/* * File : i2c-davinci.c * This file is part of RT-Thread RTOS * COPYRIGHT (C) 2006, RT-Thread Development Team * * 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. * * Change Logs: * Date Author Notes * 2011-01-13 weety first version */ #include #include #include /* ----- global defines ----------------------------------------------- */ #define BIT(nr) (1UL << (nr)) #define DAVINCI_I2C_TIMEOUT (1*RT_TICK_PER_SECOND) #define DAVINCI_I2C_MAX_TRIES 2 #define I2C_DAVINCI_INTR_ALL (DAVINCI_I2C_IMR_AAS | \ DAVINCI_I2C_IMR_SCD | \ DAVINCI_I2C_IMR_ARDY | \ DAVINCI_I2C_IMR_NACK | \ DAVINCI_I2C_IMR_AL) #define DAVINCI_I2C_OAR_REG 0x00 #define DAVINCI_I2C_IMR_REG 0x04 #define DAVINCI_I2C_STR_REG 0x08 #define DAVINCI_I2C_CLKL_REG 0x0c #define DAVINCI_I2C_CLKH_REG 0x10 #define DAVINCI_I2C_CNT_REG 0x14 #define DAVINCI_I2C_DRR_REG 0x18 #define DAVINCI_I2C_SAR_REG 0x1c #define DAVINCI_I2C_DXR_REG 0x20 #define DAVINCI_I2C_MDR_REG 0x24 #define DAVINCI_I2C_IVR_REG 0x28 #define DAVINCI_I2C_EMDR_REG 0x2c #define DAVINCI_I2C_PSC_REG 0x30 #define DAVINCI_I2C_IVR_AAS 0x07 #define DAVINCI_I2C_IVR_SCD 0x06 #define DAVINCI_I2C_IVR_XRDY 0x05 #define DAVINCI_I2C_IVR_RDR 0x04 #define DAVINCI_I2C_IVR_ARDY 0x03 #define DAVINCI_I2C_IVR_NACK 0x02 #define DAVINCI_I2C_IVR_AL 0x01 #define DAVINCI_I2C_STR_BB BIT(12) #define DAVINCI_I2C_STR_RSFULL BIT(11) #define DAVINCI_I2C_STR_SCD BIT(5) #define DAVINCI_I2C_STR_ARDY BIT(2) #define DAVINCI_I2C_STR_NACK BIT(1) #define DAVINCI_I2C_STR_AL BIT(0) #define DAVINCI_I2C_MDR_NACK BIT(15) #define DAVINCI_I2C_MDR_STT BIT(13) #define DAVINCI_I2C_MDR_STP BIT(11) #define DAVINCI_I2C_MDR_MST BIT(10) #define DAVINCI_I2C_MDR_TRX BIT(9) #define DAVINCI_I2C_MDR_XA BIT(8) #define DAVINCI_I2C_MDR_RM BIT(7) #define DAVINCI_I2C_MDR_IRS BIT(5) #define DAVINCI_I2C_IMR_AAS BIT(6) #define DAVINCI_I2C_IMR_SCD BIT(5) #define DAVINCI_I2C_IMR_XRDY BIT(4) #define DAVINCI_I2C_IMR_RRDY BIT(3) #define DAVINCI_I2C_IMR_ARDY BIT(2) #define DAVINCI_I2C_IMR_NACK BIT(1) #define DAVINCI_I2C_IMR_AL BIT(0) #ifdef RT_EDMA_DEBUG #define i2c_dbg(fmt, ...) rt_kprintf(fmt, ##__VA_ARGS__) #else #define i2c_dbg(fmt, ...) #endif struct davinci_i2c_dev { void *base; struct rt_semaphore completion; struct clk *clk; int cmd_err; rt_uint8_t *buf; rt_uint32_t buf_len; int irq; int stop; rt_uint8_t terminate; rt_uint32_t bus_freq; rt_uint32_t bus_delay; struct rt_i2c_bus_device *bus; }; static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev, int reg, rt_uint16_t val) { davinci_writew(val, i2c_dev->base + reg); } static inline rt_uint16_t davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg) { return davinci_readw(i2c_dev->base + reg); } static void udelay (rt_uint32_t us) { rt_int32_t i; for (; us > 0; us--) { i = 50000; while(i > 0) { i--; } } } #if 0 /* Generate a pulse on the i2c clock pin. */ static void generic_i2c_clock_pulse(unsigned int scl_pin) { rt_uint16_t i; if (scl_pin) { /* Send high and low on the SCL line */ for (i = 0; i < 9; i++) { gpio_set_value(scl_pin, 0); udelay(20); gpio_set_value(scl_pin, 1); udelay(20); } } } #endif /* This routine does i2c bus recovery as specified in the * i2c protocol Rev. 03 section 3.16 titled "Bus clear" */ static void i2c_recover_bus(struct davinci_i2c_dev *dev) { rt_uint32_t flag = 0; i2c_dbg("initiating i2c bus recovery\n"); /* Send NACK to the slave */ flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); flag |= DAVINCI_I2C_MDR_NACK; /* write the data into mode register */ davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag); #if 0 if (pdata) generic_i2c_clock_pulse(pdata->scl_pin); #endif /* Send STOP */ flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); flag |= DAVINCI_I2C_MDR_STP; davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag); } static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev, int val) { rt_uint16_t w; w = davinci_i2c_read_reg(i2c_dev, DAVINCI_I2C_MDR_REG); if (!val) /* put I2C into reset */ w &= ~DAVINCI_I2C_MDR_IRS; else /* take I2C out of reset */ w |= DAVINCI_I2C_MDR_IRS; davinci_i2c_write_reg(i2c_dev, DAVINCI_I2C_MDR_REG, w); } static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev) { rt_uint16_t psc; rt_uint32_t clk; rt_uint32_t d; rt_uint32_t clkh; rt_uint32_t clkl; rt_uint32_t input_clock = clk_get_rate(dev->clk); /* NOTE: I2C Clock divider programming info * As per I2C specs the following formulas provide prescaler * and low/high divider values * input clk --> PSC Div -----------> ICCL/H Div --> output clock * module clk * * output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ] * * Thus, * (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d; * * where if PSC == 0, d = 7, * if PSC == 1, d = 6 * if PSC > 1 , d = 5 */ /* get minimum of 7 MHz clock, but max of 12 MHz */ psc = (input_clock / 7000000) - 1; if ((input_clock / (psc + 1)) > 12000000) psc++; /* better to run under spec than over */ d = (psc >= 2) ? 5 : 7 - psc; clk = ((input_clock / (psc + 1)) / (dev->bus_freq * 1000)) - (d << 1); clkh = clk >> 1; clkl = clk - clkh; davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc); davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh); davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl); i2c_dbg("input_clock = %d, CLK = %d\n", input_clock, clk); } /* * This function configures I2C and brings I2C out of reset. * This function is called during I2C init function. This function * also gets called if I2C encounters any errors. */ static int i2c_davinci_init(struct davinci_i2c_dev *dev) { /* put I2C into reset */ davinci_i2c_reset_ctrl(dev, 0); /* compute clock dividers */ i2c_davinci_calc_clk_dividers(dev); /* Respond at reserved "SMBus Host" slave address" (and zero); * we seem to have no option to not respond... */ davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, 0x08); i2c_dbg("PSC = %d\n", davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG)); i2c_dbg("CLKL = %d\n", davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG)); i2c_dbg("CLKH = %d\n", davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG)); i2c_dbg("bus_freq = %dkHz, bus_delay = %d\n", dev->bus_freq, dev->bus_delay); /* Take the I2C module out of reset: */ davinci_i2c_reset_ctrl(dev, 1); /* Enable interrupts */ davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL); return 0; } /* * Waiting for bus not busy */ static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev, char allow_sleep) { unsigned long timeout; static rt_uint16_t to_cnt; RT_ASSERT(dev != RT_NULL); RT_ASSERT(dev->bus != RT_NULL); timeout = rt_tick_get() + dev->bus->timeout; while (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG) & DAVINCI_I2C_STR_BB) { if (to_cnt <= DAVINCI_I2C_MAX_TRIES) { if (rt_tick_get() >= timeout) { rt_kprintf("timeout waiting for bus ready\n"); to_cnt++; return -RT_ETIMEOUT; } else { to_cnt = 0; i2c_recover_bus(dev); i2c_davinci_init(dev); } } if (allow_sleep) rt_thread_delay(2); } return 0; } /* * Low level master read/write transaction. This function is called * from i2c_davinci_xfer. */ static int i2c_davinci_xfer_msg(struct rt_i2c_bus_device *bus, struct rt_i2c_msg *msg, int stop) { struct davinci_i2c_dev *dev = bus->priv; rt_uint32_t flag; rt_uint16_t w; int r; /* Introduce a delay, required for some boards (e.g Davinci EVM) */ if (dev->bus_delay) udelay(dev->bus_delay); /* set the slave address */ davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr); dev->buf = msg->buf; dev->buf_len = msg->len; dev->stop = stop; davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len); //INIT_COMPLETION(dev->cmd_complete); dev->cmd_err = 0; /* Take I2C out of reset and configure it as master */ flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST; /* if the slave address is ten bit address, enable XA bit */ if (msg->flags & RT_I2C_ADDR_10BIT) flag |= DAVINCI_I2C_MDR_XA; if (!(msg->flags & RT_I2C_RD)) flag |= DAVINCI_I2C_MDR_TRX; if (msg->len == 0) flag |= DAVINCI_I2C_MDR_RM; /* Enable receive or transmit interrupts */ w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG); if (msg->flags & RT_I2C_RD) w |= DAVINCI_I2C_IMR_RRDY; else w |= DAVINCI_I2C_IMR_XRDY; davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w); dev->terminate = 0; /* * Write mode register first as needed for correct behaviour * on OMAP-L138, but don't set STT yet to avoid a race with XRDY * occurring before we have loaded DXR */ davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag); /* * First byte should be set here, not after interrupt, * because transmit-data-ready interrupt can come before * NACK-interrupt during sending of previous message and * ICDXR may have wrong data * It also saves us one interrupt, slightly faster */ if ((!(msg->flags & RT_I2C_RD)) && dev->buf_len) { davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++); dev->buf_len--; } /* Set STT to begin transmit now DXR is loaded */ flag |= DAVINCI_I2C_MDR_STT; if (stop && msg->len != 0) flag |= DAVINCI_I2C_MDR_STP; davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag); r = rt_sem_take(&dev->completion, dev->bus->timeout); if (r == -RT_ETIMEOUT) { rt_kprintf("controller timed out\n"); i2c_recover_bus(dev); i2c_davinci_init(dev); dev->buf_len = 0; return -RT_ETIMEOUT; } if (dev->buf_len) { /* This should be 0 if all bytes were transferred * or dev->cmd_err denotes an error. * A signal may have aborted the transfer. */ if (r == RT_EOK) { rt_kprintf("abnormal termination buf_len=%i\n", dev->buf_len); r = -RT_EIO; } dev->terminate = 1; dev->buf_len = 0; } if (r < 0) return r; /* no error */ if (!dev->cmd_err) return msg->len; /* We have an error */ if (dev->cmd_err & DAVINCI_I2C_STR_AL) { i2c_davinci_init(dev); return -RT_EIO; } if (dev->cmd_err & DAVINCI_I2C_STR_NACK) { if (msg->flags & RT_I2C_IGNORE_NACK) return msg->len; if (stop) { w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); w |= DAVINCI_I2C_MDR_STP; davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w); } return -RT_EIO; } return -RT_EIO; } /* * Prepare controller for a transaction and call i2c_davinci_xfer_msg */ static int i2c_davinci_xfer(struct rt_i2c_bus_device *bus, struct rt_i2c_msg msgs[], int num) { struct davinci_i2c_dev *dev = bus->priv; int i; int ret; i2c_dbg("%s: msgs: %d\n", __func__, num); ret = i2c_davinci_wait_bus_not_busy(dev, 1); if (ret < 0) { i2c_dbg("timeout waiting for bus ready\n"); return ret; } for (i = 0; i < num; i++) { ret = i2c_davinci_xfer_msg(bus, &msgs[i], (i == (num - 1))); i2c_dbg("%s [%d/%d] ret: %d\n", __func__, i + 1, num, ret); if (ret < 0) return ret; } return num; } static void terminate_read(struct davinci_i2c_dev *dev) { rt_uint16_t w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); w |= DAVINCI_I2C_MDR_NACK; davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w); /* Throw away data */ davinci_i2c_read_reg(dev, DAVINCI_I2C_DRR_REG); if (!dev->terminate) rt_kprintf("RDR IRQ while no