diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-hix5hd2.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-hix5hd2.c | 557 |
1 files changed, 557 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-hix5hd2.c b/drivers/i2c/busses/i2c-hix5hd2.c new file mode 100644 index 000000000000..9490d0f4255c --- /dev/null +++ b/drivers/i2c/busses/i2c-hix5hd2.c @@ -0,0 +1,557 @@ +/* + * Copyright (c) 2014 Linaro Ltd. + * Copyright (c) 2014 Hisilicon Limited. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * Now only support 7 bit address. + */ + +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/i2c.h> +#include <linux/io.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> + +/* Register Map */ +#define HIX5I2C_CTRL 0x00 +#define HIX5I2C_COM 0x04 +#define HIX5I2C_ICR 0x08 +#define HIX5I2C_SR 0x0c +#define HIX5I2C_SCL_H 0x10 +#define HIX5I2C_SCL_L 0x14 +#define HIX5I2C_TXR 0x18 +#define HIX5I2C_RXR 0x1c + +/* I2C_CTRL_REG */ +#define I2C_ENABLE BIT(8) +#define I2C_UNMASK_TOTAL BIT(7) +#define I2C_UNMASK_START BIT(6) +#define I2C_UNMASK_END BIT(5) +#define I2C_UNMASK_SEND BIT(4) +#define I2C_UNMASK_RECEIVE BIT(3) +#define I2C_UNMASK_ACK BIT(2) +#define I2C_UNMASK_ARBITRATE BIT(1) +#define I2C_UNMASK_OVER BIT(0) +#define I2C_UNMASK_ALL (I2C_UNMASK_ACK | I2C_UNMASK_OVER) + +/* I2C_COM_REG */ +#define I2C_NO_ACK BIT(4) +#define I2C_START BIT(3) +#define I2C_READ BIT(2) +#define I2C_WRITE BIT(1) +#define I2C_STOP BIT(0) + +/* I2C_ICR_REG */ +#define I2C_CLEAR_START BIT(6) +#define I2C_CLEAR_END BIT(5) +#define I2C_CLEAR_SEND BIT(4) +#define I2C_CLEAR_RECEIVE BIT(3) +#define I2C_CLEAR_ACK BIT(2) +#define I2C_CLEAR_ARBITRATE BIT(1) +#define I2C_CLEAR_OVER BIT(0) +#define I2C_CLEAR_ALL (I2C_CLEAR_START | I2C_CLEAR_END | \ + I2C_CLEAR_SEND | I2C_CLEAR_RECEIVE | \ + I2C_CLEAR_ACK | I2C_CLEAR_ARBITRATE | \ + I2C_CLEAR_OVER) + +/* I2C_SR_REG */ +#define I2C_BUSY BIT(7) +#define I2C_START_INTR BIT(6) +#define I2C_END_INTR BIT(5) +#define I2C_SEND_INTR BIT(4) +#define I2C_RECEIVE_INTR BIT(3) +#define I2C_ACK_INTR BIT(2) +#define I2C_ARBITRATE_INTR BIT(1) +#define I2C_OVER_INTR BIT(0) + +#define HIX5I2C_MAX_FREQ 400000 /* 400k */ +#define HIX5I2C_READ_OPERATION 0x01 + +enum hix5hd2_i2c_state { + HIX5I2C_STAT_RW_ERR = -1, + HIX5I2C_STAT_INIT, + HIX5I2C_STAT_RW, + HIX5I2C_STAT_SND_STOP, + HIX5I2C_STAT_RW_SUCCESS, +}; + +struct hix5hd2_i2c_priv { + struct i2c_adapter adap; + struct i2c_msg *msg; + struct completion msg_complete; + unsigned int msg_idx; + unsigned int msg_len; + int stop; + void __iomem *regs; + struct clk *clk; + struct device *dev; + spinlock_t lock; /* IRQ synchronization */ + int err; + unsigned int freq; + enum hix5hd2_i2c_state state; +}; + +static u32 hix5hd2_i2c_clr_pend_irq(struct hix5hd2_i2c_priv *priv) +{ + u32 val = readl_relaxed(priv->regs + HIX5I2C_SR); + + writel_relaxed(val, priv->regs + HIX5I2C_ICR); + + return val; +} + +static void hix5hd2_i2c_clr_all_irq(struct hix5hd2_i2c_priv *priv) +{ + writel_relaxed(I2C_CLEAR_ALL, priv->regs + HIX5I2C_ICR); +} + +static void hix5hd2_i2c_disable_irq(struct hix5hd2_i2c_priv *priv) +{ + writel_relaxed(0, priv->regs + HIX5I2C_CTRL); +} + +static void hix5hd2_i2c_enable_irq(struct hix5hd2_i2c_priv *priv) +{ + writel_relaxed(I2C_ENABLE | I2C_UNMASK_TOTAL | I2C_UNMASK_ALL, + priv->regs + HIX5I2C_CTRL); +} + +static void hix5hd2_i2c_drv_setrate(struct hix5hd2_i2c_priv *priv) +{ + u32 rate, val; + u32 scl, sysclock; + + /* close