--- /dev/null
+/*
+ * Copyright (C) 2014 Panasonic Corporation
+ * Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <linux/types.h>
+#include <asm/io.h>
+#include <asm/errno.h>
+#include <dm/device.h>
+#include <dm/root.h>
+#include <i2c.h>
+#include <fdtdec.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct uniphier_fi2c_regs {
+ u32 cr; /* control register */
+#define I2C_CR_MST (1 << 3) /* master mode */
+#define I2C_CR_STA (1 << 2) /* start condition */
+#define I2C_CR_STO (1 << 1) /* stop condition */
+#define I2C_CR_NACK (1 << 0) /* not ACK */
+ u32 dttx; /* send FIFO (write-only) */
+#define dtrx dttx /* receive FIFO (read-only) */
+#define I2C_DTTX_CMD (1 << 8) /* send command (slave addr) */
+#define I2C_DTTX_RD (1 << 0) /* read */
+ u32 __reserved; /* no register at offset 0x08 */
+ u32 slad; /* slave address */
+ u32 cyc; /* clock cycle control */
+ u32 lctl; /* clock low period control */
+ u32 ssut; /* restart/stop setup time control */
+ u32 dsut; /* data setup time control */
+ u32 intr; /* interrupt status */
+ u32 ie; /* interrupt enable */
+ u32 ic; /* interrupt clear */
+#define I2C_INT_TE (1 << 9) /* TX FIFO empty */
+#define I2C_INT_RB (1 << 4) /* received specified bytes */
+#define I2C_INT_NA (1 << 2) /* no answer */
+#define I2C_INT_AL (1 << 1) /* arbitration lost */
+ u32 sr; /* status register */
+#define I2C_SR_DB (1 << 12) /* device busy */
+#define I2C_SR_BB (1 << 8) /* bus busy */
+#define I2C_SR_RFF (1 << 3) /* Rx FIFO full */
+#define I2C_SR_RNE (1 << 2) /* Rx FIFO not empty */
+#define I2C_SR_TNF (1 << 1) /* Tx FIFO not full */
+#define I2C_SR_TFE (1 << 0) /* Tx FIFO empty */
+ u32 __reserved2; /* no register at offset 0x30 */
+ u32 rst; /* reset control */
+#define I2C_RST_TBRST (1 << 2) /* clear Tx FIFO */
+#define I2C_RST_RBRST (1 << 1) /* clear Rx FIFO */
+#define I2C_RST_RST (1 << 0) /* forcible bus reset */
+ u32 bm; /* bus monitor */
+ u32 noise; /* noise filter control */
+ u32 tbc; /* Tx byte count setting */
+ u32 rbc; /* Rx byte count setting */
+ u32 tbcm; /* Tx byte count monitor */
+ u32 rbcm; /* Rx byte count monitor */
+ u32 brst; /* bus reset */
+#define I2C_BRST_FOEN (1 << 1) /* normal operation */
+#define I2C_BRST_RSCLO (1 << 0) /* release SCL low fixing */
+};
+
+#define FIOCLK 50000000
+
+struct uniphier_fi2c_dev {
+ struct uniphier_fi2c_regs __iomem *regs; /* register base */
+ unsigned long fioclk; /* internal operation clock */
+ unsigned long timeout; /* time out (us) */
+};
+
+static int poll_status(u32 __iomem *reg, u32 flag)
+{
+ int wait = 1000000; /* 1 sec is long enough */
+
+ while (readl(reg) & flag) {
+ if (wait-- < 0)
+ return -EREMOTEIO;
+ udelay(1);
+ }
+
+ return 0;
+}
+
+static int reset_bus(struct uniphier_fi2c_regs __iomem *regs)
+{
+ int ret;
+
+ /* bus forcible reset */
+ writel(I2C_RST_RST, ®s->rst);
+ ret = poll_status(®s->rst, I2C_RST_RST);
+ if (ret < 0)
+ debug("error: fail to reset I2C controller\n");
+
+ return ret;
+}
+
+static int check_device_busy(struct uniphier_fi2c_regs __iomem *regs)
+{
+ int ret;
+
+ ret = poll_status(®s->sr, I2C_SR_DB);
+ if (ret < 0) {
