/* linux/drivers/i2c/busses/i2c-s3c2410.c * * Copyright (C) 2004,2005,2009 Simtec Electronics * Ben Dooks * * S3C2410 I2C Controller * * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* see s3c2410x user guide, v1.1, section 9 (p447) for more info */ #define S3C2410_IICCON 0x00 #define S3C2410_IICSTAT 0x04 #define S3C2410_IICADD 0x08 #define S3C2410_IICDS 0x0C #define S3C2440_IICLC 0x10 #define S3C2410_IICCON_ACKEN (1 << 7) #define S3C2410_IICCON_TXDIV_16 (0 << 6) #define S3C2410_IICCON_TXDIV_512 (1 << 6) #define S3C2410_IICCON_IRQEN (1 << 5) #define S3C2410_IICCON_IRQPEND (1 << 4) #define S3C2410_IICCON_SCALE(x) ((x) & 0xf) #define S3C2410_IICCON_SCALEMASK (0xf) #define S3C2410_IICSTAT_MASTER_RX (2 << 6) #define S3C2410_IICSTAT_MASTER_TX (3 << 6) #define S3C2410_IICSTAT_SLAVE_RX (0 << 6) #define S3C2410_IICSTAT_SLAVE_TX (1 << 6) #define S3C2410_IICSTAT_MODEMASK (3 << 6) #define S3C2410_IICSTAT_START (1 << 5) #define S3C2410_IICSTAT_BUSBUSY (1 << 5) #define S3C2410_IICSTAT_TXRXEN (1 << 4) #define S3C2410_IICSTAT_ARBITR (1 << 3) #define S3C2410_IICSTAT_ASSLAVE (1 << 2) #define S3C2410_IICSTAT_ADDR0 (1 << 1) #define S3C2410_IICSTAT_LASTBIT (1 << 0) #define S3C2410_IICLC_SDA_DELAY0 (0 << 0) #define S3C2410_IICLC_SDA_DELAY5 (1 << 0) #define S3C2410_IICLC_SDA_DELAY10 (2 << 0) #define S3C2410_IICLC_SDA_DELAY15 (3 << 0) #define S3C2410_IICLC_SDA_DELAY_MASK (3 << 0) #define S3C2410_IICLC_FILTER_ON (1 << 2) /* Treat S3C2410 as baseline hardware, anything else is supported via quirks */ #define QUIRK_S3C2440 (1 << 0) #define QUIRK_HDMIPHY (1 << 1) #define QUIRK_NO_GPIO (1 << 2) #define QUIRK_POLL (1 << 3) /* Max time to wait for bus to become idle after a xfer (in us) */ #define S3C2410_IDLE_TIMEOUT 5000 /* i2c controller state */ enum s3c24xx_i2c_state { STATE_IDLE, STATE_START, STATE_READ, STATE_WRITE, STATE_STOP }; struct s3c24xx_i2c { wait_queue_head_t wait; unsigned int quirks; unsigned int suspended:1; struct i2c_msg *msg; unsigned int msg_num; unsigned int msg_idx; unsigned int msg_ptr; unsigned int tx_setup; unsigned int irq; enum s3c24xx_i2c_state state; unsigned long clkrate; void __iomem *regs; struct clk *clk; struct device *dev; struct i2c_adapter adap; struct s3c2410_platform_i2c *pdata; int gpios[2]; struct pinctrl *pctrl; #if defined(CONFIG_ARM_S3C24XX_CPUFREQ) struct notifier_block freq_transition; #endif }; static struct platform_device_id s3c24xx_driver_ids[] = { { .name = "s3c2410-i2c", .driver_data = 0, }, { .name = "s3c2440-i2c", .driver_data = QUIRK_S3C2440, }, { .name = "s3c2440-hdmiphy-i2c", .driver_data = QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO, }, { }, }; MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids); static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat); #ifdef CONFIG_OF static const struct of_device_id s3c24xx_i2c_match[] = { { .compatible = "samsung,s3c2410-i2c", .data = (void *)0 }, { .compatible = "samsung,s3c2440-i2c", .data = (void *)QUIRK_S3C2440 }, { .compatible = "samsung,s3c2440-hdmiphy-i2c", .data = (void *)(QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO) }, { .compatible = "samsung,exynos5440-i2c", .data = (void *)(QUIRK_S3C2440 | QUIRK_NO_GPIO) }, { .compatible = "samsung,exynos5-sata-phy-i2c", .data = (void *)(QUIRK_S3C2440 | QUIRK_POLL | QUIRK_NO_GPIO) }, {}, }; MODULE_DEVICE_TABLE(of, s3c24xx_i2c_match); #endif /* s3c24xx_get_device_quirks * * Get controller type either from device tree or platform device variant. */ static inline unsigned int s3c24xx_get_device_quirks(struct platform_device *pdev) { if (pdev->dev.of_node) { const struct of_device_id *match; match = of_match_node(s3c24xx_i2c_match, pdev->dev.of_node); return (unsigned int)match->data; } return platform_get_device_id(pdev)->driver_data; } /* s3c24xx_i2c_master_complete * * complete the message and wake up the caller, using the given return code, * or zero to mean ok. */ static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret) { dev_dbg(i2c->dev, "master_complete %d\n", ret); i2c->msg_ptr = 0; i2c->msg = NULL; i2c->msg_idx++; i2c->msg_num = 0; if (ret) i2c->msg_idx = ret; if (!