[PATCH 3/3] I2C: mediatek: Add driver for MediaTek I2C controller

Xudong Chen
2014-10-29T05:45:50Z

The mediatek SoCs have I2C controller that handle I2C transfer.
This patch include common I2C bus driver.
This driver is compatible with I2C controller on mt65xx/mt81xx.

Signed-off-by: Xudong Chen <xudong.chen@mediatek.com>
Change-Id: Icc17e326b9df46a226d536956e103f17b0382b6e
---
drivers/i2c/busses/Kconfig | 9 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-mt65xx.c | 728 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 738 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-mt65xx.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 917c358..0d7d0a4 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -564,6 +564,15 @@ config I2C_MPC
This driver can also be built as a module. If so, the module
will be called i2c-mpc.

+config I2C_MT65XX
+ tristate "MediaTek I2C adapter"
+ depends on ARCH_MEDIATEK
+ help
+ This selects the MediaTek(R) Integrated Inter Circuit bus driver
+ for MT65xx and MT81xx.
+ If you want to use MediaTek(R) I2C interface, say Y or M here.
+ If unsure, say N.
+
config I2C_MV64XXX
tristate "Marvell mv64xxx I2C Controller"
depends on MV64X60 || PLAT_ORION || ARCH_SUNXI
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 78d56c5..7a9f0f3 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_I2C_IMX) += i2c-imx.o
obj-$(CONFIG_I2C_IOP3XX) += i2c-iop3xx.o
obj-$(CONFIG_I2C_KEMPLD) += i2c-kempld.o
obj-$(CONFIG_I2C_MPC) += i2c-mpc.o
+obj-$(CONFIG_I2C_MT65XX) += i2c-mt65xx.o
obj-$(CONFIG_I2C_MV64XXX) += i2c-mv64xxx.o
obj-$(CONFIG_I2C_MXS) += i2c-mxs.o
obj-$(CONFIG_I2C_NOMADIK) += i2c-nomadik.o
diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
new file mode 100644
index 0000000..8730153
--- /dev/null
+++ b/drivers/i2c/busses/i2c-mt65xx.c
@@ -0,0 +1,728 @@
+/*
+ * Copyright (c) 2014 MediaTek Inc.
+ * Author: Xudong.chen <xudong.chen@mediatek.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/wait.h>
+#include <linux/mm.h>
+#include <linux/dma-mapping.h>
+#include <linux/scatterlist.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/clk.h>
+
+#define I2C_HS_NACKERR (1 << 2)
+#define I2C_ACKERR (1 << 1)
+#define I2C_TRANSAC_COMP (1 << 0)
+#define I2C_TRANSAC_START (1 << 0)
+#define I2C_TIMING_STEP_DIV_MASK (0x3f << 0)
+#define I2C_TIMING_SAMPLE_COUNT_MASK (0x7 << 0)
+#define I2C_TIMING_SAMPLE_DIV_MASK (0x7 << 8)
+#define I2C_TIMING_DATA_READ_MASK (0x7 << 12)
+#define I2C_DCM_DISABLE 0x0000
+#define I2C_IO_CONFIG_OPEN_DRAIN 0x0003
