Hi Guennadi,
Some comments inline...
Sascha
On Fri, Nov 07, 2008 at 07:01:26PM +0100, Guennadi Liakhovetski wrote:
> This is an updated and cleaned up i2c driver for i.MX3x from Freescale.
>
> Signed-off-by: Guennadi Liakhovetski <[EMAIL PROTECTED]>
>
> ---
>
> Please comment, I'll also have to obtain ARM Acks for the arch/arm part,
> or, maybe, split it into two parts.
>
> diff --git a/arch/arm/mach-mx3/devices.c b/arch/arm/mach-mx3/devices.c
> index 3ef1227..7c66f7c 100644
> --- a/arch/arm/mach-mx3/devices.c
> +++ b/arch/arm/mach-mx3/devices.c
> @@ -23,6 +23,7 @@
> #include <linux/gpio.h>
>
> #include <mach/hardware.h>
> +#include <mach/i2c.h>
> #include <mach/imx-uart.h>
> #include <mach/ipu.h>
> #include <mach/mxcfb.h>
> @@ -229,3 +230,94 @@ static int __init register_ipu(void)
>
> /* This is needed for the framebuffer, so, initialise early */
> arch_initcall(register_ipu);
> +
> +/*
> + * Resource definition for the I2C1
> + */
> +static struct resource mxci2c1_resources[] = {
> + [0] = {
> + .start = I2C_BASE_ADDR,
> + .end = I2C_BASE_ADDR + SZ_4K - 1,
> + .flags = IORESOURCE_MEM,
> + }, [1] = {
> + .start = MXC_INT_I2C,
> + .end = MXC_INT_I2C,
> + .flags = IORESOURCE_IRQ,
> + },
> +};
Can we drop the [0] and [1]? gcc knows how to count.
> +
> +/*
> + * Resource definition for the I2C2
> + */
> +static struct resource mxci2c2_resources[] = {
> + [0] = {
> + .start = I2C2_BASE_ADDR,
> + .end = I2C2_BASE_ADDR + SZ_4K - 1,
> + .flags = IORESOURCE_MEM,
> + }, [1] = {
> + .start = MXC_INT_I2C2,
> + .end = MXC_INT_I2C2,
> + .flags = IORESOURCE_IRQ,
> + },
> +};
> +
> +/*
> + * Resource definition for the I2C3
> + */
> +static struct resource mxci2c3_resources[] = {
> + [0] = {
> + .start = I2C3_BASE_ADDR,
> + .end = I2C3_BASE_ADDR + SZ_4K - 1,
> + .flags = IORESOURCE_MEM,
> + }, [1] = {
> + .start = MXC_INT_I2C3,
> + .end = MXC_INT_I2C3,
> + .flags = IORESOURCE_IRQ,
> + },
> +};
> +
> +/* Device definition for MXC I2C */
> +static struct platform_device mxci2c_devices[] = {
> + [0] = {
> + .name = "mxc-i2c",
> + .id = 0,
> + .num_resources = ARRAY_SIZE(mxci2c1_resources),
> + .resource = mxci2c1_resources,
> + }, [1] = {
> + .name = "mxc-i2c",
> + .id = 1,
> + .num_resources = ARRAY_SIZE(mxci2c2_resources),
> + .resource = mxci2c2_resources,
> + }, [2] = {
> + .name = "mxc-i2c",
> + .id = 2,
> + .num_resources = ARRAY_SIZE(mxci2c3_resources),
> + .resource = mxci2c3_resources,
> + },
> +};
> +
> +int mxc_i2c_register_adapters(struct mxc_i2c_board_data *data, int n)
> +{
> + int i;
> +
> + if (n > 3 || !data) {
> + printk(KERN_ERR "i2c-mxc: Wrong platform data!\n");
> + return -EINVAL;
> + }
> +
> + for (i = 0; i < n; i++) {
> + unsigned int id = data[i].id;
> + if (id > 2) {
> + printk(KERN_ERR
> + "i2c-mxc: Bad platform data #%d ID: %u!\n",
> + i, id);
> + return -EINVAL;
> + }
> + mxci2c_devices[id].dev.platform_data = &data[i].data;
> + if (platform_device_register(&mxci2c_devices[id]) < 0)
> + printk(KERN_ERR
> + "i2c-mxc: Failed to register bus %u\n", id);
> + }
> +
> + return 0;
> +}
Why not use mxc_register_device() instead? The need of an extra struct
mxc_i2c_board_data would be removed.