+ debug("error: device busy too long. reset...\n");
+ ret = reset_bus(regs);
+ }
+
+ return ret;
+}
+
+static int uniphier_fi2c_probe(struct udevice *dev)
+{
+ fdt_addr_t addr;
+ fdt_size_t size;
+ struct uniphier_fi2c_dev *priv = dev_get_priv(dev);
+ int ret;
+
+ addr = fdtdec_get_addr_size(gd->fdt_blob, dev->of_offset, "reg",
+ &size);
+
+ priv->regs = map_sysmem(addr, size);
+
+ if (!priv->regs)
+ return -ENOMEM;
+
+ priv->fioclk = FIOCLK;
+
+ /* bus forcible reset */
+ ret = reset_bus(priv->regs);
+ if (ret < 0)
+ return ret;
+
+ writel(I2C_BRST_FOEN | I2C_BRST_RSCLO, &priv->regs->brst);
+
+ return 0;
+}
+
+static int uniphier_fi2c_remove(struct udevice *dev)
+{
+ struct uniphier_fi2c_dev *priv = dev_get_priv(dev);
+
+ unmap_sysmem(priv->regs);
+
+ return 0;
+}
+
+static int uniphier_fi2c_child_pre_probe(struct udevice *dev)
+{
+ struct dm_i2c_chip *i2c_chip = dev_get_parentdata(dev);
+
+ if (dev->of_offset == -1)
+ return 0;
+ return i2c_chip_ofdata_to_platdata(gd->fdt_blob, dev->of_offset,
+ i2c_chip);
+}
+
+static int wait_for_irq(struct uniphier_fi2c_dev *dev, u32 flags,
+ bool *stop)
+{
+ u32 irq;
+ unsigned long wait = dev->timeout;
+ int ret = -EREMOTEIO;
+
+ do {
+ udelay(1);
+ irq = readl(&dev->regs->intr);
+ } while (!(irq & flags) && wait--);
+
+ if (wait < 0) {
+ debug("error: time out\n");
+ return ret;
+ }
+
+ if (irq & I2C_INT_AL) {
+ debug("error: arbitration lost\n");
+ *stop = false;
+ return ret;
+ }
+
+ if (irq & I2C_INT_NA) {
+ debug("error: no answer\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int issue_stop(struct uniphier_fi2c_dev *dev, int old_ret)
+{
+ int ret;
+
+ debug("stop condition\n");
+ writel(I2C_CR_MST | I2C_CR_STO, &dev->regs->cr);
+
+ ret = poll_status(&dev->regs->sr, I2C_SR_DB);
+ if (ret < 0)
+ debug("error: device busy after operation\n");
+
+ return old_ret ? old_ret : ret;
+}
+
+static int uniphier_fi2c_transmit(struct uniphier_fi2c_dev *dev, uint addr,
+ uint len, const u8 *buf, bool *stop)
+{
+ int ret;
+ const u32 irq_flags = I2C_INT_TE | I2C_INT_NA | I2C_INT_AL;
+ struct uniphier_fi2c_regs __iomem *regs = dev->regs;
+
+ debug("%s: addr = %x, len = %d\n", __func__, addr, len);
+
+ writel(I2C_DTTX_CMD | addr << 1, ®s->dttx);
+
+ writel(irq_flags, ®s->ie);
+ writel(irq_flags, ®s->ic);
+
+ debug("start condition\n");
+ writel(I2C_CR_MST | I2C_CR_STA, ®s->cr);
+
+ ret = wait_for_irq(dev, irq_flags, stop);
+ if (ret < 0)
+ goto error;
+
+ while (len--) {
+ debug("sending %x\n", *buf);
+ writel(*buf++, ®s->dttx);
+
+ writel(irq_flags, ®s->ic);
+
+ ret = wait_for_irq(dev, irq_flags, stop);
+ if (ret < 0)
+ goto error;
+ }
+
+error:
+ writel(irq_flags, ®s->ic);
+
+ if (*stop)
+ ret = issue_stop(dev, ret);
+
+ return ret;
+}
+
+static int uniphier_fi2c_receive(struct uniphier_fi2c_dev *dev, uint addr,
+ uint len, u8 *buf, bool *stop)
+{
+ int ret = 0;
+ const u32 irq_flags = I2C_INT_RB | I2C_INT_NA | I2C_INT_AL;
+ struct uniphier_fi2c_regs __iomem *regs = dev->regs;
+
+ debug("%s: addr = %x, len = %d\n", __func__, addr, len);
+
+ /*
+ * In case 'len == 0', only the slave address should be sent
+ * for probing, which is covered by the transmit function.
