diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-s3c2410.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-s3c2410.c | 1161 |
1 files changed, 1161 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c new file mode 100644 index 00000000..737f7218 --- /dev/null +++ b/drivers/i2c/busses/i2c-s3c2410.c @@ -0,0 +1,1161 @@ +/* linux/drivers/i2c/busses/i2c-s3c2410.c + * + * Copyright (C) 2004,2005,2009 Simtec Electronics + * Ben Dooks <ben@simtec.co.uk> + * + * 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 <linux/kernel.h> +#include <linux/module.h> + +#include <linux/i2c.h> +#include <linux/init.h> +#include <linux/time.h> +#include <linux/interrupt.h> +#include <linux/delay.h> +#include <linux/errno.h> +#include <linux/err.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/clk.h> +#include <linux/cpufreq.h> +#include <linux/slab.h> +#include <linux/io.h> +#include <linux/of_i2c.h> +#include <linux/of_gpio.h> + +#include <asm/irq.h> + +#include <plat/regs-iic.h> +#include <plat/iic.h> + +/* i2c controller state */ + +enum s3c24xx_i2c_state { + STATE_IDLE, + STATE_START, + STATE_READ, + STATE_WRITE, + STATE_STOP +}; + +enum s3c24xx_i2c_type { + TYPE_S3C2410, + TYPE_S3C2440, +}; + +struct s3c24xx_i2c { + spinlock_t lock; + wait_queue_head_t wait; + 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 resource *ioarea; + struct i2c_adapter adap; + + struct s3c2410_platform_i2c *pdata; + int gpios[2]; +#ifdef CONFIG_CPU_FREQ + struct notifier_block freq_transition; +#endif +}; + +/* default platform data removed, dev should always carry data. */ + +/* s3c24xx_i2c_is2440() + * + * return true is this is an s3c2440 +*/ + +static inline int s3c24xx_i2c_is2440(struct s3c24xx_i2c *i2c) +{ + struct platform_device *pdev = to_platform_device(i2c->dev); + enum s3c24xx_i2c_type type; + +#ifdef CONFIG_OF + if (i2c->dev->of_node) + return of_device_is_compatible(i2c->dev->of_node, + "samsung,s3c2440-i2c"); +#endif + + type = platform_get_device_id(pdev)->driver_data; + return type == TYPE_S3C2440; +} + +/* 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; + + 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); +} + + +/* 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 wether 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); +} + +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"); + + /* 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) +{ + 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 wether we are + * going to do any more read/write + */ + + byte = readb(i2c->regs + S3C2410_IICDS); + i2c->msg->buf[i2c->msg_ptr++] = 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_doxfer + * + * this starts an i2c transfer +*/ + +static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c, + struct i2c_msg *msgs, int num) +{ + unsigned long iicstat, timeout; + int spins = 20; + 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; + } + + spin_lock_irq(&i2c->lock); + + 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); + spin_unlock_irq(&i2c->lock); + + 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); + + /* ensure the stop has been through the bus */ + + dev_dbg(i2c->dev, "waiting for bus idle\n"); + + /* first, try busy waiting briefly */ + do { + cpu_relax(); + iicstat = readl(i2c->regs + S3C2410_IICSTAT); + } while ((iicstat & S3C2410_IICSTAT_START) && --spins); + + /* if that timed out sleep */ + if (!spins) { + msleep(1); + iicstat = readl(i2c->regs + S3C2410_IICSTAT); + } + + if (iicstat & S3C2410_IICSTAT_START) + dev_warn(i2c->dev, "timeout waiting for bus idle\n"); + + 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_enable(i2c->clk); + + for (retry = 0; retry < adap->retries; retry++) { + + ret = s3c24xx_i2c_doxfer(i2c, msgs, num); + + if (ret != -EAGAIN) { + clk_disable(i2c->clk); + pm_runtime_put_sync(&adap->dev); + return ret; + } + + dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry); + + udelay(100); + } + + clk_disable(i2c->clk); + pm_runtime_put_sync(&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_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; + + writel(iiccon, i2c->regs + S3C2410_IICCON); + + if (s3c24xx_i2c_is2440(i2c)) { + 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; +} + +#ifdef CONFIG_CPU_FREQ + +#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 long flags; + 