> diff --git a/arch/arm/plat-mxc/include/mach/i2c.h
> b/arch/arm/plat-mxc/include/mach/i2c.h
> new file mode 100644
> index 0000000..ce50af5
> --- /dev/null
> +++ b/arch/arm/plat-mxc/include/mach/i2c.h
> @@ -0,0 +1,33 @@
> +/*
> + * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
> + *
> + * 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., 51 Franklin Street, Fifth Floor, Boston,
> + * MA 02110-1301, USA.
> + */
> +
> +#ifndef __ASM_ARCH_I2C_H__
> +#define __ASM_ARCH_I2C_H__
> +
> +struct mxc_i2c_platform_data {
> + u32 i2c_clk;
> +};
> +
> +struct mxc_i2c_board_data {
> + struct mxc_i2c_platform_data data;
> + unsigned int id;
> +};
> +
> +extern int mxc_i2c_register_adapters(struct mxc_i2c_board_data *, int);
> +
> +#endif
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 7f95905..055a33a 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -401,6 +401,15 @@ config I2C_MV64XXX
> This driver can also be built as a module. If so, the module
> will be called i2c-mv64xxx.
>
> +config I2C_MXC
> + tristate "MXC I2C support"
> + depends on I2C && ARCH_MXC
> + help
> + If you say yes to this option, support will be included for Freescale
> + MXC I2C modules.
> +
> + This driver can also be built as a module.
> +
> config I2C_OCORES
> tristate "OpenCores I2C Controller"
> depends on EXPERIMENTAL
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index 0c2c4b2..495f040 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -37,6 +37,7 @@ obj-$(CONFIG_I2C_IOP3XX) += i2c-iop3xx.o
> obj-$(CONFIG_I2C_IXP2000) += i2c-ixp2000.o
> obj-$(CONFIG_I2C_MPC) += i2c-mpc.o
> obj-$(CONFIG_I2C_MV64XXX) += i2c-mv64xxx.o
> +obj-$(CONFIG_I2C_MXC) += i2c-mxc.o
> obj-$(CONFIG_I2C_OCORES) += i2c-ocores.o
> obj-$(CONFIG_I2C_OMAP) += i2c-omap.o
> obj-$(CONFIG_I2C_PASEMI) += i2c-pasemi.o
> diff --git a/drivers/i2c/busses/i2c-mxc.c b/drivers/i2c/busses/i2c-mxc.c
> new file mode 100644
> index 0000000..8b4e52f
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-mxc.c
> @@ -0,0 +1,744 @@
> +/*
> + * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
> + *
> + * The code contained herein is licensed under the GNU General Public
> + * License. You may obtain a copy of the GNU General Public License
> + * Version 2 or later at the following locations:
> + *
> + * http://www.opensource.org/licenses/gpl-license.html
> + * http://www.gnu.org/copyleft/gpl.html
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/platform_device.h>
> +#include <linux/i2c.h>
> +#include <linux/clk.h>
> +
> +#include <asm/irq.h>
> +#include <asm/io.h>
> +
> +#include <mach/i2c.h>
> +#include <mach/iomux-mx3.h>
> +
> +/* Address offsets of the I2C registers */
> +#define MXC_IADR 0x00 /* Address Register */
> +#define MXC_IFDR 0x04 /* Freq div register */
> +#define MXC_I2CR 0x08 /* Control regsiter */
> +#define MXC_I2SR 0x0C /* Status register */
> +#define MXC_I2DR 0x10 /* Data I/O register */
> +
> +/* Bit definitions of I2CR */
> +#define MXC_I2CR_IEN 0x0080
> +#define MXC_I2CR_IIEN 0x0040
> +#define MXC_I2CR_MSTA 0x0020
> +#define MXC_I2CR_MTX 0x0010
> +#define MXC_I2CR_TXAK 0x0008
> +#define MXC_I2CR_RSTA 0x0004
> +
> +/* Bit definitions of I2SR */
> +#define MXC_I2SR_ICF 0x0080
> +#define MXC_I2SR_IAAS 0x0040
> +#define MXC_I2SR_IBB 0x0020
> +#define MXC_I2SR_IAL 0x0010
> +#define MXC_I2SR_SRW 0x0004
> +#define MXC_I2SR_IIF 0x0002
> +#define MXC_I2SR_RXAK 0x0001
> +
> +#define MXC_ADAPTER_NAME "MXC I2C Adapter"
> +
> +/*
> + * In case the MXC device has multiple I2C modules, this structure is used to
> + * store information specific to each I2C module.
