--- /dev/null
+/*
+ * 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_RX_FIFOSIZE 4
+#define LPI2C_TX_FIFOSIZE 4
+
+#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;
+ 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_TX_FIFOSIZE >> 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_RX_FIFOSIZE >> 1))
+ temp = LPI2C_RX_FIFOSIZE >> 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_TX_FIFOSIZE) {
+ 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;
+ 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(lpi2c_imx->clk);
+ if (ret) {
+ dev_err(&pdev->dev, "clk prepare failed %d\n", ret);
+ return ret;
+ }
+
+ 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");
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff