samsung: i2c: Split the high-speed I2C code into a new driver

Now that driver model is used for I2C on all boards, we can split the
high-speed code into its own driver. There is virtually no common code,
and this significantly reduces confusion.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Heiko Schocher <hs@denx.de>

1 files changed, 561 insertions, 0 deletions

diff --git a/drivers/i2c/exynos_hs_i2c.c b/drivers/i2c/exynos_hs_i2c.c
new file mode 100644
index 0000000..9521aeb
--- /dev/null
+++ b/drivers/i2c/exynos_hs_i2c.c
@@ -0,0 +1,561 @@
+/*
+ * Copyright (c) 2016, Google Inc
+ *
+ * (C) Copyright 2002
+ * David Mueller, ELSOFT AG, d.mueller@elsoft.ch
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <i2c.h>
+#include <asm/arch/clk.h>
+#include <asm/arch/cpu.h>
+#include <asm/arch/pinmux.h>
+#include "s3c24x0_i2c.h"
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/* HSI2C-specific register description */
+
+/* I2C_CTL Register bits */
+#define HSI2C_FUNC_MODE_I2C		(1u << 0)
+#define HSI2C_MASTER			(1u << 3)
+#define HSI2C_RXCHON			(1u << 6)	/* Write/Send */
+#define HSI2C_TXCHON			(1u << 7)	/* Read/Receive */
+#define HSI2C_SW_RST			(1u << 31)
+
+/* I2C_FIFO_CTL Register bits */
+#define HSI2C_RXFIFO_EN			(1u << 0)
+#define HSI2C_TXFIFO_EN			(1u << 1)
+#define HSI2C_TXFIFO_TRIGGER_LEVEL	(0x20 << 16)
+#define HSI2C_RXFIFO_TRIGGER_LEVEL	(0x20 << 4)
+
+/* I2C_TRAILING_CTL Register bits */
+#define HSI2C_TRAILING_COUNT		(0xff)
+
+/* I2C_INT_EN Register bits */
+#define HSI2C_TX_UNDERRUN_EN		(1u << 2)
+#define HSI2C_TX_OVERRUN_EN		(1u << 3)
+#define HSI2C_RX_UNDERRUN_EN		(1u << 4)
+#define HSI2C_RX_OVERRUN_EN		(1u << 5)
+#define HSI2C_INT_TRAILING_EN		(1u << 6)
+#define HSI2C_INT_I2C_EN		(1u << 9)
+
+#define HSI2C_INT_ERROR_MASK	(HSI2C_TX_UNDERRUN_EN |\
+				 HSI2C_TX_OVERRUN_EN  |\
+				 HSI2C_RX_UNDERRUN_EN |\
+				 HSI2C_RX_OVERRUN_EN  |\
+				 HSI2C_INT_TRAILING_EN)
+
+/* I2C_CONF Register bits */
+#define HSI2C_AUTO_MODE			(1u << 31)
+#define HSI2C_10BIT_ADDR_MODE		(1u << 30)
+#define HSI2C_HS_MODE			(1u << 29)
+
+/* I2C_AUTO_CONF Register bits */
+#define HSI2C_READ_WRITE		(1u << 16)
+#define HSI2C_STOP_AFTER_TRANS		(1u << 17)
+#define HSI2C_MASTER_RUN		(1u << 31)
+
+/* I2C_TIMEOUT Register bits */
+#define HSI2C_TIMEOUT_EN		(1u << 31)
+
+/* I2C_TRANS_STATUS register bits */
+#define HSI2C_MASTER_BUSY		(1u << 17)
+#define HSI2C_SLAVE_BUSY		(1u << 16)
+#define HSI2C_TIMEOUT_AUTO		(1u << 4)
+#define HSI2C_NO_DEV			(1u << 3)
+#define HSI2C_NO_DEV_ACK		(1u << 2)
+#define HSI2C_TRANS_ABORT		(1u << 1)
+#define HSI2C_TRANS_SUCCESS		(1u << 0)