> + */
> +struct mxc_i2c_device {
> + /*
> + * This structure is used to identify the physical i2c bus along with
> + * the access algorithms necessary to access it.
> + */
> + struct i2c_adapter adap;
> +
> + /*
> + * This waitqueue is used to wait for the data transfer to complete.
> + */
> + wait_queue_head_t wq;
> +
> + /*
> + * The base address of the I2C device.
> + */
> + void __iomem *membase;
> +
> + /*
> + * The interrupt number used by the I2C device.
> + */
> + int irq;
> +
> + /*
> + * The default clock divider value to be used.
> + */
> + unsigned int clkdiv;
> +
> + /*
> + * The clock source for the device.
> + */
> + struct clk *clk;
> +
> + /*
> + * The current power state of the device
> + */
> + bool low_power;
> +
> + /*
> + * Boolean to indicate if data was transferred
> + */
> + bool transfer_done;
> +
> + /*
> + * Boolean to indicate if we received an ACK for the data transmitted
> + */
> + bool tx_success;
> +};
> +
> +struct clk_div_table {
> + int reg_value;
> + int div;
> +};
> +
> +static const struct clk_div_table i2c_clk_table[] = {
> + {0x20, 22}, {0x21, 24}, {0x22, 26}, {0x23, 28},
> + {0, 30}, {1, 32}, {0x24, 32}, {2, 36},
> + {0x25, 36}, {0x26, 40}, {3, 42}, {0x27, 44},
> + {4, 48}, {0x28, 48}, {5, 52}, {0x29, 56},
> + {6, 60}, {0x2A, 64}, {7, 72}, {0x2B, 72},
> + {8, 80}, {0x2C, 80}, {9, 88}, {0x2D, 96},
> + {0xA, 104}, {0x2E, 112}, {0xB, 128}, {0x2F, 128},
> + {0xC, 144}, {0xD, 160}, {0x30, 160}, {0xE, 192},
> + {0x31, 192}, {0x32, 224}, {0xF, 240}, {0x33, 256},
> + {0x10, 288}, {0x11, 320}, {0x34, 320}, {0x12, 384},
> + {0x35, 384}, {0x36, 448}, {0x13, 480}, {0x37, 512},
> + {0x14, 576}, {0x15, 640}, {0x38, 640}, {0x16, 768},
> + {0x39, 768}, {0x3A, 896}, {0x17, 960}, {0x3B, 1024},
> + {0x18, 1152}, {0x19, 1280}, {0x3C, 1280}, {0x1A, 1536},
> + {0x3D, 1536}, {0x3E, 1792}, {0x1B, 1920}, {0x3F, 2048},
> + {0x1C, 2304}, {0x1D, 2560}, {0x1E, 3072}, {0x1F, 3840},
> + {0, 0}
> +};
> +
> +static void gpio_i2c_active(int i2c_num)
> +{
> + switch (i2c_num) {
> + case 0:
> + mxc_iomux_mode(IOMUX_MODE(MX31_PIN_I2C_CLK, IOMUX_CONFIG_FUNC));
> + mxc_iomux_mode(IOMUX_MODE(MX31_PIN_I2C_DAT, IOMUX_CONFIG_FUNC));
> + break;
> + case 1:
> + mxc_iomux_mode(IOMUX_MODE(MX31_PIN_CSPI2_MOSI,
> IOMUX_CONFIG_ALT1));
> + mxc_iomux_mode(IOMUX_MODE(MX31_PIN_CSPI2_MISO,
> IOMUX_CONFIG_ALT1));
> + break;
> + case 2:
> + mxc_iomux_mode(IOMUX_MODE(MX31_PIN_CSPI2_SS2,
> IOMUX_CONFIG_ALT1));
> + mxc_iomux_mode(IOMUX_MODE(MX31_PIN_CSPI2_SCLK,
> IOMUX_CONFIG_ALT1));
> + }
> +}
This should be moved to the platform part. You make the driver MX31
specific with this. Also, care to update the macros in iomux-mx3.h
instead of constructing the pin definitions directly using IOMUX_MODE?
