/* * 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) 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_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:hix5hd2-i2c");