(i2c->quirks & QUIRK_POLL)) wake_up(&i2c->wait); } static inline void s3c24xx_i2c_disable_ack(struct s3c24xx_i2c *i2c) { unsigned long tmp; tmp = readl(i2c->regs + S3C2410_IICCON); writel(tmp & ~S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON); } static inline void s3c24xx_i2c_enable_ack(struct s3c24xx_i2c *i2c) { unsigned long tmp; tmp = readl(i2c->regs + S3C2410_IICCON); writel(tmp | S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON); } /* irq enable/disable functions */ static inline void s3c24xx_i2c_disable_irq(struct s3c24xx_i2c *i2c) { unsigned long tmp; tmp = readl(i2c->regs + S3C2410_IICCON); writel(tmp & ~S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON); } static inline void s3c24xx_i2c_enable_irq(struct s3c24xx_i2c *i2c) { unsigned long tmp; tmp = readl(i2c->regs + S3C2410_IICCON); writel(tmp | S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON); } static bool is_ack(struct s3c24xx_i2c *i2c) { int tries; for (tries = 50; tries; --tries) { if (readl(i2c->regs + S3C2410_IICCON) & S3C2410_IICCON_IRQPEND) { if (!(readl(i2c->regs + S3C2410_IICSTAT) & S3C2410_IICSTAT_LASTBIT)) return true; } usleep_range(1000, 2000); } dev_err(i2c->dev, "ack was not recieved\n"); return false; } /* s3c24xx_i2c_message_start * * put the start of a message onto the bus */ static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c, struct i2c_msg *msg) { unsigned int addr = (msg->addr & 0x7f) << 1; unsigned long stat; unsigned long iiccon; stat = 0; stat |= S3C2410_IICSTAT_TXRXEN; if (msg->flags & I2C_M_RD) { stat |= S3C2410_IICSTAT_MASTER_RX; addr |= 1; } else stat |= S3C2410_IICSTAT_MASTER_TX; if (msg->flags & I2C_M_REV_DIR_ADDR) addr ^= 1; /* todo - check for whether ack wanted or not */ s3c24xx_i2c_enable_ack(i2c); iiccon = readl(i2c->regs + S3C2410_IICCON); writel(stat, i2c->regs + S3C2410_IICSTAT); dev_dbg(i2c->dev, "START: %08lx to IICSTAT, %02x to DS\n", stat, addr); writeb(addr, i2c->regs + S3C2410_IICDS); /* delay here to ensure the data byte has gotten onto the bus * before the transaction is started */ ndelay(i2c->tx_setup); dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon); writel(iiccon, i2c->regs + S3C2410_IICCON); stat |= S3C2410_IICSTAT_START; writel(stat, i2c->regs + S3C2410_IICSTAT); if (i2c->quirks & QUIRK_POLL) { while ((i2c->msg_num != 0) && is_ack(i2c)) { i2c_s3c_irq_nextbyte(i2c, stat); stat = readl(i2c->regs + S3C2410_IICSTAT); if (stat & S3C2410_IICSTAT_ARBITR) dev_err(i2c->dev, "deal with arbitration loss\n"); } } } static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret) { unsigned long iicstat = readl(i2c->regs + S3C2410_IICSTAT); dev_dbg(i2c->dev, "STOP\n"); /* * The datasheet says that the STOP sequence should be: * 1) I2CSTAT.5 = 0 - Clear BUSY (or 'generate STOP') * 2) I2CCON.4 = 0 - Clear IRQPEND * 3) Wait until the stop condition takes effect. * 4*) I2CSTAT.4 = 0 - Clear TXRXEN * * Where, step "4*" is only for buses with the "HDMIPHY" quirk. * * However, after much experimentation, it appears that: * a) normal buses automatically clear BUSY and transition from * Master->Slave when they