(btw how is the general feeling about these macros? I really like it
using these macros since I don't have to read the datasheet to lookup up
a specific pin, but I may be the only one)
> +
> +static void gpio_i2c_inactive(int i2c_num)
> +{
> + /* The one who needs the pins should configure them */
> +}
> +
> +/**
> + * Transmit a \b STOP signal to the slave device.
> + *
> + * @param dev the mxc i2c structure used to get to the right i2c device
> + */
> +static void mxc_i2c_stop(struct mxc_i2c_device * dev)
> +{
> + unsigned int cr;
> + int retry = 200;
> +
> + cr = readw(dev->membase + MXC_I2CR);
> + cr &= ~(MXC_I2CR_MSTA | MXC_I2CR_MTX);
> + writew(cr, dev->membase + MXC_I2CR);
> +
> + /*
> + * Make sure STOP meets setup requirement.
> + */
> + for (;;) {
> + unsigned int sr = readw(dev->membase + MXC_I2SR);
> + if ((sr & MXC_I2SR_IBB) == 0)
> + break;
> + if (retry-- <= 0) {
> + printk(KERN_DEBUG "Bus busy\n");
use dev_dbg instead. Several other occurences follow.
> + break;
> + }
> + udelay(3);
> + }
> +}
> +
> +/**
> + * Wait for the transmission of the data byte to complete. This function
> waits
> + * till we get a signal from the interrupt service routine indicating
> completion
> + * of the address cycle or we time out.
> + *
> + * @param dev the mxc i2c structure used to get to the right i2c
> device
> + * @param trans_flag transfer flag
> + *
> + *
> + * @return The function returns 0 on success or -1 if an ack was not
> received
> + */
> +
> +static int mxc_i2c_wait_for_tc(struct mxc_i2c_device *dev, int trans_flag)
> +{
> + int retry = 16;
> +
> + while (retry-- && !dev->transfer_done)
> + wait_event_interruptible_timeout(dev->wq,
> + dev->transfer_done,
> + dev->adap.timeout);
> +
> + dev->transfer_done = false;
> +
> + if (retry <= 0) {
> + /* Unable to send data */
> + dev_warn(&dev->adap.dev, "Data not transmitted\n");
> + return -ETIMEDOUT;
> + }
> +
> + if (!dev->tx_success) {
> + /* An ACK was not received for transmitted byte */
> + dev_dbg(&dev->adap.dev, "ACK not received \n");
> + return -EREMOTEIO;
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * Transmit a \b START signal to the slave device.
> + *
> + * @param dev the mxc i2c structure used to get to the right i2c device
> + * @param *msg pointer to a message structure that contains the slave
> + * address
> + */
> +static void mxc_i2c_start(struct mxc_i2c_device * dev, struct i2c_msg *msg)
> +{
> + unsigned int cr, sr;
> + unsigned int addr_trans;
> + int retry = 16;
> +
> + /*
> + * Set the slave address and the requested transfer mode
> + * in the data register
> + */
> + addr_trans = msg->addr << 1;
> + if (msg->flags & I2C_M_RD)
> + addr_trans |= 0x01;
> +
> + /* Set the Master bit */
> + cr = readw(dev->membase + MXC_I2CR);
> + cr |= MXC_I2CR_MSTA;
> + writew(cr, dev->membase + MXC_I2CR);
> +
> + /* Wait till the Bus Busy bit is set */
> + sr = readw(dev->membase + MXC_I2SR);
> + while (retry-- && (!(sr & MXC_I2SR_IBB))) {
> + udelay(3);
> + sr = readw(dev->membase + MXC_I2SR);
> + }
> + if (retry <= 0)
> + dev_warn(&dev->adap.dev, "Could not grab Bus ownership\n");
> +
> + /* Set the Transmit bit */
> + cr = readw(dev->membase + MXC_I2CR);
> + cr |= MXC_I2CR_MTX;
> + writew(cr, dev->membase + MXC_I2CR);
> +
> + writew(addr_trans, dev->membase + MXC_I2DR);
> +}
> +
> +/**
> + * Transmit a \b REPEAT START to the slave device
> + *
> + * @param dev the mxc i2c structure used to get to the right i2c device
> + * @param *msg pointer to a message structure that contains the slave
> + * address
> + */
> +static void mxc_i2c_repstart(struct mxc_i2c_device *dev, struct i2c_msg *msg)
> +{
> + unsigned int cr;
> + unsigned int addr_trans;
> +
> + /*
> + * Set the slave address and the requested transfer mode
> + * in the data register
> + */
> + addr_trans = msg->addr << 1;
> + if (msg->flags & I2C_M_RD)
> + addr_trans |= 0x01;
> +
> + cr = readw(dev->membase + MXC_I2CR);
> + cr |= MXC_I2CR_RSTA;
> + writew(cr, dev->membase + MXC_I2CR);
> + udelay(3);
> + writew(addr_trans, dev->membase + MXC_I2DR);
> +}
> +
> +/**
> + * Read the received data. The function waits till data is available or times
> + * out. Generates a stop signal if this is the last message to be received.
