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https://github.com/AsahiLinux/u-boot
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i2c: UniPhier: add driver for UniPhier i2c controller
This commit adds on-chip I2C driver used on some old Panasonic UniPhier SoCs. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com> Reviewed-by: Simon Glass <sjg@chromium.org> Acked-by: Simon Glass <sjg@chromium.org> Acked-by: Heiko Schocher <hs@denx.de>
This commit is contained in:
Masahiro Yamada
Simon Glass
parent
b6036bcd2a
commit
26f820f3f1
3 changed files with 248 additions and 0 deletions
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@ -4,3 +4,11 @@ config DM_I2C
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help
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If you want to use driver model for I2C drivers, say Y.
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To use legacy I2C drivers, say N.
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config SYS_I2C_UNIPHIER
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bool "UniPhier I2C driver"
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depends on ARCH_UNIPHIER && DM_I2C
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default y
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help
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Support for Panasonic UniPhier I2C controller driver. This I2C
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controller is used on PH1-LD4, PH1-sLD8 or older UniPhier SoCs.
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@ -31,4 +31,5 @@ obj-$(CONFIG_SYS_I2C_SANDBOX) += sandbox_i2c.o i2c-emul-uclass.o
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obj-$(CONFIG_SYS_I2C_SH) += sh_i2c.o
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obj-$(CONFIG_SYS_I2C_SOFT) += soft_i2c.o
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obj-$(CONFIG_SYS_I2C_TEGRA) += tegra_i2c.o
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obj-$(CONFIG_SYS_I2C_UNIPHIER) += i2c-uniphier.o
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obj-$(CONFIG_SYS_I2C_ZYNQ) += zynq_i2c.o
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239
drivers/i2c/i2c-uniphier.c
Normal file
239
drivers/i2c/i2c-uniphier.c
Normal file
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@ -0,0 +1,239 @@
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/*
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* Copyright (C) 2014 Panasonic Corporation
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* Author: Masahiro Yamada <yamada.m@jp.panasonic.com>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <linux/types.h>
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#include <asm/io.h>
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#include <asm/errno.h>
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#include <dm/device.h>
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#include <dm/root.h>
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#include <i2c.h>
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#include <fdtdec.h>
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DECLARE_GLOBAL_DATA_PTR;
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struct uniphier_i2c_regs {
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u32 dtrm; /* data transmission */
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#define I2C_DTRM_STA (1 << 10)
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#define I2C_DTRM_STO (1 << 9)
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#define I2C_DTRM_NACK (1 << 8)
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#define I2C_DTRM_RD (1 << 0)
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u32 drec; /* data reception */
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#define I2C_DREC_STS (1 << 12)
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#define I2C_DREC_LRB (1 << 11)
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#define I2C_DREC_LAB (1 << 9)
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u32 myad; /* slave address */
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u32 clk; /* clock frequency control */
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u32 brst; /* bus reset */
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#define I2C_BRST_FOEN (1 << 1)
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#define I2C_BRST_BRST (1 << 0)
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u32 hold; /* hold time control */
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u32 bsts; /* bus status monitor */
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u32 noise; /* noise filter control */
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u32 setup; /* setup time control */
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};
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#define IOBUS_FREQ 100000000
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struct uniphier_i2c_dev {
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struct uniphier_i2c_regs __iomem *regs; /* register base */
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unsigned long input_clk; /* master clock (Hz) */
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unsigned long wait_us; /* wait for every byte transfer (us) */
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};
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static int uniphier_i2c_probe(struct udevice *dev)
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{
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fdt_addr_t addr;
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fdt_size_t size;
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struct uniphier_i2c_dev *priv = dev_get_priv(dev);
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addr = fdtdec_get_addr_size(gd->fdt_blob, dev->of_offset, "reg", &size);
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priv->regs = map_sysmem(addr, size);
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if (!priv->regs)
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return -ENOMEM;
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priv->input_clk = IOBUS_FREQ;
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/* deassert reset */
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writel(0x3, &priv->regs->brst);
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return 0;
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}
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static int uniphier_i2c_remove(struct udevice *dev)
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{
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struct uniphier_i2c_dev *priv = dev_get_priv(dev);
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unmap_sysmem(priv->regs);
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return 0;
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}
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static int uniphier_i2c_child_pre_probe(struct udevice *dev)
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{
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struct dm_i2c_chip *i2c_chip = dev_get_parentdata(dev);
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if (dev->of_offset == -1)
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return 0;
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return i2c_chip_ofdata_to_platdata(gd->fdt_blob, dev->of_offset,
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i2c_chip);
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}
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static int send_and_recv_byte(struct uniphier_i2c_dev *dev, u32 dtrm)
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{
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writel(dtrm, &dev->regs->dtrm);
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/*
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* This controller only provides interruption to inform the completion
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* of each byte transfer. (No status register to poll it.)
