* [PATCH V2] I2C driver for IMX
@ 2008-03-14 14:04 Darius
2008-03-18 18:03 ` Andrew Dyer
0 siblings, 1 reply; 2+ messages in thread
From: Darius @ 2008-03-14 14:04 UTC (permalink / raw)
To: linux-arm-kernel; +Cc: i2c
[-- Attachment #1: Type: text/plain, Size: 333 bytes --]
Changes after previous version:
1. Removed history
2. Defined debug macro
3. Modified clock divider setup procedure
4. Corrected indentation (spaces removed)
5. Corrected spelling
6. Corrected C syntax (comments, etc.)
7. Init data and init functions marked with __init
Signed-off-by: Darius Augulis <augulis.darius@gmail.com>
---
[-- Attachment #2: patch-imx-i2c-2.6.24 --]
[-- Type: text/plain, Size: 22655 bytes --]
diff -uprN -X linux-2.6.24.3-vanilla/Documentation/dontdiff linux-2.6.24.3-vanilla/drivers/i2c/busses/i2c-imx.c linux-2.6.24.3/drivers/i2c/busses/i2c-imx.c
--- linux-2.6.24.3-vanilla/drivers/i2c/busses/i2c-imx.c 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.24.3/drivers/i2c/busses/i2c-imx.c 2008-03-14 15:44:47.000000000 +0200
@@ -0,0 +1,597 @@
+/*
+ * 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.
+ *
+ * File Name: i2c-imx.c
+ *
+ * Author: Darius Augulis, Teltonika Inc.
+ *
+ * Desc.: Implementation of I2C Adapter/Algorithm Driver
+ * Driver for I2C Bus integrated in i.MXL, i.MX1
+ *
+ * module parameters: - clkfreq:
+ * Sets the desired clock rate
+ * The default value is 100000
+ * Max value is 400000
+ * - imxslave:
+ * IMX slave I2C address in decimal format
+ * The default value is 0xAC in hex
+ *
+ * Derived from Motorola GSG China I2C example driver
+ *
+ * Copyright (C) 2002 Motorola GSG-China
+ * Copyright (C) 2005 Torsten Koschorrek <koschorrek at synertronixx.de
+ * Portions:
+ * Copyright (C) 2005 Matthias Blaschke <blaschke at synertronixx.de
+ * Copyright (C) 2007 RightHand Technologies, Inc. <adyer at righthandtech.com>
+ * 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/fs.h>
+#include <linux/proc_fs.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/platform_device.h>
+
+#include <asm/arch/irqs.h>
+#include <asm/arch/hardware.h>
+#include <asm/io.h>
+
+#include <asm/arch/imx-regs.h>
+
+/** Defines ********************************************************************
+*******************************************************************************/
+
+/* This will be the driver name the kernel reports */
+#define DRIVER_NAME "imx-i2c"
+
+/* Default values of module parameters */
+#define IMX_I2C_SLAVE_ADDR 0xAC
+#define IMX_I2C_BIT_RATE 100000
+
+/* Timeouts */
+#define I2C_IMX_TIME_BUSY 2000
+#define I2C_IMX_TIME_ACK 2000
+
+/* Error numbers */
+#define I2C_IMX_ERR_BUSY 1
+#define I2C_IMX_ERR_TX_TIMEOUT 2
+#define I2C_IMX_ERR_RX_TIMEOUT 3
+#define I2C_IMX_ERR_RX_NO_ACK 4
+
+/* Macros */
+#define print_err(f,x...) printk(KERN_ERR f, ##x)
+#ifdef CONFIG_I2C_DEBUG_BUS
+#define print_dbg(f,x...) printk(KERN_DEBUG f, ##x)
+#else
+#define print_dbg(f,x...) ((void)0)
+#endif
+
+/** Function prototypes ********************************************************
+*******************************************************************************/
