--- /dev/null
+#include <common.h>
+#include <errno.h>
+#include <dm.h>
+#include <i2c.h>
+#include <log.h>
+#include <asm/arch/nexell.h>
+#include <asm/arch/reset.h>
+#include <asm/arch/clk.h>
+#include <asm/arch/nx_gpio.h>
+#include <linux/delay.h>
+
+#define I2C_WRITE 0
+#define I2C_READ 1
+
+#define I2CSTAT_MTM 0xC0 /* Master Transmit Mode */
+#define I2CSTAT_MRM 0x80 /* Master Receive Mode */
+#define I2CSTAT_BSY 0x20 /* Read: Bus Busy */
+#define I2CSTAT_SS 0x20 /* Write: START (1) / STOP (0) */
+#define I2CSTAT_RXTXEN 0x10 /* Rx/Tx enable */
+#define I2CSTAT_ABT 0x08 /* Arbitration bit */
+#define I2CSTAT_NACK 0x01 /* Nack bit */
+#define I2CCON_IRCLR 0x100 /* Interrupt Clear bit */
+#define I2CCON_ACKGEN 0x80 /* Acknowledge generation */
+#define I2CCON_TCP256 0x40 /* Tx-clock prescaler: 16 (0) / 256 (1) */
+#define I2CCON_IRENB 0x20 /* Interrupt Enable bit */
+#define I2CCON_IRPND 0x10 /* Interrupt pending bit */
+#define I2CCON_TCDMSK 0x0F /* I2C-bus transmit clock divider bit mask */
+
+#ifdef CONFIG_ARCH_S5P6818
+#define SDADLY_CLKSTEP 5 /* SDA delay: Reg. val. is multiple of 5 clks */
+#define SDADLY_MAX 3 /* SDA delay: Max. reg. value is 3 */
+#define I2CLC_FILTER 0x04 /* SDA filter on */
+#else
+#define STOPCON_CLR 0x01 /* Clock Line Release */
+#define STOPCON_DLR 0x02 /* Data Line Release */
+#define STOPCON_NAG 0x04 /* not-ackn. generation and data shift cont. */
+#endif
+
+#define I2C_TIMEOUT_MS 10 /* 10 ms */
+
+#define I2C_M_NOSTOP 0x100
+
+#define MAX_I2C_NUM 3
+
+#define DEFAULT_SPEED 100000 /* default I2C speed [Hz] */
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct nx_i2c_regs {
+ uint iiccon;
+ uint iicstat;
+ uint iicadd;
+ uint iicds;
+#ifdef CONFIG_ARCH_S5P6818
+ /* S5P6818: Offset 0x10 is Line Control Register (SDA-delay, Filter) */
+ uint iiclc;
+#else
+ /* S5P4418: Offset 0x10 is Stop Control Register */
+ uint iicstopcon;
+#endif
+};
+
+struct nx_i2c_bus {
+ uint bus_num;
+ struct nx_i2c_regs *regs;
+ uint speed;
+ uint target_speed;
+#ifdef CONFIG_ARCH_S5P6818
+ uint sda_delay;
+#else
+ /* setup time for Stop condition [us] */
+ uint tsu_stop;
+#endif
+};
+
+/* s5pxx18 i2c must be reset before enabled */
+static void i2c_reset(int ch)
+{
+ int rst_id = RESET_ID_I2C0 + ch;
+
+ nx_rstcon_setrst(rst_id, 0);
+ nx_rstcon_setrst(rst_id, 1);
+}
+
+static uint i2c_get_clkrate(struct nx_i2c_bus *bus)
+{
+ struct clk *clk;
+ int index = bus->bus_num;
+ char name[50] = {0, };
+
+ sprintf(name, "%s.%d", DEV_NAME_I2C, index);
+ clk = clk_get((const char *)name);
+ if (!clk)
+ return -1;
+
+ return clk_get_rate(clk);
+}
+
+static uint i2c_set_clk(struct nx_i2c_bus *bus, uint enb)
+{
+ struct clk *clk;
+ char name[50];
+
+ sprintf(name, "%s.%d", DEV_NAME_I2C, bus->bus_num);
+ clk = clk_get((const char *)name);
+ if (!clk) {
+ debug("%s(): clk_get(%s) error!\n",
+ __func__, (const char *)name);
+ return -EINVAL;
+ }
+
