diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-highlander.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-highlander.c | 476 |
1 files changed, 476 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-highlander.c b/drivers/i2c/busses/i2c-highlander.c new file mode 100644 index 0000000000..7922bc917c --- /dev/null +++ b/drivers/i2c/busses/i2c-highlander.c @@ -0,0 +1,476 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Renesas Solutions Highlander FPGA I2C/SMBus support. + * + * Supported devices: R0P7780LC0011RL, R0P7785LC0011RL + * + * Copyright (C) 2008 Paul Mundt + * Copyright (C) 2008 Renesas Solutions Corp. + * Copyright (C) 2008 Atom Create Engineering Co., Ltd. + */ +#include <linux/module.h> +#include <linux/interrupt.h> +#include <linux/i2c.h> +#include <linux/platform_device.h> +#include <linux/completion.h> +#include <linux/io.h> +#include <linux/delay.h> +#include <linux/slab.h> + +#define SMCR 0x00 +#define SMCR_START (1 << 0) +#define SMCR_IRIC (1 << 1) +#define SMCR_BBSY (1 << 2) +#define SMCR_ACKE (1 << 3) +#define SMCR_RST (1 << 4) +#define SMCR_IEIC (1 << 6) + +#define SMSMADR 0x02 + +#define SMMR 0x04 +#define SMMR_MODE0 (1 << 0) +#define SMMR_MODE1 (1 << 1) +#define SMMR_CAP (1 << 3) +#define SMMR_TMMD (1 << 4) +#define SMMR_SP (1 << 7) + +#define SMSADR 0x06 +#define SMTRDR 0x46 + +struct highlander_i2c_dev { + struct device *dev; + void __iomem *base; + struct i2c_adapter adapter; + struct completion cmd_complete; + unsigned long last_read_time; + int irq; + u8 *buf; + size_t buf_len; +}; + +static bool iic_force_poll, iic_force_normal; +static int iic_timeout = 1000, iic_read_delay; + +static inline void highlander_i2c_irq_enable(struct highlander_i2c_dev *dev) +{ + iowrite16(ioread16(dev->base + SMCR) | SMCR_IEIC, dev->base + SMCR); +} + +static inline void highlander_i2c_irq_disable(struct highlander_i2c_dev *dev) +{ + iowrite16(ioread16(dev->base + SMCR) & ~SMCR_IEIC, dev->base + SMCR); +} + +static inline void highlander_i2c_start(struct highlander_i2c_dev *dev) +{ + iowrite16(ioread16(dev->base + SMCR) | SMCR_START, dev->base + SMCR); +} + +static inline void highlander_i2c_done(struct highlander_i2c_dev *dev) +{ + iowrite16(ioread16(dev->base + SMCR) | SMCR_IRIC, dev->base + SMCR); +} + +static void highlander_i2c_setup(struct highlander_i2c_dev *dev) +{ + u16 smmr; + + smmr = ioread16(dev->base + SMMR); + smmr |= SMMR_TMMD; + + if (iic_force_normal) + smmr &= ~SMMR_SP; + else + smmr |= SMMR_SP; + + iowrite16(smmr, dev->base + SMMR); +} + +static void smbus_write_data(u8 *src, u16 *dst, int len) +{ + for (; len > 1; len -= 2) { + *dst++ = be16_to_cpup((__be16 *)src); + src += 2; + } + + if (len) + *dst = *src << 8; +} + +static void smbus_read_data(u16 *src, u8 *dst, int len) +{ + for (; len > 1; len -= 2) { + *(__be16 *)dst = cpu_to_be16p(src++); + dst += 2; + } + + if (len) + *dst = *src >> 8; +} + +static void highlander_i2c_command(struct highlander_i2c_dev *dev, + u8 command, int len) +{ + unsigned int i; + u16 cmd = (command << 8) | command; + + for (i = 0; i < len; i += 2) { + if (len - i == 1) + cmd = command << 8; + iowrite16(cmd, dev->base + SMSADR + i); + dev_dbg(dev->dev, "command data[%x] 0x%04x\n", i/2, cmd); + } +} + +static int highlander_i2c_wait_for_bbsy(struct highlander_i2c_dev *dev) +{ + unsigned long timeout; + + timeout = jiffies + msecs_to_jiffies(iic_timeout); + while (ioread16(dev->base + SMCR) & SMCR_BBSY) { + if (time_after(jiffies, timeout)) { + dev_warn(dev->dev, "timeout waiting for bus ready\n"); + return -ETIMEDOUT; + } + + msleep(1); + } + + return 0; +} + +static int highlander_i2c_reset(struct highlander_i2c_dev *dev) +{ + iowrite16(ioread16(dev->base + SMCR) | SMCR_RST, dev->base + SMCR); + return highlander_i2c_wait_for_bbsy(dev); +} + +static int highlander_i2c_wait_for_ack(struct