/* * This is i.MX low power i2c controller driver. * * Copyright 2016 Freescale Semiconductor, Inc. * * 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. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define DRIVER_NAME "imx-lpi2c" #define LPI2C_PARAM 0x04 /* i2c RX/TX FIFO size */ #define LPI2C_MCR 0x10 /* i2c contrl register */ #define LPI2C_MSR 0x14 /* i2c status register */ #define LPI2C_MIER 0x18 /* i2c interrupt enable */ #define LPI2C_MCFGR0 0x20 /* i2c master configuration */ #define LPI2C_MCFGR1 0x24 /* i2c master configuration */ #define LPI2C_MCFGR2 0x28 /* i2c master configuration */ #define LPI2C_MCFGR3 0x2C /* i2c master configuration */ #define LPI2C_MCCR0 0x48 /* i2c master clk configuration */ #define LPI2C_MCCR1 0x50 /* i2c master clk configuration */ #define LPI2C_MFCR 0x58 /* i2c master FIFO control */ #define LPI2C_MFSR 0x5C /* i2c master FIFO status */ #define LPI2C_MTDR 0x60 /* i2c master TX data register */ #define LPI2C_MRDR 0x70 /* i2c master RX data register */ /* i2c command */ #define TRAN_DATA 0X00 #define RECV_DATA 0X01 #define GEN_STOP 0X02 #define RECV_DISCARD 0X03 #define GEN_START 0X04 #define START_NACK 0X05 #define START_HIGH 0X06 #define START_HIGH_NACK 0X07 #define MCR_MEN BIT(0) #define MCR_RST BIT(1) #define MCR_DOZEN BIT(2) #define MCR_DBGEN BIT(3) #define MCR_RTF BIT(8) #define MCR_RRF BIT(9) #define MSR_TDF BIT(0) #define MSR_RDF BIT(1) #define MSR_SDF BIT(9) #define MSR_NDF BIT(10) #define MSR_ALF BIT(11) #define MSR_MBF BIT(24) #define MSR_BBF BIT(25) #define MIER_TDIE BIT(0) #define MIER_RDIE BIT(1) #define MIER_SDIE BIT(9) #define MIER_NDIE BIT(10) #define MCFGR1_AUTOSTOP BIT(8) #define MCFGR1_IGNACK BIT(9) #define MRDR_RXEMPTY BIT(14) #define I2C_CLK_RATIO 2 #define CHUNK_DATA 256 #define LPI2C_DEFAULT_RATE 100000 #define STARDARD_MAX_BITRATE 400000 #define FAST_MAX_BITRATE 1000000 #define FAST_PLUS_MAX_BITRATE 3400000 #define HIGHSPEED_MAX_BITRATE 5000000 #define I2C_PM_TIMEOUT 10 /* ms */ enum lpi2c_imx_mode { STANDARD, /* 100+Kbps */ FAST, /* 400+Kbps */ FAST_PLUS, /* 1.0+Mbps */ HS, /* 3.4+Mbps */ ULTRA_FAST, /* 5.0+Mbps */ }; enum lpi2c_imx_pincfg { TWO_PIN_OD, TWO_PIN_OO, TWO_PIN_PP, FOUR_PIN_PP, }; struct lpi2c_imx_struct { struct i2c_adapter adapter; struct clk *clk; void __iomem *base; __u8 *rx_buf; __u8 *tx_buf; struct completion complete; unsigned int msglen; unsigned int delivered; unsigned int block_data; unsigned int bitrate; unsigned int txfifosize; unsigned int rxfifosize; enum lpi2c_imx_mode mode; }; static void lpi2c_imx_intctrl(struct lpi2c_imx_struct *lpi2c_imx, unsigned int enable) { writel(enable, lpi2c_imx->base + LPI2C_MIER); } static int lpi2c_imx_bus_busy(struct lpi2c_imx_struct *lpi2c_imx) { unsigned long orig_jiffies = jiffies; unsigned int temp; while (1) { temp = readl(lpi2c_imx->base + LPI2C_MSR); /* check for arbitration lost, clear if set */ if (temp & MSR_ALF) { writel(temp, lpi2c_imx->base + LPI2C_MSR); return -EAGAIN; } if (temp & (MSR_BBF | MSR_MBF)) break; if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) { dev_dbg(&lpi2c_imx->adapter.dev, "bus