+ clk_disable(clk);
+ if (enb)
+ clk_enable(clk);
+
+ return 0;
+}
+
+#ifdef CONFIG_ARCH_S5P6818
+/* Set SDA line delay, not available at S5P4418 */
+static int nx_i2c_set_sda_delay(struct nx_i2c_bus *bus)
+{
+ struct nx_i2c_regs *i2c = bus->regs;
+ uint pclk = 0;
+ uint t_pclk = 0;
+ uint delay = 0;
+
+ /* get input clock of the I2C-controller */
+ pclk = i2c_get_clkrate(bus);
+
+ if (bus->sda_delay) {
+ /* t_pclk = period time of one pclk [ns] */
+ t_pclk = DIV_ROUND_UP(1000, pclk / 1000000);
+ /* delay = number of pclks required for sda_delay [ns] */
+ delay = DIV_ROUND_UP(bus->sda_delay, t_pclk);
+ /* delay = register value (step of 5 clocks) */
+ delay = DIV_ROUND_UP(delay, SDADLY_CLKSTEP);
+ /* max. possible register value = 3 */
+ if (delay > SDADLY_MAX) {
+ delay = SDADLY_MAX;
+ debug("%s(): sda-delay des.: %dns, sat. to max.: %dns (granularity: %dns)\n",
+ __func__, bus->sda_delay, t_pclk * delay * SDADLY_CLKSTEP,
+ t_pclk * SDADLY_CLKSTEP);
+ } else {
+ debug("%s(): sda-delay des.: %dns, act.: %dns (granularity: %dns)\n",
+ __func__, bus->sda_delay, t_pclk * delay * SDADLY_CLKSTEP,
+ t_pclk * SDADLY_CLKSTEP);
+ }
+
+ delay |= I2CLC_FILTER;
+ } else {
+ delay = 0;
+ debug("%s(): sda-delay = 0\n", __func__);
+ }
+
+ delay &= 0x7;
+ writel(delay, &i2c->iiclc);
+
+ return 0;
+}
+#endif
+
+static int nx_i2c_set_bus_speed(struct udevice *dev, uint speed)
+{
+ struct nx_i2c_bus *bus = dev_get_priv(dev);
+ struct nx_i2c_regs *i2c = bus->regs;
+ unsigned long pclk, pres = 16, div;
+
+ if (i2c_set_clk(bus, 1))
+ return -EINVAL;
+
+ /* get input clock of the I2C-controller */
+ pclk = i2c_get_clkrate(bus);
+
+ /* calculate prescaler and divisor values */
+ if ((pclk / pres / (16 + 1)) > speed)
+ /* prescaler value 16 is too less --> set to 256 */
+ pres = 256;
+
+ div = 0;
+ /* actual divider = div + 1 */
+ while ((pclk / pres / (div + 1)) > speed)
+ div++;
+
+ if (div > 0xF) {
+ debug("%s(): pres==%ld, div==0x%lx is saturated to 0xF !)\n",
+ __func__, pres, div);
+ div = 0xF;
+ } else {
+ debug("%s(): pres==%ld, div==0x%lx)\n", __func__, pres, div);
+ }
+
+ /* set Tx-clock divisor and prescaler values */
+ writel((div & I2CCON_TCDMSK) | ((pres == 256) ? I2CCON_TCP256 : 0),
+ &i2c->iiccon);
+
+ /* init to SLAVE REVEIVE and set slaveaddr */
+ writel(0, &i2c->iicstat);
+ writel(0x00, &i2c->iicadd);
+
+ /* program Master Transmit (and implicit STOP) */
+ writel(I2CSTAT_MTM | I2CSTAT_RXTXEN, &i2c->iicstat);
+
+ /* calculate actual I2C speed [Hz] */
+ bus->speed = pclk / ((div + 1) * pres);
+ debug("%s(): speed des.: %dHz, act.: %dHz\n",
+ __func__, speed, bus->speed);
+
+#ifdef CONFIG_ARCH_S5P6818
+ nx_i2c_set_sda_delay(bus);
+#else
+ /* setup time for Stop condition [us], min. 4us @ 100kHz I2C-clock */
+ bus->tsu_stop = DIV_ROUND_UP(400, bus->speed / 1000);
+#endif
+
+ if (i2c_set_clk(bus, 0))
+ return -EINVAL;
+ return 0;
+}
+
