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> -----Original Message-----
> From: Pandy Gao
> Sent: Monday, November 21, 2016 3:52 PM
> To: wsa@xxxxxxxxxxxxx; u.kleine-koenig@xxxxxxxxxxxxxx;
> cmo@xxxxxxxxxxx; robh@xxxxxxxxxx; vz@xxxxxxxxx; wsa-dev@sang-
> engineering.com
> Cc: linux-i2c@xxxxxxxxxxxxxxx; Pandy Gao <pandy.gao@xxxxxxx>; Frank
> Li <frank.li@xxxxxxx>; Andy Duan <fugang.duan@xxxxxxx>
> Subject: [Patch V5 2/2] i2c: imx: add low power i2c bus driver
>
> This patch adds lpi2c bus driver to support new i.MX products which use
> lpi2c instead of the old imx i2c.
>
> The lpi2c can continue operating in stop mode when an appropriate clock
> is available. It is also designed for low CPU overhead with DMA offloading
> of FIFO register accesses.
>
> Signed-off-by: Gao Pan <pandy.gao@xxxxxxx>
> Reviewed-by: Fugang Duan <B38611@xxxxxxxxxxxxx>
> Reviewed-by: Vladimir Zapolskiy <vz@xxxxxxxxx>
> ---
> V2:
> -stop i2c transfer under the wrong condition -add timeout check in
> while() domain
>
> V3:
> -fix typo inside commit message and the driver.
>
> V4:
> As Vladimir Zapolskiy's review, the version do below changes:
> -split devicetree binding with driver
> -prepare clk in probe()
> -replace "1<<n" BIT(n)
> -remove unnecessary variables
> -fix typo
> -use module_platform_driver()
> -use i2c_add_adapter()
>
> V5:
> -unprepare clk in lpi2c_imx_remove()
> -disable clk when lpi2c_imx_config() fails -unprepare clk when
> i2c_add_adapter() fails
>
> drivers/i2c/busses/Kconfig | 10 +
> drivers/i2c/busses/Makefile | 1 +
> drivers/i2c/busses/i2c-imx-lpi2c.c | 649
> +++++++++++++++++++++++++++++++++++++
> 3 files changed, 660 insertions(+)
>
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index
> d252276..7cff9ec 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -597,6 +597,16 @@ config I2C_IMX
> This driver can also be built as a module. If so, the module
> will be called i2c-imx.
>
> +config I2C_IMX_LPI2C
> + tristate "IMX Low Power I2C interface"
> + depends on ARCH_MXC || COMPILE_TEST
> + help
> + Say Y here if you want to use the Low Power IIC bus controller
> + on the Freescale i.MX processors.
> +
> + This driver can also be built as a module. If so, the module
> + will be called i2c-imx-lpi2c.
> +
> config I2C_IOP3XX
> tristate "Intel IOPx3xx and IXP4xx on-chip I2C interface"
> depends on ARCH_IOP32X || ARCH_IOP33X || ARCH_IXP4XX ||
> ARCH_IOP13XX diff --git a/drivers/i2c/busses/Makefile
> b/drivers/i2c/busses/Makefile index 29764cc..05195cd 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -56,6 +56,7 @@ obj-$(CONFIG_I2C_HIX5HD2) += i2c-
> hix5hd2.o
> obj-$(CONFIG_I2C_IBM_IIC) += i2c-ibm_iic.o
> obj-$(CONFIG_I2C_IMG) += i2c-img-scb.o
> obj-$(CONFIG_I2C_IMX) += i2c-imx.o
> +obj-$(CONFIG_I2C_IMX_LPI2C) += i2c-imx-lpi2c.o
> obj-$(CONFIG_I2C_IOP3XX) += i2c-iop3xx.o
> obj-$(CONFIG_I2C_JZ4780) += i2c-jz4780.o
> obj-$(CONFIG_I2C_KEMPLD) += i2c-kempld.o
> diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-
> imx-lpi2c.c
> new file mode 100644
> index 0000000..af5d1b6
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
> @@ -0,0 +1,649 @@
> +/*
> + * 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);
> + return IRQ_HANDLED;
> + }
> +
> + if (temp & MSR_TDF) {
> + lpi2c_imx_write_txfifo(lpi2c_imx);
> + return IRQ_HANDLED;
> + }
> +
> + 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@xxxxxxx>");
> MODULE_DESCRIPTION("I2C
> +adapter driver for LPI2C bus"); MODULE_LICENSE("GPL v2");
> --
> 1.9.1
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