diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-imx-lpi2c.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-imx-lpi2c.c | 652 |
1 files changed, 652 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c new file mode 100644 index 000000000000..c62b7cd475f8 --- /dev/null +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c @@ -0,0 +1,652 @@ +/* + * 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 <linux/clk.h> +#include <linux/completion.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/errno.h> +#include <linux/i2c.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/sched.h> +#include <linux/slab.h> + +#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 + +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; + u8 read; + + 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); + + read = msgs->flags & I2C_M_RD; + temp = (msgs->addr << 1 | read) | (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 = clk_enable(lpi2c_imx->clk); + if (ret) + 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 clk_disable; + + temp = readl(lpi2c_imx->base + LPI2C_MCR); + temp |= MCR_MEN; + writel(temp, lpi2c_imx->base + LPI2C_MCR); + + return 0; + +clk_disable: + clk_disable(lpi2c_imx->clk); + + 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); + + clk_disable(lpi2c_imx->clk); + + 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 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; + } + + temp = readl(lpi2c_imx->base + LPI2C_PARAM); + lpi2c_imx->txfifosize = 1 << (temp & 0x0f); + lpi2c_imx->rxfifosize = 1 << ((temp >> 8) & 0x0f); + + clk_disable(lpi2c_imx->clk); + + ret = i2c_add_adapter(&lpi2c_imx->adapter); + if (ret) + goto clk_unprepare; + + dev_info(&lpi2c_imx->adapter.dev, "LPI2C adapter registered\n"); + + return 0; + +clk_unprepare: + clk_unprepare(lpi2c_imx->clk); + + 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); + + clk_unprepare(lpi2c_imx->clk); + + return 0; +} + +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, + }, +}; + +module_platform_driver(lpi2c_imx_driver); + +MODULE_AUTHOR("Gao Pan <pandy.gao@nxp.com>"); +MODULE_DESCRIPTION("I2C adapter driver for LPI2C bus"); +MODULE_LICENSE("GPL"); |