479 lines
11 KiB
C
479 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Renesas Solutions Highlander FPGA I2C/SMBus support.
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*
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* Supported devices: R0P7780LC0011RL, R0P7785LC0011RL
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*
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* Copyright (C) 2008 Paul Mundt
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* Copyright (C) 2008 Renesas Solutions Corp.
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* Copyright (C) 2008 Atom Create Engineering Co., Ltd.
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*/
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/i2c.h>
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#include <linux/platform_device.h>
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#include <linux/completion.h>
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#include <linux/io.h>
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#include <linux/delay.h>
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#include <linux/slab.h>
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#define SMCR 0x00
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#define SMCR_START (1 << 0)
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#define SMCR_IRIC (1 << 1)
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#define SMCR_BBSY (1 << 2)
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#define SMCR_ACKE (1 << 3)
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#define SMCR_RST (1 << 4)
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#define SMCR_IEIC (1 << 6)
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#define SMSMADR 0x02
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#define SMMR 0x04
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#define SMMR_MODE0 (1 << 0)
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#define SMMR_MODE1 (1 << 1)
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#define SMMR_CAP (1 << 3)
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#define SMMR_TMMD (1 << 4)
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#define SMMR_SP (1 << 7)
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#define SMSADR 0x06
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#define SMTRDR 0x46
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struct highlander_i2c_dev {
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struct device *dev;
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void __iomem *base;
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struct i2c_adapter adapter;
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struct completion cmd_complete;
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unsigned long last_read_time;
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int irq;
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u8 *buf;
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size_t buf_len;
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};
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static bool iic_force_poll, iic_force_normal;
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static int iic_timeout = 1000, iic_read_delay;
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static inline void highlander_i2c_irq_enable(struct highlander_i2c_dev *dev)
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{
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iowrite16(ioread16(dev->base + SMCR) | SMCR_IEIC, dev->base + SMCR);
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}
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static inline void highlander_i2c_irq_disable(struct highlander_i2c_dev *dev)
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{
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iowrite16(ioread16(dev->base + SMCR) & ~SMCR_IEIC, dev->base + SMCR);
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}
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static inline void highlander_i2c_start(struct highlander_i2c_dev *dev)
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{
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iowrite16(ioread16(dev->base + SMCR) | SMCR_START, dev->base + SMCR);
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}
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static inline void highlander_i2c_done(struct highlander_i2c_dev *dev)
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{
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iowrite16(ioread16(dev->base + SMCR) | SMCR_IRIC, dev->base + SMCR);
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}
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static void highlander_i2c_setup(struct highlander_i2c_dev *dev)
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{
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u16 smmr;
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smmr = ioread16(dev->base + SMMR);
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smmr |= SMMR_TMMD;
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if (iic_force_normal)
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smmr &= ~SMMR_SP;
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else
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smmr |= SMMR_SP;
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iowrite16(smmr, dev->base + SMMR);
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}
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static void smbus_write_data(u8 *src, u16 *dst, int len)
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{
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for (; len > 1; len -= 2) {
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*dst++ = be16_to_cpup((__be16 *)src);
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src += 2;
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}
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if (len)
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*dst = *src << 8;
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}
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static void smbus_read_data(u16 *src, u8 *dst, int len)
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{
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for (; len > 1; len -= 2) {
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*(__be16 *)dst = cpu_to_be16p(src++);
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dst += 2;
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}
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if (len)
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*dst = *src >> 8;
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}
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static void highlander_i2c_command(struct highlander_i2c_dev *dev,
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u8 command, int len)
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{
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unsigned int i;
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u16 cmd = (command << 8) | command;
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for (i = 0; i < len; i += 2) {
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if (len - i == 1)
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cmd = command << 8;
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iowrite16(cmd, dev->base + SMSADR + i);
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dev_dbg(dev->dev, "command data[%x] 0x%04x\n", i/2, cmd);
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}
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}
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static int highlander_i2c_wait_for_bbsy(struct highlander_i2c_dev *dev)
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{
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unsigned long timeout;
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timeout = jiffies + msecs_to_jiffies(iic_timeout);
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while (ioread16(dev->base + SMCR) & SMCR_BBSY) {
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if (time_after(jiffies, timeout)) {
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dev_warn(dev->dev, "timeout waiting for bus ready\n");
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return -ETIMEDOUT;
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}
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msleep(1);
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}
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return 0;
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}
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static int highlander_i2c_reset(struct highlander_i2c_dev *dev)
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{
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iowrite16(ioread16(dev->base + SMCR) | SMCR_RST, dev->base + SMCR);
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return highlander_i2c_wait_for_bbsy(dev);
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}
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static int highlander_i2c_wait_for_ack(struct highlander_i2c_dev *dev)
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{
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u16 tmp = ioread16(dev->base + SMCR);
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if ((tmp & (SMCR_IRIC | SMCR_ACKE)) == SMCR_ACKE) {
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dev_warn(dev->dev, "ack abnormality\n");
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return highlander_i2c_reset(dev);
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}
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return 0;
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}
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static irqreturn_t highlander_i2c_irq(int irq, void *dev_id)
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{
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struct highlander_i2c_dev *dev = dev_id;
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highlander_i2c_done(dev);
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complete(&dev->cmd_complete);
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return IRQ_HANDLED;
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}
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static void highlander_i2c_poll(struct highlander_i2c_dev *dev)
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{
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unsigned long timeout;
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u16 smcr;
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timeout = jiffies + msecs_to_jiffies(iic_timeout);
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for (;;) {
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smcr = ioread16(dev->base + SMCR);
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/*
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* Don't bother checking ACKE here, this and the reset
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* are handled in highlander_i2c_wait_xfer_done() when
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* waiting for the ACK.