> + * Sends an ack for all the bytes received except the last byte.
> + *
> + * @param dev the mxc i2c structure used to get to the right i2c
> device
> + * @param *msg pointer to a message structure that contains the slave
> + * address and a pointer to the receive buffer
> + * @param last indicates that this is the last message to be received
> + * @param addr_comp flag indicates that we just finished the address cycle
> + *
> + * @return The function returns the number of bytes read or -1 on time out.
> + */
> +static int mxc_i2c_readbytes(struct mxc_i2c_device *dev, struct i2c_msg *msg,
> + int last, int addr_comp)
> +{
> + int i;
> + char *buf = msg->buf;
> + int len = msg->len;
> + unsigned int cr;
> +
> + cr = readw(dev->membase + MXC_I2CR);
> + /*
> + * Clear MTX to switch to receive mode.
> + */
> + cr &= ~MXC_I2CR_MTX;
> + /*
> + * Clear the TXAK bit to gen an ack when receiving only one byte.
> + */
> + if (len == 1)
> + cr |= MXC_I2CR_TXAK;
> + else
> + cr &= ~MXC_I2CR_TXAK;
> +
> + writew(cr, dev->membase + MXC_I2CR);
> + /*
> + * Dummy read only at the end of an address cycle
> + */
> + if (addr_comp > 0)
> + readw(dev->membase + MXC_I2DR);
> +
> + for (i = 0; i < len; i++) {
> + int ret;
> + /*
> + * Wait for data transmission to complete
> + */
> + ret = mxc_i2c_wait_for_tc(dev, msg->flags);
> + if (ret < 0) {
> + mxc_i2c_stop(dev);
> + return ret;
> + }
> + /*
> + * Do not generate an ACK for the last byte
> + */
> + if (i == len - 2) {
> + cr = readw(dev->membase + MXC_I2CR);
> + cr |= MXC_I2CR_TXAK;
> + writew(cr, dev->membase + MXC_I2CR);
> + } else if (i == len - 1) {
> + if (last)
> + mxc_i2c_stop(dev);
> + }
> + /* Read the data */
> + *buf++ = readw(dev->membase + MXC_I2DR);
> + }
> +
> + return i;
> +}
> +
> +/**
> + * Write the data to the data register. Generates a stop signal if this is
> + * the last message to be sent or if no ack was received for the data sent.
> + *
> + * @param dev the mxc i2c structure used to get to the right i2c device
> + * @param *msg pointer to a message structure that contains the slave
> + * address and data to be sent
> + * @param last indicates that this is the last message to be received
> + *
> + * @return The function returns the number of bytes written or -1 on time
> out
> + * or if no ack was received for the data that was sent.
> + */
> +static int mxc_i2c_writebytes(struct mxc_i2c_device *dev, struct i2c_msg
> *msg,
> + int last)
> +{
> + int i;
> + char *buf = msg->buf;
> + int len = msg->len;
> + unsigned int cr;
> +
> + cr = readw(dev->membase + MXC_I2CR);
> + /* Set MTX to switch to transmit mode */
> + writew(cr | MXC_I2CR_MTX, dev->membase + MXC_I2CR);
> +
> + for (i = 0; i < len; i++) {
> + int ret;
> + /*
> + * Write the data
> + */
> + writew(*buf++, dev->membase + MXC_I2DR);
> + ret = mxc_i2c_wait_for_tc(dev, msg->flags);
> + if (ret < 0) {
> + mxc_i2c_stop(dev);
> + return ret;
> + }
> + }
> + if (last > 0)
> + mxc_i2c_stop(dev);
> +
> + return i;
> +}
> +
> +/**
> + * Function enables the I2C module and initializes the registers.