+#define HSI2C_TRANS_ERROR_MASK	(HSI2C_TIMEOUT_AUTO |\
+				 HSI2C_NO_DEV | HSI2C_NO_DEV_ACK |\
+				 HSI2C_TRANS_ABORT)
+#define HSI2C_TRANS_FINISHED_MASK (HSI2C_TRANS_ERROR_MASK | HSI2C_TRANS_SUCCESS)
+
+
+/* I2C_FIFO_STAT Register bits */
+#define HSI2C_RX_FIFO_EMPTY		(1u << 24)
+#define HSI2C_RX_FIFO_FULL		(1u << 23)
+#define HSI2C_TX_FIFO_EMPTY		(1u << 8)
+#define HSI2C_TX_FIFO_FULL		(1u << 7)
+#define HSI2C_RX_FIFO_LEVEL(x)		(((x) >> 16) & 0x7f)
+#define HSI2C_TX_FIFO_LEVEL(x)		((x) & 0x7f)
+
+#define HSI2C_SLV_ADDR_MAS(x)		((x & 0x3ff) << 10)
+
+#define HSI2C_TIMEOUT_US 10000 /* 10 ms, finer granularity */
+
+/*
+ * Wait for transfer completion.
+ *
+ * This function reads the interrupt status register waiting for the INT_I2C
+ * bit to be set, which indicates copletion of a transaction.
+ *
+ * @param i2c: pointer to the appropriate register bank
+ *
+ * @return: I2C_OK in case of successful completion, I2C_NOK_TIMEOUT in case
+ *          the status bits do not get set in time, or an approrpiate error
+ *          value in case of transfer errors.
+ */
+static int hsi2c_wait_for_trx(struct exynos5_hsi2c *i2c)
+{
+	int i = HSI2C_TIMEOUT_US;
+
+	while (i-- > 0) {
+		u32 int_status = readl(&i2c->usi_int_stat);
+
+		if (int_status & HSI2C_INT_I2C_EN) {
+			u32 trans_status = readl(&i2c->usi_trans_status);
+
+			/* Deassert pending interrupt. */
+			writel(int_status, &i2c->usi_int_stat);
+
+			if (trans_status & HSI2C_NO_DEV_ACK) {
+				debug("%s: no ACK from device\n", __func__);
+				return I2C_NACK;
+			}
+			if (trans_status & HSI2C_NO_DEV) {
+				debug("%s: no device\n", __func__);
+				return I2C_NOK;
+			}
+			if (trans_status & HSI2C_TRANS_ABORT) {
+				debug("%s: arbitration lost\n", __func__);
+				return I2C_NOK_LA;
+			}
+			if (trans_status & HSI2C_TIMEOUT_AUTO) {
+				debug("%s: device timed out\n", __func__);
+				return I2C_NOK_TOUT;
+			}
+			return I2C_OK;
+		}
+		udelay(1);
+	}
+	debug("%s: transaction timeout!\n", __func__);
+	return I2C_NOK_TOUT;
+}
+
+static int hsi2c_get_clk_details(struct s3c24x0_i2c_bus *i2c_bus)
+{
+	struct exynos5_hsi2c *hsregs = i2c_bus->hsregs;
+	ulong clkin;
+	unsigned int op_clk = i2c_bus->clock_frequency;
+	unsigned int i = 0, utemp0 = 0, utemp1 = 0;
+	unsigned int t_ftl_cycle;
+
+#if (defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5)
+	clkin = get_i2c_clk();
+#else
+	clkin = get_PCLK();
+#endif
+	/* FPCLK / FI2C =
+	 * (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + 8 + 2 * FLT_CYCLE
+	 * uTemp0 = (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2)
+	 * uTemp1 = (TSCLK_L + TSCLK_H + 2)