+
+static int i2c_imx_xfer (struct i2c_adapter *adapter, struct i2c_msg *msgs, int num);
+static u32 i2c_imx_func (struct i2c_adapter *adapter);
+static int __init i2c_imx_probe (struct platform_device *pdev);
+static int i2c_imx_remove (struct platform_device *pdev);
+
+/** Variables ******************************************************************
+*******************************************************************************/
+
+static unsigned int clkfreq = IMX_I2C_BIT_RATE;
+static unsigned int imxslave = IMX_I2C_SLAVE_ADDR;;
+
+/*
+ * 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 int __initdata i2c_imx_clk_divider [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 }
+};
+
+static struct platform_driver i2c_imx_driver = {
+ .probe = i2c_imx_probe,
+ .remove = i2c_imx_remove,
+ .driver = {
+ .name = DRIVER_NAME,
+ .owner = THIS_MODULE,
+ }
+};
+
+static struct i2c_algorithm i2c_imx_algo = {
+ .master_xfer = i2c_imx_xfer,
+ .functionality = i2c_imx_func,
+};
+
+struct imx_i2c_struct {
+ struct i2c_adapter adapter;
+ struct resource *res;
+ 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 int i = 0;
+
+ print_dbg("I2C: <i2c_imx_bus_busy>\n");
+
+ /* wait for bus not busy */
+ for (i=0; i<I2C_IMX_TIME_BUSY; i++) {
+ if (!(readb(i2c_imx->base + IMX_I2C_I2SR) & (I2SR_IBB | I2SR_IAL)))
+ return 0;
+ udelay(1);
+ }
+ print_dbg("I2C: <i2c_imx_bus_busy> I2C bus is busy!\n");
+ return -I2C_IMX_ERR_BUSY;
+}
+
+static int i2c_imx_trx_complete (struct imx_i2c_struct *i2c_imx) {
+
+ int result;
+
+ print_dbg("I2C: <i2c_imx_trx_complete>\n");
+ result = wait_event_interruptible_timeout(i2c_imx->queue,
+ (i2c_imx->i2csr & I2SR_IIF), 5 * HZ);
+
+ if (unlikely(result < 0)) {
+ print_dbg("I2C: <i2c_imx_trx_complete> result < 0!\n");
+ return result;
+ }
+ else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
+ print_dbg("I2C: <i2c_imx_trx_complete> Timeout!\n");
+ return -I2C_IMX_ERR_TX_TIMEOUT;
+ }
+ print_dbg("I2C: <i2c_imx_trx_complete> TRX complete!\n");
+ i2c_imx->i2csr = 0;
+ return 0;
+}
+
+static int i2c_imx_acked (struct imx_i2c_struct *i2c_imx) {
+
+ unsigned int i = 0;
+
+ print_dbg("I2C: <i2c_imx_acked>\n");
+ for (i=0; i<I2C_IMX_TIME_ACK; i++) {
+ if (!(readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_RXAK)) {
+ print_dbg("I2C: <i2c_imx_acked> ACK received\n");
+ return 0;
+ }
+ udelay(1);
+ }
+ print_dbg("I2C: <i2c_imx_acked> No ACK!\n");
+ return -I2C_IMX_ERR_RX_NO_ACK; /* No ACK */
+}
+
+static void i2c_imx_enable (struct imx_i2c_struct *i2c_imx) {
+
+ print_dbg("I2C: <i2c_imx_enable>\n");
+ writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
+}
+
+static void i2c_imx_disable (struct imx_i2c_struct *i2c_imx) {
+
+ print_dbg("I2C: <i2c_imx_disable>\n");
+
+ /* setup chip registers to defaults */
+ writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
+ writeb(0, i2c_imx->base + IMX_I2C_I2SR);
+}
+
+static void i2c_imx_start (struct imx_i2c_struct *i2c_imx) {
+
+ unsigned int temp = 0;
+
+ print_dbg("I2C: <i2c_imx_start>\n");
+ 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);
