/* * 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 <linux/slab.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 ****************************************************************** *******************************************************************************/ /* * 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; unsigned int disable_delay; int stopped; unsigned int ifdr; /* IMX_I2C_IFDR */ }; /** Functions for IMX I2C adapter driver *************************************** *******************************************************************************/ static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy) { unsigned long orig_jiffies = jiffies; unsigned int temp; dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); while (1) { temp = readb(i2c_imx->base + IMX_I2C_I2SR); if (for_busy && (temp & I2SR_IBB)) break; if (!for_busy && !(temp & I2SR_IBB)) break; if (signal_pending(current)) { dev_dbg(&i2c_imx->adapter.dev, "<%s> I2C Interrupted\n", __func__); return -EINTR; } if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) { dev_dbg(&i2c_imx->adapter.dev, "<%s> I2C bus is busy\n", __func__); return -ETIMEDOUT; } schedule(); } return 0; } static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx) { wait_event_timeout(i2c_imx->queue, i2c_imx->i2csr & I2SR_IIF, HZ / 10); 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 int i2c_imx_start(struct imx_i2c_struct *i2c_imx) { unsigned int temp = 0; int result; dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); clk_enable(i2c_imx->clk); writeb(i2c_imx->ifdr, i2c_imx->base + IMX_I2C_IFDR); /* Enable I2C controller */ writeb(0, i2c_imx->base + IMX_I2C_I2SR); writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR); /* Wait controller to be stable */ udelay(50); /* Start I2C transaction */ temp = readb(i2c_imx->base + IMX_I2C_I2CR); temp |= I2CR_MSTA; writeb(temp, i2c_imx->base + IMX_I2C_I2CR); result = i2c_imx_bus_busy(i2c_imx, 1); if (result) return result; i2c_imx->stopped = 0; temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK; writeb(temp, i2c_imx->base + IMX_I2C_I2CR); return result; } static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx) { unsigned int temp = 0; if (!i2c_imx->stopped) { /* Stop I2C transaction */ dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); temp = readb(i2c_imx->base + IMX_I2C_I2CR); temp &= ~(I2CR_MSTA | I2CR_MTX); writeb(temp, i2c_imx->base + IMX_I2C_I2CR); } if (cpu_is_mx1()) { /* * This delay caused by an i.MXL hardware bug. * If no (or too short) delay, no "STOP" bit will be generated. */ udelay(i2c_imx->disable_delay); } if (!i2c_imx->stopped) { i2c_imx_bus_busy(i2c_imx, 0); i2c_imx->stopped = 1; } /* Disable I2C controller */ writeb(0, i2c_imx->base + IMX_I2C_I2CR); clk_disable(i2c_imx->clk); } 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++); /* Store divider value */ i2c_imx->ifdr = i2c_clk_div[i][1]; /* * 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. */ i2c_imx->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(&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)) { /* It must generate STOP before read I2DR to prevent controller from generating another clock cycle */ dev_dbg(&i2c_imx->adapter.dev, "<%s> clear MSTA\n", __func__); temp = readb(i2c_imx->base + IMX_I2C_I2CR); temp &= ~(I2CR_MSTA | I2CR_MTX); writeb(temp, i2c_imx->base + IMX_I2C_I2CR); i2c_imx_bus_busy(i2c_imx, 0); i2c_imx->stopped = 1; } 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__); /* Start I2C transfer */ result = i2c_imx_start(i2c_imx); if (result) goto fail0; /* 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); result = i2c_imx_bus_busy(i2c_imx, 1); if (result) goto fail0; } 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]); if (result) goto fail0; } 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); if (!request_mem_region(res->start, res_size, DRIVER_NAME)) { ret = -EBUSY; goto fail0; } base = ioremap(res->start, res_size); if (!base) { dev_err(&pdev->dev, "ioremap failed\n"); ret = -EIO; goto fail1; } 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 fail2; } /* 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 fail3; } /* 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 fail4; } /* 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 fail5; } /* 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 */ fail5: free_irq(i2c_imx->irq, i2c_imx); fail4: clk_put(i2c_imx->clk); fail3: kfree(i2c_imx); fail2: iounmap(base); fail1: release_mem_region(res->start, resource_size(res)); 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); clk_put(i2c_imx->clk); iounmap(i2c_imx->base); release_mem_region(i2c_imx->res->start, resource_size(i2c_imx->res)); kfree(i2c_imx); return 0; } static struct platform_driver i2c_imx_driver = { .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); } subsys_initcall(i2c_adap_imx_init); static void __exit i2c_adap_imx_exit(void) { platform_driver_unregister(&i2c_imx_driver); } 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);