+	 * uTemp2 = TSCLK_L + TSCLK_H
+	 */
+	t_ftl_cycle = (readl(&hsregs->usi_conf) >> 16) & 0x7;
+	utemp0 = (clkin / op_clk) - 8 - 2 * t_ftl_cycle;
+
+	/* CLK_DIV max is 256 */
+	for (i = 0; i < 256; i++) {
+		utemp1 = utemp0 / (i + 1);
+		if ((utemp1 < 512) && (utemp1 > 4)) {
+			i2c_bus->clk_cycle = utemp1 - 2;
+			i2c_bus->clk_div = i;
+			return 0;
+		}
+	}
+	return -EINVAL;
+}
+
+static void hsi2c_ch_init(struct s3c24x0_i2c_bus *i2c_bus)
+{
+	struct exynos5_hsi2c *hsregs = i2c_bus->hsregs;
+	unsigned int t_sr_release;
+	unsigned int n_clkdiv;
+	unsigned int t_start_su, t_start_hd;
+	unsigned int t_stop_su;
+	unsigned int t_data_su, t_data_hd;
+	unsigned int t_scl_l, t_scl_h;
+	u32 i2c_timing_s1;
+	u32 i2c_timing_s2;
+	u32 i2c_timing_s3;
+	u32 i2c_timing_sla;
+
+	n_clkdiv = i2c_bus->clk_div;
+	t_scl_l = i2c_bus->clk_cycle / 2;
+	t_scl_h = i2c_bus->clk_cycle / 2;
+	t_start_su = t_scl_l;
+	t_start_hd = t_scl_l;
+	t_stop_su = t_scl_l;
+	t_data_su = t_scl_l / 2;
+	t_data_hd = t_scl_l / 2;
+	t_sr_release = i2c_bus->clk_cycle;
+
+	i2c_timing_s1 = t_start_su << 24 | t_start_hd << 16 | t_stop_su << 8;
+	i2c_timing_s2 = t_data_su << 24 | t_scl_l << 8 | t_scl_h << 0;
+	i2c_timing_s3 = n_clkdiv << 16 | t_sr_release << 0;
+	i2c_timing_sla = t_data_hd << 0;
+
+	writel(HSI2C_TRAILING_COUNT, &hsregs->usi_trailing_ctl);
+
+	/* Clear to enable Timeout */
+	clrsetbits_le32(&hsregs->usi_timeout, HSI2C_TIMEOUT_EN, 0);
+
+	/* set AUTO mode */
+	writel(readl(&hsregs->usi_conf) | HSI2C_AUTO_MODE, &hsregs->usi_conf);
+
+	/* Enable completion conditions' reporting. */
+	writel(HSI2C_INT_I2C_EN, &hsregs->usi_int_en);
+
+	/* Enable FIFOs */
+	writel(HSI2C_RXFIFO_EN | HSI2C_TXFIFO_EN, &hsregs->usi_fifo_ctl);
+
+	/* Currently operating in Fast speed mode. */
+	writel(i2c_timing_s1, &hsregs->usi_timing_fs1);
+	writel(i2c_timing_s2, &hsregs->usi_timing_fs2);
+	writel(i2c_timing_s3, &hsregs->usi_timing_fs3);
+	writel(i2c_timing_sla, &hsregs->usi_timing_sla);
+}
+
+/* SW reset for the high speed bus */
+static void exynos5_i2c_reset(struct s3c24x0_i2c_bus *i2c_bus)
+{
+	struct exynos5_hsi2c *i2c = i2c_bus->hsregs;
+	u32 i2c_ctl;
+
+	/* Set and clear the bit for reset */
+	i2c_ctl = readl(&i2c->usi_ctl);
+	i2c_ctl |= HSI2C_SW_RST;
+	writel(i2c_ctl, &i2c->usi_ctl);
+
+	i2c_ctl = readl(&i2c->usi_ctl);
+	i2c_ctl &= ~HSI2C_SW_RST;
+	writel(i2c_ctl, &i2c->usi_ctl);
+
+	/* Initialize the configure registers */
+	hsi2c_ch_init(i2c_bus);
+}
+
+/*
+ * Poll the appropriate bit of the fifo status register until the interface is
+ * ready to process the next byte or timeout expires.
