[U-Boot] [RFC 2/2] dm: i2c: Add driver for Cadence I2C IP

Moritz Fischer
2015-12-28T17:47:11Z

This is a possible drop in replacement for drivers/i2c/zynq-i2c.c

Since this is cadence IP it has been renamed to cdns-i2c,
to make sense with the compatible string.

Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
---
drivers/i2c/Kconfig | 7 +
drivers/i2c/Makefile | 1 +
drivers/i2c/i2c-cdns.c | 339 +++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 347 insertions(+)
create mode 100644 drivers/i2c/i2c-cdns.c

diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
index 14adda2..c058dc5 100644
--- a/drivers/i2c/Kconfig
+++ b/drivers/i2c/Kconfig
@@ -58,6 +58,13 @@ config DM_I2C_GPIO
bindings are supported.
Binding info: doc/device-tree-bindings/i2c/i2c-gpio.txt

+config SYS_I2C_CADENCE
+ tristate "Cadence I2C Controller"
+ depends on DM_I2C && (ARCH_ZYNQ || ARM64)
+ help
+ Say yes here to select Cadence I2C Host Controller. This controller is
+ e.g. used by Xilinx Zynq.
+
config SYS_I2C_ROCKCHIP
bool "Rockchip I2C driver"
depends on DM_I2C
diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
index 811ad9b..35ad0d3 100644
--- a/drivers/i2c/Makefile
+++ b/drivers/i2c/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_PCA9564_I2C) += pca9564_i2c.o
obj-$(CONFIG_TSI108_I2C) += tsi108_i2c.o
obj-$(CONFIG_SH_SH7734_I2C) += sh_sh7734_i2c.o
obj-$(CONFIG_SYS_I2C) += i2c_core.o
+obj-$(CONFIG_SYS_I2C_CADENCE) += i2c-cdns.o
obj-$(CONFIG_SYS_I2C_DAVINCI) += davinci_i2c.o
obj-$(CONFIG_SYS_I2C_DW) += designware_i2c.o
obj-$(CONFIG_SYS_I2C_FSL) += fsl_i2c.o
diff --git a/drivers/i2c/i2c-cdns.c b/drivers/i2c/i2c-cdns.c
new file mode 100644
index 0000000..fab9609
--- /dev/null
+++ b/drivers/i2c/i2c-cdns.c
@@ -0,0 +1,339 @@
+/*
+ * Copyright (C) 2015 Moritz Fischer <moritz.fischer@ettus.com>
+ * IP from Cadence (ID T-CS-PE-0007-100, Version R1p10f2)
+ *
+ * This file is based on: drivers/i2c/zynq_i2c.c,
+ * with added driver-model support and code cleanup.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <linux/types.h>
+#include <linux/io.h>
+#include <asm/errno.h>
+#include <dm/device.h>
+#include <dm/root.h>
+#include <i2c.h>
+#include <fdtdec.h>
+#include <mapmem.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/* i2c register set */
+struct cdns_i2c_regs {
+ u32 control;
+ u32 status;
+ u32 address;
+ u32 data;
+ u32 interrupt_status;
+ u32 transfer_size;
+ u32 slave_mon_pause;
+ u32 time_out;
+ u32 interrupt_mask;
+ u32 interrupt_enable;
+ u32 interrupt_disable;
+};
+
+/* Control register fields */
+#define CDNS_I2C_CONTROL_RW 0x00000001
+#define CDNS_I2C_CONTROL_MS 0x00000002
+#define CDNS_I2C_CONTROL_NEA 0x00000004
+#define CDNS_I2C_CONTROL_ACKEN 0x00000008
+#define CDNS_I2C_CONTROL_HOLD 0x00000010
+#define CDNS_I2C_CONTROL_SLVMON 0x00000020
+#define CDNS_I2C_CONTROL_CLR_FIFO 0x00000040
+#define CDNS_I2C_CONTROL_DIV_B_SHIFT 8
+#define CDNS_I2C_CONTROL_DIV_B_MASK 0x00003F00
+#define CDNS_I2C_CONTROL_DIV_A_SHIFT 14
+#define CDNS_I2C_CONTROL_DIV_A_MASK 0x0000C000
+
+/* Status register values */
+#define CDNS_I2C_STATUS_RXDV 0x00000020
+#define CDNS_I2C_STATUS_TXDV 0x00000040
+#define CDNS_I2C_STATUS_RXOVF 0x00000080
+#define CDNS_I2C_STATUS_BA 0x00000100
+
+/* Interrupt register fields */
+#define CDNS_I2C_INTERRUPT_COMP 0x00000001
+#define CDNS_I2C_INTERRUPT_DATA 0x00000002
+#define CDNS_I2C_INTERRUPT_NACK 0x00000004
+#define CDNS_I2C_INTERRUPT_TO 0x00000008
+#define CDNS_I2C_INTERRUPT_SLVRDY 0x00000010
+#define CDNS_I2C_INTERRUPT_RXOVF 0x00000020
+#define CDNS_I2C_INTERRUPT_TXOVF 0x00000040
+#define CDNS_I2C_INTERRUPT_RXUNF 0x00000080
+#define CDNS_I2C_INTERRUPT_ARBLOST 0x00000200
+
+#define CDNS_I2C_FIFO_DEPTH 16
+#define CDNS_I2C_TRANSFER_SIZE_MAX 255 /* Controller transfer limit */
+
+#ifdef DEBUG
+static void cdns_i2c_debug_status(struct cdns_i2c_regs *cdns_i2c)
+{
+ int int_status;
+ int status;
+ int_status = readl(&cdns_i2c->interrupt_status);
+
+ status = readl(&cdns_i2c->status);
+ if (int_status || status) {
+ debug("Status: ");
+ if (int_status & CDNS_I2C_INTERRUPT_COMP)
+ debug("COMP ");
+ if (int_status & CDNS_I2C_INTERRUPT_DATA)
+ debug("DATA ");
+ if (int_status & CDNS_I2C_INTERRUPT_NACK)
+ debug("NACK ");
+ if (int_status & CDNS_I2C_INTERRUPT_TO)
+ debug("TO ");
+ if (int_status & CDNS_I2C_INTERRUPT_SLVRDY)
+ debug("SLVRDY ");
+ if (int_status & CDNS_I2C_INTERRUPT_RXOVF)
+ debug("RXOVF ");
+ if (int_status & CDNS_I2C_INTERRUPT_TXOVF)
+ debug("TXOVF ");
+ if (int_status & CDNS_I2C_INTERRUPT_RXUNF)
+ debug("RXUNF ");
+ if (int_status & CDNS_I2C_INTERRUPT_ARBLOST)
+ debug("ARBLOST ");
+ if (status & CDNS_I2C_STATUS_RXDV)
+ debug("RXDV ");
+ if (status & CDNS_I2C_STATUS_TXDV)
+ debug("TXDV ");
+ if (status & CDNS_I2C_STATUS_RXOVF)
+ debug("RXOVF ");
+ if (status & CDNS_I2C_STATUS_BA)
+ debug("BA ");
+ debug("TS%d ", readl(&cdns_i2c->transfer_size));
+ debug("\n");
+ }
+}
+#endif
+
+struct i2c_cdns_bus {
+ int id;
+ struct cdns_i2c_regs __iomem *regs; /* register base */
+};
+
+
+/** cdns_i2c_probe() - Probe method
+ * @dev: udevice pointer
+ *
+ * DM callback called when device is probed
+ */
+static int cdns_i2c_probe(struct udevice *dev)
+{
+ struct i2c_cdns_bus *bus = dev_get_priv(dev);
+ fdt_addr_t addr;
+ fdt_size_t size;
+
+ addr = fdtdec_get_addr_size(gd->fdt_blob, dev->of_offset, "reg", &size);
+ bus->regs = map_sysmem(addr, size);
+
+ if (!bus->regs)
+ return -ENOMEM;
+
+ /* TODO: Calculate dividers based on CPU_CLK_1X */
+ /* 111MHz / ( (3 * 17) * 22 ) = ~100KHz */
+ writel((16 << CDNS_I2C_CONTROL_DIV_B_SHIFT) |
+ (2 << CDNS_I2C_CONTROL_DIV_A_SHIFT), &bus->regs->control);
+
+ /* Enable master mode, ack, and 7-bit addressing */
+ setbits_le32(&bus->regs->control, CDNS_I2C_CONTROL_MS |
+ CDNS_I2C_CONTROL_ACKEN | CDNS_I2C_CONTROL_NEA);
+
+ debug("%s bus %d at %p\n", __func__, dev->seq, bus->regs);
+
+ return 0;
+}
+
+static int cdns_i2c_remove(struct udevice *dev)
+{
+ struct i2c_cdns_bus *bus = dev_get_priv(dev);
+
+ debug("%s bus %d at %p\n", __func__, dev->seq, bus->regs);
+
+ unmap_sysmem(bus->regs);
+
+ return 0;
+}
+
+/* Wait for an interrupt */
+static u32 cdns_i2c_wait(struct cdns_i2c_regs *cdns_i2c, u32 mask)
+{
+ int timeout, int_status;
+
+ for (timeout = 0; timeout < 100; timeout++) {
+ udelay(100);
+ int_status = readl(&cdns_i2c->interrupt_status);
+ if (int_status & mask)
+ break;
+ }
+
+ /* Clear interrupt status flags */
+ writel(int_status & mask, &cdns_i2c->interrupt_status);
+
+ return int_status & mask;
+}
+
+static int cdns_i2c_set_bus_speed(struct udevice *dev, unsigned int speed)
+{
+ if (speed != 100000) {
+ printf("%s, failed to set clock speed to %u\n", __func__,
+ speed);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/* Probe to see if a chip is present. */
+static int cdns_i2c_probe_chip(struct udevice *bus, uint chip_addr,
+ uint chip_flags)
+{
+ struct i2c_cdns_bus *i2c_bus = dev_get_priv(bus);
+ struct cdns_i2c_regs *regs = i2c_bus->regs;
+
+ /* Attempt to read a byte */
+ setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
+ CDNS_I2C_CONTROL_RW);
+ clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
+ writel(0xFF, &regs->interrupt_status);
+ writel(chip_addr, &regs->address);
+ writel(1, &regs->transfer_size);