+static void i2c_process_node(struct udevice *dev)
+{
+ struct nx_i2c_bus *bus = dev_get_priv(dev);
+
+ bus->target_speed = dev_read_s32_default(dev, "clock-frequency",
+ DEFAULT_SPEED);
+#ifdef CONFIG_ARCH_S5P6818
+ bus->sda_delay = dev_read_s32_default(dev, "i2c-sda-delay-ns", 0);
+#endif
+}
+
+static int nx_i2c_probe(struct udevice *dev)
+{
+ struct nx_i2c_bus *bus = dev_get_priv(dev);
+ fdt_addr_t addr;
+
+ /* get regs = i2c base address */
+ addr = devfdt_get_addr(dev);
+ if (addr == FDT_ADDR_T_NONE)
+ return -EINVAL;
+ bus->regs = (struct nx_i2c_regs *)addr;
+
+ bus->bus_num = dev->seq;
+
+ /* i2c node parsing */
+ i2c_process_node(dev);
+ if (!bus->target_speed)
+ return -ENODEV;
+
+ /* reset */
+ i2c_reset(bus->bus_num);
+
+ return 0;
+}
+
+/* i2c bus busy check */
+static int i2c_is_busy(struct nx_i2c_regs *i2c)
+{
+ ulong start_time;
+
+ start_time = get_timer(0);
+ while (readl(&i2c->iicstat) & I2CSTAT_BSY) {
+ if (get_timer(start_time) > I2C_TIMEOUT_MS) {
+ debug("Timeout\n");
+ return -EBUSY;
+ }
+ }
+ return 0;
+}
+
+/* irq enable/disable functions */
+static void i2c_enable_irq(struct nx_i2c_regs *i2c)
+{
+ unsigned int reg;
+
+ reg = readl(&i2c->iiccon);
+ reg |= I2CCON_IRENB;
+ writel(reg, &i2c->iiccon);
+}
+
+/* irq clear function */
+static void i2c_clear_irq(struct nx_i2c_regs *i2c)
+{
+ unsigned int reg;
+
+ reg = readl(&i2c->iiccon);
+ /* reset interrupt pending flag */
+ reg &= ~(I2CCON_IRPND);
+ /*
+ * Interrupt must also be cleared!
+ * Otherwise linux boot may hang after:
+ * [ 0.436000] NetLabel: unlabeled traffic allowed by default
+ * Next would be:
+ * [ 0.442000] clocksource: Switched to clocksource source timer
+ */
+ reg |= I2CCON_IRCLR;
+ writel(reg, &i2c->iiccon);
+}
+
+/* ack enable functions */
+static void i2c_enable_ack(struct nx_i2c_regs *i2c)
+{
+ unsigned int reg;
+
+ reg = readl(&i2c->iiccon);
+ reg |= I2CCON_ACKGEN;
+ writel(reg, &i2c->iiccon);
+}
+
+static void i2c_send_stop(struct nx_i2c_bus *bus)
+{
+ struct nx_i2c_regs *i2c = bus->regs;
+
+ if (IS_ENABLED(CONFIG_ARCH_S5P6818)) {
+ unsigned int reg;
+
+ reg = readl(&i2c->iicstat);
+ reg |= I2CSTAT_MRM | I2CSTAT_RXTXEN;
+ reg &= (~I2CSTAT_SS);
+
+ writel(reg, &i2c->iicstat);
+ i2c_clear_irq(i2c);
+ } else { /* S5P4418 */
+ writel(STOPCON_NAG, &i2c->iicstopcon);
+
+ i2c_clear_irq(i2c);
+
+ /*
+ * Clock Line Release --> SDC changes from Low to High and
+ * SDA from High to Low
+ */
+ writel(STOPCON_CLR, &i2c->iicstopcon);
+
+ /* Hold SDA Low (Setup Time for Stop condition) */
+ udelay(bus->tsu_stop);
+
+ i2c_clear_irq(i2c);
+
+ /* Master Receive Mode Stop --> SDA becomes High */
+ writel(I2CSTAT_MRM, &i2c->iicstat);
+ }
+}
+
+static int wait_for_xfer(struct nx_i2c_regs *i2c)
+{
+ unsigned long start_time = get_timer(0);
+
+ do {
+ if (readl(&i2c->iiccon) & I2CCON_IRPND)
+ /* return -EREMOTEIO if not Acknowledged, otherwise 0 */
+ return (readl(&i2c->iicstat) & I2CSTAT_NACK) ?