all i2c interrupt */ + val = readl_relaxed(priv->regs + HIX5I2C_CTRL); + writel_relaxed(val & (~I2C_UNMASK_TOTAL), priv->regs + HIX5I2C_CTRL); + + rate = priv->freq; + sysclock = clk_get_rate(priv->clk); + scl = (sysclock / (rate * 2)) / 2 - 1; + writel_relaxed(scl, priv->regs + HIX5I2C_SCL_H); + writel_relaxed(scl, priv->regs + HIX5I2C_SCL_L); + + /* restore original interrupt*/ + writel_relaxed(val, priv->regs + HIX5I2C_CTRL); + + dev_dbg(priv->dev, "%s: sysclock=%d, rate=%d, scl=%d\n", + __func__, sysclock, rate, scl); +} + +static void hix5hd2_i2c_init(struct hix5hd2_i2c_priv *priv) +{ + hix5hd2_i2c_disable_irq(priv); + hix5hd2_i2c_drv_setrate(priv); + hix5hd2_i2c_clr_all_irq(priv); + hix5hd2_i2c_enable_irq(priv); +} + +static void hix5hd2_i2c_reset(struct hix5hd2_i2c_priv *priv) +{ + clk_disable_unprepare(priv->clk); + msleep(20); + clk_prepare_enable(priv->clk); + hix5hd2_i2c_init(priv); +} + +static int hix5hd2_i2c_wait_bus_idle(struct hix5hd2_i2c_priv *priv) +{ + unsigned long stop_time; + u32 int_status; + + /* wait for 100 milli seconds for the bus to be idle */ + stop_time = jiffies + msecs_to_jiffies(100); + do { + int_status = hix5hd2_i2c_clr_pend_irq(priv); + if (!(int_status & I2C_BUSY)) + return 0; + + usleep_range(50, 200); + } while (time_before(jiffies, stop_time)); + + return -EBUSY; +} + +static void hix5hd2_rw_over(struct hix5hd2_i2c_priv *priv) +{ + if (priv->state == HIX5I2C_STAT_SND_STOP) + dev_dbg(priv->dev, "%s: rw and send stop over\n", __func__); + else + dev_dbg(priv->dev, "%s: have not data to send\n", __func__); + + priv->state = HIX5I2C_STAT_RW_SUCCESS; + priv->err = 0; +} + +static void hix5hd2_rw_handle_stop(struct hix5hd2_i2c_priv *priv) +{ + if (priv->stop) { + priv->state = HIX5I2C_STAT_SND_STOP; + writel_relaxed(I2C_STOP, priv->regs + HIX5I2C_COM); + } else { + hix5hd2_rw_over(priv); + } +} + +static void hix5hd2_read_handle(struct hix5hd2_i2c_priv *priv) +{ + if (priv->msg_len == 1) { + /* the last byte don't need send ACK */ + writel_relaxed(I2C_READ | I2C_NO_ACK, priv->regs + HIX5I2C_COM); + } else if (priv->msg_len > 1) { + /* if i2c master receive data will send ACK */ + writel_relaxed(I2C_READ, priv->regs + HIX5I2C_COM); + } else { + hix5hd2_rw_handle_stop(priv); + } +} + +static void hix5hd2_write_handle(struct hix5hd2_i2c_priv *priv) +{ + u8 data; + + if (priv->msg_len > 0) { + data = priv->msg->buf[priv->msg_idx++]; + writel_relaxed(data, priv->regs + HIX5I2C_TXR); + writel_relaxed(I2C_WRITE, priv->regs + HIX5I2C_COM); + } else { + hix5hd2_rw_handle_stop(priv); + } +} + +static int hix5hd2_rw_preprocess(struct hix5hd2_i2c_priv *priv) +{ + u8 data; + + if (priv->state == HIX5I2C_STAT_INIT) { + priv->state = HIX5I2C_STAT_RW; + } else if (priv->state == HIX5I2C_STAT_RW) { + if (priv->msg->flags & I2C_M_RD) { + data = readl_relaxed(priv->regs + HIX5I2C_RXR); + priv->msg->buf[priv->msg_idx++] = data; + } + priv->msg_len--; + } else { + dev_dbg(priv->dev, "%s: error: priv->state = %d, msg_len = %d\n", + __func__, priv->state, priv->msg_len); + return -EAGAIN; + } + return 0; +} + +static irqreturn_t hix5hd2_i2c_irq(int irqno, void *dev_id) +{ + struct hix5hd2_i2c_priv *priv = dev_id; + u32 int_status; + int ret; + + spin_lock(&priv->lock); + + int_status = hix5hd2_i2c_clr_pend_irq(priv); + + /* handle error */ + if (int_status & I2C_ARBITRATE_INTR) { + /* bus error */ + dev_dbg(priv->dev, "ARB bus loss\n"); + priv->err = -EAGAIN; + priv->state = HIX5I2C_STAT_RW_ERR; + goto stop; + } else if (int_status & I2C_ACK_INTR) { + /* ack error */ + dev_dbg(priv->dev, "No ACK from device\n"); + priv->err = -ENXIO; + priv->state = HIX5I2C_STAT_RW_ERR; + goto stop; + } + + if (int_status & I2C_OVER_INTR) { + if (priv->msg_len > 0) { + ret = hix5hd2_rw_preprocess(priv); + if (ret) { + priv->err = ret; + priv->state = HIX5I2C_STAT_RW_ERR; + goto stop; + } + if (priv->msg->flags & I2C_M_RD) + hix5hd2_read_handle(priv); + else + hix5hd2_write_handle(priv); + } else { + hix5hd2_rw_over(priv); + } + } + +stop: + if ((priv->state == HIX5I2C_STAT_RW_SUCCESS && + priv->msg->len == priv->msg_idx) || + (priv->state == HIX5I2C_STAT_RW_ERR)) { + hix5hd2_i2c_disable_irq(priv); + hix5hd2_i2c_clr_pend_irq(priv); + complete(&priv->msg_complete); + } + + spin_unlock(&priv->lock); + + return IRQ_HANDLED; +} + +static void hix5hd2_i2c_message_start(struct hix5hd2_i2c_priv *priv, int stop) +{ + unsigned long flags; + + spin_lock_irqsave(&priv->lock, flags); + hix5hd2_i2c_clr_all_irq(priv); + hix5hd2_i2c_enable_irq(priv); + + if (priv->msg->flags & I2C_M_RD) + writel_relaxed((priv->msg->addr << 1) | HIX5I2C_READ_OPERATION, + priv->regs + HIX5I2C_TXR); + else + writel_relaxed(priv->msg->addr << 1, + priv->regs + HIX5I2C_TXR); + + writel_relaxed(I2C_WRITE | I2C_START, priv->regs + HIX5I2C_COM); + spin_unlock_irqrestore(&priv->lock, flags); +} + +static int hix5hd2_i2c_xfer_msg(struct hix5hd2_i2c_priv *priv, + struct i2c_msg *msgs, int stop) +{ + unsigned long timeout; + int ret; + + priv->msg = msgs; + priv->msg_idx = 0; + priv->msg_len = priv->msg->len; + priv->stop = stop; + priv->err = 0; + priv->state = HIX5I2C_STAT_INIT; + + reinit_completion(&priv->msg_complete); + hix5hd2_i2c_message_start(priv, stop); + + timeout = wait_for_completion_timeout(&priv->msg_complete, + priv->adap.timeout); + if (timeout == 0) { + priv->state = HIX5I2C_STAT_RW_ERR; + priv->err = -ETIMEDOUT; + dev_warn(priv->dev, "%s timeout=%d\n", + msgs->flags & I2C_M_RD ? "rx" : "tx", + priv->adap.timeout); + } + ret = priv->state; + + /* + * If this is the last message to be transfered (stop == 1) + * Then check if the bus can be brought back to idle. + */ + if (priv->state == HIX5I2C_STAT_RW_SUCCESS && stop) + ret = hix5hd2_i2c_wait_bus_idle(priv); + + if (ret < 0) + hix5hd2_i2c_reset(priv); + + return priv->err; +} + +static int hix5hd2_i2c_xfer(struct i2c_adapter *adap, + struct i2c_msg *msgs, int num) +{ + struct hix5hd2_i2c_priv *priv = i2c_get_adapdata(adap); + int i, ret, stop; + + pm_runtime_get_sync(priv->dev); + + for (i = 0; i < num; i++, msgs++) { + stop = (i == num - 1); + ret = hix5hd2_i2c_xfer_msg(priv, msgs, stop); + if (ret < 0) + goto out; + } + + if (i == num) { + ret = num; + } else { + /* Only one message, cannot access the device */ + if (i == 1) + ret = -EREMOTEIO; + else + ret = i; + + dev_warn(priv->dev, "xfer message failed\n"); + } + +out: + pm_runtime_mark_last_busy(priv->dev); + pm_runtime_put_autosuspend(priv->dev); + return ret; +} + +static u32 hix5hd2_i2c_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK); +} + +static const struct i2c_algorithm hix5hd2_i2c_algorithm = { + .master_xfer = hix5hd2_i2c_xfer, + .functionality = hix5hd2_i2c_func, +}; + +static int hix5hd2_i2c_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct hix5hd2_i2c_priv *priv; + struct resource *mem; + unsigned int freq; + int