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)) { + spin_lock_irqsave(&i2c->lock, flags); + ret = s3c24xx_i2c_clockrate(i2c, &got); + spin_unlock_irqrestore(&i2c->lock, flags); + + 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; + + 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; + } + + 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; + 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; + + /* inititalise the gpio */ + + if (pdata->cfg_gpio) + pdata->cfg_gpio(to_platform_device(i2c->dev)); + else + if (s3c24xx_i2c_parse_dt_gpio(i2c)) + return -EINVAL; + + /* 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 = pdev->dev.platform_data; + 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) { + ret = -ENOMEM; + goto err_noclk; + } + + 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; + + spin_lock_init(&i2c->lock); + init_waitqueue_head(&i2c->wait); + + /* find the clock and enable it */ + + i2c->dev = &pdev->dev; + i2c->clk = clk_get(&pdev->dev, "i2c"); + if (IS_ERR(i2c->clk)) { + dev_err(&pdev->dev, "cannot get clock\n"); + ret = -ENOENT; + goto err_noclk; + } + + dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk); + + clk_enable(i2c->clk); + + /* map the registers */ + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (res == NULL) { + dev_err(&pdev->dev, "cannot find IO resource\n"); + ret = -ENOENT; + goto err_clk; + } + + i2c->ioarea = request_mem_region(res->start, resource_size(res), + pdev->name); + + if (i2c->ioarea == NULL) { + dev_err(&pdev->dev, "cannot request IO\n"); + ret = -ENXIO; + goto err_clk; + } + + i2c->regs = ioremap(res->start, resource_size(res)); + + if (i2c->regs == NULL) { + dev_err(&pdev->dev, "cannot map IO\n"); + ret = -ENXIO; + goto err_ioarea; + } + + dev_dbg(&pdev->dev, "registers %p (%p, %p)\n", + i2c->regs, i2c->ioarea, res); + + /* setup info block for the i2c core */ + + i2c->adap.algo_data = i2c; + i2c->adap.dev.parent = &pdev->dev; + + /* initialise the i2c controller */ + + ret = s3c24xx_i2c_init(i2c); + if (ret != 0) + goto err_iomap; + + /* find the IRQ for this unit (note, this relies on the init call to + * ensure no current IRQs pending + */ + + i2c->irq = ret = platform_get_irq(pdev, 0); + if (ret <= 0) { + dev_err(&pdev->dev, "cannot find IRQ\n"); + goto err_iomap; + } + + ret = request_irq(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); + goto err_iomap; + } + + ret = s3c24xx_i2c_register_cpufreq(i2c); + if (ret < 0) { + dev_err(&pdev->dev, "failed to register cpufreq notifier\n"); + goto err_irq; + } + + /* 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"); + goto err_cpufreq; + } + + of_i2c_register_devices(&i2c->adap); + 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)); + clk_disable(i2c->clk); + return 0; + + err_cpufreq: + s3c24xx_i2c_deregister_cpufreq(i2c); + + err_irq: + free_irq(i2c->irq, i2c); + + err_iomap: + iounmap(i2c->regs); + + err_ioarea: + release_resource(i2c->ioarea); + kfree(i2c->ioarea); + + err_clk: + clk_disable(i2c->clk); + clk_put(i2c->clk); + + err_noclk: + return ret; +} + +/* 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); + free_irq(i2c->irq, i2c); + + clk_disable(i2c->clk); + clk_put(i2c->clk); + + iounmap(i2c->regs); + + release_resource(i2c->ioarea); + s3c24xx_i2c_dt_gpio_free(i2c); + kfree(i2c->ioarea); + + return 0; +} + +#ifdef CONFIG_PM +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_enable(i2c->clk); + s3c24xx_i2c_init(i2c); + clk_disable(i2c->clk); + + return 0; +} + +static const struct dev_pm_ops s3c24xx_i2c_dev_pm_ops = { + .suspend_noirq = s3c24xx_i2c_suspend_noirq, + .resume = s3c24xx_i2c_resume, +}; + +#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_device_id s3c24xx_driver_ids[] = { + { + .name = "s3c2410-i2c", + .driver_data = TYPE_S3C2410, + }, { + .name = "s3c2440-i2c", + .driver_data = TYPE_S3C2440, + }, { }, +}; +MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids); + +#ifdef CONFIG_OF +static const struct of_device_id s3c24xx_i2c_match[] = { + { .compatible = "samsung,s3c2410-i2c" }, + { .compatible = "samsung,s3c2440-i2c" }, + {}, +}; +MODULE_DEVICE_TABLE(of, s3c24xx_i2c_match); +#else +#define s3c24xx_i2c_match NULL +#endif + +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 = 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, <ben@simtec.co.uk>"); +MODULE_LICENSE("GPL"); |