+ -EREMOTEIO : 0;
+ } while (get_timer(start_time) < I2C_TIMEOUT_MS);
+
+ return -ETIMEDOUT;
+}
+
+static int i2c_transfer(struct nx_i2c_regs *i2c,
+ uchar cmd_type,
+ uchar chip_addr,
+ uchar addr[],
+ uchar addr_len,
+ uchar data[],
+ unsigned short data_len,
+ uint seq)
+{
+ uint status;
+ int i = 0, result;
+
+ /* Note: data_len = 0 is supported for "probe_chip" */
+
+ i2c_enable_irq(i2c);
+ i2c_enable_ack(i2c);
+
+ /* Get the slave chip address going */
+ /* Enable Rx/Tx */
+ writel(I2CSTAT_RXTXEN, &i2c->iicstat);
+
+ writel(chip_addr, &i2c->iicds);
+ status = I2CSTAT_RXTXEN | I2CSTAT_SS;
+ if (cmd_type == I2C_WRITE || (addr && addr_len))
+ status |= I2CSTAT_MTM;
+ else
+ status |= I2CSTAT_MRM;
+
+ writel(status, &i2c->iicstat);
+ if (seq)
+ i2c_clear_irq(i2c);
+
+ /* Wait for chip address to transmit. */
+ result = wait_for_xfer(i2c);
+ if (result) {
+ debug("%s: transmitting chip address failed\n", __func__);
+ goto bailout;
+ }
+
+ /* If register address needs to be transmitted - do it now. */
+ if (addr && addr_len) { /* register addr */
+ while ((i < addr_len) && !result) {
+ writel(addr[i++], &i2c->iicds);
+ i2c_clear_irq(i2c);
+ result = wait_for_xfer(i2c);
+ }
+
+ i = 0;
+ if (result) {
+ debug("%s: transmitting register address failed\n",
+ __func__);
+ goto bailout;
+ }
+ }
+
+ switch (cmd_type) {
+ case I2C_WRITE:
+ while ((i < data_len) && !result) {
+ writel(data[i++], &i2c->iicds);
+ i2c_clear_irq(i2c);
+ result = wait_for_xfer(i2c);
+ }
+ break;
+ case I2C_READ:
+ if (addr && addr_len) {
+ /*
+ * Register address has been sent, now send slave chip
+ * address again to start the actual read transaction.
+ */
+ writel(chip_addr, &i2c->iicds);
+
+ /* Generate a re-START. */
+ writel(I2CSTAT_MRM | I2CSTAT_RXTXEN |
+ I2CSTAT_SS, &i2c->iicstat);
+ i2c_clear_irq(i2c);
+ result = wait_for_xfer(i2c);
+ if (result) {
+ debug("%s: I2C_READ: sending chip addr. failed\n",
+ __func__);
+ goto bailout;
+ }
+ }
+
+ while ((i < data_len) && !result) {
+ /* disable ACK for final READ */
+ if (i == data_len - 1)
+ clrbits_le32(&i2c->iiccon, I2CCON_ACKGEN);
+
+ i2c_clear_irq(i2c);
+ result = wait_for_xfer(i2c);
+ data[i++] = readb(&i2c->iicds);
+ }
+
+ if (result == -EREMOTEIO)
+ /* Not Acknowledged --> normal terminated read. */
+ result = 0;
+ else if (result == -ETIMEDOUT)
+ debug("%s: I2C_READ: time out\n", __func__);
+ else
+ debug("%s: I2C_READ: read not terminated with NACK\n",
+ __func__);
+ break;
+
+ default:
+ debug("%s: bad call\n", __func__);
+ result = -EINVAL;
+ break;
+ }
+
+bailout:
+ return result;
+}
+
+static int nx_i2c_read(struct udevice *dev, uchar chip_addr, uint addr,
+ uint alen, uchar *buffer, uint len, uint seq)
+{
+ struct nx_i2c_bus *i2c;
+ uchar xaddr[4];
+ int ret;
+
+ i2c = dev_get_priv(dev);
+ if (!i2c)
+ return -EFAULT;
+
+ if (alen > 4) {
+ debug("I2C read: addr len %d not supported\n", alen);
+ return -EADDRNOTAVAIL;
+ }
+
+ if (alen > 0)
+ xaddr[0] = (addr >> 24) & 0xFF;
+
+ if (alen > 0) {
+ xaddr[0] = (addr >> 24) & 0xFF;
