On Wed, Feb 16, 2011 at 01:30:48PM +0100, Jan Andersson wrote:
> This patch adds support for the I2CMST core found on LEON/GRLIB SoCs.
>
> Signed-off-by: Jan Andersson <jan@xxxxxxxxxxx>
> ---
> The I2CMST core is basically the OpenCores I2C master with an AMBA APB
> interface. This driver re-uses much of i2c-ocores.c. It is submitted as
> a separate driver since the register interfaces differ sligthly. Also the
> two IP cores are maintained separately so they may diverge further in
> the future.
Hmm, some more of that should go above the "---" line.
Going to do a quick review and then get back to this once I've had some
time to think on it.
> The driver is identical in terms of transfer handling and HW control.
> The original module author string has been kept.
>
> drivers/i2c/busses/Kconfig | 10 +
> drivers/i2c/busses/Makefile | 1 +
> drivers/i2c/busses/i2c-gr-i2cmst.c | 371 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 382 insertions(+), 0 deletions(-)
> create mode 100644 drivers/i2c/busses/i2c-gr-i2cmst.c
>
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 113505a..06a3150 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -646,6 +646,16 @@ config I2C_EG20T
> is an IOH(Input/Output Hub) for x86 embedded processor.
> This driver can access PCH I2C bus device.
>
> +config I2C_GR_I2CMST
> + tristate "Aeroflex Gaisler I2CMST I2C Controller"
> + depends on SPARC_LEON
> + help
> + If you say yes to this option, support will be included for the
> + I2CMST I2C controller present on some LEON/GRLIB SoCs.
> +
> + This driver can also be built as a module. If so, the module
> + will be called i2c-gr-i2cmst.
> +
> comment "External I2C/SMBus adapter drivers"
>
> config I2C_PARPORT
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index 9d2d0ec..1e16e66 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -62,6 +62,7 @@ obj-$(CONFIG_I2C_VERSATILE) += i2c-versatile.o
> obj-$(CONFIG_I2C_OCTEON) += i2c-octeon.o
> obj-$(CONFIG_I2C_XILINX) += i2c-xiic.o
> obj-$(CONFIG_I2C_EG20T) += i2c-eg20t.o
> +obj-$(CONFIG_I2C_GR_I2CMST) += i2c-gr-i2cmst.o
>
> # External I2C/SMBus adapter drivers
> obj-$(CONFIG_I2C_PARPORT) += i2c-parport.o
> diff --git a/drivers/i2c/busses/i2c-gr-i2cmst.c b/drivers/i2c/busses/i2c-gr-i2cmst.c
> new file mode 100644
> index 0000000..90b23a8
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-gr-i2cmst.c
> @@ -0,0 +1,371 @@
> +/*
> + * i2c-gr-i2cmst.c I2C bus driver for GRLIB I2CMST core
> + *
> + * Main parts of this driver re-used from:
> + *
> + * i2c-ocores.c: I2C bus driver for OpenCores I2C controller
> + * by Peter Korsgaard <jacmet@xxxxxxxxxx>
> + *
> + * Adaption to GRLIB/I2CMST by Jan Andersson <jan@xxxxxxxxxxx>
> + *
> + * This file is licensed under the terms of the GNU General Public License
> + * version 2. This program is licensed "as is" without any warranty of any
> + * kind, whether express or implied.
> + */
> +
> +#include <linux/of_platform.h>
> +#include <linux/of_device.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/errno.h>
> +#include <linux/i2c.h>
> +#include <linux/wait.h>
> +#include <linux/slab.h>
> +#include <linux/io.h>
> +
> +/* I2CMST APB registers */
> +struct i2cmst_regs {
> + u32 prescaler;
> + u32 control;
> + u32 data;
> + u32 cmdstat; /* Command (write), Status (read) */
> +};
using structures for memory mapped registers makes me want to go
EURGH. the compiler is free to pack and order as it feels.
