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

Heiko Schocher
2016-01-04T07:15:00Z

Hello Moritz,

Am 28.12.2015 um 18:47 schrieb Moritz Fischer:
> 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

Hmm.. I di not see the remove of "drivers/i2c/zynq-i2c.c" as
you wrote it is a replacement for it ... Can you do this, and
of course adapt the boards which use this driver?

> 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);

We really need a clk framework ...

> +
> + /* 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,
> +};
>

Looks good to me, but I cannot test it ...

bye,
Heiko
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