--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * drivers/i2c/rcar_i2c.c
+ *
+ * Copyright (C) 2018 Marek Vasut <marek.vasut@gmail.com>
+ *
+ * Clock configuration based on Linux i2c-rcar.c:
+ * Copyright (C) 2014-15 Wolfram Sang <wsa@sang-engineering.com>
+ * Copyright (C) 2011-2015 Renesas Electronics Corporation
+ * Copyright (C) 2012-14 Renesas Solutions Corp.
+ * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <i2c.h>
+#include <asm/io.h>
+#include <wait_bit.h>
+
+#define RCAR_I2C_ICSCR 0x00
+#define RCAR_I2C_ICMCR 0x04
+#define RCAR_I2C_ICMCR_MDBS BIT(7)
+#define RCAR_I2C_ICMCR_FSCL BIT(6)
+#define RCAR_I2C_ICMCR_FSDA BIT(5)
+#define RCAR_I2C_ICMCR_OBPC BIT(4)
+#define RCAR_I2C_ICMCR_MIE BIT(3)
+#define RCAR_I2C_ICMCR_TSBE BIT(2)
+#define RCAR_I2C_ICMCR_FSB BIT(1)
+#define RCAR_I2C_ICMCR_ESG BIT(0)
+#define RCAR_I2C_ICSSR 0x08
+#define RCAR_I2C_ICMSR 0x0c
+#define RCAR_I2C_ICMSR_MASK 0x7f
+#define RCAR_I2C_ICMSR_MNR BIT(6)
+#define RCAR_I2C_ICMSR_MAL BIT(5)
+#define RCAR_I2C_ICMSR_MST BIT(4)
+#define RCAR_I2C_ICMSR_MDE BIT(3)
+#define RCAR_I2C_ICMSR_MDT BIT(2)
+#define RCAR_I2C_ICMSR_MDR BIT(1)
+#define RCAR_I2C_ICMSR_MAT BIT(0)
+#define RCAR_I2C_ICSIER 0x10
+#define RCAR_I2C_ICMIER 0x14
+#define RCAR_I2C_ICCCR 0x18
+#define RCAR_I2C_ICCCR_SCGD_OFF 3
+#define RCAR_I2C_ICSAR 0x1c
+#define RCAR_I2C_ICMAR 0x20
+#define RCAR_I2C_ICRXD_ICTXD 0x24
+
+struct rcar_i2c_priv {
+ void __iomem *base;
+ struct clk clk;
+ u32 intdelay;
+ u32 icccr;
+};
+
+static int rcar_i2c_finish(struct udevice *dev)
+{
+ struct rcar_i2c_priv *priv = dev_get_priv(dev);
+ int ret;
+
+ ret = wait_for_bit_le32(priv->base + RCAR_I2C_ICMSR, RCAR_I2C_ICMSR_MST,
+ true, 10, true);
+
+ writel(0, priv->base + RCAR_I2C_ICSSR);
+ writel(0, priv->base + RCAR_I2C_ICMSR);
+ writel(0, priv->base + RCAR_I2C_ICMCR);
+
+ return ret;
+}
+
+static void rcar_i2c_recover(struct udevice *dev)
+{
+ struct rcar_i2c_priv *priv = dev_get_priv(dev);
+ u32 mcr = RCAR_I2C_ICMCR_MDBS | RCAR_I2C_ICMCR_OBPC;
+ u32 mcra = mcr | RCAR_I2C_ICMCR_FSDA;
+ int i;
+
+ /* Send 9 SCL pulses */
+ for (i = 0; i < 9; i++) {
+ writel(mcra | RCAR_I2C_ICMCR_FSCL, priv->base + RCAR_I2C_ICMCR);
+ udelay(5);
+ writel(mcra, priv->base + RCAR_I2C_ICMCR);
+ udelay(5);
+ }
+
+ /* Send stop condition */
+ udelay(5);
+ writel(mcra, priv->base + RCAR_I2C_ICMCR);
+ udelay(5);
+ writel(mcr, priv->base + RCAR_I2C_ICMCR);
+ udelay(5);
+ writel(mcr | RCAR_I2C_ICMCR_FSCL, priv->base + RCAR_I2C_ICMCR);
+ udelay(5);
+ writel(mcra | RCAR_I2C_ICMCR_FSCL, priv->base + RCAR_I2C_ICMCR);
+ udelay(5);
+}
+
+static int rcar_i2c_set_addr(struct udevice *dev, u8 chip, u8 read)
+{
+ struct rcar_i2c_priv *priv = dev_get_priv(dev);
+ u32 mask = RCAR_I2C_ICMSR_MAT |
+ (read ? RCAR_I2C_ICMSR_MDR : RCAR_I2C_ICMSR_MDE);
+ u32 val;
+ int ret;
+
+ writel(0, priv->base + RCAR_I2C_ICMIER);
+ writel(RCAR_I2C_ICMCR_MDBS, priv->base + RCAR_I2C_ICMCR);
+ writel(0, priv->base + RCAR_I2C_ICMSR);
+ writel(priv->icccr, priv->base + RCAR_I2C_ICCCR);
+
+ ret = wait_for_bit_le32(priv->base + RCAR_I2C_ICMCR,
