[PATCH V2] i2c: add driver for Freescale i.MX28
Ben Dooks
ben-i2c at fluff.org
Tue Feb 22 20:02:44 EST 2011
On Wed, Feb 16, 2011 at 01:39:16PM +0100, Wolfram Sang wrote:
> Currently only supporting the PIOQUEUE-mode, because DMA-support for
> this platform is not yet in mainline. When it becomes available and
> support has been added to this driver, it will also be suitable for
> i.MX23 and STMP3xxx.
added to -next, will do a full review later.
> Signed-off-by: Wolfram Sang <w.sang at pengutronix.de>
> Cc: Ben Dooks <ben-linux at fluff.org>
> Cc: Shawn Guo <shawn.guo at freescale.com>
> ---
>
> Changes since V1:
> * remove interruptible from completion (lots of problems with signals)
> * add modalias
> * resource failure now returning -ENOENT instead of -ENODEV
> * improve the comments, explaining functions and TODOs
> * add kerneldoc
> * fix bad strncpy
> * drop __raw-accessors
>
> Note about mxs_i2c_wait_for_data():
>
> I tried twice to use a waitqueue instead, but the interrupt for the wake did not
> work as I expected. Definately not proud of it, but at leasts it works for now.
>
> drivers/i2c/busses/Kconfig | 10 +
> drivers/i2c/busses/Makefile | 1 +
> drivers/i2c/busses/i2c-mxs.c | 412 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 423 insertions(+), 0 deletions(-)
> create mode 100644 drivers/i2c/busses/i2c-mxs.c
>
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 3a6321c..25e2dc7 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -452,6 +452,16 @@ config I2C_MV64XXX
> This driver can also be built as a module. If so, the module
> will be called i2c-mv64xxx.
>
> +config I2C_MXS
> + tristate "Freescale i.MX28 I2C interface"
> + depends on SOC_IMX28
> + help
> + Say Y here if you want to use the I2C bus controller on
> + the Freescale i.MX28 processors.
> +
> + This driver can also be built as a module. If so, the module
> + will be called i2c-mxs.
> +
> config I2C_NOMADIK
> tristate "ST-Ericsson Nomadik/Ux500 I2C Controller"
> depends on PLAT_NOMADIK
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index 84cb16a..f415132 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -43,6 +43,7 @@ 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-$(CONFIG_I2C_MXS) += i2c-mxs.o
> obj-$(CONFIG_I2C_NOMADIK) += i2c-nomadik.o
> obj-$(CONFIG_I2C_NUC900) += i2c-nuc900.o
> obj-$(CONFIG_I2C_OCORES) += i2c-ocores.o
> diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
> new file mode 100644
> index 0000000..8022e23
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-mxs.c
> @@ -0,0 +1,412 @@
> +/*
> + * Freescale MXS I2C bus driver
> + *
> + * Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
> + *
> + * based on a (non-working) driver which was:
> + *
> + * Copyright (C) 2009-2010 Freescale Semiconductor, Inc. All Rights Reserved.
> + *
> + * TODO: add dma-support if platform-support for it is available
> + *
> + * 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.
> + *
> + */
> +
> +#include <linux/slab.h>
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/i2c.h>
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/completion.h>
> +#include <linux/platform_device.h>
> +#include <linux/jiffies.h>
> +#include <linux/io.h>
> +
> +#include <mach/common.h>
> +
> +#define DRIVER_NAME "mxs-i2c"
> +
> +#define MXS_I2C_CTRL0 (0x00)
> +#define MXS_I2C_CTRL0_SET (0x04)
> +
> +#define MXS_I2C_CTRL0_SFTRST 0x80000000
> +#define MXS_I2C_CTRL0_SEND_NAK_ON_LAST 0x02000000
> +#define MXS_I2C_CTRL0_RETAIN_CLOCK 0x00200000
> +#define MXS_I2C_CTRL0_POST_SEND_STOP 0x00100000
> +#define MXS_I2C_CTRL0_PRE_SEND_START 0x00080000
> +#define MXS_I2C_CTRL0_MASTER_MODE 0x00020000
> +#define MXS_I2C_CTRL0_DIRECTION 0x00010000
> +#define MXS_I2C_CTRL0_XFER_COUNT(v) ((v) & 0x0000FFFF)
> +
> +#define MXS_I2C_CTRL1 (0x40)
> +#define MXS_I2C_CTRL1_SET (0x44)
> +#define MXS_I2C_CTRL1_CLR (0x48)
> +
> +#define MXS_I2C_CTRL1_BUS_FREE_IRQ 0x80
> +#define MXS_I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ 0x40
