diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/i2c/busses/i2c-s3c2410.c | 1272 |
1 files changed, 1272 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c new file mode 100644 index 000000000..8e3838c42 --- /dev/null +++ b/drivers/i2c/busses/i2c-s3c2410.c @@ -0,0 +1,1272 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* linux/drivers/i2c/busses/i2c-s3c2410.c + * + * Copyright (C) 2004,2005,2009 Simtec Electronics + * Ben Dooks <ben@simtec.co.uk> + * + * S3C2410 I2C Controller +*/ + +#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.h> +#include <linux/of_device.h> +#include <linux/gpio/consumer.h> +#include <linux/pinctrl/consumer.h> +#include <linux/mfd/syscon.h> +#include <linux/regmap.h> + +#include <asm/irq.h> + +#include <linux/platform_data/i2c-s3c2410.h> + +/* 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 + +/* Exynos5 Sysreg offset */ +#define EXYNOS5_SYS_I2C_CFG 0x0234 + +/* 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; + kernel_ulong_t quirks; + + 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; + struct gpio_desc *gpios[2]; + struct pinctrl *pctrl; +#if defined(CONFIG_ARM_S3C24XX_CPUFREQ) + struct notifier_block freq_transition; +#endif + struct regmap *sysreg; + unsigned int sys_i2c_cfg; +}; + +static const 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,exynos5-sata-phy-i2c", + .data = (void *)(QUIRK_S3C2440 | QUIRK_POLL | QUIRK_NO_GPIO) }, + {}, +}; +MODULE_DEVICE_TABLE(of, s3c24xx_i2c_match); +#endif + +/* + * Get controller type either from device tree or platform device variant. + */ +static inline kernel_ulong_t s3c24xx_get_device_quirks(struct platform_device *pdev) +{ + if (pdev->dev.of_node) + return (kernel_ulong_t)of_device_get_match_data(&pdev->dev); + + return platform_get_device_id(pdev)->driver_data; +} + +/* + * 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) { + unsigned long tmp = readl(i2c->regs + S3C2410_IICCON); + + if (!(tmp & S3C2410_IICCON_ACKEN)) { + /* + * Wait a bit for the bus to stabilize, + * delay estimated experimentally. + */ + usleep_range(100, 200); + return true; + } + if (tmp & 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 received\n"); + return false; +} + +/* + * 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); +} + +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 + */ + +/* + * 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); +} + +/* + * 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; +} + +/* + * 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; +} + +/* + * 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 + */ + fallthrough; + 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 + */ + dev_dbg(i2c->dev, + "missing START before write->read\n"); + s3c24xx_i2c_stop(i2c, -EINVAL); + break; + } + + 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; +} + +/* + * 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; +} + +/* + * Disable the bus so that we won't get any interrupts from now on, or try + * to drive any lines. This is the default state when we don't have + * anything to send/receive. + * + * If there is an event on the bus, or we have a pre-existing event at + * kernel boot time, we may not notice the event and the I2C controller + * will lock the bus with the I2C clock line low indefinitely. + */ +static inline void s3c24xx_i2c_disable_bus(struct s3c24xx_i2c *i2c) +{ + unsigned long tmp; + + /* Stop driving the I2C pins */ + tmp = readl(i2c->regs + S3C2410_IICSTAT); + tmp &= ~S3C2410_IICSTAT_TXRXEN; + writel(tmp, i2c->regs + S3C2410_IICSTAT); + + /* We don't expect any interrupts now, and don't want send acks */ + tmp = readl(i2c->regs + S3C2410_IICCON); + tmp &= ~(S3C2410_IICCON_IRQEN | S3C2410_IICCON_IRQPEND | + S3C2410_IICCON_ACKEN); + writel(tmp, i2c->regs + S3C2410_IICCON); +} + + +/* + * 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; +} + +/* + * 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"); +} + +/* + * this starts an i2c transfer + */ +static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c, + struct i2c_msg *msgs, int num) +{ + unsigned long timeout = 0; + int ret; + + 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) { + while ((i2c->msg_num != 0) && is_ack(i2c)) { + unsigned long stat = readl(i2c->regs + S3C2410_IICSTAT); + + 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"); + } + } else { + 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); + + s3c24xx_i2c_disable_bus(i2c); + + out: + i2c->state = STATE_IDLE; + + return ret; +} + +/* + * 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; + + ret = clk_enable(i2c->clk); + if (ret) + return ret; + + for (retry = 0; retry < adap->retries; retry++) { + + ret = s3c24xx_i2c_doxfer(i2c, msgs, num); + + if (ret != -EAGAIN) { + clk_disable(i2c->clk); + return ret; + } + + dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry); + + udelay(100); + } + + clk_disable(i2c->clk); + return -EREMOTEIO; +} + +/* declare our i2c functionality */ +static u32 s3c24xx_i2c_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL_ALL | 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, +}; + +/* + * 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); +} + +/* + * 