+ */
+ if (len == 0)
+ return uniphier_fi2c_transmit(dev, addr, len, buf, stop);
+
+ writel(I2C_DTTX_CMD | I2C_DTTX_RD | addr << 1, ®s->dttx);
+
+ writel(0, ®s->rbc);
+ writel(irq_flags, ®s->ie);
+ writel(irq_flags, ®s->ic);
+
+ debug("start condition\n");
+ writel(I2C_CR_MST | I2C_CR_STA | (len == 1 ? I2C_CR_NACK : 0),
+ ®s->cr);
+
+ while (len--) {
+ ret = wait_for_irq(dev, irq_flags, stop);
+ if (ret < 0)
+ goto error;
+
+ *buf++ = readl(®s->dtrx);
+ debug("received %x\n", *(buf - 1));
+
+ if (len == 1)
+ writel(I2C_CR_MST | I2C_CR_NACK, ®s->cr);
+
+ writel(irq_flags, ®s->ic);
+ }
+
+error:
+ writel(irq_flags, ®s->ic);
+
+ if (*stop)
+ ret = issue_stop(dev, ret);
+
+ return ret;
+}
+
+static int uniphier_fi2c_xfer(struct udevice *bus, struct i2c_msg *msg,
+ int nmsgs)
+{
+ int ret;
+ struct uniphier_fi2c_dev *dev = dev_get_priv(bus);
+ bool stop;
+
+ ret = check_device_busy(dev->regs);
+ if (ret < 0)
+ return ret;
+
+ for (; nmsgs > 0; nmsgs--, msg++) {
+ /* If next message is read, skip the stop condition */
+ stop = nmsgs > 1 && msg[1].flags & I2C_M_RD ? false : true;
+
+ if (msg->flags & I2C_M_RD)
+ ret = uniphier_fi2c_receive(dev, msg->addr, msg->len,
+ msg->buf, &stop);
+ else
+ ret = uniphier_fi2c_transmit(dev, msg->addr, msg->len,
+ msg->buf, &stop);
+
+ if (ret < 0)
+ break;
+ }
+
+ return ret;
+}
+
+static int uniphier_fi2c_set_bus_speed(struct udevice *bus, unsigned int speed)
+{
+ int ret;
+ unsigned int clk_count;
+ struct uniphier_fi2c_dev *dev = dev_get_priv(bus);
+ struct uniphier_fi2c_regs __iomem *regs = dev->regs;
+
+ /* max supported frequency is 400 kHz */
+ if (speed > 400000)
+ return -EINVAL;
+
+ ret = check_device_busy(dev->regs);
+ if (ret < 0)
+ return ret;
+
+ /* make sure the bus is idle when changing the frequency */
+ writel(I2C_BRST_RSCLO, ®s->brst);
+
+ clk_count = dev->fioclk / speed;
+
+ writel(clk_count, ®s->cyc);
+ writel(clk_count / 2, ®s->lctl);
+ writel(clk_count / 2, ®s->ssut);
+ writel(clk_count / 16, ®s->dsut);
+
+ writel(I2C_BRST_FOEN | I2C_BRST_RSCLO, ®s->brst);
+
+ /*
+ * Theoretically, each byte can be transferred in
+ * 1000000 * 9 / speed usec.
+ * This time out value is long enough.
+ */
+ dev->timeout = 100000000L / speed;
+
+ return 0;
+}
+
+static const struct dm_i2c_ops uniphier_fi2c_ops = {
+ .xfer = uniphier_fi2c_xfer,
+ .set_bus_speed = uniphier_fi2c_set_bus_speed,
+};
+
+static const struct udevice_id uniphier_fi2c_of_match[] = {
+ { .compatible = "panasonic,uniphier-fi2c" },
+ {},
+};
+
+U_BOOT_DRIVER(uniphier_fi2c) = {
+ .name = "uniphier-fi2c",
+ .id = UCLASS_I2C,
+ .of_match = uniphier_fi2c_of_match,
+ .probe = uniphier_fi2c_probe,
+ .remove = uniphier_fi2c_remove,
+ .per_child_auto_alloc_size = sizeof(struct dm_i2c_chip),
+ .child_pre_probe = uniphier_fi2c_child_pre_probe,
+ .priv_auto_alloc_size = sizeof(struct uniphier_fi2c_dev),
+ .ops = &uniphier_fi2c_ops,
+};
projects / u-boot.git / commitdiff