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* Unfortunately, U-Boot does not have a good support of interrupt.
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* Wait for a while.
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*/
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udelay(dev->wait_us);
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return readl(&dev->regs->drec);
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}
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static int send_byte(struct uniphier_i2c_dev *dev, u32 dtrm, bool *stop)
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{
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int ret = 0;
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u32 drec;
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drec = send_and_recv_byte(dev, dtrm);
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if (drec & I2C_DREC_LAB) {
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debug("uniphier_i2c: bus arbitration failed\n");
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*stop = false;
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ret = -EREMOTEIO;
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}
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if (drec & I2C_DREC_LRB) {
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debug("uniphier_i2c: slave did not return ACK\n");
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ret = -EREMOTEIO;
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}
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return ret;
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}
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static int uniphier_i2c_transmit(struct uniphier_i2c_dev *dev, uint addr,
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uint len, const u8 *buf, bool *stop)
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{
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int ret;
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debug("%s: addr = %x, len = %d\n", __func__, addr, len);
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ret = send_byte(dev, I2C_DTRM_STA | I2C_DTRM_NACK | addr << 1, stop);
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if (ret < 0)
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goto fail;
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while (len--) {
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ret = send_byte(dev, I2C_DTRM_NACK | *buf++, stop);
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if (ret < 0)
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goto fail;
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}
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fail:
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if (*stop)
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writel(I2C_DTRM_STO | I2C_DTRM_NACK, &dev->regs->dtrm);
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return ret;
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}
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static int uniphier_i2c_receive(struct uniphier_i2c_dev *dev, uint addr,
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uint len, u8 *buf, bool *stop)
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{
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int ret;
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debug("%s: addr = %x, len = %d\n", __func__, addr, len);
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ret = send_byte(dev, I2C_DTRM_STA | I2C_DTRM_NACK |
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I2C_DTRM_RD | addr << 1, stop);
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if (ret < 0)
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goto fail;
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while (len--)
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*buf++ = send_and_recv_byte(dev, len ? 0 : I2C_DTRM_NACK);
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fail:
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if (*stop)
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writel(I2C_DTRM_STO | I2C_DTRM_NACK, &dev->regs->dtrm);
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return ret;
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}
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static int uniphier_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
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int nmsgs)
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{
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int ret = 0;
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struct uniphier_i2c_dev *dev = dev_get_priv(bus);
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bool stop;
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for (; nmsgs > 0; nmsgs--, msg++) {
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/* If next message is read, skip the stop condition */
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stop = nmsgs > 1 && msg[1].flags & I2C_M_RD ? false : true;
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if (msg->flags & I2C_M_RD)
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ret = uniphier_i2c_receive(dev, msg->addr, msg->len,
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msg->buf, &stop);
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else
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ret = uniphier_i2c_transmit(dev, msg->addr, msg->len,
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msg->buf, &stop);
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if (ret < 0)
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break;
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}
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return ret;
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}
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static int uniphier_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
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{
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struct uniphier_i2c_dev *priv = dev_get_priv(bus);
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/* max supported frequency is 400 kHz */
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if (speed > 400000)
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return -EINVAL;
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/* bus reset: make sure the bus is idle when change the frequency */
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writel(0x1, &priv->regs->brst);
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writel((priv->input_clk / speed / 2 << 16) | (priv->input_clk / speed),
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&priv->regs->clk);
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writel(0x3, &priv->regs->brst);
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/*
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* Theoretically, each byte can be transferred in
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* 1000000 * 9 / speed usec. For safety, wait more than double.
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*/
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priv->wait_us = 20000000 / speed;
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return 0;
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}
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static const struct dm_i2c_ops uniphier_i2c_ops = {
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.xfer = uniphier_i2c_xfer,
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.set_bus_speed = uniphier_i2c_set_bus_speed,
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};
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static const struct udevice_id uniphier_i2c_of_match[] = {
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{ .compatible = "panasonic,uniphier-i2c" },
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{},
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};
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U_BOOT_DRIVER(uniphier_i2c) = {
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.name = "uniphier-i2c",
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.id = UCLASS_I2C,
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.of_match = uniphier_i2c_of_match,
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.probe = uniphier_i2c_probe,
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.remove = uniphier_i2c_remove,
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.per_child_auto_alloc_size = sizeof(struct dm_i2c_chip),
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.child_pre_probe = uniphier_i2c_child_pre_probe,
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.priv_auto_alloc_size = sizeof(struct uniphier_i2c_dev),
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.ops = &uniphier_i2c_ops,
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};
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