+ xaddr[1] = (addr >> 16) & 0xFF;
+ xaddr[2] = (addr >> 8) & 0xFF;
+ xaddr[3] = addr & 0xFF;
+ }
+
+ ret = i2c_transfer(i2c->regs, I2C_READ, chip_addr << 1,
+ &xaddr[4 - alen], alen, buffer, len, seq);
+
+ if (ret) {
+ debug("I2C read failed %d\n", ret);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int nx_i2c_write(struct udevice *dev, uchar chip_addr, uint addr,
+ uint alen, uchar *buffer, uint len, uint seq)
+{
+ struct nx_i2c_bus *i2c;
+ uchar xaddr[4];
+ int ret;
+
+ i2c = dev_get_priv(dev);
+ if (!i2c)
+ return -EFAULT;
+
+ if (alen > 4) {
+ debug("I2C write: addr len %d not supported\n", alen);
+ return -EINVAL;
+ }
+
+ if (alen > 0) {
+ xaddr[0] = (addr >> 24) & 0xFF;
+ xaddr[1] = (addr >> 16) & 0xFF;
+ xaddr[2] = (addr >> 8) & 0xFF;
+ xaddr[3] = addr & 0xFF;
+ }
+
+ ret = i2c_transfer(i2c->regs, I2C_WRITE, chip_addr << 1,
+ &xaddr[4 - alen], alen, buffer, len, seq);
+ if (ret) {
+ debug("I2C write failed %d\n", ret);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int nx_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs)
+{
+ struct nx_i2c_bus *bus = dev_get_priv(dev);
+ struct nx_i2c_regs *i2c = bus->regs;
+ int ret;
+ int i;
+
+ /* The power loss by the clock, only during on/off. */
+ ret = i2c_set_clk(bus, 1);
+
+ if (!ret)
+ /* Bus State(Busy) check */
+ ret = i2c_is_busy(i2c);
+ if (!ret) {
+ for (i = 0; i < nmsgs; msg++, i++) {
+ if (msg->flags & I2C_M_RD) {
+ ret = nx_i2c_read(dev, msg->addr, 0, 0,
+ msg->buf, msg->len, i);
+ } else {
+ ret = nx_i2c_write(dev, msg->addr, 0, 0,
+ msg->buf, msg->len, i);
+ }
+
+ if (ret) {
+ debug("i2c_xfer: error sending\n");
+ ret = -EREMOTEIO;
+ }
+ }
+
+ i2c_send_stop(bus);
+ if (i2c_set_clk(bus, 0))
+ ret = -EINVAL;
+ }
+
+ return ret;
+};
+
+static int nx_i2c_probe_chip(struct udevice *dev, u32 chip_addr,
+ u32 chip_flags)
+{
+ int ret;
+ struct nx_i2c_bus *bus = dev_get_priv(dev);
+
+ ret = i2c_set_clk(bus, 1);
+
+ if (!ret) {
+ /*
+ * Send Chip Address only
+ * --> I2C transfer with data length and address length = 0.
+ * If there is a Slave, i2c_transfer() returns 0 (acknowledge
+ * transfer).
+ * I2C_WRITE must be used in order Master Transmit Mode is
+ * selected. Otherwise (in Master Receive Mode, I2C_READ)
+ * sending the stop condition below is not working (SDA does
+ * not transit to High).
+ */
+ ret = i2c_transfer(bus->regs, I2C_WRITE, (uchar)chip_addr << 1,
+ NULL, 0, NULL, 0, 0);
+
+ i2c_send_stop(bus);
+ if (i2c_set_clk(bus, 0))
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+
+static const struct dm_i2c_ops nx_i2c_ops = {
+ .xfer = nx_i2c_xfer,
+ .probe_chip = nx_i2c_probe_chip,
+ .set_bus_speed = nx_i2c_set_bus_speed,
+};
+
+static const struct udevice_id nx_i2c_ids[] = {
+ { .compatible = "nexell,s5pxx18-i2c" },
+ { }
+};
+
+U_BOOT_DRIVER(i2c_nexell) = {
+ .name = "i2c_nexell",
+ .id = UCLASS_I2C,
+ .of_match = nx_i2c_ids,
+ .probe = nx_i2c_probe,
+ .priv_auto_alloc_size = sizeof(struct nx_i2c_bus),
+ .ops = &nx_i2c_ops,
+};
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