+
+ temp = readb (i2c_imx->base + IMX_I2C_I2CR);
+ print_dbg("I2C: <i2c_imx_start> CONTROL: IEN=%d, IIEN=%d, MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n",
+ (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);
+ print_dbg("I2C: <i2c_imx_start> STATUS: ICF=%d, IAAS=%d, IBB=%d, IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n",
+ (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));
+}
+
+static void i2c_imx_stop (struct imx_i2c_struct *i2c_imx) {
+
+ unsigned int temp = 0;
+
+ print_dbg("I2C: <i2c_imx_stop>\n");
+ temp = readb ( i2c_imx->base + IMX_I2C_I2CR);
+ temp &= ~I2CR_MSTA;
+ writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
+ temp = readb (i2c_imx->base + IMX_I2C_I2CR);
+ print_dbg("I2C: <i2c_imx_stop> CONTROL: IEN=%d, IIEN=%d, MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n",
+ (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);
+ print_dbg("I2C: <i2c_imx_stop> STATUS: ICF=%d, IAAS=%d, IBB=%d, IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n",
+ (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));
+}
+
+static int __init i2c_imx_set_clk (struct imx_i2c_struct *i2c_imx, unsigned int rate) {
+
+ unsigned int hclk, sysclk;
+ unsigned int desired_div;
+ int i;
+
+ print_dbg("I2C: <i2c_imx_set_clk>\n");
+ sysclk = imx_get_system_clk ();
+ hclk = imx_get_hclk();
+ desired_div = hclk / rate;
+ if (desired_div & 0x01)
+ desired_div++;
+ if (desired_div < 22)
+ desired_div = 22;
+ if (desired_div > 3840)
+ desired_div = 3840;
+ for (i=0; i<50; i++) {
+ if (i2c_imx_clk_divider[i][0] >= desired_div)
+ break;
+ }
+ print_dbg("I2C: <i2c_imx_set_clk> SYSCLK=%d, HCLK=%d, REQ DIV=%d\n", sysclk, hclk, desired_div);
+ print_dbg("I2C: <i2c_imx_set_clk> IFDR[IC]=0x%x, REAL DIV=%d\n", i2c_imx_clk_divider[i][1], i2c_imx_clk_divider[i][0]);
+ writeb(i2c_imx_clk_divider[i][1], i2c_imx->base + IMX_I2C_IFDR);
+ return (hclk / i2c_imx_clk_divider[i][0]);
+}
+
+static irqreturn_t i2c_imx_isr (int irq, void *dev_id) {
+
+ struct imx_i2c_struct *i2c_imx = dev_id;
+ unsigned int temp;
+
+ print_dbg("I2C: <i2c_imx_isr>\n");
+ temp = readb (i2c_imx->base + IMX_I2C_I2CR);
+ print_dbg("I2C: <i2c_imx_isr> CONTROL: IEN=%d, IIEN=%d, MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n",
+ (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);
+ print_dbg("I2C: <i2c_imx_isr> STATUS: ICF=%d, IAAS=%d, IBB=%d, IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n",
+ (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));
+
+ 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;
+}
+
+static int i2c_imx_write (struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) {
+
+ int i;
+
+ print_dbg("I2C: <i2c_imx_write>\n");
+ print_dbg("I2C: <i2c_imx_write> write slave address: addr=0x%x\n", (msgs->addr<<1));
+
+ /* write slave address */
+ writeb((msgs->addr<<1), i2c_imx->base + IMX_I2C_I2DR);
+ if (i2c_imx_trx_complete(i2c_imx))
+ return -I2C_IMX_ERR_TX_TIMEOUT;
+ if (i2c_imx_acked(i2c_imx))
+ return -I2C_IMX_ERR_RX_NO_ACK;
+ print_dbg("I2C: <i2c_imx_write> write data\n");