> +struct gr_i2cmst_i2c {
> + struct i2cmst_regs *regs;
> + wait_queue_head_t wait;
> + struct i2c_adapter adap;
> + struct i2c_msg *msg;
> + int pos;
> + int nmsgs;
> + int state; /* see STATE_ */
> + int clock_khz;
> +};
> +
> +/* register fields and commands */
> +#define I2CMST_CTRL_IEN 0x40
> +#define I2CMST_CTRL_EN 0x80
> +
> +#define I2CMST_CMD_START 0x91
> +#define I2CMST_CMD_STOP 0x41
> +#define I2CMST_CMD_READ 0x21
> +#define I2CMST_CMD_WRITE 0x11
> +#define I2CMST_CMD_READ_ACK 0x21
> +#define I2CMST_CMD_READ_NACK 0x29
> +#define I2CMST_CMD_IACK 0x01
> +
> +#define I2CMST_STAT_IF 0x01
> +#define I2CMST_STAT_TIP 0x02
> +#define I2CMST_STAT_ARBLOST 0x20
> +#define I2CMST_STAT_BUSY 0x40
> +#define I2CMST_STAT_NACK 0x80
> +
> +#define STATE_DONE 0
> +#define STATE_START 1
> +#define STATE_WRITE 2
> +#define STATE_READ 3
> +#define STATE_ERROR 4
> +
> +static inline void i2cmst_setreg(void __iomem *reg, u32 value)
> +{
> + __raw_writel(cpu_to_be32(value), reg);
> +}
> +
> +static inline u32 i2cmst_getreg(void __iomem *reg)
> +{
> + return be32_to_cpu(__raw_readl(reg));
> +}
do you really need to use the __raw versions of thees calls?
> +static void gr_i2cmst_process(struct gr_i2cmst_i2c *i2c)
> +{
> + struct i2c_msg *msg = i2c->msg;
> + u32 stat = i2cmst_getreg(&i2c->regs->cmdstat);
> +
> + if ((i2c->state == STATE_DONE) || (i2c->state == STATE_ERROR)) {
> + /* stop has been sent */
> + i2cmst_setreg(&i2c->regs->cmdstat, I2CMST_CMD_IACK);
> + wake_up(&i2c->wait);
> + return;
> + }
> +
> + /* error? */
> + if (stat & I2CMST_STAT_ARBLOST) {
> + i2c->state = STATE_ERROR;
> + i2cmst_setreg(&i2c->regs->cmdstat, I2CMST_CMD_STOP);
> + return;
> + }
> +
> + if ((i2c->state == STATE_START) || (i2c->state == STATE_WRITE)) {
> + i2c->state =
> + (msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE;
> +
> + if (stat & I2CMST_STAT_NACK) {
> + i2c->state = STATE_ERROR;
> + i2cmst_setreg(&i2c->regs->cmdstat, I2CMST_CMD_STOP);
> + return;
> + }
> + } else
> + msg->buf[i2c->pos++] = i2cmst_getreg(&i2c->regs->data);
> +
> + /* end of msg? */
> + if (i2c->pos == msg->len) {
> + i2c->nmsgs--;
> + i2c->msg++;
> + i2c->pos = 0;
> + msg = i2c->msg;
> +
> + if (i2c->nmsgs) { /* end? */
> + /* send start? */
> + if (!(msg->flags & I2C_M_NOSTART)) {
> + u8 addr = (msg->addr << 1);
> +
> + if (msg->flags & I2C_M_RD)
> + addr |= 1;
> +
> + i2c->state = STATE_START;
> +
> + i2cmst_setreg(&i2c->regs->data, addr);
> + i2cmst_setreg(&i2c->regs->cmdstat,
> + I2CMST_CMD_START);
> + return;
> + } else
> + i2c->state = (msg->flags & I2C_M_RD)
> + ? STATE_READ : STATE_WRITE;
> + } else {
> + i2c->state = STATE_DONE;
> + i2cmst_setreg(&i2c->regs->cmdstat, I2CMST_CMD_STOP);
> + return;
> + }
> + }
> +
> + if (i2c->state == STATE_READ) {
> + i2cmst_setreg(&i2c->regs->cmdstat, i2c->pos == (msg->len-1) ?