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 ?: I2C_MAX_STANDARD_MODE_FREQ; + + 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_bus(&i2c->adap, I2C_LOCK_ROOT_ADAPTER); + ret = s3c24xx_i2c_clockrate(i2c, &got); + i2c_unlock_bus(&i2c->adap, I2C_LOCK_ROOT_ADAPTER); + + if (ret < 0) + dev_err(i2c->dev, "cannot find frequency (%d)\n", ret); + 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 i; + + if (i2c->quirks & QUIRK_NO_GPIO) + return 0; + + for (i = 0; i < 2; i++) { + i2c->gpios[i] = devm_gpiod_get_index(i2c->dev, NULL, + i, GPIOD_ASIS); + if (IS_ERR(i2c->gpios[i])) { + dev_err(i2c->dev, "i2c gpio invalid at index %d\n", i); + return -EINVAL; + } + } + return 0; +} + +#else +static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c) +{ + return 0; +} +#endif + +/* + * initialise the controller, set the IO lines and frequency + */ +static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c) +{ + 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(0, i2c->regs + S3C2410_IICCON); + writel(0, i2c->regs + S3C2410_IICSTAT); + + /* we need to work out the divisors for the clock... */ + + if (s3c24xx_i2c_clockrate(i2c, &freq) != 0) { + 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%02x\n", + readl(i2c->regs + S3C2410_IICCON)); + + return 0; +} + +#ifdef CONFIG_OF +/* + * 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; + int id; + + 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); + /* + * Exynos5's legacy i2c controller and new high speed i2c + * controller have muxed interrupt sources. By default the + * interrupts for 4-channel HS-I2C controller are enabled. + * If nodes for first four channels of legacy i2c controller + * are available then re-configure the interrupts via the + * system register. + */ + id = of_alias_get_id(np, "i2c"); + i2c->sysreg = syscon_regmap_lookup_by_phandle(np, + "samsung,sysreg-phandle"); + if (IS_ERR(i2c->sysreg)) + return; + + regmap_update_bits(i2c->sysreg, EXYNOS5_SYS_I2C_CFG, BIT(id), 0); +} +#else +static void +s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c) { } +#endif + +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) + return -ENOMEM; + + i2c->pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); + if (!i2c->pdata) + return -ENOMEM; + + i2c->quirks = s3c24xx_get_device_quirks(pdev); + i2c->sysreg = ERR_PTR(-ENOENT); + if (pdata) + memcpy(i2c->pdata, pdata, sizeof(*pdata)); + else + s3c24xx_i2c_parse_dt(pdev->dev.of_node, i2c); + + strscpy(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_DEPRECATED; + 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 */ + ret = clk_prepare_enable(i2c->clk); + if (ret) { + dev_err(&pdev->dev, "I2C clock enable failed\n"); + return ret; + } + + ret = s3c24xx_i2c_init(i2c); + clk_disable(i2c->clk); + if (ret != 0) { + dev_err(&pdev->dev, "I2C controller init failed\n"); + clk_unprepare(i2c->clk); + 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"); + clk_unprepare(i2c->clk); + 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); + clk_unprepare(i2c->clk); + return ret; + } + } + + ret = s3c24xx_i2c_register_cpufreq(i2c); + if (ret < 0) { + dev_err(&pdev->dev, "failed to register cpufreq notifier\n"); + clk_unprepare(i2c->clk); + 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; + + platform_set_drvdata(pdev, i2c); + + pm_runtime_enable(&pdev->dev); + + ret = i2c_add_numbered_adapter(&i2c->adap); + if (ret < 0) { + pm_runtime_disable(&pdev->dev); + s3c24xx_i2c_deregister_cpufreq(i2c); + clk_unprepare(i2c->clk); + return ret; + } + + dev_info(&pdev->dev, "%s: S3C I2C adapter\n", dev_name(&i2c->adap.dev)); + return 0; +} + +static int s3c24xx_i2c_remove(struct platform_device *pdev) +{ + struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev); + + clk_unprepare(i2c->clk); + + pm_runtime_disable(&pdev->dev); + + s3c24xx_i2c_deregister_cpufreq(i2c); + + i2c_del_adapter(&i2c->adap); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int s3c24xx_i2c_suspend_noirq(struct device *dev) +{ + struct s3c24xx_i2c *i2c = dev_get_drvdata(dev); + + i2c_mark_adapter_suspended(&i2c->adap); + + if (!IS_ERR(i2c->sysreg)) + regmap_read(i2c->sysreg, EXYNOS5_SYS_I2C_CFG, &i2c->sys_i2c_cfg); + + return 0; +} + +static int s3c24xx_i2c_resume_noirq(struct device *dev) +{ + struct s3c24xx_i2c *i2c = dev_get_drvdata(dev); + int ret; + + if (!IS_ERR(i2c->sysreg)) + regmap_write(i2c->sysreg, EXYNOS5_SYS_I2C_CFG, i2c->sys_i2c_cfg); + + ret = clk_enable(i2c->clk); + if (ret) + return ret; + s3c24xx_i2c_init(i2c); + clk_disable(i2c->clk); + i2c_mark_adapter_resumed(&i2c->adap); + + return 0; +} +#endif + +#ifdef CONFIG_PM +static const struct dev_pm_ops s3c24xx_i2c_dev_pm_ops = { + SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(s3c24xx_i2c_suspend_noirq, + s3c24xx_i2c_resume_noirq) +}; + +#define S3C24XX_DEV_PM_OPS (&s3c24xx_i2c_dev_pm_ops) +#else +#define S3C24XX_DEV_PM_OPS NULL +#endif + +static struct platform_driver s3c24xx_i2c_driver = { + .probe = s3c24xx_i2c_probe, + .remove = s3c24xx_i2c_remove, + .id_table = s3c24xx_driver_ids, + .driver = { + .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 <ben@simtec.co.uk>"); +MODULE_LICENSE("GPL"); |