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. v5: usleep_range() instead of udelay() Style v3: Fixed %pa format string Dropped adapter class. Clarified licence. Removed clock parameter. v2: Matched function names to callbacks from i2c-algo-pcf Used z_readb()/z_writeb() Removed BROKEN_ON_SMP in Kconfig Moved LTC2990 to a separate commit Signed-off-by: Max Staudt <max@xxxxxxxxx> --- MAINTAINERS | 6 ++ drivers/i2c/busses/Kconfig | 11 +++ drivers/i2c/busses/Makefile | 1 + drivers/i2c/busses/i2c-icy.c | 172 +++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 190 insertions(+) create mode 100644 drivers/i2c/busses/i2c-icy.c diff --git a/MAINTAINERS b/MAINTAINERS index 1be025959..70336c083 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -7705,6 +7705,12 @@ S: Maintained F: drivers/mfd/lpc_ich.c F: drivers/gpio/gpio-ich.c +ICY I2C DRIVER +M: Max Staudt <max@xxxxxxxxx> +L: linux-i2c@xxxxxxxxxxxxxxx +S: Maintained +F: drivers/i2c/busses/i2c-icy.c + IDE SUBSYSTEM M: "David S. Miller" <davem@xxxxxxxxxxxxx> L: linux-ide@xxxxxxxxxxxxxxx diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index ee5dfb5ae..9e57e1101 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -1300,6 +1300,17 @@ config I2C_ELEKTOR This support is also available as a module. If so, the module will be called i2c-elektor. +config I2C_ICY + tristate "ICY Zorro card" + depends on ZORRO + select I2C_ALGOPCF + help + This supports the PCF8584 Zorro bus I2C adapter, known as ICY. + Say Y if you own such an adapter. + + This support is also available as a module. If so, the module + will be called i2c-icy. + config I2C_MLXCPLD tristate "Mellanox I2C driver" depends on X86_64 diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index a3245231b..d0e1c3d4e 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -139,6 +139,7 @@ obj-$(CONFIG_I2C_BCM_KONA) += i2c-bcm-kona.o obj-$(CONFIG_I2C_BRCMSTB) += i2c-brcmstb.o obj-$(CONFIG_I2C_CROS_EC_TUNNEL) += i2c-cros-ec-tunnel.o obj-$(CONFIG_I2C_ELEKTOR) += i2c-elektor.o +obj-$(CONFIG_I2C_ICY) += i2c-icy.o obj-$(CONFIG_I2C_MLXCPLD) += i2c-mlxcpld.o obj-$(CONFIG_I2C_OPAL) += i2c-opal.o obj-$(CONFIG_I2C_PCA_ISA) += i2c-pca-isa.o diff --git a/drivers/i2c/busses/i2c-icy.c b/drivers/i2c/busses/i2c-icy.c new file mode 100644 index 000000000..7b7083da8 --- /dev/null +++ b/drivers/i2c/busses/i2c-icy.c @@ -0,0 +1,172 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * I2C driver for stand-alone PCF8584 style adapters on Zorro cards + * + * Original ICY documentation can be found on Aminet: + * https://aminet.net/package/docs/hard/icy + * + * There has been a modern community re-print of this design in 2019: + * https://www.a1k.org/forum/index.php?threads/70106/ + * + * The card is basically a Philips PCF8584 connected straight to the + * beginning of the AutoConfig'd address space (register S1 on base+2), + * with /INT on /INT2 on the Zorro bus. + * + * Copyright (c) 2019 Max Staudt <max@xxxxxxxxx> + * + * This started as a fork of i2c-elektor.c and has evolved since. + * Thanks go to its authors for providing a base to grow on. + * + * + * IRQ support is currently not implemented. + * + * As it turns out, i2c-algo-pcf is really written with i2c-elektor's + * edge-triggered ISA interrupts in mind, while the Amiga's Zorro bus has + * level-triggered interrupts. This means that once an interrupt occurs, we + * have to tell the PCF8584 to shut up immediately, or it will keep the + * interrupt