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 <[email protected]> > --- > 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 <[email protected]> > + * > + * Adaption to GRLIB/I2CMST by Jan Andersson <[email protected]> > + * > + * 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 <[email protected]>"); > +MODULE_DESCRIPTION("GRLIB I2CMST I2C bus driver"); > +MODULE_LICENSE("GPL"); -- Ben Dooks, [email protected], http://www.fluff.org/ben/ Large Hadron Colada: A large Pina Colada that makes the universe disappear. -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
