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Message-ID: <CABuKBe+RXboBEZD7Bu_kSbVwiapJJcAuuw_wo=xw67osJWJ20w@mail.gmail.com>
Date: Thu, 30 Oct 2014 14:16:04 +0100
From: Matthias Brugger <matthias.bgg@...il.com>
To: Xudong Chen <xudong.chen@...iatek.com>
Cc: Mark Rutland <mark.rutland@....com>, arm@...nel.org,
Wolfram Sang <wsa@...-dreams.de>,
srv_heupstream <srv_heupstream@...iatek.com>,
Sascha Hauer <kernel@...gutronix.de>,
Rob Herring <robh+dt@...nel.org>,
Pawel Moll <pawel.moll@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>,
Russell King <linux@....linux.org.uk>,
Grant Likely <grant.likely@...aro.org>,
Jean Delvare <jdelvare@...e.de>, Arnd Bergmann <arnd@...db.de>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>, linux-i2c@...r.kernel.org,
Yingjoe Chen <yingjoe.chen@...iatek.com>,
Eddie Huang <eddie.huang@...iatek.com>,
Nathan Chung <nathan.chung@...iatek.com>,
YH Chen <yh.chen@...iatek.com>
Subject: Re: [PATCH 3/3] I2C: mediatek: Add driver for MediaTek I2C controller
2014-10-29 6:37 GMT+01:00 Xudong Chen <xudong.chen@...iatek.com>:
> 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@...iatek.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-$(CONFIG_I2C_MT65XX) += i2c-mt65xx.o
As it works for mt65xx and mt81xx series, better rename it to i2c-mtk.c
> obj-$(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@...iatek.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
> +
> +
> +
One new line is enough.
> +#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 {
Please rename all mt_ prefixes to mtk_ prefix to keep consistency
throughout the kernel.
> + 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);
So this is some sort of multiplexer bit, right?
I think in this case we need to build a multi function device (mfd)
where the pmic driver will set this bit.
> +
> + 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@...iatek.com>");
> --
> 1.8.1.1.dirty
>
--
motzblog.wordpress.com
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