highlander_i2c_dev *dev) +{ + u16 tmp = ioread16(dev->base + SMCR); + + if ((tmp & (SMCR_IRIC | SMCR_ACKE)) == SMCR_ACKE) { + dev_warn(dev->dev, "ack abnormality\n"); + return highlander_i2c_reset(dev); + } + + return 0; +} + +static irqreturn_t highlander_i2c_irq(int irq, void *dev_id) +{ + struct highlander_i2c_dev *dev = dev_id; + + highlander_i2c_done(dev); + complete(&dev->cmd_complete); + + return IRQ_HANDLED; +} + +static void highlander_i2c_poll(struct highlander_i2c_dev *dev) +{ + unsigned long timeout; + u16 smcr; + + timeout = jiffies + msecs_to_jiffies(iic_timeout); + for (;;) { + smcr = ioread16(dev->base + SMCR); + + /* + * Don't bother checking ACKE here, this and the reset + * are handled in highlander_i2c_wait_xfer_done() when + * waiting for the ACK. + */ + + if (smcr & SMCR_IRIC) + return; + if (time_after(jiffies, timeout)) + break; + + cpu_relax(); + cond_resched(); + } + + dev_err(dev->dev, "polling timed out\n"); +} + +static inline int highlander_i2c_wait_xfer_done(struct highlander_i2c_dev *dev) +{ + if (dev->irq) + wait_for_completion_timeout(&dev->cmd_complete, + msecs_to_jiffies(iic_timeout)); + else + /* busy looping, the IRQ of champions */ + highlander_i2c_poll(dev); + + return highlander_i2c_wait_for_ack(dev); +} + +static int highlander_i2c_read(struct highlander_i2c_dev *dev) +{ + int i, cnt; + u16 data[16]; + + if (highlander_i2c_wait_for_bbsy(dev)) + return -EAGAIN; + + highlander_i2c_start(dev); + + if (highlander_i2c_wait_xfer_done(dev)) { + dev_err(dev->dev, "Arbitration loss\n"); + return -EAGAIN; + } + + /* + * The R0P7780LC0011RL FPGA needs a significant delay between + * data read cycles, otherwise the transceiver gets confused and + * garbage is returned when the read is subsequently aborted. + * + * It is not sufficient to wait for BBSY. + * + * While this generally only applies to the older SH7780-based + * Highlanders, the same issue can be observed on SH7785 ones, + * albeit less frequently. SH7780-based Highlanders may need + * this to be as high as 1000 ms. + */ + if (iic_read_delay && time_before(jiffies, dev->last_read_time + + msecs_to_jiffies(iic_read_delay))) + msleep(jiffies_to_msecs((dev->last_read_time + + msecs_to_jiffies(iic_read_delay)) - jiffies)); + + cnt = (dev->buf_len + 1) >> 1; + for (i = 0; i < cnt; i++) { + data[i] = ioread16(dev->base + SMTRDR + (i * sizeof(u16))); + dev_dbg(dev->dev, "read data[%x] 0x%04x\n", i, data[i]); + } + + smbus_read_data(data, dev->buf, dev->buf_len); + + dev->last_read_time = jiffies; + + return 0; +} + +static int highlander_i2c_write(struct highlander_i2c_dev *dev) +{ + int i, cnt; + u16 data[16]; + + smbus_write_data(dev->buf, data, dev->buf_len); + + cnt = (dev->buf_len + 1) >> 1; + for (i = 0; i < cnt; i++) { + iowrite16(data[i], dev->base + SMTRDR + (i * sizeof(u16))); + dev_dbg(dev->dev, "write data[%x] 0x%04x\n", i, data[i]); + } + + if (highlander_i2c_wait_for_bbsy(dev)) + return -EAGAIN; + + highlander_i2c_start(dev); + + return highlander_i2c_wait_xfer_done(dev); +} + +static int highlander_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, + union i2c_smbus_data *data) +{ + struct highlander_i2c_dev *dev = i2c_get_adapdata(adap); + u16 tmp; + + init_completion(&dev->cmd_complete); + + dev_dbg(dev->dev, "addr %04x, command %02x, read_write %d, size %d\n", + addr, command, read_write, size); + + /* + * Set up the buffer and transfer size + */ + switch (size) { + case I2C_SMBUS_BYTE_DATA: + dev->buf = &data->byte; + dev->buf_len = 1; + break; + case I2C_SMBUS_I2C_BLOCK_DATA: + dev->buf = &data->block[1]; + dev->buf_len = data->block[0]; + break; + default: + dev_err(dev->dev, "unsupported command %d\n", size); + return -EINVAL; + } + + /* + * Encode the mode setting + */ + tmp = ioread16(dev->base + SMMR); + tmp &= ~(SMMR_MODE0 | SMMR_MODE1); + + switch (dev->buf_len) { + case 1: + /* default */ + break; + case 8: + tmp |= SMMR_MODE0; + break; + case 16: + tmp |= SMMR_MODE1; + break; + case 32: + tmp |= (SMMR_MODE0 | SMMR_MODE1); + break; + default: + dev_err(dev->dev, "unsupported xfer size %zu\n", dev->buf_len); + return -EINVAL; + } + + iowrite16(tmp, dev->base + SMMR); + + /* Ensure we're in a sane state */ + highlander_i2c_done(dev); + + /* Set slave address */ + iowrite16((addr << 1) | read_write, dev->base + SMSMADR); + + highlander_i2c_command(dev, command, dev->buf_len); + + if (read_write == I2C_SMBUS_READ) + return highlander_i2c_read(dev); + else + return highlander_i2c_write(dev); +} + +static u32 highlander_i2c_func(struct i2c_adapter *adapter) +{ + return I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK; +} + +static const struct i2c_algorithm highlander_i2c_algo = { + .smbus_xfer = highlander_i2c_smbus_xfer, + .functionality = highlander_i2c_func, +}; + +static int highlander_i2c_probe(struct platform_device *pdev) +{ + struct highlander_i2c_dev *dev; + struct i2c_adapter *adap; + struct resource *res; + int ret; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (unlikely(!res)) { + dev_err(&pdev->dev, "no mem resource\n"); + return -ENODEV; + } + + dev = kzalloc(sizeof(struct highlander_i2c_dev), GFP_KERNEL); + if (unlikely(!dev)) + return -ENOMEM; + + dev->base = ioremap(res->start, resource_size(res)); + if (unlikely(!dev->base)) { + ret = -ENXIO; + goto err; + } + + dev->dev = &pdev->dev; + platform_set_drvdata(pdev, dev); + + dev->irq = platform_get_irq(pdev, 0); + if (dev->irq < 0 || iic_force_poll) + dev->irq = 0; + + if (dev->irq) { + ret = request_irq(dev->irq, highlander_i2c_irq, 0, + pdev->name, dev); + if (unlikely(ret)) + goto err_unmap; + + highlander_i2c_irq_enable(dev); + } else { + dev_notice(&pdev->dev, "no IRQ, using polling mode\n"); + highlander_i2c_irq_disable(dev); + } + + dev->last_read_time = jiffies; /* initial read jiffies */ + + highlander_i2c_setup(dev); + + adap = &dev->adapter; + i2c_set_adapdata(adap, dev); + adap->owner = THIS_MODULE; + adap->class = I2C_CLASS_HWMON; + strscpy(adap->name, "HL FPGA I2C adapter", sizeof(adap->name)); + adap->algo = &highlander_i2c_algo; + adap->dev.parent = &pdev->dev; + adap->nr = pdev->id; + + /* + * Reset the adapter + */ + ret = highlander_i2c_reset(dev); + if (unlikely(ret)) { + dev_err(&pdev->dev, "controller didn't come up\n"); + goto err_free_irq; + } + + ret = i2c_add_numbered_adapter(adap); + if (unlikely(ret)) { + dev_err(&pdev->dev, "failure adding adapter\n"); + goto err_free_irq; + } + + return 0; + +err_free_irq: + if (dev->irq) + free_irq(dev->irq, dev); +err_unmap: + iounmap(dev->base); +err: + kfree(dev); + + return ret; +} + +static void highlander_i2c_remove(struct platform_device *pdev) +{ + struct highlander_i2c_dev *dev = platform_get_drvdata(pdev); + + i2c_del_adapter(&dev->adapter); + + if (dev->irq) + free_irq(dev->irq, dev); + + iounmap(dev->base); + kfree(dev); +} + +static struct platform_driver highlander_i2c_driver = { + .driver = { + .name = "i2c-highlander", + }, + + .probe = highlander_i2c_probe, + .remove_new = highlander_i2c_remove, +}; + +module_platform_driver(highlander_i2c_driver); + +MODULE_AUTHOR("Paul Mundt"); +MODULE_DESCRIPTION("Renesas Highlander FPGA I2C/SMBus adapter"); +MODULE_LICENSE("GPL v2"); + +module_param(iic_force_poll, bool, 0); +module_param(iic_force_normal, bool, 0); +module_param(iic_timeout, int, 0); +module_param(iic_read_delay, int, 0); + +MODULE_PARM_DESC(iic_force_poll, "Force polling mode"); +MODULE_PARM_DESC(iic_force_normal, + "Force normal mode (100 kHz), default is fast mode (400 kHz)"); +MODULE_PARM_DESC(iic_timeout, "Set timeout value in msecs (default 1000 ms)"); +MODULE_PARM_DESC(iic_read_delay, + "Delay between data read cycles (default 0 ms)"); |