> + I2CMST_CMD_READ_NACK : I2CMST_CMD_READ_ACK);
> + } else {
> + i2cmst_setreg(&i2c->regs->data, msg->buf[i2c->pos++]);
> + i2cmst_setreg(&i2c->regs->cmdstat, I2CMST_CMD_WRITE);
> + }
> +}
> +
> +static irqreturn_t gr_i2cmst_isr(int irq, void *dev_id)
> +{
> + struct gr_i2cmst_i2c *i2c = dev_id;
> +
> + gr_i2cmst_process(i2c);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int gr_i2cmst_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
> +{
> + struct gr_i2cmst_i2c *i2c = i2c_get_adapdata(adap);
> +
> + i2c->msg = msgs;
> + i2c->pos = 0;
> + i2c->nmsgs = num;
> + i2c->state = STATE_START;
> +
> + i2cmst_setreg(&i2c->regs->data, (i2c->msg->addr << 1) |
> + ((i2c->msg->flags & I2C_M_RD) ? 1 : 0));
> +
> + i2cmst_setreg(&i2c->regs->cmdstat, I2CMST_CMD_START);
> +
> + if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) ||
> + (i2c->state == STATE_DONE), HZ))
> + return (i2c->state == STATE_DONE) ? num : -EIO;
> + else
> + return -ETIMEDOUT;
> +}
> +
> +static void gr_i2cmst_init(struct gr_i2cmst_i2c *i2c)
> +{
> + int prescale;
> + u32 ctrl = i2cmst_getreg(&i2c->regs->control);
> +
> + /* make sure the device is disabled */
> + i2cmst_setreg(&i2c->regs->control,
> + ctrl & ~(I2CMST_CTRL_EN|I2CMST_CTRL_IEN));
> +
> + /* Required prescaler = (AMBAfreq)/(5 * SCLfreq)-1 */
> + prescale = (i2c->clock_khz / (5*100)) - 1;
> + /* Minimum value of precaler is 3 due to HW sync */
> + prescale = prescale < 3 ? 3 : prescale;
> + i2cmst_setreg(&i2c->regs->prescaler, prescale);
> +
> + /* Init the device */
> + i2cmst_setreg(&i2c->regs->cmdstat, I2CMST_CMD_IACK);
> + ctrl |= I2CMST_CTRL_IEN | I2CMST_CTRL_EN;
> + i2cmst_setreg(&i2c->regs->control, ctrl);
> +}
> +
> +
> +static u32 gr_i2cmst_func(struct i2c_adapter *adap)
> +{
> + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> +}
> +
> +static const struct i2c_algorithm gr_i2cmst_algorithm = {
> + .master_xfer = gr_i2cmst_xfer,
> + .functionality = gr_i2cmst_func,
> +};
> +
> +static struct i2c_adapter gr_i2cmst_adapter = {
> + .owner = THIS_MODULE,
> + .name = "i2c-gr-i2cmst",
> + .class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
> + .algo = &gr_i2cmst_algorithm,
> +};
> +
> +
> +static int __devinit gr_i2cmst_of_probe(struct platform_device *ofdev, const struct of_device_id *match)
please avoid line-wrap like this.
> +{
> + struct gr_i2cmst_i2c *i2c;
> + const unsigned int *busfreq;
> + int ret;
> +
> + i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
> + if (!i2c)
> + return -ENOMEM;
would be nice to have an error print here.
> + /* Get frequency of APB bus that core is attached to */
> + busfreq = of_get_property(ofdev->dev.of_node, "freq", NULL);
> + if (!busfreq) {
> + dev_err(&ofdev->dev, "Missing parameter 'freq'\n");
> + return -ENODEV;
> + }
> + i2c->clock_khz = *busfreq/1000;
> +
> + i2c->regs = of_ioremap(&ofdev->resource[0], 0,
> + resource_size(&ofdev->resource[0]),
> + "grlib-i2cmst regs");
> + if (!i2c->regs) {
> + dev_err(&ofdev->dev, "Unable to map registers\n");
> + ret = -EIO;
> + goto map_failed;
> + }
> +
> + gr_i2cmst_init(i2c);
> +
> + init_waitqueue_head(&i2c->wait);
> + ret = request_irq(ofdev->archdata.irqs[0], gr_i2cmst_isr, 0,
> + ofdev->name, i2c);
> + if (ret) {
> + dev_err(&ofdev->dev, "Cannot claim IRQ\n");
> + goto request_irq_failed;
> + }
> +
> + /* hook up driver to tree */
> + dev_set_drvdata(&ofdev->dev, i2c);
> + i2c->adap = gr_i2cmst_adapter;
> + i2c_set_adapdata(&i2c->adap, i2c);
> + i2c->adap.dev.parent = &ofdev->dev;
> + i2c->adap.dev.of_node = ofdev->dev.of_node;
> +
> + /* add i2c adapter to i2c tree */
> + ret = i2c_add_adapter(&i2c->adap);
> + if (ret) {
> + dev_err(&ofdev->dev, "Failed to add adapter\n");
> + goto add_adapter_failed;
> + }
> +
> + return 0;
> +
> +add_adapter_failed:
> + free_irq(ofdev->archdata.irqs[0], i2c);
> +request_irq_failed:
> + of_iounmap(&ofdev->resource[0], i2c->regs,
> + resource_size(&ofdev->resource[0]));
> +map_failed:
> + kfree(i2c);
> +
> + return ret;
> +}
> +
> +static int __devexit gr_i2cmst_of_remove(struct platform_device *ofdev)
> +{
> + struct gr_i2cmst_i2c *i2c = dev_get_drvdata(&ofdev->dev);
> + u32 ctrl = i2cmst_getreg(&i2c->regs->control);
> +
> + /* disable i2c logic */
> + i2cmst_setreg(&i2c->regs->control,
> + ctrl & ~(I2CMST_CTRL_EN|I2CMST_CTRL_IEN));
> +
> + /* remove adapter & data */
> + i2c_del_adapter(&i2c->adap);
> + dev_set_drvdata(&ofdev->dev, NULL);
> +
> + free_irq(ofdev->archdata.irqs[0], i2c);
> +
> + of_iounmap(&ofdev->resource[0], i2c->regs,
> + resource_size(&ofdev->resource[0]));
> +
> + kfree(i2c);
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_PM
> +static int gr_i2cmst_suspend(struct platform_device *ofdev, pm_message_t state)
> +{
> + struct gr_i2cmst_i2c *i2c = dev_get_drvdata(&ofdev->dev);
> + u32 ctrl = gr_i2cmst_getreg(&i2c->regs->control);
> +
> + /* make sure the device is disabled */
> + gr_i2cmst_setreg(&i2c->regs->control,
> + ctrl & ~(I2CMST_CTRL_EN|I2CMST_CTRL_IEN));
> +
> + return 0;
> +}
> +
> +static int gr_i2cmst_resume(struct platform_device *ofdev)
> +{
> + struct gr_i2cmst_i2c *i2c = dev_get_drvdata(&ofdev->dev);
> +
> + gr_i2cmst_init(i2c);
> +
> + return 0;
> +}
> +#else
> +#define gr_i2cmst_suspend NULL
> +#define gr_i2cmst_resume NULL
> +#endif
> +
> +static struct of_device_id gr_i2cmst_of_match[] = {
> + { .name = "GAISLER_I2CMST", },
> + { .name = "01_028", },
> + {},
> +};
> +
> +MODULE_DEVICE_TABLE(of, gr_i2cmst_of_match);
> +
> +static struct of_platform_driver gr_i2cmst_of_driver = {
> + .driver = {
> + .name = "grlib-i2cmst",
> + .owner = THIS_MODULE,
> + .of_match_table = gr_i2cmst_of_match,
> + },
> + .probe = gr_i2cmst_of_probe,
> + .remove = __devexit_p(gr_i2cmst_of_remove),
> + .suspend = gr_i2cmst_suspend,
> + .resume = gr_i2cmst_resume,
> +};
> +
> +
> +static int __init i2cmst_init(void)
> +{
> + return of_register_platform_driver(&gr_i2cmst_of_driver);
> +}
> +
> +static void __exit i2cmst_exit(void)
> +{
> + of_unregister_platform_driver(&gr_i2cmst_of_driver);
> +}
> +
> +module_init(i2cmst_init);
> +module_exit(i2cmst_exit);
> +
> +MODULE_AUTHOR("Peter Korsgaard <jacmet@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("GRLIB I2CMST I2C bus driver");
> +MODULE_LICENSE("GPL");
--
Ben Dooks, ben@xxxxxxxxx, http://www.fluff.org/ben/
Large Hadron Colada: A large Pina Colada that makes the universe disappear.
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