> + *
> + * @param dev the mxc i2c structure used to get to the right i2c device
> + * @param trans_flag transfer flag
> + */
> +static void mxc_i2c_module_en(struct mxc_i2c_device *dev, int trans_flag)
> +{
> + clk_enable(dev->clk);
> + /* Set the frequency divider */
> + writew(dev->clkdiv, dev->membase + MXC_IFDR);
Can't we do this only once during probe()?
> + /* Clear the status register */
> + writew(0x0, dev->membase + MXC_I2SR);
> + /* Enable I2C and its interrupts */
> + writew(MXC_I2CR_IEN, dev->membase + MXC_I2CR);
> + writew(MXC_I2CR_IEN | MXC_I2CR_IIEN, dev->membase + MXC_I2CR);
> +}
> +
> +/**
> + * Disables the I2C module.
> + *
> + * @param dev the mxc i2c structure used to get to the right i2c device
> + */
> +static void mxc_i2c_module_dis(struct mxc_i2c_device * dev)
> +{
> + writew(0x0, dev->membase + MXC_I2CR);
> + clk_disable(dev->clk);
> +}
> +
> +/**
> + * The function is registered in the adapter structure. It is called when an
> MXC
> + * driver wishes to transfer data to a device connected to the I2C device.
> + *
> + * @param adap adapter structure for the MXC i2c device
> + * @param msgs[] array of messages to be transferred to the device
> + * @param num number of messages to be transferred to the device
> + *
> + * @return The function returns the number of messages transferred,
> + * \b -EREMOTEIO on I2C failure and a 0 if the num argument is
> + * less than 0.
> + */
> +static int mxc_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int
> num)
> +{
> + struct mxc_i2c_device *dev = i2c_get_adapdata(adap);
> + int i, ret = 0, addr_comp = 0;
> + unsigned int sr;
> +
> + if (dev->low_power) {
> + dev_warn(&dev->adap.dev, "I2C Device in low power mode\n");
> + return -EREMOTEIO;
> + }
> +
> + if (num < 1)
> + return 0;
> +
> + mxc_i2c_module_en(dev, msgs[0].flags);
> + sr = readw(dev->membase + MXC_I2SR);
> + /*
> + * Check bus state
> + */
> + if (sr & MXC_I2SR_IBB) {
> + mxc_i2c_module_dis(dev);
> + printk(KERN_DEBUG "Bus busy\n");
> + return -EREMOTEIO;
> + }
> +
> + dev->transfer_done = false;
> + dev->tx_success = false;
> + for (i = 0; i < num && ret >= 0; i++) {
> + addr_comp = 0;
> + /*
> + * Send the slave address and transfer direction in the
> + * address cycle
> + */
> + if (i == 0) {
> + /*
> + * Send a start or repeat start signal
> + */
> + mxc_i2c_start(dev, &msgs[0]);
> + /* Wait for the address cycle to complete */
> + if (mxc_i2c_wait_for_tc(dev, msgs[0].flags)) {
> + mxc_i2c_stop(dev);
> + mxc_i2c_module_dis(dev);
> + return -EREMOTEIO;
> + }
> + addr_comp = 1;
> + } else {
> + /*
> + * Generate repeat start only if required i.e. the
> + * address changed or the transfer direction changed
> + */
> + if ((msgs[i].addr != msgs[i - 1].addr) ||
> + ((msgs[i].flags & I2C_M_RD) !=
> + (msgs[i - 1].flags & I2C_M_RD))) {
> + mxc_i2c_repstart(dev, &msgs[i]);
> + /* Wait for the address cycle to complete */
> + if (mxc_i2c_wait_for_tc(dev, msgs[i].flags)) {
> + mxc_i2c_stop(dev);
> + mxc_i2c_module_dis(dev);
> + return -EREMOTEIO;
> + }
> + addr_comp = 1;
> + }
> + }
> +
> + /* Transfer the data */
> + if (msgs[i].flags & I2C_M_RD) {
> + /* Read the data */
> + ret = mxc_i2c_readbytes(dev, &msgs[i], (i + 1 == num),
> + addr_comp);
> + if (ret < 0) {
> + printk(KERN_ERR "mxc_i2c_readbytes: fail.\n");
> + break;
> + }
> + } else {
> + /* Write the data */
> + ret = mxc_i2c_writebytes(dev, &msgs[i], (i + 1 == num));
> + if (ret < 0) {
> + printk(KERN_ERR "mxc_i2c_writebytes: fail.\n");
> + break;
> + }
> + }
> + }
> +
> + mxc_i2c_module_dis(dev);
> + /*
> + * Decrease by 1 as we do not want Start message to be included in
> + * the count
> + */
> + return i - 1;
> +}
> +
> +/**
> + * Returns the i2c functionality supported by this driver.