> +#define MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ 0x20
> +#define MXS_I2C_CTRL1_OVERSIZE_XFER_TERM_IRQ 0x10
> +#define MXS_I2C_CTRL1_EARLY_TERM_IRQ 0x08
> +#define MXS_I2C_CTRL1_MASTER_LOSS_IRQ 0x04
> +#define MXS_I2C_CTRL1_SLAVE_STOP_IRQ 0x02
> +#define MXS_I2C_CTRL1_SLAVE_IRQ 0x01
> +
> +#define MXS_I2C_IRQ_MASK (MXS_I2C_CTRL1_DATA_ENGINE_CMPLT_IRQ | \
> + MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ | \
> + MXS_I2C_CTRL1_EARLY_TERM_IRQ | \
> + MXS_I2C_CTRL1_MASTER_LOSS_IRQ | \
> + MXS_I2C_CTRL1_SLAVE_STOP_IRQ | \
> + MXS_I2C_CTRL1_SLAVE_IRQ)
> +
> +#define MXS_I2C_QUEUECTRL (0x60)
> +#define MXS_I2C_QUEUECTRL_SET (0x64)
> +#define MXS_I2C_QUEUECTRL_CLR (0x68)
> +
> +#define MXS_I2C_QUEUECTRL_QUEUE_RUN 0x20
> +#define MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE 0x04
> +
> +#define MXS_I2C_QUEUESTAT (0x70)
> +#define MXS_I2C_QUEUESTAT_RD_QUEUE_EMPTY 0x00002000
> +
> +#define MXS_I2C_QUEUECMD (0x80)
> +
> +#define MXS_I2C_QUEUEDATA (0x90)
> +
> +#define MXS_I2C_DATA (0xa0)
> +
> +
> +#define MXS_CMD_I2C_SELECT (MXS_I2C_CTRL0_RETAIN_CLOCK | \
> + MXS_I2C_CTRL0_PRE_SEND_START | \
> + MXS_I2C_CTRL0_MASTER_MODE | \
> + MXS_I2C_CTRL0_DIRECTION | \
> + MXS_I2C_CTRL0_XFER_COUNT(1))
> +
> +#define MXS_CMD_I2C_WRITE (MXS_I2C_CTRL0_PRE_SEND_START | \
> + MXS_I2C_CTRL0_MASTER_MODE | \
> + MXS_I2C_CTRL0_DIRECTION)
> +
> +#define MXS_CMD_I2C_READ (MXS_I2C_CTRL0_SEND_NAK_ON_LAST | \
> + MXS_I2C_CTRL0_MASTER_MODE)
> +
> +/**
> + * struct mxs_i2c_dev - per device, private MXS-I2C data
> + *
> + * @dev: driver model device node
> + * @regs: IO registers pointer
> + * @cmd_complete: completion object for transaction wait
> + * @cmd_err: error code for last transaction
> + * @adapter: i2c subsystem adapter node
> + */
> +struct mxs_i2c_dev {
> + struct device *dev;
> + void __iomem *regs;
> + struct completion cmd_complete;
> + u32 cmd_err;
> + struct i2c_adapter adapter;
> +};
> +
> +/*
> + * TODO: check if calls to here are really needed. If not, we could get rid of
> + * mxs_reset_block and the mach-dependency. Needs an I2C analyzer, probably.
> + */
> +static void mxs_i2c_reset(struct mxs_i2c_dev *i2c)
> +{
> + mxs_reset_block(i2c->regs);
> + writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_SET);
> +}
> +
> +static void mxs_i2c_pioq_setup_read(struct mxs_i2c_dev *i2c, u8 addr, int len,
> + int flags)
> +{
> + u32 data;
> +
> + writel(MXS_CMD_I2C_SELECT, i2c->regs + MXS_I2C_QUEUECMD);
> +
> + data = (addr << 1) | I2C_SMBUS_READ;
> + writel(data, i2c->regs + MXS_I2C_DATA);
> +
> + data = MXS_CMD_I2C_READ | MXS_I2C_CTRL0_XFER_COUNT(len) | flags;
> + writel(data, i2c->regs + MXS_I2C_QUEUECMD);
> +}
> +
> +static void mxs_i2c_pioq_setup_write(struct mxs_i2c_dev *i2c,
> + u8 addr, u8 *buf, int len, int flags)
> +{
> + u32 data;
> + int i, shifts_left;
> +
> + data = MXS_CMD_I2C_WRITE | MXS_I2C_CTRL0_XFER_COUNT(len + 1) | flags;
> + writel(data, i2c->regs + MXS_I2C_QUEUECMD);
> +
> + /*
> + * We have to copy the slave address (u8) and buffer (arbitrary number
> + * of u8) into the data register (u32). To achieve that, the u8 are put
> + * into the MSBs of 'data' which is then shifted for the next u8. When
> + * apropriate, 'data' is written to MXS_I2C_DATA. So, the first u32
> + * looks like this:
> + *
> + * 3 2 1 0
> + * 10987654|32109876|54321098|76543210
> + * --------+--------+--------+--------
> + * buffer+2|buffer+1|buffer+0|slave_addr
> + */
> +
> + data = ((addr << 1) | I2C_SMBUS_WRITE) << 24;
> +
> + for (i = 0; i < len; i++) {
> + data >>= 8;
> + data |= buf[i] << 24;
> + if ((i & 3) == 2)
> + writel(data, i2c->regs + MXS_I2C_DATA);
> + }
> +
> + /* Write out the remaining bytes if any */
> + shifts_left = 24 - (i & 3) * 8;
> + if (shifts_left)
> + writel(data >> shifts_left, i2c->regs + MXS_I2C_DATA);
> +}
> +
> +/*
> + * TODO: should be replaceable with a waitqueue and RD_QUEUE_IRQ (setting the
> + * rd_threshold to 1). Couldn't get this to work, though.
> + */
> +static int mxs_i2c_wait_for_data(struct mxs_i2c_dev *i2c)
> +{
> + unsigned long timeout = jiffies + msecs_to_jiffies(1000);
> +
> + while (readl(i2c->regs + MXS_I2C_QUEUESTAT)
> + & MXS_I2C_QUEUESTAT_RD_QUEUE_EMPTY) {
> + if (time_after(jiffies, timeout))
> + return -ETIMEDOUT;
> + cond_resched();
> + }
> +
> + return 0;
> +}
> +
> +static int mxs_i2c_finish_read(struct mxs_i2c_dev *i2c, u8 *buf, int len)
> +{
> + u32 data;
> + int i;
> +
> + for (i = 0; i < len; i++) {
> + if ((i & 3) == 0) {
> + if (mxs_i2c_wait_for_data(i2c))
> + return -ETIMEDOUT;
> + data = readl(i2c->regs + MXS_I2C_QUEUEDATA);
> + }
> + buf[i] = data & 0xff;
> + data >>= 8;
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * Low level master read/write transaction.
> + */
> +static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg,
> + int stop)
> +{
> + struct mxs_i2c_dev *i2c = i2c_get_adapdata(adap);
> + int ret;
> + int flags;
> +
> + init_completion(&i2c->cmd_complete);
> +
> + dev_dbg(i2c->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
> + msg->addr, msg->len, msg->flags, stop);
> +
> + if (msg->len == 0)
> + return -EINVAL;
> +
> + flags = stop ? MXS_I2C_CTRL0_POST_SEND_STOP : 0;
> +
> + if (msg->flags & I2C_M_RD)
> + mxs_i2c_pioq_setup_read(i2c, msg->addr, msg->len, flags);
> + else
> + mxs_i2c_pioq_setup_write(i2c, msg->addr, msg->buf, msg->len,
> + flags);
> +
> + writel(MXS_I2C_QUEUECTRL_QUEUE_RUN,
> + i2c->regs + MXS_I2C_QUEUECTRL_SET);
> +
> + ret = wait_for_completion_timeout(&i2c->cmd_complete,
> + msecs_to_jiffies(1000));
> + if (ret == 0)
> + goto timeout;
> +
> + if ((!i2c->cmd_err) && (msg->flags & I2C_M_RD)) {
> + ret = mxs_i2c_finish_read(i2c, msg->buf, msg->len);
> + if (ret)
> + goto timeout;
> + }
> +
> + if (i2c->cmd_err == -ENXIO)
> + mxs_i2c_reset(i2c);
> +
> + dev_dbg(i2c->dev, "Done with err=%d\n", i2c->cmd_err);
> +
> + return i2c->cmd_err;
> +
> +timeout:
> + dev_dbg(i2c->dev, "Timeout!\n");
> + mxs_i2c_reset(i2c);
> + return -ETIMEDOUT;
> +}
> +
> +static int mxs_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
> + int num)
> +{
> + int i;
> + int err;
> +
> + for (i = 0; i < num; i++) {
> + err = mxs_i2c_xfer_msg(adap, &msgs[i], i == (num - 1));
> + if (err)
> + return err;
> + }
> +
> + return num;
> +}
> +
> +static u32 mxs_i2c_func(struct i2c_adapter *adap)
> +{
> + return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
> +}
> +
> +static irqreturn_t mxs_i2c_isr(int this_irq, void *dev_id)
> +{
> + struct mxs_i2c_dev *i2c = dev_id;
> + u32 stat = readl(i2c->regs + MXS_I2C_CTRL1) & MXS_I2C_IRQ_MASK;
> +
> + if (!stat)
> + return IRQ_NONE;
> +
> + if (stat & MXS_I2C_CTRL1_NO_SLAVE_ACK_IRQ)
> + i2c->cmd_err = -ENXIO;
> + else if (stat & (MXS_I2C_CTRL1_EARLY_TERM_IRQ |
> + MXS_I2C_CTRL1_MASTER_LOSS_IRQ |
> + MXS_I2C_CTRL1_SLAVE_STOP_IRQ | MXS_I2C_CTRL1_SLAVE_IRQ))
> + /* MXS_I2C_CTRL1_OVERSIZE_XFER_TERM_IRQ is only for slaves */
> + i2c->cmd_err = -EIO;
> + else
> + i2c->cmd_err = 0;
> +
> + complete(&i2c->cmd_complete);