+
+ /* write data */
+ for (i = 0; i<msgs->len; i++) {
+ print_dbg("I2C: <i2c_imx_write> write byte: %d, b=0x%x\n", i, msgs->buf[i]);
+ writeb(msgs->buf[i], i2c_imx->base + IMX_I2C_I2DR);
+ if (i2c_imx_trx_complete(i2c_imx))
+ return -I2C_IMX_ERR_TX_TIMEOUT;
+ if (i2c_imx_acked(i2c_imx))
+ return -I2C_IMX_ERR_RX_NO_ACK;
+ }
+ return 0;
+}
+
+static int i2c_imx_read (struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs) {
+
+ int i;
+ unsigned int temp;
+
+ print_dbg("I2C: <i2c_imx_read>\n");
+ print_dbg("I2C: <i2c_imx_read> write slave address: addr=0x%x\n", (msgs->addr<<1));
+
+ /* write slave address */
+ writeb((msgs->addr<<1)|0x01, i2c_imx->base + IMX_I2C_I2DR);
+ if (i2c_imx_trx_complete(i2c_imx))
+ return -I2C_IMX_ERR_TX_TIMEOUT;
+ if (i2c_imx_acked(i2c_imx))
+ return -I2C_IMX_ERR_RX_NO_ACK;
+
+ print_dbg("I2C: <i2c_imx_read> setup bus\n");
+
+ /* 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);
+
+ print_dbg("I2C: <i2c_imx_read> dummy read\n");
+ readb(i2c_imx->base + IMX_I2C_I2DR); /* dummy read */
+
+ print_dbg("I2C: <i2c_imx_read> read data\n");
+
+ /* read data */
+ for (i=0; i < msgs->len; i++) {
+
+ if (i2c_imx_trx_complete(i2c_imx))
+ return -I2C_IMX_ERR_RX_TIMEOUT;
+
+ if (i==(msgs->len-1)) {
+ print_dbg("I2C: <i2c_imx_read> clear MSTA\n");
+ 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)) {
+ print_dbg("I2C: <i2c_imx_read> set TXAK\n");
+ temp = readb(i2c_imx->base + IMX_I2C_I2CR);
+ temp |= I2CR_TXAK;
+ writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
+ }
+ print_dbg("I2C: <i2c_imx_read> read byte B%d\n", i);
+ msgs->buf[i] = readb(i2c_imx->base + IMX_I2C_I2DR);
+ }
+ return 0;
+}
+
+static int i2c_imx_xfer (struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) {
+
+ int i, temp;
+ int err = 0;
+ struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter);
+
+ print_dbg("I2C: <i2c_imx_xfer>\n");
+
+ /* Check or i2c bus is not busy */
+ err = i2c_imx_bus_busy(i2c_imx);
+ if (err)
+ goto fail0;
+
+ /* Enable i2c */
+ i2c_imx_enable(i2c_imx);
+
+ /* Start I2C transfer */
+ i2c_imx_start (i2c_imx);
+
+ temp = readb (i2c_imx->base + IMX_I2C_I2CR);
+ print_dbg("I2C: <i2c_imx_xfer> CONTROL: IEN=%d, IIEN=%d, MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n",
+ (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);
+ print_dbg("I2C: <i2c_imx_xfer> STATUS: ICF=%d, IAAS=%d, IBB=%d, IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n",
+ (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));
+
+ /* read/write data */
+ for (i=0; i<num; i++) {
+ if (i) {
+ print_dbg("I2C: <i2c_imx_read> repeated start\n");
+ temp = readb(i2c_imx->base + IMX_I2C_I2CR);
+ temp |= I2CR_RSTA;
+ writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
+ }
+ print_dbg("I2C: <i2c_imx_xfer> transfer message: %d\n", i);
+ /* write/read data */
+ if (!(msgs[i].flags & I2C_M_RD))
+ err = i2c_imx_write (i2c_imx, &msgs[i]);
+ else
+ err = i2c_imx_read (i2c_imx, &msgs[i]);
+ }
+
+fail0:
+ /* Stop bus */
+ i2c_imx_stop (i2c_imx);
+ /* disable i2c bus */
+ i2c_imx_disable (i2c_imx);