> + *
> + * @param adap adapter structure for this i2c device
> + *
> + * @return Returns the functionality that is supported.
> + */
> +static u32 mxc_i2c_func(struct i2c_adapter *adap)
> +{
> + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> +}
> +
> +static struct i2c_algorithm mxc_i2c_algorithm = {
> + .master_xfer = mxc_i2c_xfer,
> + .functionality = mxc_i2c_func
> +};
> +
> +/*
> + * Interrupt Service Routine. It signals to the process about the data
> transfer
> + * completion. Also sets a flag if bus arbitration is lost.
> + */
> +static irqreturn_t mxc_i2c_handler(int irq, void *dev_id)
> +{
> + struct mxc_i2c_device *dev = dev_id;
> + unsigned int sr, cr;
> +
> + sr = readw(dev->membase + MXC_I2SR);
> + cr = readw(dev->membase + MXC_I2CR);
> +
> + /*
> + * Clear the interrupt bit
> + */
> + writew(0x0, dev->membase + MXC_I2SR);
> +
> + if (sr & MXC_I2SR_IAL) {
> + printk(KERN_DEBUG "Bus Arbitration lost\n");
> + } else {
> + /* Interrupt due byte transfer completion */
> + dev->tx_success = true;
> + /* Check if RXAK is received in Transmit mode */
> + if ((cr & MXC_I2CR_MTX) && (sr & MXC_I2SR_RXAK))
> + dev->tx_success = false;
> +
> + dev->transfer_done = true;
> + wake_up_interruptible(&dev->wq);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int mxci2c_suspend(struct platform_device *pdev, pm_message_t state)
> +{
> + struct mxc_i2c_device *mxcdev = platform_get_drvdata(pdev);
> + unsigned int sr;
> +
> + if (mxcdev == NULL)
> + return -ENODEV;
> +
> + /* Prevent further calls to be processed */
> + mxcdev->low_power = true;
> + /* Wait till we finish the current transfer */
> + sr = readw(mxcdev->membase + MXC_I2SR);
> + while (sr & MXC_I2SR_IBB) {
> + msleep(10);
> + sr = readw(mxcdev->membase + MXC_I2SR);
> + }
> + gpio_i2c_inactive(mxcdev->adap.nr);
> +
> + return 0;
> +}
> +
> +static int mxci2c_resume(struct platform_device *pdev)
> +{
> + struct mxc_i2c_device *mxcdev = platform_get_drvdata(pdev);
> +
> + if (mxcdev == NULL)
> + return -ENODEV;
> +
> + mxcdev->low_power = false;
> + gpio_i2c_active(mxcdev->adap.nr);
> +
> + return 0;
> +}
> +
> +static int mxci2c_probe(struct platform_device *pdev)
> +{
> + struct mxc_i2c_device *mxc_i2c;
> + struct mxc_i2c_platform_data *i2c_plat_data = pdev->dev.platform_data;
> + struct resource *res;
> + int id = pdev->id;
> + u32 clk_freq;
> + int ret;
> + int i;
> +
> + mxc_i2c = kzalloc(sizeof(struct mxc_i2c_device), GFP_KERNEL);
> + if (!mxc_i2c)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (res == NULL) {
> + ret = -ENODEV;
> + goto err1;
> + }
> + mxc_i2c->membase = IO_ADDRESS(res->start);
Please use ioremap instead.