data requested\n"); } static void terminate_write(struct davinci_i2c_dev *dev) { rt_uint16_t w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); w |= DAVINCI_I2C_MDR_RM | DAVINCI_I2C_MDR_STP; davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w); if (!dev->terminate) i2c_dbg("TDR IRQ while no data to send\n"); } /* * Interrupt service routine. This gets called whenever an I2C interrupt * occurs. */ static void i2c_davinci_isr(int irq, void *param) { struct davinci_i2c_dev *dev = (struct davinci_i2c_dev *)param; rt_uint32_t stat; int count = 0; rt_uint16_t w; while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) { i2c_dbg("%s: stat=0x%x\n", __func__, stat); if (count++ == 100) { rt_kprintf("Too much work in one IRQ\n"); break; } switch (stat) { case DAVINCI_I2C_IVR_AL: /* Arbitration lost, must retry */ dev->cmd_err |= DAVINCI_I2C_STR_AL; dev->buf_len = 0; rt_sem_release(&dev->completion); break; case DAVINCI_I2C_IVR_NACK: dev->cmd_err |= DAVINCI_I2C_STR_NACK; dev->buf_len = 0; rt_sem_release(&dev->completion); break; case DAVINCI_I2C_IVR_ARDY: davinci_i2c_write_reg(dev, DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY); if (((dev->buf_len == 0) && (dev->stop != 0)) || (dev->cmd_err & DAVINCI_I2C_STR_NACK)) { w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); w |= DAVINCI_I2C_MDR_STP; davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w); } rt_sem_release(&dev->completion); break; case DAVINCI_I2C_IVR_RDR: if (dev->buf_len) { *dev->buf++ = davinci_i2c_read_reg(dev, DAVINCI_I2C_DRR_REG); dev->buf_len--; if (dev->buf_len) continue; davinci_i2c_write_reg(dev, DAVINCI_I2C_STR_REG, DAVINCI_I2C_IMR_RRDY); } else { /* signal can terminate transfer */ terminate_read(dev); } break; case DAVINCI_I2C_IVR_XRDY: if (dev->buf_len) { davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++); dev->buf_len--; if (dev->buf_len) continue; w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG); w &= ~DAVINCI_I2C_IMR_XRDY; davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w); } else { /* signal can terminate transfer */ terminate_write(dev); } break; case DAVINCI_I2C_IVR_SCD: davinci_i2c_write_reg(dev, DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_SCD); rt_sem_release(&dev->completion); break; case DAVINCI_I2C_IVR_AAS: i2c_dbg("Address as slave interrupt\n"); break; default: i2c_dbg("Unrecognized irq stat %d\n", stat); break; } } } static struct rt_i2c_bus_device_ops bus_ops = { .master_xfer = i2c_davinci_xfer, }; int davinci_i2c_init(char *bus_name) { struct rt_i2c_bus_device *bus; struct davinci_i2c_dev *dev; int r; bus = rt_malloc(sizeof(struct rt_i2c_bus_device)); if (bus == RT_NULL) { rt_kprintf("rt_malloc failed\n"); return -RT_ENOMEM; } rt_memset((void *)bus, 0, sizeof(struct rt_i2c_bus_device)); bus->ops = &bus_ops; bus->timeout = DAVINCI_I2C_TIMEOUT; dev = rt_malloc(sizeof(struct davinci_i2c_dev)); if (!dev) { r = -RT_ENOMEM; goto err; } rt_memset((void *)dev, 0, sizeof(struct davinci_i2c_dev)); rt_sem_init(&dev->completion, "i2c_ack", 0, RT_IPC_FLAG_FIFO); dev->irq = IRQ_I2C; dev->clk = clk_get("I2CCLK"); if (dev->clk == RT_NULL) { r = -RT_ERROR; goto err1; } psc_change_state(DAVINCI_DM365_LPSC_I2C, 3); dev->base = DAVINCI_I2C_BASE; dev->bus_freq = 100; dev->bus_delay = 0; dev->bus = bus; bus->priv = dev; i2c_davinci_init(dev); rt_hw_interrupt_install(dev->irq, i2c_davinci_isr, (void *)dev, "I2C"); rt_hw_interrupt_umask(dev->irq); return rt_i2c_bus_device_register(bus, bus_name); err1: rt_free(dev); err: rt_free(bus); return r; } int rt_hw_iic_init(void) { davinci_i2c_init("I2C1"); } INIT_DEVICE_EXPORT(rt_hw_iic_init);