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270 lines
5.8 KiB
270 lines
5.8 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* Renesas RCar IIC driver |
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* |
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* Copyright (C) 2017 Marek Vasut <[email protected]> |
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* |
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* Based on |
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* Copyright (C) 2011, 2013 Renesas Solutions Corp. |
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* Copyright (C) 2011, 2013 Nobuhiro Iwamatsu <[email protected]> |
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*/ |
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#include <common.h> |
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#include <clk.h> |
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#include <dm.h> |
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#include <i2c.h> |
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#include <asm/io.h> |
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struct rcar_iic_priv { |
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void __iomem *base; |
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struct clk clk; |
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u8 iccl; |
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u8 icch; |
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}; |
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#define RCAR_IIC_ICDR 0x00 |
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#define RCAR_IIC_ICCR 0x04 |
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#define RCAR_IIC_ICSR 0x08 |
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#define RCAR_IIC_ICIC 0x0c |
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#define RCAR_IIC_ICCL 0x10 |
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#define RCAR_IIC_ICCH 0x14 |
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/* ICCR */ |
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#define RCAR_IIC_ICCR_ICE BIT(7) |
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#define RCAR_IIC_ICCR_RACK BIT(6) |
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#define RCAR_IIC_ICCR_RTS BIT(4) |
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#define RCAR_IIC_ICCR_BUSY BIT(2) |
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#define RCAR_IIC_ICCR_SCP BIT(0) |
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/* ICSR / ICIC */ |
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#define RCAR_IC_BUSY BIT(4) |
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#define RCAR_IC_TACK BIT(2) |
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#define RCAR_IC_DTE BIT(0) |
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#define IRQ_WAIT 1000 |
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static void sh_irq_dte(struct udevice *dev) |
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{ |
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struct rcar_iic_priv *priv = dev_get_priv(dev); |
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int i; |
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for (i = 0; i < IRQ_WAIT; i++) { |
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if (RCAR_IC_DTE & readb(priv->base + RCAR_IIC_ICSR)) |
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break; |
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udelay(10); |
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} |
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} |
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static int sh_irq_dte_with_tack(struct udevice *dev) |
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{ |
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struct rcar_iic_priv *priv = dev_get_priv(dev); |
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int i; |
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for (i = 0; i < IRQ_WAIT; i++) { |
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if (RCAR_IC_DTE & readb(priv->base + RCAR_IIC_ICSR)) |
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break; |
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if (RCAR_IC_TACK & readb(priv->base + RCAR_IIC_ICSR)) |
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return -ETIMEDOUT; |
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udelay(10); |
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} |
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return 0; |
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} |
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static void sh_irq_busy(struct udevice *dev) |
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{ |
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struct rcar_iic_priv *priv = dev_get_priv(dev); |
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int i; |
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for (i = 0; i < IRQ_WAIT; i++) { |
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if (!(RCAR_IC_BUSY & readb(priv->base + RCAR_IIC_ICSR))) |
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break; |
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udelay(10); |
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} |
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} |
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static int rcar_iic_set_addr(struct udevice *dev, u8 chip, u8 read) |
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{ |
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struct rcar_iic_priv *priv = dev_get_priv(dev); |
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clrbits_8(priv->base + RCAR_IIC_ICCR, RCAR_IIC_ICCR_ICE); |
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setbits_8(priv->base + RCAR_IIC_ICCR, RCAR_IIC_ICCR_ICE); |
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writeb(priv->iccl, priv->base + RCAR_IIC_ICCL); |
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writeb(priv->icch, priv->base + RCAR_IIC_ICCH); |
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writeb(RCAR_IC_TACK, priv->base + RCAR_IIC_ICIC); |
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writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_RTS | RCAR_IIC_ICCR_BUSY, |
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priv->base + RCAR_IIC_ICCR); |
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sh_irq_dte(dev); |
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clrbits_8(priv->base + RCAR_IIC_ICSR, RCAR_IC_TACK); |
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writeb(chip << 1 | read, priv->base + RCAR_IIC_ICDR); |
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return sh_irq_dte_with_tack(dev); |
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} |
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static void rcar_iic_finish(struct udevice *dev) |
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{ |
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struct rcar_iic_priv *priv = dev_get_priv(dev); |
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writeb(0, priv->base + RCAR_IIC_ICSR); |
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clrbits_8(priv->base + RCAR_IIC_ICCR, RCAR_IIC_ICCR_ICE); |
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} |
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static int rcar_iic_read_common(struct udevice *dev, struct i2c_msg *msg) |
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{ |
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struct rcar_iic_priv *priv = dev_get_priv(dev); |
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int i, ret = -EREMOTEIO; |
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if (rcar_iic_set_addr(dev, msg->addr, 1) != 0) |
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goto err; |
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udelay(10); |
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writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_SCP, |
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priv->base + RCAR_IIC_ICCR); |
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for (i = 0; i < msg->len; i++) { |
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if (sh_irq_dte_with_tack(dev) != 0) |
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goto err; |
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msg->buf[i] = readb(priv->base + RCAR_IIC_ICDR) & 0xff; |
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if (msg->len - 1 == i) { |