complete generating a STOP condition. * Therefore, step (3) can be done in doxfer() by polling I2CCON.4 * after starting the STOP generation here. * b) HDMIPHY bus does neither, so there is no way to do step 3. * There is no indication when this bus has finished generating * STOP. * * In fact, we have found that as soon as the IRQPEND bit is cleared in * step 2, the HDMIPHY bus generates the STOP condition, and then * immediately starts transferring another data byte, even though the * bus is supposedly stopped. This is presumably because the bus is * still in "Master" mode, and its BUSY bit is still set. * * To avoid these extra post-STOP transactions on HDMI phy devices, we * just disable Serial Output on the bus (I2CSTAT.4 = 0) directly, * instead of first generating a proper STOP condition. This should * float SDA & SCK terminating the transfer. Subsequent transfers * start with a proper START condition, and proceed normally. * * The HDMIPHY bus is an internal bus that always has exactly two * devices, the host as Master and the HDMIPHY device as the slave. * Skipping the STOP condition has been tested on this bus and works. */ if (i2c->quirks & QUIRK_HDMIPHY) { /* Stop driving the I2C pins */ iicstat &= ~S3C2410_IICSTAT_TXRXEN; } else { /* stop the transfer */ iicstat &= ~S3C2410_IICSTAT_START; } writel(iicstat, i2c->regs + S3C2410_IICSTAT); i2c->state = STATE_STOP; s3c24xx_i2c_master_complete(i2c, ret); s3c24xx_i2c_disable_irq(i2c); } /* helper functions to determine the current state in the set of * messages we are sending */ /* is_lastmsg() * * returns TRUE if the current message is the last in the set */ static inline int is_lastmsg(struct s3c24xx_i2c *i2c) { return i2c->msg_idx >= (i2c->msg_num - 1); } /* is_msglast * * returns TRUE if we this is the last byte in the current message */ static inline int is_msglast(struct s3c24xx_i2c *i2c) { /* msg->len is always 1 for the first byte of smbus block read. * Actual length will be read from slave. More bytes will be * read according to the length then. */ if (i2c->msg->flags & I2C_M_RECV_LEN && i2c->msg->len == 1) return 0; return i2c->msg_ptr == i2c->msg->len-1; } /* is_msgend * * returns TRUE if we reached the end of the current message */ static inline int is_msgend(struct s3c24xx_i2c *i2c) { return i2c->msg_ptr >= i2c->msg->len; } /* i2c_s3c_irq_nextbyte * * process an interrupt and work out what to do */ static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat) { unsigned long tmp; unsigned char byte; int ret = 0; switch (i2c->state) { case STATE_IDLE: dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__); goto out; case STATE_STOP: dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__); s3c24xx_i2c_disable_irq(i2c); goto out_ack; case STATE_START: /* last thing we did was send a start condition on the * bus, or started a new i2c message */ if (iicstat & S3C2410_IICSTAT_LASTBIT && !(i2c->msg->flags & I2C_M_IGNORE_NAK)) { /* ack was not received... */ dev_dbg(i2c->dev, "ack was not received\n"); s3c24xx_i2c_stop(i2c, -ENXIO); goto out_ack; } if (i2c->msg->flags & I2C_M_RD) i2c->state = STATE_READ; else i2c->state = STATE_WRITE; /* terminate the transfer if there is nothing to do * as this is used by the i2c probe to find devices. */ if (is_lastmsg(i2c) && i2c->msg->len == 0) { s3c24xx_i2c_stop(i2c, 0); goto out_ack; } if (i2c->state == STATE_READ) goto prepare_read; /* fall through to the write state, as we will need to * send a byte as well */ case STATE_WRITE: /* we are writing data to the device... check for the * end of the message, and if so, work out what to do */ if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) { if (iicstat & S3C2410_IICSTAT_LASTBIT) { dev_dbg(i2c->dev, "WRITE: No Ack\n"); s3c24xx_i2c_stop(i2c, -ECONNREFUSED); goto out_ack; } } retry_write: if (!is_msgend(i2c)) { byte = i2c->msg->buf[i2c->msg_ptr++]; writeb(byte, i2c->regs + S3C2410_IICDS); /* delay after writing the byte to allow the * data setup time on the bus, as writing the * data to the register causes the first bit * to appear on SDA, and SCL will change as * soon as the interrupt is acknowledged */ ndelay(i2c->tx_setup); } else if (!is_lastmsg(i2c)) { /* we need to go to the next i2c message */ dev_dbg(i2c->dev, "WRITE: Next Message\n"); i2c->msg_ptr = 0; i2c->msg_idx++; i2c->msg++; /* check to see if we need to do another message */ if (i2c->msg->flags & I2C_M_NOSTART) { if (i2c->msg->flags & I2C_M_RD) { /* cannot do this, the controller * forces us to send a new START * when we change direction */ s3c24xx_i2c_stop(i2c, -EINVAL); } goto retry_write; } else { /* send the new start */ s3c24xx_i2c_message_start(i2c, i2c->msg); i2c->state = STATE_START; } } else { /* send stop */ s3c24xx_i2c_stop(i2c, 0); } break; case STATE_READ: /* we have a byte of data in the data register, do * something with it, and then work out whether we are * going to do any more read/write */ byte = readb(i2c->regs + S3C2410_IICDS); i2c->msg->buf[i2c->msg_ptr++] = byte; /* Add actual length to read for smbus block read */ if (i2c->msg->flags & I2C_M_RECV_LEN && i2c->msg->len == 1) i2c->msg->len += byte; prepare_read: if (is_msglast(i2c)) { /* last byte of buffer */ if (is_lastmsg(i2c)) s3c24xx_i2c_disable_ack(i2c); } else if (is_msgend(i2c)) { /* ok, we've read the entire buffer, see if there * is anything else we need to do */ if (is_lastmsg(i2c)) { /* last message, send stop and complete */ dev_dbg(i2c->dev, "READ: Send Stop\n"); s3c24xx_i2c_stop(i2c, 0); } else { /* go to the next transfer */ dev_dbg(i2c->dev, "READ: Next Transfer\n"); i2c->msg_ptr = 0; i2c->msg_idx++; i2c->msg++; } } break; } /* acknowlegde the IRQ and get back on with the work */ out_ack: tmp = readl(i2c->regs + S3C2410_IICCON); tmp &= ~S3C2410_IICCON_IRQPEND; writel(tmp, i2c->regs + S3C2410_IICCON); out: return ret; } /* s3c24xx_i2c_irq * * top level IRQ servicing routine */ static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id) { struct s3c24xx_i2c *i2c = dev_id; unsigned long status; unsigned long tmp; status = readl(i2c->regs + S3C2410_IICSTAT); if (status & S3C2410_IICSTAT_ARBITR) { /* deal with arbitration loss */ dev_err(i2c->dev, "deal with arbitration loss\n"); } if (i2c->state == STATE_IDLE) { dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n"); tmp = readl(i2c->regs + S3C2410_IICCON); tmp &= ~S3C2410_IICCON_IRQPEND; writel(tmp, i2c->regs + S3C2410_IICCON); goto out; } /* pretty much this leaves us with the fact that we've * transmitted or received whatever byte we last sent */ i2c_s3c_irq_nextbyte(i2c, status); out: return IRQ_HANDLED; } /* s3c24xx_i2c_set_master * * get the i2c bus for a master transaction */ static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c) { unsigned long iicstat; int timeout = 400; while (timeout-- > 0) { iicstat = readl(i2c->regs + S3C2410_IICSTAT); if (!