Thanks Tushar, On 7 December 2012 17:33, Tushar Behera <tushar.beh...@linaro.org> wrote: > On 12/03/2012 05:46 PM, Giridhar Maruthy wrote: >> This patch adds slave support to i2c. The dt entry i2c-mode >> decides at probe time if the controller needs to work in >> slave mode and the controller is accordingly programmed. >> >> Signed-off-by: Giridhar Maruthy <giridhar.maru...@linaro.org> >> --- >> drivers/i2c/busses/i2c-s3c2410.c | 100 >> ++++++++++++++++++++++++++------------ >> 1 file changed, 68 insertions(+), 32 deletions(-) >> >> diff --git a/drivers/i2c/busses/i2c-s3c2410.c >> b/drivers/i2c/busses/i2c-s3c2410.c >> index e93e7d6..d83a6d7 100644 >> --- a/drivers/i2c/busses/i2c-s3c2410.c >> +++ b/drivers/i2c/busses/i2c-s3c2410.c >> @@ -53,6 +53,9 @@ >> /* Max time to wait for bus to become idle after a xfer (in us) */ >> #define S3C2410_IDLE_TIMEOUT 5000 >> >> +/* To find the master/slave mode of current controller */ >> +#define is_master(i2c) (!i2c->i2c_mode) >> + >> /* i2c controller state */ >> enum s3c24xx_i2c_state { >> STATE_IDLE, >> @@ -89,6 +92,8 @@ struct s3c24xx_i2c { >> #ifdef CONFIG_CPU_FREQ >> struct notifier_block freq_transition; >> #endif >> + /* i2c_mode: 0 is for master; and 1 is for slave */ >> + unsigned int i2c_mode; >> }; >> >> static struct platform_device_id s3c24xx_driver_ids[] = { >> @@ -202,11 +207,21 @@ static void s3c24xx_i2c_message_start(struct >> s3c24xx_i2c *i2c, >> stat = 0; >> stat |= S3C2410_IICSTAT_TXRXEN; >> >> - if (msg->flags & I2C_M_RD) { >> - stat |= S3C2410_IICSTAT_MASTER_RX; >> - addr |= 1; >> - } else >> - stat |= S3C2410_IICSTAT_MASTER_TX; >> + if (is_master(i2c)) { >> + /* Master mode */ >> + if (msg->flags & I2C_M_RD) { >> + stat |= S3C2410_IICSTAT_MASTER_RX; >> + addr |= 1; >> + } else >> + stat |= S3C2410_IICSTAT_MASTER_TX; >> + } else { >> + /* Slave mode */ >> + if (msg->flags & I2C_M_RD) { >> + stat |= S3C2410_IICSTAT_SLAVE_RX; >> + addr |= 1; >> + } else >> + stat |= S3C2410_IICSTAT_SLAVE_TX; >> + } >> >> if (msg->flags & I2C_M_REV_DIR_ADDR) >> addr ^= 1; >> @@ -228,8 +243,10 @@ static void s3c24xx_i2c_message_start(struct >> s3c24xx_i2c *i2c, >> dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon); >> writel(iiccon, i2c->regs + S3C2410_IICCON); >> >> - stat |= S3C2410_IICSTAT_START; >> - writel(stat, i2c->regs + S3C2410_IICSTAT); >> + if (is_master(i2c)) { >> + stat |= S3C2410_IICSTAT_START; >> + writel(stat, i2c->regs + S3C2410_IICSTAT); >> + } >> } >> >> static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret) >> @@ -272,14 +289,19 @@ static inline void s3c24xx_i2c_stop(struct >> s3c24xx_i2c *i2c, int ret) >> * devices, the host as Master and the HDMIPHY device as the slave. >> * Skipping the STOP condition has been tested on this bus and >> works. >> */ >> - if (i2c->quirks & QUIRK_HDMIPHY) { >> - /* Stop driving the I2C pins */ >> - iicstat &= ~S3C2410_IICSTAT_TXRXEN; >> - } else { >> - /* stop the transfer */ >> - iicstat &= ~S3C2410_IICSTAT_START; >> + if (is_master(i2c)) { >> + if (i2c->quirks & QUIRK_HDMIPHY) { >> + /* Stop driving the I2C pins */ >> + iicstat &= ~S3C2410_IICSTAT_TXRXEN; >> + } else { >> + /* stop the transfer */ >> + if (is_master(i2c)) { > > This is executed only if is_master(i2c) is true, so there seems no need > to checking it again. >