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*/
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if (smcr & SMCR_IRIC)
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return;
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if (time_after(jiffies, timeout))
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break;
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cpu_relax();
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cond_resched();
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}
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dev_err(dev->dev, "polling timed out\n");
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}
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static inline int highlander_i2c_wait_xfer_done(struct highlander_i2c_dev *dev)
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{
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if (dev->irq)
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wait_for_completion_timeout(&dev->cmd_complete,
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msecs_to_jiffies(iic_timeout));
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else
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/* busy looping, the IRQ of champions */
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highlander_i2c_poll(dev);
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return highlander_i2c_wait_for_ack(dev);
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}
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static int highlander_i2c_read(struct highlander_i2c_dev *dev)
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{
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int i, cnt;
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u16 data[16];
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if (highlander_i2c_wait_for_bbsy(dev))
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return -EAGAIN;
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highlander_i2c_start(dev);
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if (highlander_i2c_wait_xfer_done(dev)) {
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dev_err(dev->dev, "Arbitration loss\n");
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return -EAGAIN;
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}
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/*
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* The R0P7780LC0011RL FPGA needs a significant delay between
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* data read cycles, otherwise the transceiver gets confused and
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* garbage is returned when the read is subsequently aborted.
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*
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* It is not sufficient to wait for BBSY.
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*
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* While this generally only applies to the older SH7780-based
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* Highlanders, the same issue can be observed on SH7785 ones,
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* albeit less frequently. SH7780-based Highlanders may need
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* this to be as high as 1000 ms.
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*/
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if (iic_read_delay && time_before(jiffies, dev->last_read_time +
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msecs_to_jiffies(iic_read_delay)))
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msleep(jiffies_to_msecs((dev->last_read_time +
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msecs_to_jiffies(iic_read_delay)) - jiffies));
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cnt = (dev->buf_len + 1) >> 1;
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for (i = 0; i < cnt; i++) {
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data[i] = ioread16(dev->base + SMTRDR + (i * sizeof(u16)));
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dev_dbg(dev->dev, "read data[%x] 0x%04x\n", i, data[i]);
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}
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smbus_read_data(data, dev->buf, dev->buf_len);
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dev->last_read_time = jiffies;
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return 0;
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}
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static int highlander_i2c_write(struct highlander_i2c_dev *dev)
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{
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int i, cnt;
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u16 data[16];
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smbus_write_data(dev->buf, data, dev->buf_len);
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cnt = (dev->buf_len + 1) >> 1;
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for (i = 0; i < cnt; i++) {
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iowrite16(data[i], dev->base + SMTRDR + (i * sizeof(u16)));
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dev_dbg(dev->dev, "write data[%x] 0x%04x\n", i, data[i]);
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}
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if (highlander_i2c_wait_for_bbsy(dev))
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return -EAGAIN;
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highlander_i2c_start(dev);
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return highlander_i2c_wait_xfer_done(dev);
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}
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static int highlander_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr,
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unsigned short flags, char read_write,
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u8 command, int size,
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union i2c_smbus_data *data)
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{
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struct highlander_i2c_dev *dev = i2c_get_adapdata(adap);
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u16 tmp;
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init_completion(&dev->cmd_complete);
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dev_dbg(dev->dev, "addr %04x, command %02x, read_write %d, size %d\n",
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addr, command, read_write, size);
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/*
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* Set up the buffer and transfer size
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*/
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switch (size) {
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case I2C_SMBUS_BYTE_DATA:
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dev->buf = &data->byte;
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dev->buf_len = 1;
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break;
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case I2C_SMBUS_I2C_BLOCK_DATA:
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dev->buf = &data->block[1];
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dev->buf_len = data->block[0];
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break;
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default:
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dev_err(dev->dev, "unsupported command %d\n", size);
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return -EINVAL;
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}
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/*
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* Encode the mode setting
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*/
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tmp = ioread16(dev->base + SMMR);
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tmp &= ~(SMMR_MODE0 | SMMR_MODE1);
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switch (dev->buf_len) {
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case 1:
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/* default */
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break;
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case 8:
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tmp |= SMMR_MODE0;
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break;
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case 16:
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tmp |= SMMR_MODE1;
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break;
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case 32:
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tmp |= (SMMR_MODE0 | SMMR_MODE1);
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break;
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default:
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dev_err(dev->dev, "unsupported xfer size %zu\n", dev->buf_len);
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return -EINVAL;
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}