+#define I2C_IO_CONFIG_PUSH_PULL 0x0000
+#define I2C_SOFT_RST 0x0001
+#define I2C_FIFO_ADDR_CLR 0x0001
+#define I2C_DELAY_LEN 0x0002
+#define I2C_ST_START_CON 0x8001
+#define I2C_FS_START_CON 0x1800
+#define I2C_TIME_CLR_VALUE 0x0000
+#define I2C_TIME_DEFAULT_VALUE 0x0003
+#define I2C_WRRD_TRANAC_VALUE 0x0002
+#define I2C_RD_TRANAC_VALUE 0x0001
+
+
+
+#define I2C_DMA_CON_TX 0x0000
+#define I2C_DMA_CON_RX 0x0001
+#define I2C_DMA_START_EN 0x0001
+#define I2C_DMA_INT_FLAG_NONE 0x0000
+#define I2C_DMA_CLR_FLAG 0x0000
+
+#define I2C_DEFAUT_SPEED 100000 /* hz */
+#define MAX_FS_MODE_SPEED 400000
+#define MAX_HS_MODE_SPEED 3400000
+#define MAX_DMA_TRANS_SIZE 255
+#define MAX_WRRD_TRANS_SIZE 32
+#define MAX_SAMPLE_CNT_DIV 8
+#define MAX_STEP_CNT_DIV 64
+#define MAX_HS_STEP_CNT_DIV 8
+
+#define I2C_CONTROL_RS (0x1 << 1)
+#define I2C_CONTROL_DMA_EN (0x1 << 2)
+#define I2C_CONTROL_CLK_EXT_EN (0x1 << 3)
+#define I2C_CONTROL_DIR_CHANGE (0x1 << 4)
+#define I2C_CONTROL_ACKERR_DET_EN (0x1 << 5)
+#define I2C_CONTROL_TRANSFER_LEN_CHANGE (0x1 << 6)
+#define I2C_CONTROL_WRAPPER (0x1 << 0)
+
+#define I2C_DRV_NAME "mt-i2c"
+
+enum DMA_REGS_OFFSET {
+ OFFSET_INT_FLAG = 0x0,
+ OFFSET_INT_EN = 0x04,
+ OFFSET_EN = 0x08,
+ OFFSET_CON = 0x18,
+ OFFSET_TX_MEM_ADDR = 0x1c,
+ OFFSET_RX_MEM_ADDR = 0x20,
+ OFFSET_TX_LEN = 0x24,
+ OFFSET_RX_LEN = 0x28,
+};
+
+enum i2c_trans_st_rs {
+ I2C_TRANS_STOP = 0,
+ I2C_TRANS_REPEATED_START,
+};
+
+enum {
+ FS_MODE,
+ HS_MODE,
+};
+
+enum mt_trans_op {
+ I2C_MASTER_WR = 1,
+ I2C_MASTER_RD,
+ I2C_MASTER_WRRD,
+};
+
+enum I2C_REGS_OFFSET {
+ OFFSET_DATA_PORT = 0x0,
+ OFFSET_SLAVE_ADDR = 0x04,
+ OFFSET_INTR_MASK = 0x08,
+ OFFSET_INTR_STAT = 0x0c,
+ OFFSET_CONTROL = 0x10,
+ OFFSET_TRANSFER_LEN = 0x14,
+ OFFSET_TRANSAC_LEN = 0x18,
+ OFFSET_DELAY_LEN = 0x1c,
+ OFFSET_TIMING = 0x20,
+ OFFSET_START = 0x24,
+ OFFSET_EXT_CONF = 0x28,
+ OFFSET_FIFO_STAT = 0x30,
+ OFFSET_FIFO_THRESH = 0x34,
+ OFFSET_FIFO_ADDR_CLR = 0x38,
+ OFFSET_IO_CONFIG = 0x40,
+ OFFSET_RSV_DEBUG = 0x44,
+ OFFSET_HS = 0x48,
+ OFFSET_SOFTRESET = 0x50,
+ OFFSET_DCM_EN = 0x54,
+ OFFSET_PATH_DIR = 0x60,
+ OFFSET_DEBUGSTAT = 0x64,
+ OFFSET_DEBUGCTRL = 0x68,
+ OFFSET_TRANSFER_LEN_AUX = 0x6c,
+};
+
+struct mt_i2c_data {
+ unsigned int clk_frequency; /* bus speed in Hz */
+ unsigned int flags;
+ unsigned int clk_src_div;
+};
+
+struct i2c_dma_buf {
+ u8 *vaddr;
+ dma_addr_t paddr;
+};
+
+struct mt_i2c {
+ struct i2c_adapter adap; /* i2c host adapter */
+ struct device *dev;
+ wait_queue_head_t wait; /* i2c transfer wait queue */
+ /* set in i2c probe */
+ void __iomem *base; /* i2c base addr */
+ void __iomem *pdmabase; /* dma base address*/
+ int irqnr; /* i2c interrupt number */
+ struct i2c_dma_buf dma_buf; /* memory alloc for DMA mode */
+ struct clk *clk_main; /* main clock for i2c bus */
+ struct clk *clk_dma; /* DMA clock for i2c via DMA */
+ struct clk *clk_pmic; /* PMIC clock for i2c from PMIC */
+ bool have_pmic; /* can use i2c pins form PMIC */
+ bool have_dcm; /* HW DCM function */
+ bool use_push_pull; /* IO config push-pull mode */
+ /* set when doing the transfer */
+ u16 irq_stat; /* interrupt status */
+ unsigned int speed_hz; /* The speed in transfer */
+ bool trans_stop; /* i2c transfer stop */
+ enum mt_trans_op op;
+ u16 msg_len;
+ u8 *msg_buf; /* pointer to msg data */
+ u16 msg_aux_len; /* WRRD mode to set AUX_LEN register*/
+ u16 addr; /* 7bit slave address, without read/write bit */
+ u16 timing_reg;
+ u16 high_speed_reg;
+};
+
+static inline void i2c_writew(u16 value, struct mt_i2c *i2c, u8 offset)
+{
+ writew(value, i2c->base + offset);
+}
+
+static inline u16 i2c_readw(struct mt_i2c *i2c, u8 offset)
+{
+ return readw(i2c->base + offset);
+}
+
+static inline void i2c_writel_dma(u32 value, struct mt_i2c *i2c, u8 offset)
+{
+ writel(value, i2c->pdmabase + offset);
+}
+
+static int mt_i2c_clock_enable(struct mt_i2c *i2c)
+{
+ int ret;
+
+ ret = clk_prepare_enable(i2c->clk_dma);
+ if (ret)
+ return ret;
+
+ ret = clk_prepare_enable(i2c->clk_main);
+ if (ret)
+ goto err_main;
+
+ if (i2c->have_pmic) {
+ ret = clk_prepare_enable(i2c->clk_pmic);
+ if (ret)
+ goto err_pmic;
+ }
+ return 0;
+
+err_pmic:
+ clk_disable_unprepare(i2c->clk_main);
+err_main:
+ clk_disable_unprepare(i2c->clk_dma);
+
+ return ret;
+}
+
+static void mt_i2c_clock_disable(struct mt_i2c *i2c)
+{
+ if (i2c->have_pmic)
+ clk_disable_unprepare(i2c->clk_pmic);
+
+ clk_disable_unprepare(i2c->clk_main);
+ clk_disable_unprepare(i2c->clk_dma);
+}
+
+static void free_i2c_dma_bufs(struct mt_i2c *i2c)
+{
+ dma_free_coherent(i2c->adap.dev.parent, PAGE_SIZE,
+ i2c->dma_buf.vaddr, i2c->dma_buf.paddr);
+}
+
+static inline void mt_i2c_init_hw(struct mt_i2c *i2c)
+{
+ i2c_writew(I2C_SOFT_RST, i2c, OFFSET_SOFTRESET);
+ /* Set ioconfig */
+ if (i2c->use_push_pull)
+ i2c_writew(I2C_IO_CONFIG_PUSH_PULL, i2c, OFFSET_IO_CONFIG);
+ else
+ i2c_writew(I2C_IO_CONFIG_OPEN_DRAIN, i2c, OFFSET_IO_CONFIG);
+
+ if (i2c->have_dcm)
+ i2c_writew(I2C_DCM_DISABLE, i2c, OFFSET_DCM_EN);
+
+ i2c_writew(i2c->timing_reg, i2c, OFFSET_TIMING);