not work\n"); return -ETIMEDOUT; } schedule(); } return 0; } static void lpi2c_imx_set_mode(struct lpi2c_imx_struct *lpi2c_imx) { unsigned int bitrate = lpi2c_imx->bitrate; enum lpi2c_imx_mode mode; if (bitrate < STARDARD_MAX_BITRATE) mode = STANDARD; else if (bitrate < FAST_MAX_BITRATE) mode = FAST; else if (bitrate < FAST_PLUS_MAX_BITRATE) mode = FAST_PLUS; else if (bitrate < HIGHSPEED_MAX_BITRATE) mode = HS; else mode = ULTRA_FAST; lpi2c_imx->mode = mode; } static int lpi2c_imx_start(struct lpi2c_imx_struct *lpi2c_imx, struct i2c_msg *msgs) { unsigned int temp; temp = readl(lpi2c_imx->base + LPI2C_MCR); temp |= MCR_RRF | MCR_RTF; writel(temp, lpi2c_imx->base + LPI2C_MCR); writel(0x7f00, lpi2c_imx->base + LPI2C_MSR); temp = i2c_8bit_addr_from_msg(msgs) | (GEN_START << 8); writel(temp, lpi2c_imx->base + LPI2C_MTDR); return lpi2c_imx_bus_busy(lpi2c_imx); } static void lpi2c_imx_stop(struct lpi2c_imx_struct *lpi2c_imx) { unsigned long orig_jiffies = jiffies; unsigned int temp; writel(GEN_STOP << 8, lpi2c_imx->base + LPI2C_MTDR); do { temp = readl(lpi2c_imx->base + LPI2C_MSR); if (temp & MSR_SDF) break; if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) { dev_dbg(&lpi2c_imx->adapter.dev, "stop timeout\n"); break; } schedule(); } while (1); } /* CLKLO = I2C_CLK_RATIO * CLKHI, SETHOLD = CLKHI, DATAVD = CLKHI/2 */ static int lpi2c_imx_config(struct lpi2c_imx_struct *lpi2c_imx) { u8 prescale, filt, sethold, clkhi, clklo, datavd; unsigned int clk_rate, clk_cycle; enum lpi2c_imx_pincfg pincfg; unsigned int temp; lpi2c_imx_set_mode(lpi2c_imx); clk_rate = clk_get_rate(lpi2c_imx->clk); if (lpi2c_imx->mode == HS || lpi2c_imx->mode == ULTRA_FAST) filt = 0; else filt = 2; for (prescale = 0; prescale <= 7; prescale++) { clk_cycle = clk_rate / ((1 << prescale) * lpi2c_imx->bitrate) - 3 - (filt >> 1); clkhi = (clk_cycle + I2C_CLK_RATIO) / (I2C_CLK_RATIO + 1); clklo = clk_cycle - clkhi; if (clklo < 64) break; } if (prescale > 7) return -EINVAL; /* set MCFGR1: PINCFG, PRESCALE, IGNACK */ if (lpi2c_imx->mode == ULTRA_FAST) pincfg = TWO_PIN_OO; else pincfg = TWO_PIN_OD; temp = prescale | pincfg << 24; if (lpi2c_imx->mode == ULTRA_FAST) temp |= MCFGR1_IGNACK; writel(temp, lpi2c_imx->base + LPI2C_MCFGR1); /* set MCFGR2: FILTSDA, FILTSCL */ temp = (filt << 16) | (filt << 24); writel(temp, lpi2c_imx->base + LPI2C_MCFGR2); /* set MCCR: DATAVD, SETHOLD, CLKHI, CLKLO */ sethold = clkhi; datavd = clkhi >> 1; temp = datavd << 24 | sethold << 16 | clkhi << 8 | clklo; if (lpi2c_imx->mode == HS) writel(temp, lpi2c_imx->base + LPI2C_MCCR1); else writel(temp, lpi2c_imx->base + LPI2C_MCCR0); return 0; } static int lpi2c_imx_master_enable(struct lpi2c_imx_struct *lpi2c_imx) { unsigned int temp; int ret; ret = pm_runtime_get_sync(lpi2c_imx->adapter.dev.parent); if (ret < 0) return ret; temp = MCR_RST; writel(temp, lpi2c_imx->base + LPI2C_MCR); writel(0, lpi2c_imx->base + LPI2C_MCR); ret = lpi2c_imx_config(lpi2c_imx); if (ret) goto rpm_put; temp = readl(lpi2c_imx->base + LPI2C_MCR); temp |= MCR_MEN; writel(temp, lpi2c_imx->base + LPI2C_MCR); return 