From 18f98b1e3147afdb51e545cc6ff2b016c7d088a7 Mon Sep 17 00:00:00 2001 From: Peter Korsgaard Date: Sun, 4 Jun 2006 20:01:08 +0200 Subject: [PATCH] [PATCH] i2c: New bus driver for the OpenCores I2C controller The following patch adds support for the OpenCores I2C controller IP core (See http://www.opencores.org/projects.cgi/web/i2c/overview). Signed-off-by: Peter Korsgaard Signed-off-by: Andrew Morton Signed-off-by: Jean Delvare Signed-off-by: Greg Kroah-Hartman --- Documentation/i2c/busses/i2c-ocores | 51 +++++ drivers/i2c/busses/Kconfig | 11 + drivers/i2c/busses/Makefile | 1 + drivers/i2c/busses/i2c-ocores.c | 343 ++++++++++++++++++++++++++++ include/linux/i2c-ocores.h | 19 ++ 5 files changed, 425 insertions(+) create mode 100644 Documentation/i2c/busses/i2c-ocores create mode 100644 drivers/i2c/busses/i2c-ocores.c create mode 100644 include/linux/i2c-ocores.h diff --git a/Documentation/i2c/busses/i2c-ocores b/Documentation/i2c/busses/i2c-ocores new file mode 100644 index 000000000000..cfcebb10d14e --- /dev/null +++ b/Documentation/i2c/busses/i2c-ocores @@ -0,0 +1,51 @@ +Kernel driver i2c-ocores + +Supported adapters: + * OpenCores.org I2C controller by Richard Herveille (see datasheet link) + Datasheet: http://www.opencores.org/projects.cgi/web/i2c/overview + +Author: Peter Korsgaard + +Description +----------- + +i2c-ocores is an i2c bus driver for the OpenCores.org I2C controller +IP core by Richard Herveille. + +Usage +----- + +i2c-ocores uses the platform bus, so you need to provide a struct +platform_device with the base address and interrupt number. The +dev.platform_data of the device should also point to a struct +ocores_i2c_platform_data (see linux/i2c-ocores.h) describing the +distance between registers and the input clock speed. + +E.G. something like: + +static struct resource ocores_resources[] = { + [0] = { + .start = MYI2C_BASEADDR, + .end = MYI2C_BASEADDR + 8, + .flags = IORESOURCE_MEM, + }, + [1] = { + .start = MYI2C_IRQ, + .end = MYI2C_IRQ, + .flags = IORESOURCE_IRQ, + }, +}; + +static struct ocores_i2c_platform_data myi2c_data = { + .regstep = 2, /* two bytes between registers */ + .clock_khz = 50000, /* input clock of 50MHz */ +}; + +static struct platform_device myi2c = { + .name = "ocores-i2c", + .dev = { + .platform_data = &myi2c_data, + }, + .num_resources = ARRAY_SIZE(ocores_resources), + .resource = ocores_resources, +}; diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index d25a8cbbec0a..f7af7e9bb7d9 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -276,6 +276,17 @@ config I2C_NFORCE2 This driver can also be built as a module. If so, the module will be called i2c-nforce2. +config I2C_OCORES + tristate "OpenCores I2C Controller" + depends on I2C && EXPERIMENTAL + help + If you say yes to this option, support will be included for the + OpenCores I2C controller. For details see + http://www.opencores.org/projects.cgi/web/i2c/overview + + This driver can also be built as a module. If so, the module + will be called i2c-ocores. + config I2C_PARPORT tristate "Parallel port adapter" depends on I2C && PARPORT diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index b44831dff683..ac56df53155b 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -23,6 +23,7 @@ obj-$(CONFIG_I2C_POWERMAC) += i2c-powermac.o obj-$(CONFIG_I2C_MPC) += i2c-mpc.o obj-$(CONFIG_I2C_MV64XXX) += i2c-mv64xxx.o obj-$(CONFIG_I2C_NFORCE2) += i2c-nforce2.o +obj-$(CONFIG_I2C_OCORES) += i2c-ocores.o obj-$(CONFIG_I2C_PARPORT) += i2c-parport.o obj-$(CONFIG_I2C_PARPORT_LIGHT) += i2c-parport-light.o obj-$(CONFIG_I2C_PCA_ISA) += i2c-pca-isa.o diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c new file mode 100644 index 000000000000..d5c0610bfe6d --- /dev/null +++ b/drivers/i2c/busses/i2c-ocores.c @@ -0,0 +1,343 @@ +/* + * i2c-ocores.c: I2C bus driver for OpenCores I2C controller + * (http://www.opencores.org/projects.cgi/web/i2c/overview). + * + * Peter Korsgaard + * + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct ocores_i2c { + void __iomem *base; + int regstep; + wait_queue_head_t wait; + struct i2c_adapter adap; + struct i2c_msg *msg; + int pos; + int nmsgs; + int state; /* see STATE_ */ +}; + +/* registers */ +#define OCI2C_PRELOW 0 +#define OCI2C_PREHIGH 1 +#define OCI2C_CONTROL 2 +#define OCI2C_DATA 3 +#define OCI2C_CMD 4 +#define OCI2C_STATUS 4 + +#define OCI2C_CTRL_IEN 0x40 +#define OCI2C_CTRL_EN 0x80 + +#define OCI2C_CMD_START 0x91 +#define OCI2C_CMD_STOP 0x41 +#define OCI2C_CMD_READ 0x21 +#define OCI2C_CMD_WRITE 0x11 +#define OCI2C_CMD_READ_ACK 0x21 +#define OCI2C_CMD_READ_NACK 0x29 +#define OCI2C_CMD_IACK 0x01 + +#define OCI2C_STAT_IF 0x01 +#define OCI2C_STAT_TIP 0x02 +#define OCI2C_STAT_ARBLOST 0x20 +#define OCI2C_STAT_BUSY 0x40 +#define OCI2C_STAT_NACK 0x80 + +#define STATE_DONE 0 +#define STATE_START 1 +#define STATE_WRITE 2 +#define STATE_READ 3 +#define STATE_ERROR 4 + +static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value) +{ + iowrite8(value, i2c->base + reg * i2c->regstep); +} + +static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg) +{ + return ioread8(i2c->base + reg * i2c->regstep); +} + +static void ocores_process(struct ocores_i2c *i2c) +{ + struct i2c_msg *msg = i2c->msg; + u8 stat = oc_getreg(i2c, OCI2C_STATUS); + + if ((i2c->state == STATE_DONE) || (i2c->state == STATE_ERROR)) { + /* stop has been sent */ + oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK); + wake_up(&i2c->wait); + return; + } + + /* error? */ + if (stat & OCI2C_STAT_ARBLOST) { + i2c->state = STATE_ERROR; + oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP); + return; + } + + if ((i2c->state == STATE_START) || (i2c->state == STATE_WRITE)) { + i2c->state = + (msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE; + + if (stat & OCI2C_STAT_NACK) { + i2c->state = STATE_ERROR; + oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP); + return; + } + } else + msg->buf[i2c->pos++] = oc_getreg(i2c, OCI2C_DATA); + + /* end of msg? */ + if (i2c->pos == msg->len) { + i2c->nmsgs--; + i2c->msg++; + i2c->pos = 0; + msg = i2c->msg; + + if (i2c->nmsgs) { /* end? */ + /* send start? */ + if (!(msg->flags & I2C_M_NOSTART)) { + u8 addr = (msg->addr << 1); + + if (msg->flags & I2C_M_RD) + addr |= 1; + + i2c->state = STATE_START; + + oc_setreg(i2c, OCI2C_DATA, addr); + oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START); + return; + } else + i2c->state = (msg->flags & I2C_M_RD) + ? STATE_READ : STATE_WRITE; + } else { + i2c->state = STATE_DONE; + oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP); + return; + } + } + + if (i2c->state == STATE_READ) { + oc_setreg(i2c, OCI2C_CMD, i2c->pos == (msg->len-1) ? + OCI2C_CMD_READ_NACK : OCI2C_CMD_READ_ACK); + } else { + oc_setreg(i2c, OCI2C_DATA, msg->buf[i2c->pos++]); + oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_WRITE); + } +} + +static irqreturn_t ocores_isr(int irq, void *dev_id, struct pt_regs *regs) +{ + struct ocores_i2c *i2c = dev_id; + + ocores_process(i2c); + + return IRQ_HANDLED; +} + +static int ocores_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) +{ + struct ocores_i2c *i2c = i2c_get_adapdata(adap); + + i2c->msg = msgs; + i2c->pos = 0; + i2c->nmsgs = num; + i2c->state = STATE_START; + + oc_setreg(i2c, OCI2C_DATA, + (i2c->msg->addr << 1) | + ((i2c->msg->flags & I2C_M_RD) ? 1:0)); + + oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START); + + if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) || + (i2c->state == STATE_DONE), HZ)) + return (i2c->state == STATE_DONE) ? num : -EIO; + else + return -ETIMEDOUT; +} + +static void ocores_init(struct ocores_i2c *i2c, + struct ocores_i2c_platform_data *pdata) +{ + int prescale; + u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL); + + /* make sure the device is disabled */ + oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN)); + + prescale = (pdata->clock_khz / (5*100)) - 1; + oc_setreg(i2c, OCI2C_PRELOW, prescale & 0xff); + oc_setreg(i2c, OCI2C_PREHIGH, prescale >> 8); + + /* Init the device */ + oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK); + oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_IEN | OCI2C_CTRL_EN); +} + + +static u32 ocores_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static struct i2c_algorithm ocores_algorithm = { + .master_xfer = ocores_xfer, + .functionality = ocores_func, +}; + +static struct i2c_adapter ocores_adapter = { + .owner = THIS_MODULE, + .name = "i2c-ocores", + .class = I2C_CLASS_HWMON, + .algo = &ocores_algorithm, + .timeout = 2, + .retries = 1, +}; + + +static int __devinit ocores_i2c_probe(struct platform_device *pdev) +{ + struct ocores_i2c *i2c; + struct ocores_i2c_platform_data *pdata; + struct resource *res, *res2; + int ret; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -ENODEV; + + res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0); + if (!res2) + return -ENODEV; + + pdata = (struct ocores_i2c_platform_data*) pdev->dev.platform_data; + if (!pdata) + return -ENODEV; + + i2c = kzalloc(sizeof(*i2c), GFP_KERNEL); + if (!i2c) + return -ENOMEM; + + if (!request_mem_region(res->start, res->end - res->start + 1, + pdev->name)) { + dev_err(&pdev->dev, "Memory region busy\n"); + ret = -EBUSY; + goto request_mem_failed; + } + + i2c->base = ioremap(res->start, res->end - res->start + 1); + if (!i2c->base) { + dev_err(&pdev->dev, "Unable to map registers\n"); + ret = -EIO; + goto map_failed; + } + + i2c->regstep = pdata->regstep; + ocores_init(i2c, pdata); + + init_waitqueue_head(&i2c->wait); + ret = request_irq(res2->start, ocores_isr, 0, pdev->name, i2c); + if (ret) { + dev_err(&pdev->dev, "Cannot claim IRQ\n"); + goto request_irq_failed; + } + + /* hook up driver to tree */ + platform_set_drvdata(pdev, i2c); + i2c->adap = ocores_adapter; + i2c_set_adapdata(&i2c->adap, i2c); + i2c->adap.dev.parent = &pdev->dev; + + /* add i2c adapter to i2c tree */ + ret = i2c_add_adapter(&i2c->adap); + if (ret) { + dev_err(&pdev->dev, "Failed to add adapter\n"); + goto add_adapter_failed; + } + + return 0; + +add_adapter_failed: + free_irq(res2->start, i2c); +request_irq_failed: + iounmap(i2c->base); +map_failed: + release_mem_region(res->start, res->end - res->start + 1); +request_mem_failed: + kfree(i2c); + + return ret; +} + +static int __devexit ocores_i2c_remove(struct platform_device* pdev) +{ + struct ocores_i2c *i2c = platform_get_drvdata(pdev); + struct resource *res; + + /* disable i2c logic */ + oc_setreg(i2c, OCI2C_CONTROL, oc_getreg(i2c, OCI2C_CONTROL) + & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN)); + + /* remove adapter & data */ + i2c_del_adapter(&i2c->adap); + platform_set_drvdata(pdev, NULL); + + res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); + if (res) + free_irq(res->start, i2c); + + iounmap(i2c->base); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (res) + release_mem_region(res->start, res->end - res->start + 1); + + kfree(i2c); + + return 0; +} + +static struct platform_driver ocores_i2c_driver = { + .probe = ocores_i2c_probe, + .remove = __devexit_p(ocores_i2c_remove), + .driver = { + .owner = THIS_MODULE, + .name = "ocores-i2c", + }, +}; + +static int __init ocores_i2c_init(void) +{ + return platform_driver_register(&ocores_i2c_driver); +} + +static void __exit ocores_i2c_exit(void) +{ + platform_driver_unregister(&ocores_i2c_driver); +} + +module_init(ocores_i2c_init); +module_exit(ocores_i2c_exit); + +MODULE_AUTHOR("Peter Korsgaard "); +MODULE_DESCRIPTION("OpenCores I2C bus driver"); +MODULE_LICENSE("GPL"); diff --git a/include/linux/i2c-ocores.h b/include/linux/i2c-ocores.h new file mode 100644 index 000000000000..8ed591b0887e --- /dev/null +++ b/include/linux/i2c-ocores.h @@ -0,0 +1,19 @@ +/* + * i2c-ocores.h - definitions for the i2c-ocores interface + * + * Peter Korsgaard + * + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + */ + +#ifndef _LINUX_I2C_OCORES_H +#define _LINUX_I2C_OCORES_H + +struct ocores_i2c_platform_data { + u32 regstep; /* distance between registers */ + u32 clock_khz; /* input clock in kHz */ +}; + +#endif /* _LINUX_I2C_OCORES_H */ -- 2.20.1