+ print_dbg("I2C: <i2c_imx_xfer> exit with: %s: %d\n", (err < 0)?"error":"success msg", (err < 0)?err:num);
+ return (err < 0) ? err : num;
+}
+
+static u32 i2c_imx_func (struct i2c_adapter *adapter) {
+ return I2C_FUNC_I2C;
+}
+
+static int __init i2c_imx_probe (struct platform_device *pdev) {
+
+ struct imx_i2c_struct *i2c_imx;
+ struct resource *res;
+ void __iomem *base;
+ int irq;
+ int res_size;
+ int ret;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ irq = platform_get_irq(pdev, 0);
+ if (!res) {
+ print_err("I2C: can't get device resources!\n");
+ return -ENODEV;
+ }
+ if (irq < 0) {
+ print_err("I2C: can't get irq number!\n");
+ return -ENODEV;
+ }
+ res_size = (res->end) - (res->start) + 1;
+ if (!request_mem_region(res->start, res_size, res->name)) {
+ print_err("I2C: can't allocate %d bytes at %d address!\n", res_size, res->start);
+ return -ENOMEM;
+ }
+ base = ioremap (res->start, res_size);
+ if (!base) {
+ print_err("I2C: ioremap failed!\n");
+ ret = -EIO;
+ goto fail0;
+ }
+ i2c_imx = kzalloc(sizeof(struct imx_i2c_struct), GFP_KERNEL);
+ if (!i2c_imx) {
+ print_err("I2C: 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->irq = irq;
+ i2c_imx->base = base;
+ i2c_imx->res = res;
+
+ init_waitqueue_head(&i2c_imx->queue);
+
+ /* Set up platform driver data */
+ platform_set_drvdata(pdev, i2c_imx);
+
+ ret = request_irq(i2c_imx->irq, i2c_imx_isr, IRQF_DISABLED, pdev->name, i2c_imx);
+ if (ret) {
+ print_err("I2C: %s: cannot claim irq %d !\n", i2c_imx->adapter.dev.bus_id, i2c_imx->irq);
+ goto fail2;
+ }
+
+ /* Set up clock divider */
+ i2c_imx_set_clk(i2c_imx, clkfreq);
+
+ /* Set up IMX I2C slave address */
+ writeb(imxslave, i2c_imx->base + IMX_I2C_IADR);
+
+ /* Set up I/O pins for I2C*/
+ imx_gpio_mode(PA15_PF_I2C_SDA);
+ imx_gpio_mode(PA16_PF_I2C_SCL);
+
+ /* Set up chip registers to defaults */
+ writeb(0, i2c_imx->base + IMX_I2C_I2CR);
+ writeb(0, i2c_imx->base + IMX_I2C_I2SR);
+
+ /* Set up adapter data */
+ i2c_set_adapdata(&i2c_imx->adapter, i2c_imx);
+
+ /* Add I2C adapter */
+ ret = i2c_add_adapter(&i2c_imx->adapter);
+ if (ret < 0) {
+ print_err("I2C: %s: registration failed\n", i2c_imx->adapter.dev.bus_id);
+ goto fail3;
+ }
+
+ print_dbg("I2C: %s: claimed irq %d\n", i2c_imx->adapter.dev.bus_id, i2c_imx->irq);
+ print_dbg("I2C: %s: device resources from 0x%x to 0x%x\n", i2c_imx->adapter.dev.bus_id, i2c_imx->res->start, i2c_imx->res->end);
+ print_dbg("I2C: %s: allocated %d bytes at 0x%x \n", i2c_imx->adapter.dev.bus_id, res_size, i2c_imx->res->start);
+ print_dbg("I2C: %s: adapter name: \"%s\"\n", i2c_imx->adapter.dev.bus_id, i2c_imx->adapter.name);
+ print_dbg("I2C: adapter \"%s\" associated with driver \"%s\"\n", i2c_imx->adapter.dev.bus_id, i2c_imx_driver.driver.name);
+ print_dbg("I2C: %s: IMX I2C adapter registered\n", i2c_imx->adapter.dev.bus_id);
+ return 0; /* Return OK */
+
+fail3:
+ free_irq(i2c_imx->irq, i2c_imx);
+fail2:
+ platform_set_drvdata(pdev, NULL);
+ kfree(i2c_imx);
+fail1:
+ iounmap(i2c_imx->base);
+fail0:
+ release_mem_region(res->start, res_size);
+ return ret; /* Return error number */
