/* * TI OMAP I2C master mode driver * * Copyright (C) 2003 MontaVista Software, Inc. * Copyright (C) 2004 Texas Instruments. * * Updated to work with multiple I2C interfaces on 24xx by * Tony Lindgren and Imre Deak * Copyright (C) 2005 Nokia Corporation * * Cleaned up by Juha Yrjölä * * 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include #include #include #include #include #include #include #include /* timeout waiting for the controller to respond */ #define OMAP_I2C_TIMEOUT (msecs_to_jiffies(1000)) #define OMAP_I2C_REV_REG 0x00 #define OMAP_I2C_IE_REG 0x04 #define OMAP_I2C_STAT_REG 0x08 #define OMAP_I2C_IV_REG 0x0c #define OMAP_I2C_SYSS_REG 0x10 #define OMAP_I2C_BUF_REG 0x14 #define OMAP_I2C_CNT_REG 0x18 #define OMAP_I2C_DATA_REG 0x1c #define OMAP_I2C_SYSC_REG 0x20 #define OMAP_I2C_CON_REG 0x24 #define OMAP_I2C_OA_REG 0x28 #define OMAP_I2C_SA_REG 0x2c #define OMAP_I2C_PSC_REG 0x30 #define OMAP_I2C_SCLL_REG 0x34 #define OMAP_I2C_SCLH_REG 0x38 #define OMAP_I2C_SYSTEST_REG 0x3c /* I2C Interrupt Enable Register (OMAP_I2C_IE): */ #define OMAP_I2C_IE_XRDY (1 << 4) /* TX data ready int enable */ #define OMAP_I2C_IE_RRDY (1 << 3) /* RX data ready int enable */ #define OMAP_I2C_IE_ARDY (1 << 2) /* Access ready int enable */ #define OMAP_I2C_IE_NACK (1 << 1) /* No ack interrupt enable */ #define OMAP_I2C_IE_AL (1 << 0) /* Arbitration lost int ena */ /* I2C Status Register (OMAP_I2C_STAT): */ #define OMAP_I2C_STAT_SBD (1 << 15) /* Single byte data */ #define OMAP_I2C_STAT_BB (1 << 12) /* Bus busy */ #define OMAP_I2C_STAT_ROVR (1 << 11) /* Receive overrun */ #define OMAP_I2C_STAT_XUDF (1 << 10) /* Transmit underflow */ #define OMAP_I2C_STAT_AAS (1 << 9) /* Address as slave */ #define OMAP_I2C_STAT_AD0 (1 << 8) /* Address zero */ #define OMAP_I2C_STAT_XRDY (1 << 4) /* Transmit data ready */ #define OMAP_I2C_STAT_RRDY (1 << 3) /* Receive data ready */ #define OMAP_I2C_STAT_ARDY (1 << 2) /* Register access ready */ #define OMAP_I2C_STAT_NACK (1 << 1) /* No ack interrupt enable */ #define OMAP_I2C_STAT_AL (1 << 0) /* Arbitration lost int ena */ /* I2C Buffer Configuration Register (OMAP_I2C_BUF): */ #define OMAP_I2C_BUF_RDMA_EN (1 << 15) /* RX DMA channel enable */ #define OMAP_I2C_BUF_XDMA_EN (1 << 7) /* TX DMA channel enable */ /* I2C Configuration Register (OMAP_I2C_CON): */ #define OMAP_I2C_CON_EN (1 << 15) /* I2C module enable */ #define OMAP_I2C_CON_BE (1 << 14) /* Big endian mode */ #define OMAP_I2C_CON_STB (1 << 11) /* Start byte mode (master) */ #define OMAP_I2C_CON_MST (1 << 10) /* Master/slave mode */ #define OMAP_I2C_CON_TRX (1 << 9) /* TX/RX mode (master only) */ #define OMAP_I2C_CON_XA (1 << 8) /* Expand address */ #define OMAP_I2C_CON_RM (1 << 2) /* Repeat mode (master only) */ #define OMAP_I2C_CON_STP (1 << 1) /* Stop cond (master only) */ #define OMAP_I2C_CON_STT (1 << 0) /* Start condition (master) */ /* I2C System Test Register (OMAP_I2C_SYSTEST): */ #ifdef DEBUG #define OMAP_I2C_SYSTEST_ST_EN (1 << 15) /* System test enable */ #define OMAP_I2C_SYSTEST_FREE (1 << 14) /* Free running mode */ #define OMAP_I2C_SYSTEST_TMODE_MASK (3 << 12) /* Test mode select */ #define OMAP_I2C_SYSTEST_TMODE_SHIFT (12) /* Test mode select */ #define OMAP_I2C_SYSTEST_SCL_I (1 << 3) /* SCL line sense in */ #define OMAP_I2C_SYSTEST_SCL_O (1 << 2) /* SCL line drive out */ #define OMAP_I2C_SYSTEST_SDA_I (1 << 1) /* SDA line sense in */ #define OMAP_I2C_SYSTEST_SDA_O (1 << 0) /* SDA