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iowrite16(tmp, dev->base + SMMR);
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/* Ensure we're in a sane state */
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highlander_i2c_done(dev);
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/* Set slave address */
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iowrite16((addr << 1) | read_write, dev->base + SMSMADR);
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highlander_i2c_command(dev, command, dev->buf_len);
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if (read_write == I2C_SMBUS_READ)
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return highlander_i2c_read(dev);
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else
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return highlander_i2c_write(dev);
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}
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static u32 highlander_i2c_func(struct i2c_adapter *adapter)
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{
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return I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK;
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}
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static const struct i2c_algorithm highlander_i2c_algo = {
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.smbus_xfer = highlander_i2c_smbus_xfer,
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.functionality = highlander_i2c_func,
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};
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static int highlander_i2c_probe(struct platform_device *pdev)
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{
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struct highlander_i2c_dev *dev;
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struct i2c_adapter *adap;
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struct resource *res;
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int ret;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (unlikely(!res)) {
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dev_err(&pdev->dev, "no mem resource\n");
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return -ENODEV;
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}
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dev = kzalloc(sizeof(struct highlander_i2c_dev), GFP_KERNEL);
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if (unlikely(!dev))
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return -ENOMEM;
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dev->base = ioremap(res->start, resource_size(res));
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if (unlikely(!dev->base)) {
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ret = -ENXIO;
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goto err;
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}
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dev->dev = &pdev->dev;
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platform_set_drvdata(pdev, dev);
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dev->irq = platform_get_irq(pdev, 0);
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if (dev->irq < 0 || iic_force_poll)
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dev->irq = 0;
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if (dev->irq) {
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ret = request_irq(dev->irq, highlander_i2c_irq, 0,
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pdev->name, dev);
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if (unlikely(ret))
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goto err_unmap;
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highlander_i2c_irq_enable(dev);
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} else {
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dev_notice(&pdev->dev, "no IRQ, using polling mode\n");
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highlander_i2c_irq_disable(dev);
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}
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dev->last_read_time = jiffies; /* initial read jiffies */
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highlander_i2c_setup(dev);
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adap = &dev->adapter;
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i2c_set_adapdata(adap, dev);
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adap->owner = THIS_MODULE;
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adap->class = I2C_CLASS_HWMON;
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strscpy(adap->name, "HL FPGA I2C adapter", sizeof(adap->name));
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adap->algo = &highlander_i2c_algo;
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adap->dev.parent = &pdev->dev;
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adap->nr = pdev->id;
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/*
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* Reset the adapter
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*/
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ret = highlander_i2c_reset(dev);
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if (unlikely(ret)) {
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dev_err(&pdev->dev, "controller didn't come up\n");
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goto err_free_irq;
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}
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ret = i2c_add_numbered_adapter(adap);
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if (unlikely(ret)) {
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dev_err(&pdev->dev, "failure adding adapter\n");
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goto err_free_irq;
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}
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return 0;
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err_free_irq:
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if (dev->irq)
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free_irq(dev->irq, dev);
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err_unmap:
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iounmap(dev->base);
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err:
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kfree(dev);
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return ret;
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}
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static int highlander_i2c_remove(struct platform_device *pdev)
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{
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struct highlander_i2c_dev *dev = platform_get_drvdata(pdev);
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i2c_del_adapter(&dev->adapter);
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if (dev->irq)
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free_irq(dev->irq, dev);
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iounmap(dev->base);
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kfree(dev);
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return 0;
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}
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static struct platform_driver highlander_i2c_driver = {
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.driver = {
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.name = "i2c-highlander",
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},
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.probe = highlander_i2c_probe,
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.remove = highlander_i2c_remove,
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};
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module_platform_driver(highlander_i2c_driver);
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MODULE_AUTHOR("Paul Mundt");
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MODULE_DESCRIPTION("Renesas Highlander FPGA I2C/SMBus adapter");
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MODULE_LICENSE("GPL v2");
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module_param(iic_force_poll, bool, 0);
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module_param(iic_force_normal, bool, 0);
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module_param(iic_timeout, int, 0);
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module_param(iic_read_delay, int, 0);
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MODULE_PARM_DESC(iic_force_poll, "Force polling mode");
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MODULE_PARM_DESC(iic_force_normal,
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"Force normal mode (100 kHz), default is fast mode (400 kHz)");
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MODULE_PARM_DESC(iic_timeout, "Set timeout value in msecs (default 1000 ms)");
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MODULE_PARM_DESC(iic_read_delay,
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"Delay between data read cycles (default 0 ms)");
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