+}
+
+static int i2c_imx_remove (struct platform_device *pdev) {
+
+ struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev);
+
+ /* remove adapter */
+ print_dbg("I2C: 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);
+
+ /* release memory */
+ release_mem_region(i2c_imx->res->start, (i2c_imx->res->end - i2c_imx->res->start) + 1);
+ iounmap(i2c_imx->base);
+ kfree(i2c_imx);
+ return 0;
+}
+
+static int __init i2c_adap_imx_init (void) {
+ return platform_driver_register(&i2c_imx_driver);
+}
+
+static void __exit i2c_adap_imx_exit (void) {
+ platform_driver_unregister(&i2c_imx_driver);
+ return;
+}
+
+module_init(i2c_adap_imx_init);
+module_exit(i2c_adap_imx_exit);
+
+MODULE_AUTHOR("Darius Augulis");
+MODULE_DESCRIPTION("I2C adapter driver for IMX I2C bus");
+MODULE_LICENSE("GPL");
+
+module_param(clkfreq, uint, S_IRUGO);
+MODULE_PARM_DESC(clkfreq, "desired IMX I2C Clock Rate in Hz");
+
+module_param(imxslave, uint, S_IRUGO);
+MODULE_PARM_DESC(imxslave, "desired IMX I2C slave address");
diff -uprN -X linux-2.6.24.3-vanilla/Documentation/dontdiff linux-2.6.24.3-vanilla/drivers/i2c/busses/Kconfig linux-2.6.24.3/drivers/i2c/busses/Kconfig
--- linux-2.6.24.3-vanilla/drivers/i2c/busses/Kconfig 2008-01-25 00:58:37.000000000 +0200
+++ linux-2.6.24.3/drivers/i2c/busses/Kconfig 2008-03-14 14:15:34.000000000 +0200
@@ -249,6 +249,16 @@ config I2C_IBM_IIC
This driver can also be built as a module. If so, the module
will be called i2c-ibm_iic.
+config I2C_IMX
+ tristate "IMX I2C interface"
+ depends on ARCH_IMX
+ help
+ Say Y here if you want to use the IIC bus controller on
+ the Freescale i.MXL and i.MX1 processors.
+
+ This driver can also be built as a module. If so, the module
+ will be called i2c-imx.
+
config I2C_IOP3XX
tristate "Intel IOPx3xx and IXP4xx on-chip I2C interface"
depends on ARCH_IOP32X || ARCH_IOP33X || ARCH_IXP4XX || ARCH_IOP13XX
diff -uprN -X linux-2.6.24.3-vanilla/Documentation/dontdiff linux-2.6.24.3-vanilla/drivers/i2c/busses/Makefile linux-2.6.24.3/drivers/i2c/busses/Makefile
--- linux-2.6.24.3-vanilla/drivers/i2c/busses/Makefile 2008-01-25 00:58:37.000000000 +0200
+++ linux-2.6.24.3/drivers/i2c/busses/Makefile 2008-03-13 17:25:39.000000000 +0200
@@ -18,6 +18,7 @@ obj-$(CONFIG_I2C_HYDRA) += i2c-hydra.o
obj-$(CONFIG_I2C_I801) += i2c-i801.o
obj-$(CONFIG_I2C_I810) += i2c-i810.o
obj-$(CONFIG_I2C_IBM_IIC) += i2c-ibm_iic.o
+obj-$(CONFIG_I2C_IMX) += i2c-imx.o
obj-$(CONFIG_I2C_IOP3XX) += i2c-iop3xx.o
obj-$(CONFIG_I2C_IXP2000) += i2c-ixp2000.o
obj-$(CONFIG_I2C_IXP4XX) += i2c-ixp4xx.o
diff -uprN -X linux-2.6.24.3-vanilla/Documentation/dontdiff linux-2.6.24.3-vanilla/include/asm-arm/arch-imx/imx-regs.h linux-2.6.24.3/include/asm-arm/arch-imx/imx-regs.h
--- linux-2.6.24.3-vanilla/include/asm-arm/arch-imx/imx-regs.h 2008-01-25 00:58:37.000000000 +0200
+++ linux-2.6.24.3/include/asm-arm/arch-imx/imx-regs.h 2008-03-14 14:01:56.000000000 +0200
@@ -479,4 +479,29 @@
#define LCDISR_EOF (1<<1)
#define LCDISR_BOF (1<<0)
+/*
+ * I2C
+ */
+
+#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 */
+