+ RCAR_I2C_ICMCR_FSDA, false, 2, true);
+ if (ret) {
+ rcar_i2c_recover(dev);
+ val = readl(priv->base + RCAR_I2C_ICMSR);
+ if (val & RCAR_I2C_ICMCR_FSDA) {
+ dev_err(dev, "Bus busy, aborting\n");
+ return ret;
+ }
+ }
+
+ writel((chip << 1) | read, priv->base + RCAR_I2C_ICMAR);
+ writel(0, priv->base + RCAR_I2C_ICMSR);
+ writel(RCAR_I2C_ICMCR_MDBS | RCAR_I2C_ICMCR_MIE | RCAR_I2C_ICMCR_ESG,
+ priv->base + RCAR_I2C_ICMCR);
+
+ ret = wait_for_bit_le32(priv->base + RCAR_I2C_ICMSR, mask,
+ true, 100, true);
+ if (ret)
+ return ret;
+
+ /* Check NAK */
+ if (readl(priv->base + RCAR_I2C_ICMSR) & RCAR_I2C_ICMSR_MNR)
+ return -EREMOTEIO;
+
+ return 0;
+}
+
+static int rcar_i2c_read_common(struct udevice *dev, struct i2c_msg *msg)
+{
+ struct rcar_i2c_priv *priv = dev_get_priv(dev);
+ u32 icmcr = RCAR_I2C_ICMCR_MDBS | RCAR_I2C_ICMCR_MIE;
+ int i, ret = -EREMOTEIO;
+
+ ret = rcar_i2c_set_addr(dev, msg->addr, 1);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < msg->len; i++) {
+ if (msg->len - 1 == i)
+ icmcr |= RCAR_I2C_ICMCR_FSB;
+
+ writel(icmcr, priv->base + RCAR_I2C_ICMCR);
+ writel(~RCAR_I2C_ICMSR_MDR, priv->base + RCAR_I2C_ICMSR);
+
+ ret = wait_for_bit_le32(priv->base + RCAR_I2C_ICMSR,
+ RCAR_I2C_ICMSR_MDR, true, 100, true);
+ if (ret)
+ return ret;
+
+ msg->buf[i] = readl(priv->base + RCAR_I2C_ICRXD_ICTXD) & 0xff;
+ }
+
+ writel(~RCAR_I2C_ICMSR_MDR, priv->base + RCAR_I2C_ICMSR);
+
+ return rcar_i2c_finish(dev);
+}
+
+static int rcar_i2c_write_common(struct udevice *dev, struct i2c_msg *msg)
+{
+ struct rcar_i2c_priv *priv = dev_get_priv(dev);
+ u32 icmcr = RCAR_I2C_ICMCR_MDBS | RCAR_I2C_ICMCR_MIE;
+ int i, ret = -EREMOTEIO;
+
+ ret = rcar_i2c_set_addr(dev, msg->addr, 0);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < msg->len; i++) {
+ writel(msg->buf[i], priv->base + RCAR_I2C_ICRXD_ICTXD);
+ writel(icmcr, priv->base + RCAR_I2C_ICMCR);
+ writel(~RCAR_I2C_ICMSR_MDE, priv->base + RCAR_I2C_ICMSR);
+
+ ret = wait_for_bit_le32(priv->base + RCAR_I2C_ICMSR,
+ RCAR_I2C_ICMSR_MDE, true, 100, true);
+ if (ret)
+ return ret;
+ }
+
+ writel(~RCAR_I2C_ICMSR_MDE, priv->base + RCAR_I2C_ICMSR);
+ icmcr |= RCAR_I2C_ICMCR_FSB;
+ writel(icmcr, priv->base + RCAR_I2C_ICMCR);
+
+ return rcar_i2c_finish(dev);
+}
+
+static int rcar_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs)
+{
+ int ret;
+
+ for (; nmsgs > 0; nmsgs--, msg++) {
+ if (msg->flags & I2C_M_RD)
+ ret = rcar_i2c_read_common(dev, msg);
+ else
+ ret = rcar_i2c_write_common(dev, msg);
+
+ if (ret)
+ return -EREMOTEIO;
+ }
+
+ return ret;
+}
+
+static int rcar_i2c_probe_chip(struct udevice *dev, uint addr, uint flags)
+{
+ struct rcar_i2c_priv *priv = dev_get_priv(dev);
+ int ret;
+
+ /* Ignore address 0, slave address */
+ if (addr == 0)
+ return -EINVAL;
+
+ ret = rcar_i2c_set_addr(dev, addr, 1);
+ writel(0, priv->base + RCAR_I2C_ICMSR);
+ return ret;
+}
+
+static int rcar_i2c_set_speed(struct udevice *dev, uint bus_freq_hz)
+{
+ struct rcar_i2c_priv *priv = dev_get_priv(dev);
+ u32 scgd, cdf, round, ick, sum, scl;
+ unsigned long rate;
+
+ /*
+ * calculate SCL clock