Agreed, I will correct this. >> + /* Start/Stop required only for master */ >> + iicstat &= ~S3C2410_IICSTAT_START; >> + } >> + } >> + writel(iicstat, i2c->regs + S3C2410_IICSTAT); >> } >> - writel(iicstat, i2c->regs + S3C2410_IICSTAT); >> >> i2c->state = STATE_STOP; >> >> @@ -348,7 +370,8 @@ static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c >> *i2c, unsigned long iicstat) >> */ >> >> if (iicstat & S3C2410_IICSTAT_LASTBIT && >> - !(i2c->msg->flags & I2C_M_IGNORE_NAK)) { >> + !(i2c->msg->flags & I2C_M_IGNORE_NAK) && >> + is_master(i2c)) { >> /* ack was not received... */ >> >> dev_dbg(i2c->dev, "ack was not received\n"); >> @@ -380,7 +403,7 @@ static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c >> *i2c, unsigned long iicstat) >> * end of the message, and if so, work out what to do >> */ >> >> - if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) { >> + if (!(i2c->msg->flags & I2C_M_IGNORE_NAK) && >> is_master(i2c)) { >> if (iicstat & S3C2410_IICSTAT_LASTBIT) { >> dev_dbg(i2c->dev, "WRITE: No Ack\n"); >> >> @@ -432,7 +455,6 @@ static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c >> *i2c, unsigned long iicstat) >> >> } else { >> /* send stop */ >> - >> s3c24xx_i2c_stop(i2c, 0); >> } >> break; >> @@ -447,7 +469,7 @@ static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c >> *i2c, unsigned long iicstat) >> i2c->msg->buf[i2c->msg_ptr++] = byte; >> >> prepare_read: >> - if (is_msglast(i2c)) { >> + if (is_msglast(i2c) && is_master(i2c)) { >> /* last byte of buffer */ >> >> if (is_lastmsg(i2c)) >> @@ -612,11 +634,13 @@ static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c, >> if (i2c->suspended) >> return -EIO; >> >> - ret = s3c24xx_i2c_set_master(i2c); >> - if (ret != 0) { >> - dev_err(i2c->dev, "cannot get bus (error %d)\n", ret); >> - ret = -EAGAIN; >> - goto out; >> + if (is_master(i2c)) { >> + ret = s3c24xx_i2c_set_master(i2c); >> + if (ret != 0) { >> + dev_err(i2c->dev, "cannot get bus (error %d)\n", >> ret); >> + ret = -EAGAIN; >> + goto out; >> + } >> } >> >> i2c->msg = msgs; >> @@ -628,23 +652,29 @@ static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c, >> s3c24xx_i2c_enable_irq(i2c); >> s3c24xx_i2c_message_start(i2c, msgs); >> >> - timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5); >> + if (is_master(i2c)) >> + timeout = wait_event_timeout(i2c->wait,\ >> + i2c->msg_num == 0, HZ * 5); >> + else >> + wait_event_interruptible(i2c->wait, i2c->msg_num == 0); >> >> ret = i2c->msg_idx; >> >> /* having these next two as dev_err() makes life very >> * noisy when doing an i2cdetect */ >> >> - if (timeout == 0) >> - dev_dbg(i2c->dev, "timeout\n"); >> - else if (ret != num) >> - dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret); >> + if (is_master(i2c)) { >> + if (timeout == 0) >> + dev_dbg(i2c->dev, "timeout\n"); >> + else if (ret != num) >> + dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret); >> >> - /* For QUIRK_HDMIPHY, bus is already disabled */ >> - if (i2c->quirks & QUIRK_HDMIPHY) >> - goto out; >> + /* For QUIRK_HDMIPHY, bus is already disabled */ >> + if (i2c->quirks & QUIRK_HDMIPHY) >> + goto out; >> >> - s3c24xx_i2c_wait_idle(i2c); >> + s3c24xx_i2c_wait_idle(i2c); >> + } >> >> out: >> return ret; >> @@ -963,6 +993,7 @@ s3c24xx_i2c_parse_dt(struct device_node *np, struct >> s3c24xx_i2c *i2c) >> of_property_read_u32(np, "samsung,i2c-slave-addr", >> &pdata->slave_addr); >> of_property_read_u32(np, "samsung,i2c-max-bus-freq", >> (u32 *)&pdata->frequency); >> + of_property_read_u32(np, "samsung,i2c-mode", &i2c->i2c_mode); >> } >> #else >> static void >> @@ -1004,6 +1035,10 @@ static int s3c24xx_i2c_probe(struct platform_device >> *pdev) >> goto err_noclk; >> } >> >> + /* By default, i2c works in master mode */ >> + /* This currently will be updated using DT */ >> + i2c->i2c_mode = 0; >> + >> i2c->quirks = s3c24xx_get_device_quirks(pdev); >> if (pdata) >> memcpy(i2c->pdata, pdata, sizeof(*pdata)); >> @@ -1017,6 +1052,7 @@ static int s3c24xx_i2c_probe(struct platform_device >> *pdev) >> i2c->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD; >> i2c->tx_setup = 50; >> >> + >> init_waitqueue_head(&i2c->wait); >> >> /* find the clock and enable it */ >> -- >> 1.7.9.5 >> >> >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-ker...@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >> > > > -- > Tushar Behera -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/