+#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
+
#endif // _IMX_REGS_H
[-- Attachment #3: Type: text/plain, Size: 271 bytes --]
-------------------------------------------------------------------
List admin: http://lists.arm.linux.org.uk/mailman/listinfo/linux-arm-kernel
FAQ: http://www.arm.linux.org.uk/mailinglists/faq.php
Etiquette: http://www.arm.linux.org.uk/mailinglists/etiquette.php
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH V2] I2C driver for IMX
2008-03-14 14:04 [PATCH V2] I2C driver for IMX Darius
@ 2008-03-18 18:03 ` Andrew Dyer
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Dyer @ 2008-03-18 18:03 UTC (permalink / raw)
To: Darius; +Cc: linux-arm-kernel, i2c
On Fri, Mar 14, 2008 at 9:04 AM, Darius <augulis.darius@gmail.com> wrote:
> diff -uprN -X linux-2.6.24.3-vanilla/Documentation/dontdiff linux-2.6.24.3-vanilla/drivers/i2c/busses/i2c-imx.c linux-2.6.24.3/drivers/i2c/busses/i2c-imx.c
> --- linux-2.6.24.3-vanilla/drivers/i2c/busses/i2c-imx.c 1970-01-01 03:00:00.000000000 +0300
> +++ linux-2.6.24.3/drivers/i2c/busses/i2c-imx.c 2008-03-14 15:44:47.000000000 +0200
+/* Macros */
+#define print_err(f,x...) printk(KERN_ERR f, ##x)
+#ifdef CONFIG_I2C_DEBUG_BUS
+#define print_dbg(f,x...) printk(KERN_DEBUG f, ##x)
+#else
+#define print_dbg(f,x...) ((void)0)
+#endif
why not use standard kernel macros dev_err() and dev_dbg()?
...stuff deleted...
> +static int i2c_imx_bus_busy (struct imx_i2c_struct *i2c_imx) {
> +
> + unsigned int i = 0;
> +
> + print_dbg("I2C: <i2c_imx_bus_busy>\n");
> +
> + /* wait for bus not busy */
> + for (i=0; i<I2C_IMX_TIME_BUSY; i++) {
> + if (!(readb(i2c_imx->base + IMX_I2C_I2SR) & (I2SR_IBB | I2SR_IAL)))
> + return 0;
> + udelay(1);
> + }
> + print_dbg("I2C: <i2c_imx_bus_busy> I2C bus is busy!\n");
> + return -I2C_IMX_ERR_BUSY;
> +}
This function is a little problematic - for the case where there is
I2C traffic but are no other bus masters, it usually takes a few
cycles before the bus comes ready, so for throughput you don't want to
go back through the scheduler, but it's probably not a good idea to
busy-wait on a multi-master bus where some other i2c transaction might
take a long time. Maybe this could be modified to a two-stage scheme,
where the first wait could use udelay() for a few cycles, and then
switch to msleep()
Also I2C_IMX_TIME_* are not really times, they're loop counts - poor
naming on my part :-(
> +
> +static int i2c_imx_trx_complete (struct imx_i2c_struct *i2c_imx) {
> +
> + int result;
> +
> + print_dbg("I2C: <i2c_imx_trx_complete>\n");
> + result = wait_event_interruptible_timeout(i2c_imx->queue,
> + (i2c_imx->i2csr & I2SR_IIF), 5 * HZ);
hardcoded 5 sec. constant here
> +
> + if (unlikely(result < 0)) {
> + print_dbg("I2C: <i2c_imx_trx_complete> result < 0!\n");
> + return result;
> + }
> + else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
> + print_dbg("I2C: <i2c_imx_trx_complete> Timeout!\n");
> + return -I2C_IMX_ERR_TX_TIMEOUT;
> + }
> + print_dbg("I2C: <i2c_imx_trx_complete> TRX complete!\n");
> + i2c_imx->i2csr = 0;
> + return 0;
> +}
...stuff deleted...
