dreams.de>alistair/sunxi64-5.4-dsi
Max Staudt
Wolfram Sang
parent
250212b59a
commit
4768e90eca
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@ -7750,6 +7750,12 @@ S: Maintained
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F: drivers/mfd/lpc_ich.c
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F: drivers/gpio/gpio-ich.c
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ICY I2C DRIVER
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M: Max Staudt <max@enpas.org>
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L: linux-i2c@vger.kernel.org
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S: Maintained
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F: drivers/i2c/busses/i2c-icy.c
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IDE SUBSYSTEM
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M: "David S. Miller" <davem@davemloft.net>
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L: linux-ide@vger.kernel.org
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@ -1309,6 +1309,17 @@ config I2C_ELEKTOR
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This support is also available as a module. If so, the module
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will be called i2c-elektor.
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config I2C_ICY
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tristate "ICY Zorro card"
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depends on ZORRO
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select I2C_ALGOPCF
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help
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This supports the PCF8584 Zorro bus I2C adapter, known as ICY.
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Say Y if you own such an adapter.
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This support is also available as a module. If so, the module
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will be called i2c-icy.
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config I2C_MLXCPLD
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tristate "Mellanox I2C driver"
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depends on X86_64
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@ -140,6 +140,7 @@ obj-$(CONFIG_I2C_BCM_KONA) += i2c-bcm-kona.o
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obj-$(CONFIG_I2C_BRCMSTB) += i2c-brcmstb.o
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obj-$(CONFIG_I2C_CROS_EC_TUNNEL) += i2c-cros-ec-tunnel.o
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obj-$(CONFIG_I2C_ELEKTOR) += i2c-elektor.o
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obj-$(CONFIG_I2C_ICY) += i2c-icy.o
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obj-$(CONFIG_I2C_MLXCPLD) += i2c-mlxcpld.o
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obj-$(CONFIG_I2C_OPAL) += i2c-opal.o
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obj-$(CONFIG_I2C_PCA_ISA) += i2c-pca-isa.o
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@ -0,0 +1,173 @@
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// SPDX-License-Identifier: GPL-2.0
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/*
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* I2C driver for stand-alone PCF8584 style adapters on Zorro cards
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*
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* Original ICY documentation can be found on Aminet:
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* https://aminet.net/package/docs/hard/icy
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*
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* There has been a modern community re-print of this design in 2019:
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* https://www.a1k.org/forum/index.php?threads/70106/
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*
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* The card is basically a Philips PCF8584 connected straight to the
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* beginning of the AutoConfig'd address space (register S1 on base+2),
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* with /INT on /INT2 on the Zorro bus.
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*
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* Copyright (c) 2019 Max Staudt <max@enpas.org>
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*
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* This started as a fork of i2c-elektor.c and has evolved since.
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* Thanks go to its authors for providing a base to grow on.
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*
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*
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* IRQ support is currently not implemented.
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*
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* As it turns out, i2c-algo-pcf is really written with i2c-elektor's
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* edge-triggered ISA interrupts in mind, while the Amiga's Zorro bus has
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* level-triggered interrupts. This means that once an interrupt occurs, we
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* have to tell the PCF8584 to shut up immediately, or it will keep the
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* interrupt line busy and cause an IRQ storm.
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* However, because of the PCF8584's host-side protocol, there is no good
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* way to just quieten it without side effects. Rather, we have to perform
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* the next read/write operation straight away, which will reset the /INT
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* pin. This entails re-designing the core of i2c-algo-pcf in the future.
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* For now, we never request an IRQ from the PCF8584, and poll it instead.
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*/
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/ioport.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/i2c-algo-pcf.h>
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#include <asm/amigaints.h>
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#include <linux/zorro.h>
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#include "../algos/i2c-algo-pcf.h"
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struct icy_i2c {
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struct i2c_adapter adapter;
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void __iomem *reg_s0;
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void __iomem *reg_s1;
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};
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/*
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* Functions called by i2c-algo-pcf
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*/
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static void icy_pcf_setpcf(void *data, int ctl, int val)
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{
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struct icy_i2c *i2c = (struct icy_i2c *)data;
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u8 __iomem *address = ctl ? i2c->reg_s1 : i2c->reg_s0;
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z_writeb(val, address);
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}
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static int icy_pcf_getpcf(void *data, int ctl)
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{
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struct icy_i2c *i2c = (struct icy_i2c *)data;
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u8 __iomem *address = ctl ? i2c->reg_s1 : i2c->reg_s0;
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return z_readb(address);
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}
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static int icy_pcf_getown(void *data)
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{
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return 0x55;
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}
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static int icy_pcf_getclock(void *data)
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{
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return 0x1c;
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}
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static void icy_pcf_waitforpin(void *data)
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{
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usleep_range(50, 150);
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}
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/*
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* Main i2c-icy part
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*/
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static int icy_probe(struct zorro_dev *z,
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const struct zorro_device_id *ent)
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{
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struct icy_i2c *i2c;
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struct i2c_algo_pcf_data *algo_data;
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i2c = devm_kzalloc(&z->dev, sizeof(*i2c), GFP_KERNEL);
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if (!i2c)
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return -ENOMEM;
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algo_data = devm_kzalloc(&z->dev, sizeof(*algo_data), GFP_KERNEL);
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if (!algo_data)
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return -ENOMEM;
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dev_set_drvdata(&z->dev, i2c);
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i2c->adapter.dev.parent = &z->dev;
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i2c->adapter.owner = THIS_MODULE;
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/* i2c->adapter.algo assigned by i2c_pcf_add_bus() */
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i2c->adapter.algo_data = algo_data;
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strlcpy(i2c->adapter.name, "ICY I2C Zorro adapter",
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sizeof(i2c->adapter.name));
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if (!devm_request_mem_region(&z->dev,
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z->resource.start,
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4, i2c->adapter.name))
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return -ENXIO;
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/* Driver private data */
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i2c->reg_s0 = ZTWO_VADDR(z->resource.start);
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i2c->reg_s1 = ZTWO_VADDR(z->resource.start + 2);
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algo_data->data = i2c;
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algo_data->setpcf = icy_pcf_setpcf;
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algo_data->getpcf = icy_pcf_getpcf;
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algo_data->getown = icy_pcf_getown;
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algo_data->getclock = icy_pcf_getclock;
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algo_data->waitforpin = icy_pcf_waitforpin;
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if (i2c_pcf_add_bus(&i2c->adapter)) {
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dev_err(&z->dev, "i2c_pcf_add_bus() failed\n");
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return -ENXIO;
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}
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dev_info(&z->dev, "ICY I2C controller at %pa, IRQ not implemented\n",
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&z->resource.start);
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return 0;
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}
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static void icy_remove(struct zorro_dev *z)
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{
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struct icy_i2c *i2c = dev_get_drvdata(&z->dev);
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i2c_del_adapter(&i2c->adapter);
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}
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static const struct zorro_device_id icy_zorro_tbl[] = {
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{ ZORRO_ID(VMC, 15, 0), },
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{ 0 }
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};
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MODULE_DEVICE_TABLE(zorro, icy_zorro_tbl);
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static struct zorro_driver icy_driver = {
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.name = "i2c-icy",
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.id_table = icy_zorro_tbl,
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.probe = icy_probe,
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.remove = icy_remove,
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};
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module_driver(icy_driver,
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zorro_register_driver,
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zorro_unregister_driver);
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MODULE_AUTHOR("Max Staudt <max@enpas.org>");
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MODULE_DESCRIPTION("I2C bus via PCF8584 on ICY Zorro card");
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MODULE_LICENSE("GPL v2");
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