+ i2c_writew(i2c->high_speed_reg, i2c, OFFSET_HS);
+}
+
+/* calculate i2c port speed */
+static int i2c_set_speed(struct mt_i2c *i2c, unsigned int clk_src_in_hz)
+{
+ int mode;
+ unsigned int khz;
+ unsigned int step_cnt;
+ unsigned int sample_cnt;
+ unsigned int sclk;
+ unsigned int hclk;
+ unsigned int max_step_cnt;
+ unsigned int sample_div = MAX_SAMPLE_CNT_DIV;
+ unsigned int step_div;
+ unsigned int min_div;
+ unsigned int best_mul;
+ unsigned int cnt_mul;
+
+ if (i2c->speed_hz > MAX_HS_MODE_SPEED) {
+ return -EINVAL;
+ } else if (i2c->speed_hz > MAX_FS_MODE_SPEED) {
+ mode = HS_MODE;
+ max_step_cnt = MAX_HS_STEP_CNT_DIV;
+ } else {
+ mode = FS_MODE;
+ max_step_cnt = MAX_STEP_CNT_DIV;
+ }
+
+ step_div = max_step_cnt;
+ /* Find the best combination */
+ khz = i2c->speed_hz / 1000;
+ hclk = clk_src_in_hz / 1000;
+ min_div = ((hclk >> 1) + khz - 1) / khz;
+ best_mul = MAX_SAMPLE_CNT_DIV * max_step_cnt;
+
+ for (sample_cnt = 1; sample_cnt <= MAX_SAMPLE_CNT_DIV; sample_cnt++) {
+ step_cnt = (min_div + sample_cnt - 1) / sample_cnt;
+ cnt_mul = step_cnt * sample_cnt;
+ if (step_cnt > max_step_cnt)
+ continue;
+
+ if (cnt_mul < best_mul) {
+ best_mul = cnt_mul;
+ sample_div = sample_cnt;
+ step_div = step_cnt;
+ if (best_mul == min_div)
+ break;
+ }
+ }
+
+ sample_cnt = sample_div;
+ step_cnt = step_div;
+ sclk = hclk / (2 * sample_cnt * step_cnt);
+ if (sclk > khz) {
+ dev_dbg(i2c->dev, "%s mode: unsupported speed (%ldkhz)\n",
+ (mode == HS_MODE) ? "HS" : "ST/FT", (long int)khz);
+ return -ENOTSUPP;
+ }
+
+ step_cnt--;
+ sample_cnt--;
+
+ if (mode == HS_MODE) {
+ /* Set the hign speed mode register */
+ i2c->timing_reg = I2C_TIME_CLR_VALUE;
+ i2c->high_speed_reg = I2C_TIME_DEFAULT_VALUE |
+ (sample_cnt & I2C_TIMING_SAMPLE_COUNT_MASK) << 12 |
+ (step_cnt & I2C_TIMING_SAMPLE_COUNT_MASK) << 8;
+ } else {
+ i2c->timing_reg =
+ (sample_cnt & I2C_TIMING_SAMPLE_COUNT_MASK) << 8 |
+ (step_cnt & I2C_TIMING_STEP_DIV_MASK) << 0;
+ /* Disable the high speed transaction */
+ i2c->high_speed_reg = I2C_TIME_CLR_VALUE;
+ }
+
+ return 0;
+}
+
+static int mt_i2c_do_transfer(struct mt_i2c *i2c)
+{
+ u16 addr_reg;
+ u16 control_reg;
+ int tmo = i2c->adap.timeout;
+
+ i2c->trans_stop = false;
+ i2c->irq_stat = 0;
+
+ /* If use i2c pin from PMIC mt6397 side, need set PATH_DIR first */
+ if (i2c->have_pmic)
+ i2c_writew(I2C_CONTROL_WRAPPER, i2c, OFFSET_PATH_DIR);
+
+ control_reg = I2C_CONTROL_ACKERR_DET_EN |
+ I2C_CONTROL_CLK_EXT_EN | I2C_CONTROL_DMA_EN;
+ if (i2c->speed_hz > 400000)