line busy and cause an IRQ storm. + + * However, because of the PCF8584's host-side protocol, there is no good + * way to just quieten it without side effects. Rather, we have to perform + * the next read/write operation straight away, which will reset the /INT + * pin. This entails re-designing the core of i2c-algo-pcf in the future. + * For now, we never request an IRQ from the PCF8584, and poll it instead. + */ + +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/ioport.h> +#include <linux/kernel.h> +#include <linux/module.h> + +#include <linux/i2c.h> +#include <linux/i2c-algo-pcf.h> + +#include <asm/amigaints.h> +#include <linux/zorro.h> + +#include "../algos/i2c-algo-pcf.h" + +struct icy_i2c { + struct i2c_adapter adapter; + + void __iomem *reg_s0; + void __iomem *reg_s1; +}; + +/* + * Functions called by i2c-algo-pcf + */ +static void icy_pcf_setpcf(void *data, int ctl, int val) +{ + struct icy_i2c *i2c = (struct icy_i2c *)data; + + u8 __iomem *address = ctl ? i2c->reg_s1 : i2c->reg_s0; + + z_writeb(val, address); +} + +static int icy_pcf_getpcf(void *data, int ctl) +{ + struct icy_i2c *i2c = (struct icy_i2c *)data; + + u8 __iomem *address = ctl ? i2c->reg_s1 : i2c->reg_s0; + return z_readb(address); +} + +static int icy_pcf_getown(void *data) +{ + return 0x55; +} + +static int icy_pcf_getclock(void *data) +{ + return 0x1c; +} + +static void icy_pcf_waitforpin(void *data) +{ + usleep_range(50, 150); +} + +/* + * Main i2c-icy part + */ +static int icy_probe(struct zorro_dev *z, + const struct zorro_device_id *ent) +{ + struct icy_i2c *i2c; + struct i2c_algo_pcf_data *algo_data; + + i2c = devm_kzalloc(&z->dev, sizeof(*i2c), GFP_KERNEL); + if (!i2c) + return -ENOMEM; + + algo_data = devm_kzalloc(&z->dev, sizeof(*algo_data), GFP_KERNEL); + if (!algo_data) + return -ENOMEM; + + dev_set_drvdata(&z->dev, i2c); + i2c->adapter.dev.parent = &z->dev; + i2c->adapter.owner = THIS_MODULE; + /* i2c->adapter.algo assigned by i2c_pcf_add_bus() */ + i2c->adapter.algo_data = algo_data; + strlcpy(i2c->adapter.name, "ICY I2C Zorro adapter", + sizeof(i2c->adapter.name)); + + if (!devm_request_mem_region(&z->dev, + z->resource.start, + 4, i2c->adapter.name)) + return -ENXIO; + + /* Driver private data */ + i2c->reg_s0 = ZTWO_VADDR(z->resource.start); + i2c->reg_s1 = ZTWO_VADDR(z->resource.start + 2); + + algo_data->data = i2c; + algo_data->setpcf = icy_pcf_setpcf; + algo_data->getpcf = icy_pcf_getpcf; + algo_data->getown = icy_pcf_getown; + algo_data->getclock = icy_pcf_getclock; + algo_data->waitforpin = icy_pcf_waitforpin; + + if (i2c_pcf_add_bus(&i2c->adapter)) { + dev_err(&z->dev, "i2c_pcf_add_bus() failed\n"); + return -ENXIO; + } + + dev_info(&z->dev, "ICY I2C controller at %pa, IRQ not implemented\n", + &z->resource.start); + + return 0; +} + +static void icy_remove(struct zorro_dev *z) +{ + struct icy_i2c *i2c = dev_get_drvdata(&z->dev); + + i2c_del_adapter(&i2c->adapter); +} + +static const struct zorro_device_id icy_zorro_tbl[] = { + { ZORRO_ID(VMC, 15, 0), }, + { 0 } +}; + +MODULE_DEVICE_TABLE(zorro, icy_zorro_tbl); + +static struct zorro_driver icy_driver = { + .name = "i2c-icy", + .id_table = icy_zorro_tbl, + .probe = icy_probe, + .remove = icy_remove, +}; + +module_driver(icy_driver, + zorro_register_driver, + zorro_unregister_driver); + +MODULE_AUTHOR("Max Staudt <max@xxxxxxxxx>"); +MODULE_DESCRIPTION("I2C bus via PCF8584 on ICY Zorro card"); +MODULE_LICENSE("GPL v2"); -- 2.11.0