> +
> + /*
> + * Request the I2C interrupt
> + */
> + mxc_i2c->irq = platform_get_irq(pdev, 0);
> + if (mxc_i2c->irq < 0) {
> + ret = mxc_i2c->irq;
> + goto err1;
> + }
> +
> + ret = request_irq(mxc_i2c->irq, mxc_i2c_handler,
> + 0, pdev->name, mxc_i2c);
> + if (ret < 0)
> + goto err1;
> +
> + init_waitqueue_head(&mxc_i2c->wq);
> +
> + mxc_i2c->low_power = false;
> + mxc_i2c->transfer_done = false;
> + mxc_i2c->tx_success = false;
> +
> + gpio_i2c_active(id);
> +
> + mxc_i2c->clk = clk_get(&pdev->dev, "i2c_clk");
The corresponding clk_put is missing in the error path.
> + clk_freq = clk_get_rate(mxc_i2c->clk);
> + mxc_i2c->clkdiv = -1;
> + if (i2c_plat_data->i2c_clk) {
> + /* Calculate divider and round up any fractional part */
> + int div = (clk_freq + i2c_plat_data->i2c_clk - 1) /
> + i2c_plat_data->i2c_clk;
> + for (i = 0; i2c_clk_table[i].div != 0; i++) {
> + if (i2c_clk_table[i].div >= div) {
> + mxc_i2c->clkdiv = i2c_clk_table[i].reg_value;
> + break;
> + }
> + }
> + }
> + if (mxc_i2c->clkdiv == -1) {
> + i = ARRAY_SIZE(i2c_clk_table) - 2;
> + mxc_i2c->clkdiv = 0x1F; /* Use max divider */
> + }
> + dev_dbg(&pdev->dev, "i2c speed is %d/%d = %d bps, reg val = 0x%02X\n",
> + clk_freq, i2c_clk_table[i].div,
> + clk_freq / i2c_clk_table[i].div, mxc_i2c->clkdiv);
> +
> + /*
> + * Set the adapter information
> + */
> + strcpy(mxc_i2c->adap.name, MXC_ADAPTER_NAME);
> + mxc_i2c->adap.nr = id;
> + mxc_i2c->adap.algo = &mxc_i2c_algorithm;
> + mxc_i2c->adap.timeout = 1;
> + mxc_i2c->adap.dev.parent= &pdev->dev;
> + mxc_i2c->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
> + platform_set_drvdata(pdev, mxc_i2c);
> + i2c_set_adapdata(&mxc_i2c->adap, mxc_i2c);
> + if ((ret = i2c_add_numbered_adapter(&mxc_i2c->adap)) < 0)
> + goto err2;
> +
> + return 0;
> +
> +err2:
> + free_irq(mxc_i2c->irq, mxc_i2c);
> + gpio_i2c_inactive(id);
> +err1:
> + dev_err(&pdev->dev, "failed to probe i2c adapter\n");
> + kfree(mxc_i2c);
> + return ret;
> +}
> +
> +static int mxci2c_remove(struct platform_device *pdev)
> +{
> + struct mxc_i2c_device *mxc_i2c = platform_get_drvdata(pdev);
> + int id = pdev->id;
> +
> + free_irq(mxc_i2c->irq, mxc_i2c);
> + i2c_del_adapter(&mxc_i2c->adap);
> + gpio_i2c_inactive(id);
> + clk_put(mxc_i2c->clk);
> + platform_set_drvdata(pdev, NULL);
> + return 0;
> +}
> +
> +static struct platform_driver mxci2c_driver = {
> + .driver = {
> + .name = "mxc-i2c",
> + .owner = THIS_MODULE,
> + },
> + .probe = mxci2c_probe,
> + .remove = __exit_p(mxci2c_remove),
> + .suspend = mxci2c_suspend,
> + .resume = mxci2c_resume,
> +};
> +
> +static int __init mxc_i2c_init(void)
> +{
> + return platform_driver_register(&mxci2c_driver);
> +}
> +
> +static void __exit mxc_i2c_exit(void)
> +{
> + platform_driver_unregister(&mxci2c_driver);
> +}
> +
> +subsys_initcall(mxc_i2c_init);
> +module_exit(mxc_i2c_exit);
> +
> +MODULE_AUTHOR("Freescale Semiconductor, Inc.");
> +MODULE_DESCRIPTION("MXC I2C driver");
> +MODULE_LICENSE("GPL");
>
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