diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-imx.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-imx.c | 617 |
1 files changed, 617 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c new file mode 100644 index 000000000000..22cf200ecb3e --- /dev/null +++ b/drivers/i2c/busses/i2c-imx.c @@ -0,0 +1,617 @@ +/* + * Copyright (C) 2002 Motorola GSG-China + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + * USA. + * + * Author: + * Darius Augulis, Teltonika Inc. + * + * Desc.: + * Implementation of I2C Adapter/Algorithm Driver + * for I2C Bus integrated in Freescale i.MX/MXC processors + * + * Derived from Motorola GSG China I2C example driver + * + * Copyright (C) 2005 Torsten Koschorrek <koschorrek at synertronixx.de + * Copyright (C) 2005 Matthias Blaschke <blaschke at synertronixx.de + * Copyright (C) 2007 RightHand Technologies, Inc. + * Copyright (C) 2008 Darius Augulis <darius.augulis at teltonika.lt> + * + */ + +/** Includes ******************************************************************* +*******************************************************************************/ + +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/errno.h> +#include <linux/err.h> +#include <linux/interrupt.h> +#include <linux/delay.h> +#include <linux/i2c.h> +#include <linux/io.h> +#include <linux/sched.h> +#include <linux/platform_device.h> +#include <linux/clk.h> + +#include <mach/irqs.h> +#include <mach/hardware.h> +#include <mach/i2c.h> + +/** Defines ******************************************************************** +*******************************************************************************/ + +/* This will be the driver name the kernel reports */ +#define DRIVER_NAME "imx-i2c" + +/* Default value */ +#define IMX_I2C_BIT_RATE 100000 /* 100kHz */ + +/* IMX I2C registers */ +#define IMX_I2C_IADR 0x00 /* i2c slave address */ +#define IMX_I2C_IFDR 0x04 /* i2c frequency divider */ +#define IMX_I2C_I2CR 0x08 /* i2c control */ +#define IMX_I2C_I2SR 0x0C /* i2c status */ +#define IMX_I2C_I2DR 0x10 /* i2c transfer data */ + +/* Bits of IMX I2C registers */ +#define I2SR_RXAK 0x01 +#define I2SR_IIF 0x02 +#define I2SR_SRW 0x04 +#define I2SR_IAL 0x10 +#define I2SR_IBB 0x20 +#define I2SR_IAAS 0x40 +#define I2SR_ICF 0x80 +#define I2CR_RSTA 0x04 +#define I2CR_TXAK 0x08 +#define I2CR_MTX 0x10 +#define I2CR_MSTA 0x20 +#define I2CR_IIEN 0x40 +#define I2CR_IEN 0x80 + +/** Variables ****************************************************************** +*******************************************************************************/ + +static unsigned int disable_delay; /* Dummy delay */ + +/* + * sorted list of clock divider, register value pairs + * taken from table 26-5, p.26-9, Freescale i.MX + * Integrated Portable System Processor Reference Manual + * Document Number: MC9328MXLRM, Rev. 5.1, 06/2007 + * + * Duplicated divider values removed from list + */ + +static u16 __initdata i2c_clk_div[50][2] = { + { 22, 0x20 }, { 24, 0x21 }, { 26, 0x22 }, { 28, 0x23 }, + { 30, 0x00 }, { 32, 0x24 }, { 36, 0x25 }, { 40, 0x26 }, + { 42, 0x03 }, { 44, 0x27 }, { 48, 0x28 }, { 52, 0x05 }, + { 56, 0x29 }, { 60, 0x06 }, { 64, 0x2A }, { 72, 0x2B }, + { 80, 0x2C }, { 88, 0x09 }, { 96, 0x2D }, { 104, 0x0A }, + { 112, 0x2E }, { 128, 0x2F }, { 144, 0x0C }, { 160, 0x30 }, + { 192, 0x31 }, { 224, 0x32 }, { 240, 0x0F }, { 256, 0x33 }, + { 288, 0x10 }, { 320, 0x34 }, { 384, 0x35 }, { 448, 0x36 }, + { 480, 0x13 }, { 512, 0x37 }, { 576, 0x14 }, { 640, 0x38 }, + { 768, 0x39 }, { 896, 0x3A }, { 960, 0x17 }, { 1024, 0x3B }, + { 1152, 0x18 }, { 1280, 0x3C }, { 1536, 0x3D }, { 1792, 0x3E }, + { 1920, 0x1B }, { 2048, 0x3F }, { 2304, 0x1C }, { 2560, 0x1D }, + { 3072, 0x1E }, { 3840, 0x1F } +}; + +struct imx_i2c_struct { + struct i2c_adapter adapter; + struct resource *res; + struct clk *clk; + void __iomem *base; + int irq; + wait_queue_head_t queue; + unsigned long i2csr; +}; + +/** Functions for IMX I2C adapter driver *************************************** +*******************************************************************************/ + +static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx) +{ + unsigned long orig_jiffies = jiffies; + + dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); + + /* wait for bus not busy */ + while (readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_IBB) { + if (signal_pending(current)) { + dev_dbg(&i2c_imx->adapter.dev, + "<%s> I2C Interrupted\n", __func__); + return -EINTR; + } + if (time_after(jiffies, orig_jiffies + HZ / 1000)) { + dev_dbg(&i2c_imx->adapter.dev, + "<%s> I2C bus is busy\n", __func__); + return -EIO; + } + schedule(); + } + + return 0; +} + +static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx) +{ + int result; + + result = wait_event_interruptible_timeout(i2c_imx->queue, + i2c_imx->i2csr & I2SR_IIF, HZ / 10); + + if (unlikely(result < 0)) { + dev_dbg(&i2c_imx->adapter.dev, "<%s> result < 0\n", __func__); + return result; + } else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) { + dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__); + return -ETIMEDOUT; + } + dev_dbg(&i2c_imx->adapter.dev, "<%s> TRX complete\n", __func__); + i2c_imx->i2csr = 0; + return 0; +} + +static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx) +{ + if (readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_RXAK) { + dev_dbg(&i2c_imx->adapter.dev, "<%s> No ACK\n", __func__); + return -EIO; /* No ACK */ + } + + dev_dbg(&i2c_imx->adapter.dev, "<%s> ACK received\n", __func__); + return 0; +} + +static void i2c_imx_start(struct imx_i2c_struct *i2c_imx) +{ + unsigned int temp = 0; + + dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); + + /* Enable I2C controller */ + writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR); + /* Start I2C transaction */ + temp = readb(i2c_imx->base + IMX_I2C_I2CR); + temp |= I2CR_MSTA; + writeb(temp, i2c_imx->base + IMX_I2C_I2CR); + temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK; + writeb(temp, i2c_imx->base + IMX_I2C_I2CR); +} + +static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx) +{ + unsigned int temp = 0; + + /* Stop I2C transaction */ + dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); + temp = readb(i2c_imx->base + IMX_I2C_I2CR); + temp &= ~I2CR_MSTA; + writeb(temp, i2c_imx->base + IMX_I2C_I2CR); + /* setup chip registers to defaults */ + writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR); + writeb(0, i2c_imx->base + IMX_I2C_I2SR); + /* + * This delay caused by an i.MXL hardware bug. + * If no (or too short) delay, no "STOP" bit will be generated. + */ + udelay(disable_delay); + /* Disable I2C controller */ + writeb(0, i2c_imx->base + IMX_I2C_I2CR); +} + +static void __init i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx, + unsigned int rate) +{ + unsigned int i2c_clk_rate; + unsigned int div; + int i; + + /* Divider value calculation */ + i2c_clk_rate = clk_get_rate(i2c_imx->clk); + div = (i2c_clk_rate + rate - 1) / rate; + if (div < i2c_clk_div[0][0]) + i = 0; + else if (div > i2c_clk_div[ARRAY_SIZE(i2c_clk_div) - 1][0]) + i = ARRAY_SIZE(i2c_clk_div) - 1; + else + for (i = 0; i2c_clk_div[i][0] < div; i++); + + /* Write divider value to register */ + writeb(i2c_clk_div[i][1], i2c_imx->base + IMX_I2C_IFDR); + + /* + * There dummy delay is calculated. + * It should be about one I2C clock period long. + * This delay is used in I2C bus disable function + * to fix chip hardware bug. + */ + disable_delay = (500000U * i2c_clk_div[i][0] + + (i2c_clk_rate / 2) - 1) / (i2c_clk_rate / 2); + + /* dev_dbg() can't be used, because adapter is not yet registered */ +#ifdef CONFIG_I2C_DEBUG_BUS + printk(KERN_DEBUG "I2C: <%s> I2C_CLK=%d, REQ DIV=%d\n", + __func__, i2c_clk_rate, div); + printk(KERN_DEBUG "I2C: <%s> IFDR[IC]=0x%x, REAL DIV=%d\n", + __func__, i2c_clk_div[i][1], i2c_clk_div[i][0]); +#endif +} + +static irqreturn_t i2c_imx_isr(int irq, void *dev_id) +{ + struct imx_i2c_struct *i2c_imx = dev_id; + unsigned int temp; + + temp = readb(i2c_imx->base + IMX_I2C_I2SR); + if (temp & I2SR_IIF) { + /* save status register */ + i2c_imx->i2csr = temp; + temp &= ~I2SR_IIF; + writeb(temp, i2c_imx->base + IMX_I2C_I2SR); + wake_up_interruptible(&i2c_imx->queue); + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static int i2c_imx_write(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) +{ + int i, result; + + dev_dbg(&i2c_imx->adapter.dev, "<%s> write slave address: addr=0x%x\n", + __func__, msgs->addr << 1); + + /* write slave address */ + writeb(msgs->addr << 1, i2c_imx->base + IMX_I2C_I2DR); + result = i2c_imx_trx_complete(i2c_imx); + if (result) + return result; + result = i2c_imx_acked(i2c_imx); + if (result) + return result; + dev_dbg(&i2c_imx->adapter.dev, "<%s> write data\n", __func__); + + /* write data */ + for (i = 0; i < msgs->len; i++) { + dev_dbg(&i2c_imx->adapter.dev, + "<%s> write byte: B%d=0x%X\n", + __func__, i, msgs->buf[i]); + writeb(msgs->buf[i], i2c_imx->base + IMX_I2C_I2DR); + result = i2c_imx_trx_complete(i2c_imx); + if (result) + return result; + result = i2c_imx_acked(i2c_imx); + if (result) + return result; + } + return 0; +} + +static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) +{ + int i, result; + unsigned int temp; + + dev_dbg(&i2c_imx->adapter.dev, + "<%s> write slave address: addr=0x%x\n", + __func__, (msgs->addr << 1) | 0x01); + + /* write slave address */ + writeb((msgs->addr << 1) | 0x01, i2c_imx->base + IMX_I2C_I2DR); + result = i2c_imx_trx_complete(i2c_imx); + if (result) + return result; + result = i2c_imx_acked(i2c_imx); + if (result) + return result; + + dev_dbg(&i2c_imx->adapter.dev, "<%s> setup bus\n", __func__); + + /* setup bus to read data */ + temp = readb(i2c_imx->base + IMX_I2C_I2CR); + temp &= ~I2CR_MTX; + if (msgs->len - 1) + temp &= ~I2CR_TXAK; + writeb(temp, i2c_imx->base + IMX_I2C_I2CR); + readb(i2c_imx->base + IMX_I2C_I2DR); /* dummy read */ + + dev_dbg(&i2c_imx->adapter.dev, "<%s> read data\n", __func__); + + /* read data */ + for (i = 0; i < msgs->len; i++) { + result = i2c_imx_trx_complete(i2c_imx); + if (result) + return result; + if (i == (msgs->len - 1)) { + dev_dbg(&i2c_imx->adapter.dev, + "<%s> clear MSTA\n", __func__); + temp = readb(i2c_imx->base + IMX_I2C_I2CR); + temp &= ~I2CR_MSTA; + writeb(temp, i2c_imx->base + IMX_I2C_I2CR); + } else if (i == (msgs->len - 2)) { + dev_dbg(&i2c_imx->adapter.dev, + "<%s> set TXAK\n", __func__); + temp = readb(i2c_imx->base + IMX_I2C_I2CR); + temp |= I2CR_TXAK; + writeb(temp, i2c_imx->base + IMX_I2C_I2CR); + } + msgs->buf[i] = readb(i2c_imx->base + IMX_I2C_I2DR); + dev_dbg(&i2c_imx->adapter.dev, + "<%s> read byte: B%d=0x%X\n", + __func__, i, msgs->buf[i]); + } + return 0; +} + +static int i2c_imx_xfer(struct i2c_adapter *adapter, + struct i2c_msg *msgs, int num) +{ + unsigned int i, temp; + int result; + struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter); + + dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); + + /* Check if i2c bus is not busy */ + result = i2c_imx_bus_busy(i2c_imx); + if (result) + goto fail0; + + /* Start I2C transfer */ + i2c_imx_start(i2c_imx); + + /* read/write data */ + for (i = 0; i < num; i++) { + if (i) { + dev_dbg(&i2c_imx->adapter.dev, + "<%s> repeated start\n", __func__); + temp = readb(i2c_imx->base + IMX_I2C_I2CR); + temp |= I2CR_RSTA; + writeb(temp, i2c_imx->base + IMX_I2C_I2CR); + } + dev_dbg(&i2c_imx->adapter.dev, + "<%s> transfer message: %d\n", __func__, i); + /* write/read data */ +#ifdef CONFIG_I2C_DEBUG_BUS + temp = readb(i2c_imx->base + IMX_I2C_I2CR); + dev_dbg(&i2c_imx->adapter.dev, "<%s> CONTROL: IEN=%d, IIEN=%d, " + "MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n", __func__, + (temp & I2CR_IEN ? 1 : 0), (temp & I2CR_IIEN ? 1 : 0), + (temp & I2CR_MSTA ? 1 : 0), (temp & I2CR_MTX ? 1 : 0), + (temp & I2CR_TXAK ? 1 : 0), (temp & I2CR_RSTA ? 1 : 0)); + temp = readb(i2c_imx->base + IMX_I2C_I2SR); + dev_dbg(&i2c_imx->adapter.dev, + "<%s> STATUS: ICF=%d, IAAS=%d, IBB=%d, " + "IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n", __func__, + (temp & I2SR_ICF ? 1 : 0), (temp & I2SR_IAAS ? 1 : 0), + (temp & I2SR_IBB ? 1 : 0), (temp & I2SR_IAL ? 1 : 0), + (temp & I2SR_SRW ? 1 : 0), (temp & I2SR_IIF ? 1 : 0), + (temp & I2SR_RXAK ? 1 : 0)); +#endif + if (msgs[i].flags & I2C_M_RD) + result = i2c_imx_read(i2c_imx, &msgs[i]); + else + result = i2c_imx_write(i2c_imx, &msgs[i]); + } + +fail0: + /* Stop I2C transfer */ + i2c_imx_stop(i2c_imx); + + dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__, + (result < 0) ? "error" : "success msg", + (result < 0) ? result : num); + return (result < 0) ? result : num; +} + +static u32 i2c_imx_func(struct i2c_adapter *adapter) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static struct i2c_algorithm i2c_imx_algo = { + .master_xfer = i2c_imx_xfer, + .functionality = i2c_imx_func, +}; + +static int __init i2c_imx_probe(struct platform_device *pdev) +{ + struct imx_i2c_struct *i2c_imx; + struct resource *res; + struct imxi2c_platform_data *pdata; + void __iomem *base; + resource_size_t res_size; + int irq; + int ret; + + dev_dbg(&pdev->dev, "<%s>\n", __func__); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + dev_err(&pdev->dev, "can't get device resources\n"); + return -ENOENT; + } + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + dev_err(&pdev->dev, "can't get irq number\n"); + return -ENOENT; + } + + pdata = pdev->dev.platform_data; + + if (pdata && pdata->init) { + ret = pdata->init(&pdev->dev); + if (ret) + return ret; + } + + res_size = resource_size(res); + base = ioremap(res->start, res_size); + if (!base) { + dev_err(&pdev->dev, "ioremap failed\n"); + ret = -EIO; + goto fail0; + } + + i2c_imx = kzalloc(sizeof(struct imx_i2c_struct), GFP_KERNEL); + if (!i2c_imx) { + dev_err(&pdev->dev, "can't allocate interface\n"); + ret = -ENOMEM; + goto fail1; + } + + /* Setup i2c_imx driver structure */ + strcpy(i2c_imx->adapter.name, pdev->name); + i2c_imx->adapter.owner = THIS_MODULE; + i2c_imx->adapter.algo = &i2c_imx_algo; + i2c_imx->adapter.dev.parent = &pdev->dev; + i2c_imx->adapter.nr = pdev->id; + i2c_imx->irq = irq; + i2c_imx->base = base; + i2c_imx->res = res; + + /* Get I2C clock */ + i2c_imx->clk = clk_get(&pdev->dev, "i2c_clk"); + if (IS_ERR(i2c_imx->clk)) { + ret = PTR_ERR(i2c_imx->clk); + dev_err(&pdev->dev, "can't get I2C clock\n"); + goto fail2; + } + clk_enable(i2c_imx->clk); + + /* Request IRQ */ + ret = request_irq(i2c_imx->irq, i2c_imx_isr, 0, pdev->name, i2c_imx); + if (ret) { + dev_err(&pdev->dev, "can't claim irq %d\n", i2c_imx->irq); + goto fail3; + } + + /* Init queue */ + init_waitqueue_head(&i2c_imx->queue); + + /* Set up adapter data */ + i2c_set_adapdata(&i2c_imx->adapter, i2c_imx); + + /* Set up clock divider */ + if (pdata && pdata->bitrate) + i2c_imx_set_clk(i2c_imx, pdata->bitrate); + else + i2c_imx_set_clk(i2c_imx, IMX_I2C_BIT_RATE); + + /* Set up chip registers to defaults */ + writeb(0, i2c_imx->base + IMX_I2C_I2CR); + writeb(0, i2c_imx->base + IMX_I2C_I2SR); + + /* Add I2C adapter */ + ret = i2c_add_numbered_adapter(&i2c_imx->adapter); + if (ret < 0) { + dev_err(&pdev->dev, "registration failed\n"); + goto fail4; + } + + /* Set up platform driver data */ + platform_set_drvdata(pdev, i2c_imx); + + dev_dbg(&i2c_imx->adapter.dev, "claimed irq %d\n", i2c_imx->irq); + dev_dbg(&i2c_imx->adapter.dev, "device resources from 0x%x to 0x%x\n", + i2c_imx->res->start, i2c_imx->res->end); + dev_dbg(&i2c_imx->adapter.dev, "allocated %d bytes at 0x%x \n", + res_size, i2c_imx->res->start); + dev_dbg(&i2c_imx->adapter.dev, "adapter name: \"%s\"\n", + i2c_imx->adapter.name); + dev_dbg(&i2c_imx->adapter.dev, "IMX I2C adapter registered\n"); + + return 0; /* Return OK */ + +fail4: + free_irq(i2c_imx->irq, i2c_imx); +fail3: + clk_disable(i2c_imx->clk); + clk_put(i2c_imx->clk); +fail2: + kfree(i2c_imx); +fail1: + iounmap(base); +fail0: + if (pdata && pdata->exit) + pdata->exit(&pdev->dev); + return ret; /* Return error number */ +} + +static int __exit i2c_imx_remove(struct platform_device *pdev) +{ + struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev); + struct imxi2c_platform_data *pdata = pdev->dev.platform_data; + + /* remove adapter */ + dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n"); + i2c_del_adapter(&i2c_imx->adapter); + platform_set_drvdata(pdev, NULL); + + /* free interrupt */ + free_irq(i2c_imx->irq, i2c_imx); + + /* setup chip registers to defaults */ + writeb(0, i2c_imx->base + IMX_I2C_IADR); + writeb(0, i2c_imx->base + IMX_I2C_IFDR); + writeb(0, i2c_imx->base + IMX_I2C_I2CR); + writeb(0, i2c_imx->base + IMX_I2C_I2SR); + + /* Shut down hardware */ + if (pdata && pdata->exit) + pdata->exit(&pdev->dev); + + /* Disable I2C clock */ + clk_disable(i2c_imx->clk); + clk_put(i2c_imx->clk); + + iounmap(i2c_imx->base); + kfree(i2c_imx); + return 0; +} + +static struct platform_driver i2c_imx_driver = { + .probe = i2c_imx_probe, + .remove = __exit_p(i2c_imx_remove), + .driver = { + .name = DRIVER_NAME, + .owner = THIS_MODULE, + } +}; + +static int __init i2c_adap_imx_init(void) +{ + return platform_driver_probe(&i2c_imx_driver, i2c_imx_probe); +} + +static void __exit i2c_adap_imx_exit(void) +{ + platform_driver_unregister(&i2c_imx_driver); +} + +module_init(i2c_adap_imx_init); +module_exit(i2c_adap_imx_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Darius Augulis"); +MODULE_DESCRIPTION("I2C adapter driver for IMX I2C bus"); +MODULE_ALIAS("platform:" DRIVER_NAME); |