0; rpm_put: pm_runtime_mark_last_busy(lpi2c_imx->adapter.dev.parent); pm_runtime_put_autosuspend(lpi2c_imx->adapter.dev.parent); return ret; } static int lpi2c_imx_master_disable(struct lpi2c_imx_struct *lpi2c_imx) { u32 temp; temp = readl(lpi2c_imx->base + LPI2C_MCR); temp &= ~MCR_MEN; writel(temp, lpi2c_imx->base + LPI2C_MCR); pm_runtime_mark_last_busy(lpi2c_imx->adapter.dev.parent); pm_runtime_put_autosuspend(lpi2c_imx->adapter.dev.parent); return 0; } static int lpi2c_imx_msg_complete(struct lpi2c_imx_struct *lpi2c_imx) { unsigned long timeout; timeout = wait_for_completion_timeout(&lpi2c_imx->complete, HZ); return timeout ? 0 : -ETIMEDOUT; } static int lpi2c_imx_txfifo_empty(struct lpi2c_imx_struct *lpi2c_imx) { unsigned long orig_jiffies = jiffies; u32 txcnt; do { txcnt = readl(lpi2c_imx->base + LPI2C_MFSR) & 0xff; if (readl(lpi2c_imx->base + LPI2C_MSR) & MSR_NDF) { dev_dbg(&lpi2c_imx->adapter.dev, "NDF detected\n"); return -EIO; } if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) { dev_dbg(&lpi2c_imx->adapter.dev, "txfifo empty timeout\n"); return -ETIMEDOUT; } schedule(); } while (txcnt); return 0; } static void lpi2c_imx_set_tx_watermark(struct lpi2c_imx_struct *lpi2c_imx) { writel(lpi2c_imx->txfifosize >> 1, lpi2c_imx->base + LPI2C_MFCR); } static void lpi2c_imx_set_rx_watermark(struct lpi2c_imx_struct *lpi2c_imx) { unsigned int temp, remaining; remaining = lpi2c_imx->msglen - lpi2c_imx->delivered; if (remaining > (lpi2c_imx->rxfifosize >> 1)) temp = lpi2c_imx->rxfifosize >> 1; else temp = 0; writel(temp << 16, lpi2c_imx->base + LPI2C_MFCR); } static void lpi2c_imx_write_txfifo(struct lpi2c_imx_struct *lpi2c_imx) { unsigned int data, txcnt; txcnt = readl(lpi2c_imx->base + LPI2C_MFSR) & 0xff; while (txcnt < lpi2c_imx->txfifosize) { if (lpi2c_imx->delivered == lpi2c_imx->msglen) break; data = lpi2c_imx->tx_buf[lpi2c_imx->delivered++]; writel(data, lpi2c_imx->base + LPI2C_MTDR); txcnt++; } if (lpi2c_imx->delivered < lpi2c_imx->msglen) lpi2c_imx_intctrl(lpi2c_imx, MIER_TDIE | MIER_NDIE); else complete(&lpi2c_imx->complete); } static void lpi2c_imx_read_rxfifo(struct lpi2c_imx_struct *lpi2c_imx) { unsigned int blocklen, remaining; unsigned int temp, data; do { data = readl(lpi2c_imx->base + LPI2C_MRDR); if (data & MRDR_RXEMPTY) break; lpi2c_imx->rx_buf[lpi2c_imx->delivered++] = data & 0xff; } while (1); /* * First byte is the length of remaining packet in the SMBus block * data read. Add it to msgs->len. */ if (lpi2c_imx->block_data) { blocklen = lpi2c_imx->rx_buf[0]; lpi2c_imx->msglen += blocklen; } remaining = lpi2c_imx->msglen - lpi2c_imx->delivered; if (!remaining) { complete(&lpi2c_imx->complete); return; } /* not finished, still waiting for rx data */ lpi2c_imx_set_rx_watermark(lpi2c_imx); /* multiple receive commands */ if (lpi2c_imx->block_data) { lpi2c_imx->block_data = 0; temp = remaining; temp |= (RECV_DATA << 8); writel(temp, lpi2c_imx->base + LPI2C_MTDR); } else if (!