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writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_RACK, |
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priv->base + RCAR_IIC_ICCR); |
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} |
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} |
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sh_irq_busy(dev); |
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ret = 0; |
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err: |
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rcar_iic_finish(dev); |
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return ret; |
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} |
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static int rcar_iic_write_common(struct udevice *dev, struct i2c_msg *msg) |
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{ |
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struct rcar_iic_priv *priv = dev_get_priv(dev); |
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int i, ret = -EREMOTEIO; |
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if (rcar_iic_set_addr(dev, msg->addr, 0) != 0) |
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goto err; |
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udelay(10); |
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for (i = 0; i < msg->len; i++) { |
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writeb(msg->buf[i], priv->base + RCAR_IIC_ICDR); |
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if (sh_irq_dte_with_tack(dev) != 0) |
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goto err; |
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} |
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if (msg->flags & I2C_M_STOP) { |
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writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_RTS, |
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priv->base + RCAR_IIC_ICCR); |
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if (sh_irq_dte_with_tack(dev) != 0) |
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goto err; |
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} |
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sh_irq_busy(dev); |
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ret = 0; |
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err: |
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rcar_iic_finish(dev); |
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return ret; |
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} |
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static int rcar_iic_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs) |
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{ |
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int ret; |
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for (; nmsgs > 0; nmsgs--, msg++) { |
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if (msg->flags & I2C_M_RD) |
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ret = rcar_iic_read_common(dev, msg); |
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else |
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ret = rcar_iic_write_common(dev, msg); |
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if (ret) |
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return -EREMOTEIO; |
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} |
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return ret; |
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} |
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static int rcar_iic_set_speed(struct udevice *dev, uint speed) |
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{ |
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struct rcar_iic_priv *priv = dev_get_priv(dev); |
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const unsigned int ratio_high = 4; |
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const unsigned int ratio_low = 5; |
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int clkrate, denom; |
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clkrate = clk_get_rate(&priv->clk); |
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if (clkrate < 0) |
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return clkrate; |
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/* |
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* Calculate the value for ICCL and ICCH. From the data sheet: |
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* iccl = (p-clock / transfer-rate) * (L / (L + H)) |
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* icch = (p clock / transfer rate) * (H / (L + H)) |
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* where L and H are the SCL low and high ratio. |
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*/ |
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denom = speed * (ratio_high + ratio_low); |
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priv->iccl = DIV_ROUND_CLOSEST(clkrate * ratio_low, denom); |
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priv->icch = DIV_ROUND_CLOSEST(clkrate * ratio_high, denom); |
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return 0; |
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} |
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static int rcar_iic_probe_chip(struct udevice *dev, uint addr, uint flags) |
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{ |
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struct rcar_iic_priv *priv = dev_get_priv(dev); |
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int ret; |
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rcar_iic_set_addr(dev, addr, 1); |
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writeb(RCAR_IIC_ICCR_ICE | RCAR_IIC_ICCR_SCP, |
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priv->base + RCAR_IIC_ICCR); |
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ret = sh_irq_dte_with_tack(dev); |
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rcar_iic_finish(dev); |
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return ret; |
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} |
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static int rcar_iic_probe(struct udevice *dev) |
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{ |
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struct rcar_iic_priv *priv = dev_get_priv(dev); |
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int ret; |
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priv->base = dev_read_addr_ptr(dev); |
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ret = clk_get_by_index(dev, 0, &priv->clk); |
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if (ret) |
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return ret; |
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ret = clk_enable(&priv->clk); |
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if (ret) |
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return ret; |
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rcar_iic_finish(dev); |
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return rcar_iic_set_speed(dev, 100000); |
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} |
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static const struct dm_i2c_ops rcar_iic_ops = { |
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.xfer = rcar_iic_xfer, |
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.probe_chip = rcar_iic_probe_chip, |
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.set_bus_speed = rcar_iic_set_speed, |
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}; |
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static const struct udevice_id rcar_iic_ids[] = { |
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{ .compatible = "renesas,rmobile-iic" }, |
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{ } |
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}; |
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U_BOOT_DRIVER(iic_rcar) = { |
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.name = "iic_rcar", |
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.id = UCLASS_I2C, |
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.of_match = rcar_iic_ids, |
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.probe = rcar_iic_probe, |
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.priv_auto_alloc_size = sizeof(struct rcar_iic_priv), |
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.ops = &rcar_iic_ops, |
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};
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