(iicstat & S3C2410_IICSTAT_BUSBUSY)) return 0; msleep(1); } return -ETIMEDOUT; } /* s3c24xx_i2c_wait_idle * * wait for the i2c bus to become idle. */ static void s3c24xx_i2c_wait_idle(struct s3c24xx_i2c *i2c) { unsigned long iicstat; ktime_t start, now; unsigned long delay; int spins; /* ensure the stop has been through the bus */ dev_dbg(i2c->dev, "waiting for bus idle\n"); start = now = ktime_get(); /* * Most of the time, the bus is already idle within a few usec of the * end of a transaction. However, really slow i2c devices can stretch * the clock, delaying STOP generation. * * On slower SoCs this typically happens within a very small number of * instructions so busy wait briefly to avoid scheduling overhead. */ spins = 3; iicstat = readl(i2c->regs + S3C2410_IICSTAT); while ((iicstat & S3C2410_IICSTAT_START) && --spins) { cpu_relax(); iicstat = readl(i2c->regs + S3C2410_IICSTAT); } /* * If we do get an appreciable delay as a compromise between idle * detection latency for the normal, fast case, and system load in the * slow device case, use an exponential back off in the polling loop, * up to 1/10th of the total timeout, then continue to poll at a * constant rate up to the timeout. */ delay = 1; while ((iicstat & S3C2410_IICSTAT_START) && ktime_us_delta(now, start) < S3C2410_IDLE_TIMEOUT) { usleep_range(delay, 2 * delay); if (delay < S3C2410_IDLE_TIMEOUT / 10) delay <<= 1; now = ktime_get(); iicstat = readl(i2c->regs + S3C2410_IICSTAT); } if (iicstat & S3C2410_IICSTAT_START) dev_warn(i2c->dev, "timeout waiting for bus idle\n"); } /* s3c24xx_i2c_doxfer * * this starts an i2c transfer */ static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c, struct i2c_msg *msgs, int num) { unsigned long timeout; int ret; if (i2c->suspended) return -EIO; ret = s3c24xx_i2c_set_master(i2c); if (ret != 0) { dev_err(i2c->dev, "cannot get bus (error %d)\n", ret); ret = -EAGAIN; goto out; } i2c->msg = msgs; i2c->msg_num = num; i2c->msg_ptr = 0; i2c->msg_idx = 0; i2c->state = STATE_START; s3c24xx_i2c_enable_irq(i2c); s3c24xx_i2c_message_start(i2c, msgs); if (i2c->quirks & QUIRK_POLL) { ret = i2c->msg_idx; if (ret != num) dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret); goto out; } timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5); ret = i2c->msg_idx; /* having these next two as dev_err() makes life very * noisy when doing an i2cdetect */ if (timeout == 0) dev_dbg(i2c->dev, "timeout\n"); else if (ret != num) dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret); /* For QUIRK_HDMIPHY, bus is already disabled */ if (i2c->quirks & QUIRK_HDMIPHY) goto out; s3c24xx_i2c_wait_idle(i2c); out: return ret; } /* s3c24xx_i2c_xfer * * first port of call from the i2c bus code when an message needs * transferring across the i2c bus. */ static int s3c24xx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data; int retry; int ret; pm_runtime_get_sync(&adap->dev); clk_prepare_enable(i2c->clk); for (retry = 0; retry < adap->retries; retry++) { ret = s3c24xx_i2c_doxfer(i2c, msgs, num); if (ret != -EAGAIN) { clk_disable_unprepare(i2c->clk); pm_runtime_put(&adap->dev); return ret; } dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry); udelay(100); } clk_disable_unprepare(i2c->clk); pm_runtime_put(&adap->dev); return -EREMOTEIO; } /* declare our i2c functionality */ static u32 s3c24xx_i2c_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART | I2C_FUNC_PROTOCOL_MANGLING; } /* i2c bus registration info */ static const struct i2c_algorithm s3c24xx_i2c_algorithm = { .master_xfer = s3c24xx_i2c_xfer, .functionality = s3c24xx_i2c_func, }; /* s3c24xx_i2c_calcdivisor * * return the divisor settings for a given frequency */ static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted, unsigned int *div1, unsigned int *divs) { unsigned int calc_divs = clkin / wanted; unsigned int calc_div1; if (calc_divs > (16*16)) calc_div1 = 512; else calc_div1 = 16; calc_divs += calc_div1-1; calc_divs /= calc_div1; if (calc_divs == 0) calc_divs = 1; if (calc_divs > 17) calc_divs = 17; *divs = calc_divs; *div1 = calc_div1; return clkin / (calc_divs * calc_div1); } /* s3c24xx_i2c_clockrate * * work out a divisor for the user requested frequency setting, * either by the requested frequency, or scanning the acceptable * range of frequencies until something is found */ static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got) { struct s3c2410_platform_i2c *pdata = i2c->pdata; unsigned long clkin = clk_get_rate(i2c->clk); unsigned int divs, div1; unsigned long target_frequency; u32 iiccon; int freq; i2c->clkrate = clkin; clkin /= 1000; /* clkin now in KHz */ dev_dbg(i2c->dev, "pdata desired frequency %lu\n", pdata->frequency); target_frequency = pdata->frequency ? pdata->frequency : 100000; target_frequency /= 1000; /* Target frequency now in KHz */ freq = s3c24xx_i2c_calcdivisor(clkin, target_frequency, &div1, &divs); if (freq > target_frequency) { dev_err(i2c->dev, "Unable to achieve desired frequency %luKHz." \ " Lowest achievable %dKHz\n", target_frequency, freq); return -EINVAL; } *got = freq; iiccon = readl(i2c->regs + S3C2410_IICCON); iiccon &= ~(S3C2410_IICCON_SCALEMASK | S3C2410_IICCON_TXDIV_512); iiccon |= (divs-1); if (div1 == 512) iiccon |= S3C2410_IICCON_TXDIV_512; if (i2c->quirks & QUIRK_POLL) iiccon |= S3C2410_IICCON_SCALE(2); writel(iiccon, i2c->regs + S3C2410_IICCON); if (i2c->quirks & QUIRK_S3C2440) { unsigned long sda_delay; if (pdata->sda_delay) { sda_delay = clkin * pdata->sda_delay; sda_delay = DIV_ROUND_UP(sda_delay, 1000000); sda_delay = DIV_ROUND_UP(sda_delay, 5); if (sda_delay > 3) sda_delay = 3; sda_delay |= S3C2410_IICLC_FILTER_ON; } else sda_delay = 0; dev_dbg(i2c->dev, "IICLC=%08lx\n", sda_delay); writel(sda_delay, i2c->regs + S3C2440_IICLC); } return 0; } #if defined(CONFIG_ARM_S3C24XX_CPUFREQ) #define freq_to_i2c(_n) container_of(_n, struct s3c24xx_i2c, freq_transition) static int s3c24xx_i2c_cpufreq_transition(struct notifier_block *nb, unsigned long val, void *data) { struct s3c24xx_i2c *i2c = freq_to_i2c(nb); unsigned int got; int delta_f; int ret; delta_f = clk_get_rate(i2c->clk) - i2c->clkrate; /* if we're post-change and the input clock has slowed down * or at pre-change and the clock is about to speed up, then * adjust our clock rate. <0 is slow, >0 speedup. */ if ((val == CPUFREQ_POSTCHANGE && delta_f < 0) || (val == CPUFREQ_PRECHANGE && delta_f > 0)) { i2c_lock_adapter(&i2c->adap); ret = s3c24xx_i2c_clockrate(i2c, &got); i2c_unlock_adapter(&i2c->adap); if (ret < 0) dev_err(i2c->dev, "cannot find frequency\n"); else dev_info(i2c->dev, "setting freq %d\n", got); } return 0; } static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c) { i2c->freq_transition.notifier_call = s3c24xx_i2c_cpufreq_transition; return cpufreq_register_notifier(&i2c->freq_transition, CPUFREQ_TRANSITION_NOTIFIER); } static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c) { cpufreq_unregister_notifier(&i2c->freq_transition, CPUFREQ_TRANSITION_NOTIFIER); } #else static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c) { return 0; } static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c) { } #endif #ifdef CONFIG_OF static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c) { int idx, gpio, ret; if (i2c->quirks & QUIRK_NO_GPIO) return 0; for (idx = 0; idx < 2; idx++) { gpio = of_get_gpio(i2c->dev->of_node, idx); if (!gpio_is_valid(gpio)) { dev_err(i2c->dev, "invalid gpio[%d]: %d\n", idx, gpio); goto free_gpio; } i2c->gpios[idx] = gpio; ret = gpio_request(gpio, "i2c-bus"); if (ret) { dev_err(i2c->dev, "gpio [%d] request