> +static void i2c_imx_enable (struct imx_i2c_struct *i2c_imx) {
> +
> + print_dbg("I2C: <i2c_imx_enable>\n");
> + writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
> +}
> +
> +static void i2c_imx_disable (struct imx_i2c_struct *i2c_imx) {
> +
> + print_dbg("I2C: <i2c_imx_disable>\n");
> +
> + /* setup chip registers to defaults */
> + writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
> + writeb(0, i2c_imx->base + IMX_I2C_I2SR);
> +}
this looks wrong - you're setting the enable bit in the disable function
> +
> +static void i2c_imx_start (struct imx_i2c_struct *i2c_imx) {
> +
> + unsigned int temp = 0;
> +
> + print_dbg("I2C: <i2c_imx_start>\n");
> + 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);
> +
> + temp = readb (i2c_imx->base + IMX_I2C_I2CR);
> + print_dbg("I2C: <i2c_imx_start> CONTROL: IEN=%d, IIEN=%d, MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n",
> + (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);
> + print_dbg("I2C: <i2c_imx_start> STATUS: ICF=%d, IAAS=%d, IBB=%d, IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n",
> + (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));
I would wrap these register debug statements in macros since they
appear a few more times, and add a space after commas or some newlines
to make this a bit easier to parse.
> +}
> +
> +static void i2c_imx_stop (struct imx_i2c_struct *i2c_imx) {
> +
> + unsigned int temp = 0;
> +
> + print_dbg("I2C: <i2c_imx_stop>\n");
> + temp = readb ( i2c_imx->base + IMX_I2C_I2CR);
> + temp &= ~I2CR_MSTA;
> + writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
> + temp = readb (i2c_imx->base + IMX_I2C_I2CR);
> + print_dbg("I2C: <i2c_imx_stop> CONTROL: IEN=%d, IIEN=%d, MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n",
> + (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);
> + print_dbg("I2C: <i2c_imx_stop> STATUS: ICF=%d, IAAS=%d, IBB=%d, IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n",
> + (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));
> +}
> +
> +static int __init i2c_imx_set_clk (struct imx_i2c_struct *i2c_imx, unsigned int rate) {
> +
> + unsigned int hclk, sysclk;
> + unsigned int desired_div;
> + int i;
> +
> + print_dbg("I2C: <i2c_imx_set_clk>\n");
> + sysclk = imx_get_system_clk ();
> + hclk = imx_get_hclk();
> + desired_div = hclk / rate;
> + if (desired_div & 0x01)
> + desired_div++;
> + if (desired_div < 22)
> + desired_div = 22;
> + if (desired_div > 3840)
> + desired_div = 3840;
still have the magic constant numbers in here...
> + for (i=0; i<50; i++) {
> + if (i2c_imx_clk_divider[i][0] >= desired_div)
> + break;
--
Hardware, n.:
The parts of a computer system that can be kicked.
-------------------------------------------------------------------
List admin: http://lists.arm.linux.org.uk/mailman/listinfo/linux-arm-kernel
FAQ: http://www.arm.linux.org.uk/mailinglists/faq.php
Etiquette: http://www.arm.linux.org.uk/mailinglists/etiquette.php
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2008-03-18 18:03 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2008-03-14 14:04 [PATCH V2] I2C driver for IMX Darius
2008-03-18 18:03 ` Andrew Dyer
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox