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

[Heiko Schocher]

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 at 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 at 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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