diff options
Diffstat (limited to 'drivers/i2c/i2c-uniphier-f.c')
| -rw-r--r-- | drivers/i2c/i2c-uniphier-f.c | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-uniphier-f.c b/drivers/i2c/i2c-uniphier-f.c new file mode 100644 index 0000000..6707edd --- /dev/null +++ b/drivers/i2c/i2c-uniphier-f.c @@ -0,0 +1,367 @@ +/* + * 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 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, + .priv_auto_alloc_size = sizeof(struct uniphier_fi2c_dev), + .ops = &uniphier_fi2c_ops, +}; |