+ control_reg |= I2C_CONTROL_RS;
+ if (i2c->op == I2C_MASTER_WRRD)
+ control_reg |= I2C_CONTROL_DIR_CHANGE | I2C_CONTROL_RS;
+ i2c_writew(control_reg, i2c, OFFSET_CONTROL);
+
+ /* set start condition */
+ if (i2c->speed_hz <= 100000)
+ i2c_writew(I2C_ST_START_CON, i2c, OFFSET_EXT_CONF);
+ else
+ i2c_writew(I2C_FS_START_CON, i2c, OFFSET_EXT_CONF);
+
+ if (~control_reg & I2C_CONTROL_RS)
+ i2c_writew(I2C_DELAY_LEN, i2c, OFFSET_DELAY_LEN);
+
+ addr_reg = i2c->addr << 1;
+ if (i2c->op == I2C_MASTER_RD)
+ addr_reg |= 0x1;
+ i2c_writew(addr_reg, i2c, OFFSET_SLAVE_ADDR);
+
+ /* Clear interrupt status */
+ i2c_writew(I2C_HS_NACKERR | I2C_ACKERR | I2C_TRANSAC_COMP,
+ i2c, OFFSET_INTR_STAT);
+ i2c_writew(I2C_FIFO_ADDR_CLR, i2c, OFFSET_FIFO_ADDR_CLR);
+
+ /* Enable interrupt */
+ i2c_writew(I2C_HS_NACKERR | I2C_ACKERR | I2C_TRANSAC_COMP,
+ i2c, OFFSET_INTR_MASK);
+
+ /* Set transfer and transaction len */
+ if (i2c->op == I2C_MASTER_WRRD) {
+ i2c_writew(i2c->msg_len | (i2c->msg_aux_len) << 8,
+ i2c, OFFSET_TRANSFER_LEN);
+ i2c_writew(I2C_WRRD_TRANAC_VALUE, i2c, OFFSET_TRANSAC_LEN);
+ } else {
+ i2c_writew(i2c->msg_len, i2c, OFFSET_TRANSFER_LEN);
+ i2c_writew(I2C_RD_TRANAC_VALUE, i2c, OFFSET_TRANSAC_LEN);
+ }
+
+ /* Prepare buffer data to start transfer */
+ if (i2c->op == I2C_MASTER_RD) {
+ i2c_writel_dma(I2C_DMA_INT_FLAG_NONE, i2c, OFFSET_INT_FLAG);
+ i2c_writel_dma(I2C_DMA_CON_RX, i2c, OFFSET_CON);
+ i2c_writel_dma((u32)i2c->msg_buf, i2c, OFFSET_RX_MEM_ADDR);
+ i2c_writel_dma(i2c->msg_len, i2c, OFFSET_RX_LEN);
+ } else if (i2c->op == I2C_MASTER_WR) {
+ i2c_writel_dma(I2C_DMA_INT_FLAG_NONE, i2c, OFFSET_INT_FLAG);
+ i2c_writel_dma(I2C_DMA_CON_TX, i2c, OFFSET_CON);
+ i2c_writel_dma((u32)i2c->msg_buf, i2c, OFFSET_TX_MEM_ADDR);
+ i2c_writel_dma(i2c->msg_len, i2c, OFFSET_TX_LEN);
+ } else {
+ i2c_writel_dma(I2C_DMA_CLR_FLAG, i2c, OFFSET_INT_FLAG);
+ i2c_writel_dma(I2C_DMA_CLR_FLAG, i2c, OFFSET_CON);
+ i2c_writel_dma((u32)i2c->msg_buf, i2c, OFFSET_TX_MEM_ADDR);
+ i2c_writel_dma((u32)i2c->dma_buf.paddr, i2c,
+ OFFSET_RX_MEM_ADDR);
+ i2c_writel_dma(i2c->msg_len, i2c, OFFSET_TX_LEN);
+ i2c_writel_dma(i2c->msg_aux_len, i2c, OFFSET_RX_LEN);
+ }
+
+ /* flush before sending start */
+ mb();
+ i2c_writel_dma(I2C_DMA_START_EN, i2c, OFFSET_EN);
+ i2c_writew(I2C_TRANSAC_START, i2c, OFFSET_START);
+
+ tmo = wait_event_timeout(i2c->wait, i2c->trans_stop, tmo);
+ if (tmo == 0) {
+ dev_dbg(i2c->dev, "addr: %x, transfer timeout\n", i2c->addr);
+ mt_i2c_init_hw(i2c);
+ return -ETIMEDOUT;
+ }
+