failed\n", gpio); goto free_gpio; } } return 0; free_gpio: while (--idx >= 0) gpio_free(i2c->gpios[idx]); return -EINVAL; } static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c) { unsigned int idx; if (i2c->quirks & QUIRK_NO_GPIO) return; for (idx = 0; idx < 2; idx++) gpio_free(i2c->gpios[idx]); } #else static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c) { return 0; } static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c) { } #endif /* s3c24xx_i2c_init * * initialise the controller, set the IO lines and frequency */ static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c) { unsigned long iicon = S3C2410_IICCON_IRQEN | S3C2410_IICCON_ACKEN; struct s3c2410_platform_i2c *pdata; unsigned int freq; /* get the plafrom data */ pdata = i2c->pdata; /* write slave address */ writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD); dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr); writel(iicon, i2c->regs + S3C2410_IICCON); /* we need to work out the divisors for the clock... */ if (s3c24xx_i2c_clockrate(i2c, &freq) != 0) { writel(0, i2c->regs + S3C2410_IICCON); dev_err(i2c->dev, "cannot meet bus frequency required\n"); return -EINVAL; } /* todo - check that the i2c lines aren't being dragged anywhere */ dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq); dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02lx\n", iicon); return 0; } #ifdef CONFIG_OF /* s3c24xx_i2c_parse_dt * * Parse the device tree node and retreive the platform data. */ static void s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c) { struct s3c2410_platform_i2c *pdata = i2c->pdata; if (!np) return; pdata->bus_num = -1; /* i2c bus number is dynamically assigned */ of_property_read_u32(np, "samsung,i2c-sda-delay", &pdata->sda_delay); of_property_read_u32(np, "samsung,i2c-slave-addr", &pdata->slave_addr); of_property_read_u32(np, "samsung,i2c-max-bus-freq", (u32 *)&pdata->frequency); } #else static void s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c) { return; } #endif /* s3c24xx_i2c_probe * * called by the bus driver when a suitable device is found */ static int s3c24xx_i2c_probe(struct platform_device *pdev) { struct s3c24xx_i2c *i2c; struct s3c2410_platform_i2c *pdata = NULL; struct resource *res; int ret; if (!pdev->dev.of_node) { pdata = dev_get_platdata(&pdev->dev); if (!pdata) { dev_err(&pdev->dev, "no platform data\n"); return -EINVAL; } } i2c = devm_kzalloc(&pdev->dev, sizeof(struct s3c24xx_i2c), GFP_KERNEL); if (!i2c) { dev_err(&pdev->dev, "no memory for state\n"); return -ENOMEM; } i2c->pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); if (!i2c->pdata) { dev_err(&pdev->dev, "no memory for platform data\n"); return -ENOMEM; } i2c->quirks = s3c24xx_get_device_quirks(pdev); if (pdata) memcpy(i2c->pdata, pdata, sizeof(*pdata)); else s3c24xx_i2c_parse_dt(pdev->dev.of_node, i2c); strlcpy(i2c->adap.name, "s3c2410-i2c", sizeof(i2c->adap.name)); i2c->adap.owner = THIS_MODULE; i2c->adap.algo = &s3c24xx_i2c_algorithm; i2c->adap.retries = 2; i2c->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD; i2c->tx_setup = 50; init_waitqueue_head(&i2c->wait); /* find the clock and enable it */ i2c->dev = &pdev->dev; i2c->clk = devm_clk_get(&pdev->dev, "i2c"); if (IS_ERR(i2c->clk)) { dev_err(&pdev->dev, "cannot get clock\n"); return -ENOENT; } dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk); /* map the registers */ res = platform_get_resource(pdev, IORESOURCE_MEM, 0); i2c->regs = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(i2c->regs)) return PTR_ERR(i2c->regs); dev_dbg(&pdev->dev, "registers %p (%p)\n", i2c->regs, res); /* setup