line drive out */ #endif /* I2C System Status register (OMAP_I2C_SYSS): */ #define OMAP_I2C_SYSS_RDONE (1 << 0) /* Reset Done */ /* I2C System Configuration Register (OMAP_I2C_SYSC): */ #define OMAP_I2C_SYSC_SRST (1 << 1) /* Soft Reset */ /* REVISIT: Use platform_data instead of module parameters */ /* Fast Mode = 400 kHz, Standard = 100 kHz */ static int clock = 100; /* Default: 100 kHz */ module_param(clock, int, 0); MODULE_PARM_DESC(clock, "Set I2C clock in kHz: 400=fast mode (default == 100)"); struct omap_i2c_dev { struct device *dev; void __iomem *base; /* virtual */ int irq; struct clk *iclk; /* Interface clock */ struct clk *fclk; /* Functional clock */ struct completion cmd_complete; struct resource *ioarea; u16 cmd_err; u8 *buf; size_t buf_len; struct i2c_adapter adapter; unsigned rev1:1; unsigned idle:1; u16 iestate; /* Saved interrupt register */ }; static inline void omap_i2c_write_reg(struct omap_i2c_dev *i2c_dev, int reg, u16 val) { __raw_writew(val, i2c_dev->base + reg); } static inline u16 omap_i2c_read_reg(struct omap_i2c_dev *i2c_dev, int reg) { return __raw_readw(i2c_dev->base + reg); } static int omap_i2c_get_clocks(struct omap_i2c_dev *dev) { if (cpu_is_omap16xx() || cpu_is_omap24xx()) { dev->iclk = clk_get(dev->dev, "i2c_ick"); if (IS_ERR(dev->iclk)) { dev->iclk = NULL; return -ENODEV; } } dev->fclk = clk_get(dev->dev, "i2c_fck"); if (IS_ERR(dev->fclk)) { if (dev->iclk != NULL) { clk_put(dev->iclk); dev->iclk = NULL; } dev->fclk = NULL; return -ENODEV; } return 0; } static void omap_i2c_put_clocks(struct omap_i2c_dev *dev) { clk_put(dev->fclk); dev->fclk = NULL; if (dev->iclk != NULL) { clk_put(dev->iclk); dev->iclk = NULL; } } static void omap_i2c_unidle(struct omap_i2c_dev *dev) { if (dev->iclk != NULL) clk_enable(dev->iclk); clk_enable(dev->fclk); if (dev->iestate) omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate); dev->idle = 0; } static void omap_i2c_idle(struct omap_i2c_dev *dev) { u16 iv; dev->idle = 1; dev->iestate = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG); omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, 0); if (dev->rev1) iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG); /* Read clears */ else omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, dev->iestate); clk_disable(dev->fclk); if (dev->iclk != NULL) clk_disable(dev->iclk); } static int omap_i2c_init(struct omap_i2c_dev *dev) { u16 psc = 0; unsigned long fclk_rate = 12000000; unsigned long timeout; if (!dev->rev1) { omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, OMAP_I2C_SYSC_SRST); /* For some reason we need to set the EN bit before the * reset done bit gets set. */ timeout = jiffies + OMAP_I2C_TIMEOUT; omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN); while (!(omap_i2c_read_reg(dev, OMAP_I2C_SYSS_REG) & OMAP_I2C_SYSS_RDONE)) { if (time_after(jiffies, timeout)) { dev_warn(dev->dev, "timeout waiting " "for controller reset\n"); return -ETIMEDOUT; } msleep(1); } } omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0); if (cpu_class_is_omap1()) { struct clk *armxor_ck; armxor_ck = clk_get(NULL, "armxor_ck"); if (IS_ERR(armxor_ck)) dev_warn(dev->dev, "Could not get armxor_ck\n"); else { fclk_rate = clk_get_rate(armxor_ck); clk_put(armxor_ck); } /* TRM for 5912 says the I2C clock must be prescaled to be * between 7 - 12 MHz. The XOR input clock is typically * 12, 13 or 19.2 MHz. So we should have code that produces: * * XOR MHz Divider Prescaler * 12 1 0 * 13 2 1 * 19.2 2 1 */ if (fclk_rate > 12000000) psc = fclk_rate / 12000000; } /* Setup clock prescaler to obtain approx 12MHz I2C module clock: */ omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, psc); /* Program desired operating rate */ fclk_rate /= (psc + 1) * 1000; if (psc > 2) psc = 2; omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, fclk_rate / (clock * 2) - 7 + psc); omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, fclk_rate / (clock * 2) - 7 + psc); /* Take the I2C module out of reset: */ omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN); /* Enable interrupts */ omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, (OMAP_I2C_IE_XRDY | OMAP_I2C_IE_RRDY | OMAP_I2C_IE_ARDY | OMAP_I2C_IE_NACK | OMAP_I2C_IE_AL)); return 0; } /* * Waiting on Bus Busy */ static int omap_i2c_wait_for_bb(struct omap_i2c_dev *dev) { unsigned long timeout; timeout = jiffies + OMAP_I2C_TIMEOUT; while (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG) & OMAP_I2C_STAT_BB) { if (time_after(jiffies, timeout)) { dev_warn(dev->dev, "timeout waiting for bus ready\n"); return -ETIMEDOUT; } msleep(1); } return 0; } /* * Low level master read/write transaction. */ static int omap_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop) { struct omap_i2c_dev *dev = i2c_get_adapdata(adap); int r; u16 w; dev_dbg(dev->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; omap_i2c_write_reg(dev, OMAP_I2C_SA_REG, msg->addr); /* REVISIT: Could the STB bit of I2C_CON be used with probing? */ dev->buf = msg->buf; dev->buf_len = msg->len; omap_i2c_write_reg(dev, OMAP_I2C_CNT_REG, dev->buf_len); init_completion(&dev->cmd_complete); dev->cmd_err = 0; w = OMAP_I2C_CON_EN | OMAP_I2C_CON_MST | OMAP_I2C_CON_STT; if (msg->flags & I2C_M_TEN) w |= OMAP_I2C_CON_XA; if (!(msg->flags & I2C_M_RD)) w |= OMAP_I2C_CON_TRX; if (stop) w |= OMAP_I2C_CON_STP; omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w); /* * REVISIT: We should abort the transfer on signals, but the bus goes * into arbitration and we're currently unable to recover from it. */ r = wait_for_completion_timeout(&dev->cmd_complete, OMAP_I2C_TIMEOUT); dev->buf_len = 0; if (r < 0) return r; if (r == 0) { dev_err(dev->dev, "controller timed out\n"); omap_i2c_init(dev); return -ETIMEDOUT; } if (likely(!dev->cmd_err)) return 0; /* We have an error */ if (dev->cmd_err & (OMAP_I2C_STAT_AL | OMAP_I2C_STAT_ROVR | OMAP_I2C_STAT_XUDF)) { omap_i2c_init(dev); return -EIO; } if (dev->cmd_err & OMAP_I2C_STAT_NACK) { if (msg->flags & I2C_M_IGNORE_NAK) return 0; if (stop) { w = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG); w |= OMAP_I2C_CON_STP; omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w); } return -EREMOTEIO; } return -EIO; } /* * Prepare controller for a transaction and call omap_i2c_xfer_msg * to do the work during IRQ processing. */ static int omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) { struct omap_i2c_dev *dev = i2c_get_adapdata(adap); int i; int r; omap_i2c_unidle(dev); if ((r = omap_i2c_wait_for_bb(dev)) < 0) goto out; for (i = 0; i < num; i++) { r = omap_i2c_xfer_msg(adap, &msgs[i], (i == (num - 1))); if (r != 0) break; } if (r == 0) r = num; out: omap_i2c_idle(dev); return r; } static u32 omap_i2c_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK); } static inline void omap_i2c_complete_cmd(struct omap_i2c_dev *dev, u16 err) { dev->cmd_err |= err; complete(&dev->cmd_complete); } static inline void omap_i2c_ack_stat(struct omap_i2c_dev *dev, u16 stat) { omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat); } static irqreturn_t omap_i2c_rev1_isr(int this_irq, void *dev_id) { struct omap_i2c_dev *dev = dev_id; u16 iv, w; if (dev->idle) return IRQ_NONE; iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG); switch (iv) { case 0x00: /* None */ break; case 0x01: /* Arbitration lost */ dev_err(dev->dev, "Arbitration lost\n"); omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_AL); break; case 0x02: /* No acknowledgement */ omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_NACK); omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_STP); break; case 0x03: /* Register access ready */ omap_i2c_complete_cmd(dev, 0); break; case 0x04: /* Receive data ready */ if (dev->buf_len) { w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG); *dev->buf++ = w; dev->buf_len--; if (dev->buf_len) { *dev->buf++ = w >> 8; dev->buf_len--; } } else dev_err(dev->dev, "RRDY IRQ while no data requested\n"); break; case 0x05: /* Transmit data ready */ if (dev->buf_len) { w = *dev->buf++; dev->buf_len--; if (dev->buf_len) { w |= *dev->buf++ << 8; dev->buf_len--; } omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w); } else dev_err(dev->dev, "XRDY IRQ while no data to send\n"); break; default: return IRQ_NONE; } return IRQ_HANDLED; } static irqreturn_t omap_i2c_isr(int this_irq, void *dev_id) { struct omap_i2c_dev *dev = dev_id; u16 bits; u16 stat, w; int count = 0; if (dev->idle) return IRQ_NONE; bits = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG); while ((stat = (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG))) & bits) { dev_dbg(dev->dev, "IRQ (ISR = 0x%04x)\n", stat); if (count++ == 100) { dev_warn(dev->dev, "Too much work in one IRQ\n"); break; } omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat); if (stat & OMAP_I2C_STAT_ARDY) { omap_i2c_complete_cmd(dev, 0); continue; } if (stat & OMAP_I2C_STAT_RRDY) { w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG); if (dev->buf_len) { *dev->buf++ = w; dev->buf_len--; if (dev->buf_len) { *dev->buf++ = w >> 8; dev->buf_len--; } } else dev_err(dev->dev, "RRDY IRQ while no data " "requested\n"); omap_i2c_ack_stat(dev, OMAP_I2C_STAT_RRDY); continue; } if (stat & OMAP_I2C_STAT_XRDY) { w = 0; if (dev->buf_len) { w = *dev->buf++; dev->buf_len--; if (dev->buf_len) { w |= *dev->buf++ << 8; dev->buf_len--; } } else dev_err(dev->dev, "XRDY IRQ while no " "data to send\n"); omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w); omap_i2c_ack_stat(dev, OMAP_I2C_STAT_XRDY); continue; } if (stat & OMAP_I2C_STAT_ROVR) { dev_err(dev->dev, "Receive overrun\n"); dev->cmd_err |= OMAP_I2C_STAT_ROVR; } if (stat & OMAP_I2C_STAT_XUDF) { dev_err(dev->dev, "Transmit overflow\n"); dev->cmd_err |= OMAP_I2C_STAT_XUDF; } if (stat & OMAP_I2C_STAT_NACK) { omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_NACK); omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_STP); } if (stat & OMAP_I2C_STAT_AL) { dev_err(dev->dev, "Arbitration lost\n"); omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_AL); } } return count ? IRQ_HANDLED : IRQ_NONE; } static const struct i2c_algorithm omap_i2c_algo = { .master_xfer = omap_i2c_xfer, .functionality = omap_i2c_func, }; static int omap_i2c_probe(struct platform_device *pdev) { struct omap_i2c_dev *dev; struct i2c_adapter *adap; struct resource *mem, *irq, *ioarea; int r; /* NOTE: driver uses the static register mapping */ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!mem) { dev_err(&pdev->dev, "no mem resource?\n"); return -ENODEV; } irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); if (!irq) { dev_err(&pdev->dev, "no irq resource?\n"); return -ENODEV; } ioarea = request_mem_region(mem->start, (mem->end - mem->start) + 1, pdev->name); if (!ioarea) { dev_err(&pdev->dev, "I2C region already claimed\n"); return -EBUSY; } if (clock > 200) clock = 400; /* Fast mode */ else clock = 100; /* Standard mode */ dev = kzalloc(sizeof(struct omap_i2c_dev), GFP_KERNEL); if (!dev) { r = -ENOMEM; goto err_release_region; } dev->dev = &pdev->dev; dev->irq = irq->start; dev->base = ioremap(mem->start, mem->end - mem->start + 1); if (!dev->base) { r = -ENOMEM; goto err_free_mem; } platform_set_drvdata(pdev, dev); if ((r = omap_i2c_get_clocks(dev)) != 0) goto err_iounmap; omap_i2c_unidle(dev); if (cpu_is_omap15xx()) dev->rev1 = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) < 0x20; /* reset ASAP, clearing any IRQs */ omap_i2c_init(dev); r = request_irq(dev->irq, dev->rev1 ? omap_i2c_rev1_isr : omap_i2c_isr, 0, pdev->name, dev); if (r) { dev_err(dev->dev, "failure requesting irq %i\n", dev->irq); goto err_unuse_clocks; } r = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) & 0xff; dev_info(dev->dev, "bus %d rev%d.%d at %d kHz\n", pdev->id, r >> 4, r & 0xf, clock); adap = &dev->adapter; i2c_set_adapdata(adap, dev); adap->owner = THIS_MODULE; adap->class = I2C_CLASS_HWMON; strncpy(adap->name, "OMAP I2C adapter", sizeof(adap->name)); adap->algo = &omap_i2c_algo; adap->dev.parent = &pdev->dev; /* i2c device drivers may be active on return from add_adapter() */ adap->nr = pdev->id; r = i2c_add_numbered_adapter(adap); if (r) { dev_err(dev->dev, "failure adding adapter\n"); goto err_free_irq; } omap_i2c_idle(dev); return 0; err_free_irq: free_irq(dev->irq, dev); err_unuse_clocks: omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0); omap_i2c_idle(dev); omap_i2c_put_clocks(dev); err_iounmap: iounmap(dev->base); err_free_mem: platform_set_drvdata(pdev, NULL); kfree(dev); err_release_region: release_mem_region(mem->start, (mem->end - mem->start) + 1); return r; } static int omap_i2c_remove(struct platform_device *pdev) { struct omap_i2c_dev *dev = platform_get_drvdata(pdev); struct resource *mem; platform_set_drvdata(pdev, NULL); free_irq(dev->irq, dev); i2c_del_adapter(&dev->adapter); omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0); omap_i2c_put_clocks(dev); iounmap(dev->base); kfree(dev); mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); release_mem_region(mem->start, (mem->end - mem->start) + 1); return 0; } static struct platform_driver omap_i2c_driver = { .probe = omap_i2c_probe, .remove = omap_i2c_remove, .driver = { .name = "i2c_omap", .owner = THIS_MODULE, }, }; /* I2C may be needed to bring up other drivers */ static int __init omap_i2c_init_driver(void) { return platform_driver_register(&omap_i2c_driver); } subsys_initcall(omap_i2c_init_driver); static void __exit omap_i2c_exit_driver(void) { platform_driver_unregister(&omap_i2c_driver); } module_exit(omap_i2c_exit_driver); MODULE_AUTHOR("MontaVista Software, Inc. (and others)"); MODULE_DESCRIPTION("TI OMAP I2C bus adapter"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:i2c_omap");