irq, ret; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + if (of_property_read_u32(np, "clock-frequency", &freq)) { + /* use 100k as default value */ + priv->freq = 100000; + } else { + if (freq > HIX5I2C_MAX_FREQ) { + priv->freq = HIX5I2C_MAX_FREQ; + dev_warn(priv->dev, "use max freq %d instead\n", + HIX5I2C_MAX_FREQ); + } else { + priv->freq = freq; + } + } + + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + priv->regs = devm_ioremap_resource(&pdev->dev, mem); + if (IS_ERR(priv->regs)) + return PTR_ERR(priv->regs); + + irq = platform_get_irq(pdev, 0); + if (irq <= 0) { + dev_err(&pdev->dev, "cannot find HS-I2C IRQ\n"); + return irq; + } + + priv->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(priv->clk)) { + dev_err(&pdev->dev, "cannot get clock\n"); + return PTR_ERR(priv->clk); + } + clk_prepare_enable(priv->clk); + + strlcpy(priv->adap.name, "hix5hd2-i2c", sizeof(priv->adap.name)); + priv->dev = &pdev->dev; + priv->adap.owner = THIS_MODULE; + priv->adap.algo = &hix5hd2_i2c_algorithm; + priv->adap.retries = 3; + priv->adap.dev.of_node = np; + priv->adap.algo_data = priv; + priv->adap.dev.parent = &pdev->dev; + i2c_set_adapdata(&priv->adap, priv); + platform_set_drvdata(pdev, priv); + spin_lock_init(&priv->lock); + init_completion(&priv->msg_complete); + + hix5hd2_i2c_init(priv); + + ret = devm_request_irq(&pdev->dev, irq, hix5hd2_i2c_irq, + IRQF_NO_SUSPEND | IRQF_ONESHOT, + dev_name(&pdev->dev), priv); + if (ret != 0) { + dev_err(&pdev->dev, "cannot request HS-I2C IRQ %d\n", irq); + goto err_clk; + } + + pm_suspend_ignore_children(&pdev->dev, true); + pm_runtime_set_autosuspend_delay(priv->dev, MSEC_PER_SEC); + pm_runtime_use_autosuspend(priv->dev); + pm_runtime_set_active(priv->dev); + pm_runtime_enable(priv->dev); + + ret = i2c_add_adapter(&priv->adap); + if (ret < 0) { + dev_err(&pdev->dev, "failed to add bus to i2c core\n"); + goto err_runtime; + } + + return ret; + +err_runtime: + pm_runtime_disable(priv->dev); + pm_runtime_set_suspended(priv->dev); +err_clk: + clk_disable_unprepare(priv->clk); + return ret; +} + +static int hix5hd2_i2c_remove(struct platform_device *pdev) +{ + struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev); + + i2c_del_adapter(&priv->adap); + pm_runtime_disable(priv->dev); + pm_runtime_set_suspended(priv->dev); + + return 0; +} + +#ifdef CONFIG_PM +static int hix5hd2_i2c_runtime_suspend(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev); + + clk_disable_unprepare(priv->clk); + + return 0; +} + +static int hix5hd2_i2c_runtime_resume(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev); + + clk_prepare_enable(priv->clk); + hix5hd2_i2c_init(priv); + + return 0; +} +#endif + +static const struct dev_pm_ops hix5hd2_i2c_pm_ops = { + SET_PM_RUNTIME_PM_OPS(hix5hd2_i2c_runtime_suspend, + hix5hd2_i2c_runtime_resume, + NULL) +}; + +static const struct of_device_id hix5hd2_i2c_match[] = { + { .compatible = "hisilicon,hix5hd2-i2c" }, + {}, +}; +MODULE_DEVICE_TABLE(of, hix5hd2_i2c_match); + +static struct platform_driver hix5hd2_i2c_driver = { + .probe = hix5hd2_i2c_probe, + .remove = hix5hd2_i2c_remove, + .driver = { + .name = "hix5hd2-i2c", + .pm = &hix5hd2_i2c_pm_ops, + .of_match_table = hix5hd2_i2c_match, + }, +}; + +module_platform_driver(hix5hd2_i2c_driver); + +MODULE_DESCRIPTION("Hix5hd2 I2C Bus driver"); +MODULE_AUTHOR("Wei Yan <sledge.yanwei@huawei.com>"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:i2c-hix5hd2"); |