info block for the i2c core */ i2c->adap.algo_data = i2c; i2c->adap.dev.parent = &pdev->dev; i2c->pctrl = devm_pinctrl_get_select_default(i2c->dev); /* inititalise the i2c gpio lines */ if (i2c->pdata->cfg_gpio) { i2c->pdata->cfg_gpio(to_platform_device(i2c->dev)); } else if (IS_ERR(i2c->pctrl) && s3c24xx_i2c_parse_dt_gpio(i2c)) { return -EINVAL; } /* initialise the i2c controller */ clk_prepare_enable(i2c->clk); ret = s3c24xx_i2c_init(i2c); clk_disable_unprepare(i2c->clk); if (ret != 0) { dev_err(&pdev->dev, "I2C controller init failed\n"); return ret; } /* find the IRQ for this unit (note, this relies on the init call to * ensure no current IRQs pending */ if (!(i2c->quirks & QUIRK_POLL)) { i2c->irq = ret = platform_get_irq(pdev, 0); if (ret <= 0) { dev_err(&pdev->dev, "cannot find IRQ\n"); return ret; } ret = devm_request_irq(&pdev->dev, i2c->irq, s3c24xx_i2c_irq, 0, dev_name(&pdev->dev), i2c); if (ret != 0) { dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq); return ret; } } ret = s3c24xx_i2c_register_cpufreq(i2c); if (ret < 0) { dev_err(&pdev->dev, "failed to register cpufreq notifier\n"); return ret; } /* Note, previous versions of the driver used i2c_add_adapter() * to add the bus at any number. We now pass the bus number via * the platform data, so if unset it will now default to always * being bus 0. */ i2c->adap.nr = i2c->pdata->bus_num; i2c->adap.dev.of_node = pdev->dev.of_node; ret = i2c_add_numbered_adapter(&i2c->adap); if (ret < 0) { dev_err(&pdev->dev, "failed to add bus to i2c core\n"); s3c24xx_i2c_deregister_cpufreq(i2c); return ret; } platform_set_drvdata(pdev, i2c); pm_runtime_enable(&pdev->dev); pm_runtime_enable(&i2c->adap.dev); dev_info(&pdev->dev, "%s: S3C I2C adapter\n", dev_name(&i2c->adap.dev)); return 0; } /* s3c24xx_i2c_remove * * called when device is removed from the bus */ static int s3c24xx_i2c_remove(struct platform_device *pdev) { struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev); pm_runtime_disable(&i2c->adap.dev); pm_runtime_disable(&pdev->dev); s3c24xx_i2c_deregister_cpufreq(i2c); i2c_del_adapter(&i2c->adap); if (pdev->dev.of_node && IS_ERR(i2c->pctrl)) s3c24xx_i2c_dt_gpio_free(i2c); return 0; } #ifdef CONFIG_PM_SLEEP static int s3c24xx_i2c_suspend_noirq(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev); i2c->suspended = 1; return 0; } static int s3c24xx_i2c_resume(struct device *dev) { struct platform_device *pdev = to_platform_device(dev); struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev); i2c->suspended = 0; clk_prepare_enable(i2c->clk); s3c24xx_i2c_init(i2c); clk_disable_unprepare(i2c->clk); return 0; } #endif #ifdef CONFIG_PM static const struct dev_pm_ops s3c24xx_i2c_dev_pm_ops = { #ifdef CONFIG_PM_SLEEP .suspend_noirq = s3c24xx_i2c_suspend_noirq, .resume = s3c24xx_i2c_resume, #endif }; #define S3C24XX_DEV_PM_OPS (&s3c24xx_i2c_dev_pm_ops) #else #define S3C24XX_DEV_PM_OPS NULL #endif /* device driver for platform bus bits */ static struct platform_driver s3c24xx_i2c_driver = { .probe = s3c24xx_i2c_probe, .remove = s3c24xx_i2c_remove, .id_table = s3c24xx_driver_ids, .driver = { .owner = THIS_MODULE, .name = "s3c-i2c", .pm = S3C24XX_DEV_PM_OPS, .of_match_table = of_match_ptr(s3c24xx_i2c_match), }, }; static int __init i2c_adap_s3c_init(void) { return platform_driver_register(&s3c24xx_i2c_driver); } subsys_initcall(i2c_adap_s3c_init); static void __exit i2c_adap_s3c_exit(void) { platform_driver_unregister(&s3c24xx_i2c_driver); } module_exit(i2c_adap_s3c_exit); MODULE_DESCRIPTION("S3C24XX I2C Bus driver"); MODULE_AUTHOR("Ben Dooks, "); MODULE_LICENSE("GPL");