+
+ return (cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP |
+ CDNS_I2C_INTERRUPT_NACK) &
+ CDNS_I2C_INTERRUPT_COMP) ? 0 : -ETIMEDOUT;
+}
+
+static int cdns_i2c_write_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
+ u32 len, bool next_is_read)
+{
+ u8 *cur_data = data;
+
+ struct cdns_i2c_regs *regs = i2c_bus->regs;
+
+ setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
+ CDNS_I2C_CONTROL_HOLD);
+
+ /* if next is a read, we need to clear HOLD, doesn't work */
+ if (next_is_read)
+ clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
+
+ clrbits_le32(&regs->control, CDNS_I2C_CONTROL_RW);
+
+ writel(0xFF, &regs->interrupt_status);
+ writel(addr, &regs->address);
+
+ while (len--) {
+ writel(*(cur_data++), &regs->data);
+ if (readl(&regs->transfer_size) == CDNS_I2C_FIFO_DEPTH) {
+ if (!cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP)) {
+ /* Release the bus */
+ clrbits_le32(&regs->control,
+ CDNS_I2C_CONTROL_HOLD);
+ return -ETIMEDOUT;
+ }
+ }
+ }
+
+ /* All done... release the bus */
+ clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
+ /* Wait for the address and data to be sent */
+ if (!cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP))
+ return -ETIMEDOUT;
+ return 0;
+}
+
+static int cdns_i2c_read_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data,
+ u32 len)
+{
+ u32 status;
+ u32 i = 0;
+ u8 *cur_data = data;
+
+ /* TODO: Fix this */
+ struct cdns_i2c_regs *regs = i2c_bus->regs;
+
+ /* Check the hardware can handle the requested bytes */
+ if ((len < 0) || (len > CDNS_I2C_TRANSFER_SIZE_MAX))
+ return -EINVAL;
+
+ setbits_le32(&regs->control, CDNS_I2C_CONTROL_CLR_FIFO |
+ CDNS_I2C_CONTROL_RW);
+
+ /* Start reading data */
+ writel(addr, &regs->address);
+ writel(len, &regs->transfer_size);
+
+ /* Wait for data */
+ do {
+ status = cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP |
+ CDNS_I2C_INTERRUPT_DATA);
+ if (!status) {
+ /* Release the bus */
+ clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
+ return -ETIMEDOUT;
+ }
+ debug("Read %d bytes\n",
+ len - readl(&regs->transfer_size));
+ for (; i < len - readl(&regs->transfer_size); i++)
+ *(cur_data++) = readl(&regs->data);
+ } while (readl(&regs->transfer_size) != 0);
+ /* All done... release the bus */
+ clrbits_le32(&regs->control, CDNS_I2C_CONTROL_HOLD);
+
+#ifdef DEBUG
+ cdns_i2c_debug_status(regs);
+#endif
+ return 0;
+}
+
+static int cdns_i2c_xfer(struct udevice *dev, struct i2c_msg *msg,
+ int nmsgs)
+{
+ struct i2c_cdns_bus *i2c_bus = dev_get_priv(dev);
+ int ret;
+
+ debug("i2c_xfer: %d messages\n", nmsgs);
+ for (; nmsgs > 0; nmsgs--, msg++) {
+ bool next_is_read = nmsgs > 1 && (msg[1].flags & I2C_M_RD);
+
+ debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len);
+ if (msg->flags & I2C_M_RD) {
+ ret = cdns_i2c_read_data(i2c_bus, msg->addr, msg->buf,
+ msg->len);
+ } else {
+ ret = cdns_i2c_write_data(i2c_bus, msg->addr, msg->buf,
+ msg->len, next_is_read);
+ }
+ if (ret) {
+ debug("i2c_write: error sending\n");
+ return -EREMOTEIO;
+ }
+ }
+
+ return 0;
+}
+
+static const struct dm_i2c_ops cdns_i2c_ops = {
+ .xfer = cdns_i2c_xfer,
+ .probe_chip = cdns_i2c_probe_chip,
+ .set_bus_speed = cdns_i2c_set_bus_speed,
+};
+
+static const struct udevice_id cdns_i2c_of_match[] = {
+ { .compatible = "cdns,i2c-r1p10" },
+ { /* end of table */ }
+};
+
+U_BOOT_DRIVER(cdns_i2c) = {
+ .name = "i2c-cdns",
+ .id = UCLASS_I2C,
+ .of_match = cdns_i2c_of_match,
+ .probe = cdns_i2c_probe,
+ .remove = cdns_i2c_remove,
+ .priv_auto_alloc_size = sizeof(struct i2c_cdns_bus),
+ .ops = &cdns_i2c_ops,
+};
--
2.4.3