> +
> + writel(stat, i2c->regs + MXS_I2C_CTRL1_CLR);
> + return IRQ_HANDLED;
> +}
> +
> +static const struct i2c_algorithm mxs_i2c_algo = {
> + .master_xfer = mxs_i2c_xfer,
> + .functionality = mxs_i2c_func,
> +};
> +
> +static int __devinit mxs_i2c_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct mxs_i2c_dev *i2c;
> + struct i2c_adapter *adap;
> + struct resource *res;
> + resource_size_t res_size;
> + int err, irq;
> +
> + i2c = devm_kzalloc(dev, sizeof(struct mxs_i2c_dev), GFP_KERNEL);
> + if (!i2c)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res)
> + return -ENOENT;
> +
> + res_size = resource_size(res);
> + if (!devm_request_mem_region(dev, res->start, res_size, res->name))
> + return -EBUSY;
> +
> + i2c->regs = devm_ioremap_nocache(dev, res->start, res_size);
> + if (!i2c->regs)
> + return -EBUSY;
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0)
> + return irq;
> +
> + err = devm_request_irq(dev, irq, mxs_i2c_isr, 0, dev_name(dev), i2c);
> + if (err)
> + return err;
> +
> + i2c->dev = dev;
> + platform_set_drvdata(pdev, i2c);
> +
> + /* Do reset to enforce correct startup after pinmuxing */
> + mxs_i2c_reset(i2c);
> + writel(MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE,
> + i2c->regs + MXS_I2C_QUEUECTRL_SET);
> +
> + adap = &i2c->adapter;
> + strlcpy(adap->name, "MXS I2C adapter", sizeof(adap->name));
> + adap->owner = THIS_MODULE;
> + adap->algo = &mxs_i2c_algo;
> + adap->dev.parent = dev;
> + adap->nr = pdev->id;
> + i2c_set_adapdata(adap, i2c);
> + err = i2c_add_numbered_adapter(adap);
> + if (err) {
> + dev_err(dev, "Failed to add adapter (%d)\n", err);
> + writel(MXS_I2C_CTRL0_SFTRST,
> + i2c->regs + MXS_I2C_CTRL0_SET);
> + return err;
> + }
> +
> + return 0;
> +}
> +
> +static int __devexit mxs_i2c_remove(struct platform_device *pdev)
> +{
> + struct mxs_i2c_dev *i2c = platform_get_drvdata(pdev);
> + int ret;
> +
> + ret = i2c_del_adapter(&i2c->adapter);
> + if (ret)
> + return -EBUSY;
> +
> + writel(MXS_I2C_QUEUECTRL_QUEUE_RUN,
> + i2c->regs + MXS_I2C_QUEUECTRL_CLR);
> + writel(MXS_I2C_CTRL0_SFTRST, i2c->regs + MXS_I2C_CTRL0_SET);
> +
> + platform_set_drvdata(pdev, NULL);
> +
> + return 0;
> +}
> +
> +static struct platform_driver mxs_i2c_driver = {
> + .driver = {
> + .name = DRIVER_NAME,
> + .owner = THIS_MODULE,
> + },
> + .remove = __devexit_p(mxs_i2c_remove),
> +};
> +
> +static int __init mxs_i2c_init(void)
> +{
> + return platform_driver_probe(&mxs_i2c_driver, mxs_i2c_probe);
> +}
> +subsys_initcall(mxs_i2c_init);
> +
> +static void __exit mxs_i2c_exit(void)
> +{
> + platform_driver_unregister(&mxs_i2c_driver);
> +}
> +module_exit(mxs_i2c_exit);
> +
> +MODULE_AUTHOR("Wolfram Sang <w.sang at pengutronix.de>");
> +MODULE_DESCRIPTION("MXS I2C Bus Driver");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:" DRIVER_NAME);
> --
> 1.7.2.3
>
> --
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--
Ben Dooks, ben at fluff.org, http://www.fluff.org/ben/
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