(lpi2c_imx->delivered & 0xff)) { temp = (remaining > CHUNK_DATA ? CHUNK_DATA : remaining) - 1; temp |= (RECV_DATA << 8); writel(temp, lpi2c_imx->base + LPI2C_MTDR); } lpi2c_imx_intctrl(lpi2c_imx, MIER_RDIE); } static void lpi2c_imx_write(struct lpi2c_imx_struct *lpi2c_imx, struct i2c_msg *msgs) { lpi2c_imx->tx_buf = msgs->buf; lpi2c_imx_set_tx_watermark(lpi2c_imx); lpi2c_imx_write_txfifo(lpi2c_imx); } static void lpi2c_imx_read(struct lpi2c_imx_struct *lpi2c_imx, struct i2c_msg *msgs) { unsigned int temp; lpi2c_imx->rx_buf = msgs->buf; lpi2c_imx->block_data = msgs->flags & I2C_M_RECV_LEN; lpi2c_imx_set_rx_watermark(lpi2c_imx); temp = msgs->len > CHUNK_DATA ? CHUNK_DATA - 1 : msgs->len - 1; temp |= (RECV_DATA << 8); writel(temp, lpi2c_imx->base + LPI2C_MTDR); lpi2c_imx_intctrl(lpi2c_imx, MIER_RDIE | MIER_NDIE); } static int lpi2c_imx_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) { struct lpi2c_imx_struct *lpi2c_imx = i2c_get_adapdata(adapter); unsigned int temp; int i, result; result = lpi2c_imx_master_enable(lpi2c_imx); if (result) return result; for (i = 0; i < num; i++) { result = lpi2c_imx_start(lpi2c_imx, &msgs[i]); if (result) goto disable; /* quick smbus */ if (num == 1 && msgs[0].len == 0) goto stop; lpi2c_imx->delivered = 0; lpi2c_imx->msglen = msgs[i].len; init_completion(&lpi2c_imx->complete); if (msgs[i].flags & I2C_M_RD) lpi2c_imx_read(lpi2c_imx, &msgs[i]); else lpi2c_imx_write(lpi2c_imx, &msgs[i]); result = lpi2c_imx_msg_complete(lpi2c_imx); if (result) goto stop; if (!(msgs[i].flags & I2C_M_RD)) { result = lpi2c_imx_txfifo_empty(lpi2c_imx); if (result) goto stop; } } stop: lpi2c_imx_stop(lpi2c_imx); temp = readl(lpi2c_imx->base + LPI2C_MSR); if ((temp & MSR_NDF) && !result) result = -EIO; disable: lpi2c_imx_master_disable(lpi2c_imx); dev_dbg(&lpi2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__, (result < 0) ? "error" : "success msg", (result < 0) ? result : num); return (result < 0) ? result : num; } static irqreturn_t lpi2c_imx_isr(int irq, void *dev_id) { struct lpi2c_imx_struct *lpi2c_imx = dev_id; unsigned int temp; lpi2c_imx_intctrl(lpi2c_imx, 0); temp = readl(lpi2c_imx->base + LPI2C_MSR); if (temp & MSR_RDF) lpi2c_imx_read_rxfifo(lpi2c_imx); if (temp & MSR_TDF) lpi2c_imx_write_txfifo(lpi2c_imx); if (temp & MSR_NDF) complete(&lpi2c_imx->complete); return IRQ_HANDLED; } static u32 lpi2c_imx_func(struct i2c_adapter *adapter) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_READ_BLOCK_DATA; } static const struct i2c_algorithm lpi2c_imx_algo = { .master_xfer = lpi2c_imx_xfer, .functionality = lpi2c_imx_func, }; static const struct of_device_id lpi2c_imx_of_match[] = { { .compatible = "fsl,imx7ulp-lpi2c" }, { .compatible = "fsl,imx8dv-lpi2c" }, { }, }; MODULE_DEVICE_TABLE(of, lpi2c_imx_of_match); static int lpi2c_imx_probe(struct platform_device *pdev) { struct lpi2c_imx_struct *lpi2c_imx; struct resource *res; unsigned int temp; int irq, ret; lpi2c_imx = devm_kzalloc(&pdev->dev, sizeof(*lpi2c_imx), GFP_KERNEL); if (!lpi2c_imx) return -ENOMEM; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); lpi2c_imx->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(lpi2c_imx->base)) return PTR_ERR(lpi2c_imx->base); irq = platform_get_irq(pdev, 0); if (irq < 0) { dev_err(&pdev->dev, "can't get irq number\n"); return irq; } lpi2c_imx->adapter.owner = THIS_MODULE; lpi2c_imx->adapter.algo = &lpi2c_imx_algo; lpi2c_imx->adapter.dev.parent = &pdev->dev; lpi2c_imx->adapter.dev.of_node = pdev->dev.of_node; strlcpy(lpi2c_imx->adapter.name, pdev->name, sizeof(lpi2c_imx->adapter.name)); lpi2c_imx->clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(lpi2c_imx->clk)) { dev_err(&pdev->dev, "can't get I2C peripheral clock\n"); return PTR_ERR(lpi2c_imx->clk); } ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency", &lpi2c_imx->bitrate); if (ret) lpi2c_imx->bitrate = LPI2C_DEFAULT_RATE; ret = devm_request_irq(&pdev->dev, irq, lpi2c_imx_isr, 0, pdev->name, lpi2c_imx); if (ret) { dev_err(&pdev->dev, "can't claim irq %d\n", irq); return ret; } i2c_set_adapdata(&lpi2c_imx->adapter, lpi2c_imx); platform_set_drvdata(pdev, lpi2c_imx); ret = clk_prepare_enable(lpi2c_imx->clk); if (ret) { dev_err(&pdev->dev, "clk enable failed %d\n", ret); return ret; } pm_runtime_set_autosuspend_delay(&pdev->dev, I2C_PM_TIMEOUT); pm_runtime_use_autosuspend(&pdev->dev); pm_runtime_get_noresume(&pdev->dev); pm_runtime_set_active(&pdev->dev); pm_runtime_enable(&pdev->dev); temp = readl(lpi2c_imx->base + LPI2C_PARAM); lpi2c_imx->txfifosize = 1 << (temp & 0x0f); lpi2c_imx->rxfifosize = 1 << ((temp >> 8) & 0x0f); ret = i2c_add_adapter(&lpi2c_imx->adapter); if (ret) goto rpm_disable; pm_runtime_mark_last_busy(&pdev->dev); pm_runtime_put_autosuspend(&pdev->dev); dev_info(&lpi2c_imx->adapter.dev, "LPI2C adapter registered\n"); return 0; rpm_disable: pm_runtime_put(&pdev->dev); pm_runtime_disable(&pdev->dev); pm_runtime_dont_use_autosuspend(&pdev->dev); return ret; } static int lpi2c_imx_remove(struct platform_device *pdev) { struct lpi2c_imx_struct *lpi2c_imx = platform_get_drvdata(pdev); i2c_del_adapter(&lpi2c_imx->adapter); pm_runtime_disable(&pdev->dev); pm_runtime_dont_use_autosuspend(&pdev->dev); return 0; } #ifdef CONFIG_PM_SLEEP static int lpi2c_runtime_suspend(struct device *dev) { struct lpi2c_imx_struct *lpi2c_imx = dev_get_drvdata(dev); clk_disable_unprepare(lpi2c_imx->clk); pinctrl_pm_select_sleep_state(dev); return 0; } static int lpi2c_runtime_resume(struct device *dev) { struct lpi2c_imx_struct *lpi2c_imx = dev_get_drvdata(dev); int ret; pinctrl_pm_select_default_state(dev); ret = clk_prepare_enable(lpi2c_imx->clk); if (ret) { dev_err(dev, "failed to enable I2C clock, ret=%d\n", ret); return ret; } return 0; } static const struct dev_pm_ops lpi2c_pm_ops = { SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume) SET_RUNTIME_PM_OPS(lpi2c_runtime_suspend, lpi2c_runtime_resume, NULL) }; #define IMX_LPI2C_PM (&lpi2c_pm_ops) #else #define IMX_LPI2C_PM NULL #endif static struct platform_driver lpi2c_imx_driver = { .probe = lpi2c_imx_probe, .remove = lpi2c_imx_remove, .driver = { .name = DRIVER_NAME, .of_match_table = lpi2c_imx_of_match, .pm = IMX_LPI2C_PM, }, }; module_platform_driver(lpi2c_imx_driver); MODULE_AUTHOR("Gao Pan "); MODULE_DESCRIPTION("I2C adapter driver for LPI2C bus"); MODULE_LICENSE("GPL");