+ *
+ * In addition to the FIFO status register this function also polls the
+ * interrupt status register to be able to detect unexpected transaction
+ * completion.
+ *
+ * When FIFO is ready to process the next byte, this function returns I2C_OK.
+ * If in course of polling the INT_I2C assertion is detected, the function
+ * returns I2C_NOK. If timeout happens before any of the above conditions is
+ * met - the function returns I2C_NOK_TOUT;
+
+ * @param i2c: pointer to the appropriate i2c register bank.
+ * @param rx_transfer: set to True if the receive transaction is in progress.
+ * @return: as described above.
+ */
+static unsigned hsi2c_poll_fifo(struct exynos5_hsi2c *i2c, bool rx_transfer)
+{
+	u32 fifo_bit = rx_transfer ? HSI2C_RX_FIFO_EMPTY : HSI2C_TX_FIFO_FULL;
+	int i = HSI2C_TIMEOUT_US;
+
+	while (readl(&i2c->usi_fifo_stat) & fifo_bit) {
+		if (readl(&i2c->usi_int_stat) & HSI2C_INT_I2C_EN) {
+			/*
+			 * There is a chance that assertion of
+			 * HSI2C_INT_I2C_EN and deassertion of
+			 * HSI2C_RX_FIFO_EMPTY happen simultaneously. Let's
+			 * give FIFO status priority and check it one more
+			 * time before reporting interrupt. The interrupt will
+			 * be reported next time this function is called.
+			 */
+			if (rx_transfer &&
+			    !(readl(&i2c->usi_fifo_stat) & fifo_bit))
+				break;
+			return I2C_NOK;
+		}
+		if (!i--) {
+			debug("%s: FIFO polling timeout!\n", __func__);
+			return I2C_NOK_TOUT;
+		}
+		udelay(1);
+	}
+	return I2C_OK;
+}
+
+/*
+ * Preapre hsi2c transaction, either read or write.
+ *
+ * Set up transfer as described in section 27.5.1.2 'I2C Channel Auto Mode' of
+ * the 5420 UM.
+ *
+ * @param i2c: pointer to the appropriate i2c register bank.
+ * @param chip: slave address on the i2c bus (with read/write bit exlcuded)
+ * @param len: number of bytes expected to be sent or received
+ * @param rx_transfer: set to true for receive transactions
+ * @param: issue_stop: set to true if i2c stop condition should be generated
+ *         after this transaction.
+ * @return: I2C_NOK_TOUT in case the bus remained busy for HSI2C_TIMEOUT_US,
+ *          I2C_OK otherwise.
+ */
+static int hsi2c_prepare_transaction(struct exynos5_hsi2c *i2c,
+				     u8 chip,
+				     u16 len,
+				     bool rx_transfer,
+				     bool issue_stop)
+{
+	u32 conf;
+
+	conf = len | HSI2C_MASTER_RUN;
+
+	if (issue_stop)
+		conf |= HSI2C_STOP_AFTER_TRANS;
+
+	/* Clear to enable Timeout */
+	writel(readl(&i2c->usi_timeout) & ~HSI2C_TIMEOUT_EN, &i2c->usi_timeout);
+
+	/* Set slave address */
+	writel(HSI2C_SLV_ADDR_MAS(chip), &i2c->i2c_addr);
+
+	if (rx_transfer) {
+		/* i2c master, read transaction */
+		writel((HSI2C_RXCHON | HSI2C_FUNC_MODE_I2C | HSI2C_MASTER),
+		       &i2c->usi_ctl);
+
+		/* read up to len bytes, stop after transaction is finished */
+		writel(conf | HSI2C_READ_WRITE, &i2c->usi_auto_conf);
+	} else {
+		/* i2c master, write transaction */
+		writel((HSI2C_TXCHON | HSI2C_FUNC_MODE_I2C | HSI2C_MASTER),
+		       &i2c->usi_ctl);
+
+		/* write up to len bytes, stop after transaction is finished */
+		writel(conf, &i2c->usi_auto_conf);
+	}
+
+	/* Reset all pending interrupt status bits we care about, if any */
+	writel(HSI2C_INT_I2C_EN, &i2c->usi_int_stat);
+
+	return I2C_OK;
+}
+
+/*
+ * Wait while i2c bus is settling down (mostly stop gets completed).