+ if (i2c->irq_stat & (I2C_HS_NACKERR | I2C_ACKERR)) {
+ dev_dbg(i2c->dev, "addr: %x, transfer ACK error\n", i2c->addr);
+ mt_i2c_init_hw(i2c);
+ return -EREMOTEIO;
+ }
+
+ dev_dbg(i2c->dev, "i2c transfer done.\n");
+
+ return 0;
+}
+
+static inline void mt_i2c_copy_to_dma(struct mt_i2c *i2c, struct i2c_msg *msg)
+{
+ /* if the operate is write, need to copy the data to DMA memory */
+ if (!(msg->flags & I2C_M_RD))
+ memcpy(i2c->dma_buf.vaddr, msg->buf, msg->len);
+}
+
+static inline void mt_i2c_copy_from_dma(struct mt_i2c *i2c,
+ struct i2c_msg *msg)
+{
+ /* if the operate is read, need to copy the data from DMA memory */
+ if (msg->flags & I2C_M_RD)
+ memcpy(msg->buf, i2c->dma_buf.vaddr, msg->len);
+}
+
+/*
+ * In MTK platform the STOP will be issued after each
+ * message was transferred which is not flow the clarify
+ * for i2c_transfer(), several I2C devices tolerate the STOP,
+ * but some device need Repeat-Start and do not compatible with STOP
+ * MTK platform has WRRD mode which can write then read with
+ * Repeat-Start between two message, so we combined two
+ * messages into one transaction.
+ * The max read length is 31
+ */
+static bool mt_i2c_should_combine(struct i2c_msg *msg)
+{
+ struct i2c_msg *next_msg = msg + 1;
+
+ if ((next_msg->len < MAX_WRRD_TRANS_SIZE) &&
+ msg->addr == next_msg->addr &&
+ !(msg->flags & I2C_M_RD) &&
+ (next_msg->flags & I2C_M_RD) == I2C_M_RD) {
+ return true;
+ }
+
+ return false;
+}
+
+static int mt_i2c_transfer(struct i2c_adapter *adap,
+ struct i2c_msg msgs[], int num)
+{
+ int ret;
+ int left_num = num;
+ struct mt_i2c *i2c = i2c_get_adapdata(adap);
+
+ ret = mt_i2c_clock_enable(i2c);
+ if (ret)
+ return ret;
+
+ while (left_num--) {
+ /* In MTK platform the max transfer number is 255 */
+ if (msgs->len > MAX_DMA_TRANS_SIZE) {
+ dev_dbg(i2c->dev,
+ " message data length is more than 255\n");
+ ret = -EINVAL;
+ goto err_exit;
+ }
+
+ if (msgs->addr == 0) {
+ dev_dbg(i2c->dev, " addr is invalid.\n");
+ ret = -EINVAL;
+ goto err_exit;
+ }
+
+ if (msgs->buf == NULL) {
+ dev_dbg(i2c->dev, " data buffer is NULL.\n");
+ ret = -EINVAL;
+ goto err_exit;
+ }
+
+ i2c->addr = msgs->addr;
+ i2c->msg_len = msgs->len;
+ i2c->msg_buf = msgs->buf;
+
+ if (msgs->flags & I2C_M_RD)
+ i2c->op = I2C_MASTER_RD;
+ else
+ i2c->op = I2C_MASTER_WR;
+
+ /* combined two messages into one transaction */
+ if (left_num >= 1 && mt_i2c_should_combine(msgs)) {
+ i2c->msg_aux_len = (msgs + 1)->len;
+ i2c->op = I2C_MASTER_WRRD;
+ left_num--;
+ }
+
+ /*
+ * always use DMA mode.