+ * see
+ * ICCCR
+ *
+ * ick = clkp / (1 + CDF)
+ * SCL = ick / (20 + SCGD * 8 + F[(ticf + tr + intd) * ick])
+ *
+ * ick : I2C internal clock < 20 MHz
+ * ticf : I2C SCL falling time
+ * tr : I2C SCL rising time
+ * intd : LSI internal delay
+ * clkp : peripheral_clk
+ * F[] : integer up-valuation
+ */
+ rate = clk_get_rate(&priv->clk);
+ cdf = rate / 20000000;
+ if (cdf >= 8) {
+ dev_err(dev, "Input clock %lu too high\n", rate);
+ return -EIO;
+ }
+ ick = rate / (cdf + 1);
+
+ /*
+ * it is impossible to calculate large scale
+ * number on u32. separate it
+ *
+ * F[(ticf + tr + intd) * ick] with sum = (ticf + tr + intd)
+ * = F[sum * ick / 1000000000]
+ * = F[(ick / 1000000) * sum / 1000]
+ */
+ sum = 35 + 200 + priv->intdelay;
+ round = (ick + 500000) / 1000000 * sum;
+ round = (round + 500) / 1000;
+
+ /*
+ * SCL = ick / (20 + SCGD * 8 + F[(ticf + tr + intd) * ick])
+ *
+ * Calculation result (= SCL) should be less than
+ * bus_speed for hardware safety
+ *
+ * We could use something along the lines of
+ * div = ick / (bus_speed + 1) + 1;
+ * scgd = (div - 20 - round + 7) / 8;
+ * scl = ick / (20 + (scgd * 8) + round);
+ * (not fully verified) but that would get pretty involved
+ */
+ for (scgd = 0; scgd < 0x40; scgd++) {
+ scl = ick / (20 + (scgd * 8) + round);
+ if (scl <= bus_freq_hz)
+ goto scgd_find;
+ }
+ dev_err(dev, "it is impossible to calculate best SCL\n");
+ return -EIO;
+
+scgd_find:
+ dev_dbg(dev, "clk %d/%d(%lu), round %u, CDF:0x%x, SCGD: 0x%x\n",
+ scl, bus_freq_hz, clk_get_rate(&priv->clk), round, cdf, scgd);
+
+ priv->icccr = (scgd << RCAR_I2C_ICCCR_SCGD_OFF) | cdf;
+ writel(priv->icccr, priv->base + RCAR_I2C_ICCCR);
+
+ return 0;
+}
+
+static int rcar_i2c_probe(struct udevice *dev)
+{
+ struct rcar_i2c_priv *priv = dev_get_priv(dev);
+ int ret;
+
+ priv->base = dev_read_addr_ptr(dev);
+ priv->intdelay = dev_read_u32_default(dev,
+ "i2c-scl-internal-delay-ns", 5);
+
+ ret = clk_get_by_index(dev, 0, &priv->clk);
+ if (ret)
+ return ret;
+
+ ret = clk_enable(&priv->clk);
+ if (ret)
+ return ret;
+
+ /* reset slave mode */
+ writel(0, priv->base + RCAR_I2C_ICSIER);
+ writel(0, priv->base + RCAR_I2C_ICSAR);
+ writel(0, priv->base + RCAR_I2C_ICSCR);
+ writel(0, priv->base + RCAR_I2C_ICSSR);
+
+ /* reset master mode */
+ writel(0, priv->base + RCAR_I2C_ICMIER);
+ writel(0, priv->base + RCAR_I2C_ICMCR);
+ writel(0, priv->base + RCAR_I2C_ICMSR);
+ writel(0, priv->base + RCAR_I2C_ICMAR);
+
+ ret = rcar_i2c_set_speed(dev, 100000);
+ if (ret)
+ clk_disable(&priv->clk);
+
+ return ret;
+}
+
+static const struct dm_i2c_ops rcar_i2c_ops = {
+ .xfer = rcar_i2c_xfer,
+ .probe_chip = rcar_i2c_probe_chip,
+ .set_bus_speed = rcar_i2c_set_speed,
+};
+
+static const struct udevice_id rcar_i2c_ids[] = {
+ { .compatible = "renesas,rcar-gen2-i2c" },
+ { }
+};
+
+U_BOOT_DRIVER(i2c_rcar) = {
+ .name = "i2c_rcar",
+ .id = UCLASS_I2C,
+ .of_match = rcar_i2c_ids,
+ .probe = rcar_i2c_probe,
+ .priv_auto_alloc_size = sizeof(struct rcar_i2c_priv),
+ .ops = &rcar_i2c_ops,
+};
projects / u-boot / commitdiff