+ */
+static int hsi2c_wait_while_busy(struct exynos5_hsi2c *i2c)
+{
+	int i = HSI2C_TIMEOUT_US;
+
+	while (readl(&i2c->usi_trans_status) & HSI2C_MASTER_BUSY) {
+		if (!i--) {
+			debug("%s: bus busy\n", __func__);
+			return I2C_NOK_TOUT;
+		}
+		udelay(1);
+	}
+	return I2C_OK;
+}
+
+static int hsi2c_write(struct exynos5_hsi2c *i2c,
+		       unsigned char chip,
+		       unsigned char addr[],
+		       unsigned char alen,
+		       unsigned char data[],
+		       unsigned short len,
+		       bool issue_stop)
+{
+	int i, rv = 0;
+
+	if (!(len + alen)) {
+		/* Writes of zero length not supported in auto mode. */
+		debug("%s: zero length writes not supported\n", __func__);
+		return I2C_NOK;
+	}
+
+	rv = hsi2c_prepare_transaction
+		(i2c, chip, len + alen, false, issue_stop);
+	if (rv != I2C_OK)
+		return rv;
+
+	/* Move address, if any, and the data, if any, into the FIFO. */
+	for (i = 0; i < alen; i++) {
+		rv = hsi2c_poll_fifo(i2c, false);
+		if (rv != I2C_OK) {
+			debug("%s: address write failed\n", __func__);
+			goto write_error;
+		}
+		writel(addr[i], &i2c->usi_txdata);
+	}
+
+	for (i = 0; i < len; i++) {
+		rv = hsi2c_poll_fifo(i2c, false);
+		if (rv != I2C_OK) {
+			debug("%s: data write failed\n", __func__);
+			goto write_error;
+		}
+		writel(data[i], &i2c->usi_txdata);
+	}
+
+	rv = hsi2c_wait_for_trx(i2c);
+
+ write_error:
+	if (issue_stop) {
+		int tmp_ret = hsi2c_wait_while_busy(i2c);
+		if (rv == I2C_OK)
+			rv = tmp_ret;
+	}
+
+	writel(HSI2C_FUNC_MODE_I2C, &i2c->usi_ctl); /* done */
+	return rv;
+}
+
+static int hsi2c_read(struct exynos5_hsi2c *i2c,
+		      unsigned char chip,
+		      unsigned char addr[],
+		      unsigned char alen,
+		      unsigned char data[],
+		      unsigned short len)
+{
+	int i, rv, tmp_ret;
+	bool drop_data = false;
+
+	if (!len) {
+		/* Reads of zero length not supported in auto mode. */
+		debug("%s: zero length read adjusted\n", __func__);
+		drop_data = true;
+		len = 1;
+	}
+
+	if (alen) {
+		/* Internal register adress needs to be written first. */
+		rv = hsi2c_write(i2c, chip, addr, alen, NULL, 0, false);
+		if (rv != I2C_OK)
+			return rv;
+	}
+
+	rv = hsi2c_prepare_transaction(i2c, chip, len, true, true);
+
+	if (rv != I2C_OK)
+		return rv;
+
+	for (i = 0; i < len; i++) {
+		rv = hsi2c_poll_fifo(i2c, true);
+		if (rv != I2C_OK)
+			goto read_err;
+		if (drop_data)
+			continue;
+		data[i] = readl(&i2c->usi_rxdata);
+	}
+
+	rv = hsi2c_wait_for_trx(i2c);
+
+ read_err:
+	tmp_ret = hsi2c_wait_while_busy(i2c);