+ * 1st when write need copy the data of message to dma memory
+ * 2nd when read need copy the DMA data to the message buffer.
+ * The length should be less than 255.
+ */
+ mt_i2c_copy_to_dma(i2c, msgs);
+ i2c->msg_buf = (u8 *)i2c->dma_buf.paddr;
+ ret = mt_i2c_do_transfer(i2c);
+ if (ret < 0)
+ goto err_exit;
+
+ if (i2c->op == I2C_MASTER_WRRD)
+ mt_i2c_copy_from_dma(i2c, msgs + 1);
+ else
+ mt_i2c_copy_from_dma(i2c, msgs);
+
+ msgs++;
+
+ /* after combined two messages so we need ignore one */
+ if (left_num > 0 && i2c->op == I2C_MASTER_WRRD)
+ msgs++;
+ }
+ /* the return value is number of executed messages */
+ ret = num;
+
+err_exit:
+ mt_i2c_clock_disable(i2c);
+ return ret;
+}
+
+static irqreturn_t mt_i2c_irq(int irqno, void *dev_id)
+{
+ struct mt_i2c *i2c = dev_id;
+
+ /* Clear interrupt mask */
+ i2c_writew(~(I2C_HS_NACKERR | I2C_ACKERR | I2C_TRANSAC_COMP),
+ i2c, OFFSET_INTR_MASK);
+
+ i2c->irq_stat = i2c_readw(i2c, OFFSET_INTR_STAT);
+ i2c_writew(I2C_HS_NACKERR | I2C_ACKERR | I2C_TRANSAC_COMP,
+ i2c, OFFSET_INTR_STAT);
+ i2c->trans_stop = true;
+ wake_up(&i2c->wait);
+
+ return IRQ_HANDLED;
+}
+
+static u32 mt_i2c_functionality(struct i2c_adapter *adap)
+{
+ return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm mt_i2c_algorithm = {
+ .master_xfer = mt_i2c_transfer,
+ .functionality = mt_i2c_functionality,
+};
+
+static int mt_i2c_parse_dt(struct device_node *np, struct mt_i2c *i2c,
+ unsigned int *clk_src_div)
+{
+ i2c->speed_hz = I2C_DEFAUT_SPEED;
+ of_property_read_u32(np, "clock-frequency", &i2c->speed_hz);
+ of_property_read_u32(np, "clock-div", clk_src_div);
+ if (*clk_src_div == 0)
+ return -EINVAL;
+
+ i2c->have_pmic = of_property_read_bool(np, "mediatek,have-pmic");
+ i2c->have_dcm = of_property_read_bool(np, "mediatek,have-dcm");
+ i2c->use_push_pull =
+ of_property_read_bool(np, "mediatek,use-push-pull");
+
+ return 0;
+}
+
+static int mt_i2c_probe(struct platform_device *pdev)
+{
+ int ret = 0;
+ struct mt_i2c *i2c;
+ unsigned int clk_src_in_hz;
+ unsigned int clk_src_div;
+ struct resource *res;
+
+ i2c = devm_kzalloc(&pdev->dev, sizeof(struct mt_i2c), GFP_KERNEL);
+ if (i2c == NULL)
+ return -ENOMEM;
+
+ ret = mt_i2c_parse_dt(pdev->dev.of_node, i2c, &clk_src_div);
+ if (ret)
+ return -EINVAL;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+ i2c->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(i2c->base))
+ return PTR_ERR(i2c->base);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+
+ i2c->pdmabase = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(i2c->pdmabase))
+ return PTR_ERR(i2c->pdmabase);
+
+ i2c->irqnr = platform_get_irq(pdev, 0);
+ if (i2c->irqnr <= 0)
+ return -EINVAL;
+
+ ret = devm_request_irq(&pdev->dev, i2c->irqnr, mt_i2c_irq,
+ IRQF_TRIGGER_NONE, I2C_DRV_NAME, i2c);
+ if (ret < 0) {