+	if (rv == I2C_OK)
+		rv = tmp_ret;
+
+	writel(HSI2C_FUNC_MODE_I2C, &i2c->usi_ctl); /* done */
+	return rv;
+}
+
+static int exynos_hs_i2c_xfer(struct udevice *dev, struct i2c_msg *msg,
+			      int nmsgs)
+{
+	struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
+	struct exynos5_hsi2c *hsregs = i2c_bus->hsregs;
+	int ret;
+
+	for (; nmsgs > 0; nmsgs--, msg++) {
+		if (msg->flags & I2C_M_RD) {
+			ret = hsi2c_read(hsregs, msg->addr, 0, 0, msg->buf,
+					 msg->len);
+		} else {
+			ret = hsi2c_write(hsregs, msg->addr, 0, 0, msg->buf,
+					  msg->len, true);
+		}
+		if (ret) {
+			exynos5_i2c_reset(i2c_bus);
+			return -EREMOTEIO;
+		}
+	}
+
+	return 0;
+}
+
+static int s3c24x0_i2c_set_bus_speed(struct udevice *dev, unsigned int speed)
+{
+	struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
+
+	i2c_bus->clock_frequency = speed;
+
+	if (hsi2c_get_clk_details(i2c_bus))
+		return -EFAULT;
+	hsi2c_ch_init(i2c_bus);
+
+	return 0;
+}
+
+static int s3c24x0_i2c_probe(struct udevice *dev, uint chip, uint chip_flags)
+{
+	struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
+	uchar buf[1];
+	int ret;
+
+	buf[0] = 0;
+
+	/*
+	 * What is needed is to send the chip address and verify that the
+	 * address was <ACK>ed (i.e. there was a chip at that address which
+	 * drove the data line low).
+	 */
+	ret = hsi2c_read(i2c_bus->hsregs, chip, 0, 0, buf, 1);
+
+	return ret != I2C_OK;
+}
+
+static int s3c_i2c_ofdata_to_platdata(struct udevice *dev)
+{
+	const void *blob = gd->fdt_blob;
+	struct s3c24x0_i2c_bus *i2c_bus = dev_get_priv(dev);
+	int node;
+
+	node = dev->of_offset;
+
+	i2c_bus->hsregs = (struct exynos5_hsi2c *)dev_get_addr(dev);
+
+	i2c_bus->id = pinmux_decode_periph_id(blob, node);
+
+	i2c_bus->clock_frequency = fdtdec_get_int(blob, node,
+						  "clock-frequency", 100000);
+	i2c_bus->node = node;
+	i2c_bus->bus_num = dev->seq;
+
+	exynos_pinmux_config(i2c_bus->id, PINMUX_FLAG_HS_MODE);
+
+	i2c_bus->active = true;
+
+	return 0;
+}
+
+static const struct dm_i2c_ops exynos_hs_i2c_ops = {
+	.xfer		= exynos_hs_i2c_xfer,
+	.probe_chip	= s3c24x0_i2c_probe,
+	.set_bus_speed	= s3c24x0_i2c_set_bus_speed,
+};
+
+static const struct udevice_id exynos_hs_i2c_ids[] = {
+	{ .compatible = "samsung,exynos5-hsi2c" },
+	{ }
+};
+
+U_BOOT_DRIVER(hs_i2c) = {
+	.name	= "i2c_s3c_hs",
+	.id	= UCLASS_I2C,
+	.of_match = exynos_hs_i2c_ids,
+	.ofdata_to_platdata = s3c_i2c_ofdata_to_platdata,
+	.priv_auto_alloc_size = sizeof(struct s3c24x0_i2c_bus),
+	.ops	= &exynos_hs_i2c_ops,
+};