+ dev_err(&pdev->dev,
+ "Request I2C IRQ %d fail\n", i2c->irqnr);
+ return ret;
+ }
+
+ i2c->adap.dev.of_node = pdev->dev.of_node;
+ i2c->dev = &i2c->adap.dev;
+ i2c->adap.dev.parent = &pdev->dev;
+ i2c->adap.owner = THIS_MODULE;
+ i2c->adap.algo = &mt_i2c_algorithm;
+ i2c->adap.algo_data = NULL;
+ i2c->adap.timeout = 2 * HZ;
+ i2c->adap.retries = 1;
+
+ i2c->clk_main = devm_clk_get(&pdev->dev, "main");
+ if (IS_ERR(i2c->clk_main)) {
+ dev_err(&pdev->dev, "cannot get main clock\n");
+ return PTR_ERR(i2c->clk_main);
+ }
+
+ i2c->clk_dma = devm_clk_get(&pdev->dev, "dma");
+ if (IS_ERR(i2c->clk_dma)) {
+ dev_err(&pdev->dev, "cannot get dma clock\n");
+ return PTR_ERR(i2c->clk_dma);
+ }
+
+ if (i2c->have_pmic) {
+ i2c->clk_pmic = devm_clk_get(&pdev->dev, "pmic");
+ if (IS_ERR(i2c->clk_pmic)) {
+ dev_err(&pdev->dev, "cannot get pmic clock\n");
+ return PTR_ERR(i2c->clk_pmic);
+ }
+ clk_src_in_hz = clk_get_rate(i2c->clk_pmic) / clk_src_div;
+ } else {
+ clk_src_in_hz = clk_get_rate(i2c->clk_main) / clk_src_div;
+ }
+
+ dev_dbg(&pdev->dev, "clock source %p,clock src frequency %d\n",
+ i2c->clk_main, clk_src_in_hz);
+ strlcpy(i2c->adap.name, I2C_DRV_NAME, sizeof(i2c->adap.name));
+ init_waitqueue_head(&i2c->wait);
+
+ ret = i2c_set_speed(i2c, clk_src_in_hz);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to set the speed\n");
+ return -EINVAL;
+ }
+
+ ret = mt_i2c_clock_enable(i2c);
+ if (ret) {
+ dev_err(&pdev->dev, "clock enable failed!\n");
+ return ret;
+ }
+ mt_i2c_init_hw(i2c);
+ mt_i2c_clock_disable(i2c);
+
+ i2c->dma_buf.vaddr = dma_alloc_coherent(&pdev->dev,
+ PAGE_SIZE, &i2c->dma_buf.paddr, GFP_KERNEL);
+ if (i2c->dma_buf.vaddr == NULL) {
+ dev_err(&pdev->dev, "dma_alloc_coherent fail\n");
+ return -ENOMEM;
+ }
+
+ i2c_set_adapdata(&i2c->adap, i2c);
+ ret = i2c_add_adapter(&i2c->adap);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to add i2c bus to i2c core\n");
+ free_i2c_dma_bufs(i2c);
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, i2c);
+
+ return 0;
+}
+
+static int mt_i2c_remove(struct platform_device *pdev)
+{
+ struct mt_i2c *i2c = platform_get_drvdata(pdev);
+
+ i2c_del_adapter(&i2c->adap);
+ free_i2c_dma_bufs(i2c);
+ platform_set_drvdata(pdev, NULL);
+
+ return 0;
+}
+
+static const struct of_device_id mtk_i2c_of_match[] = {
+ { .compatible = "mediatek,mt6577-i2c", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, mt_i2c_match);
+
+static struct platform_driver mt_i2c_driver = {
+ .probe = mt_i2c_probe,
+ .remove = mt_i2c_remove,
+ .driver = {
+ .name = I2C_DRV_NAME,
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(mtk_i2c_of_match),
+ },
+};
+
+module_platform_driver(mt_i2c_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("MediaTek I2C Bus Driver");
+MODULE_AUTHOR("Xudong Chen <xudong.chen@mediatek.com>");
--
1.8.1.1.dirty