i2c: sh_mobile: don't send a stop condition by default inside transfers (e7890297) · Commits · e / devices / android_kernel_xiaomi_markw

drivers/i2c/busses/i2c-sh_mobile.c

+59 −20

Original line number	Diff line number	Diff line
		@@ -38,21 +38,21 @@
		/* Transmit operation: */
		/* */
		/* 0 byte transmit */
		/* BUS: S A8 ACK P */
		/* BUS: S A8 ACK P() /
		/* IRQ: DTE WAIT */
		/* ICIC: */
		/* ICCR: 0x94 0x90 */
		/* ICDR: A8 */
		/* */
		/* 1 byte transmit */
		/* BUS: S A8 ACK D8(1) ACK P */
		/* BUS: S A8 ACK D8(1) ACK P() /
		/* IRQ: DTE WAIT WAIT */
		/* ICIC: -DTE */
		/* ICCR: 0x94 0x90 */
		/* ICDR: A8 D8(1) */
		/* */
		/* 2 byte transmit */
		/* BUS: S A8 ACK D8(1) ACK D8(2) ACK P */
		/* BUS: S A8 ACK D8(1) ACK D8(2) ACK P() /
		/* IRQ: DTE WAIT WAIT WAIT */
		/* ICIC: -DTE */
		/* ICCR: 0x94 0x90 */
		@@ -66,20 +66,20 @@
		/* 0 byte receive - not supported since slave may hold SDA low */
		/* */
		/* 1 byte receive [TX] \| [RX] */
		/* BUS: S A8 ACK \| D8(1) ACK P */
		/* BUS: S A8 ACK \| D8(1) ACK P() /
		/* IRQ: DTE WAIT \| WAIT DTE */
		/* ICIC: -DTE \| +DTE */
		/* ICCR: 0x94 0x81 \| 0xc0 */
		/* ICDR: A8 \| D8(1) */
		/* */
		/* 2 byte receive [TX]\| [RX] */
		/* BUS: S A8 ACK \| D8(1) ACK D8(2) ACK P */
		/* BUS: S A8 ACK \| D8(1) ACK D8(2) ACK P() /
		/* IRQ: DTE WAIT \| WAIT WAIT DTE */
		/* ICIC: -DTE \| +DTE */
		/* ICCR: 0x94 0x81 \| 0xc0 */
		/* ICDR: A8 \| D8(1) D8(2) */
		/* */
		/* 3 byte receive [TX] \| [RX] */
		/* 3 byte receive [TX] \| [RX] () /
		/* BUS: S A8 ACK \| D8(1) ACK D8(2) ACK D8(3) ACK P */
		/* IRQ: DTE WAIT \| WAIT WAIT WAIT DTE */
		/* ICIC: -DTE \| +DTE */
		@@ -94,7 +94,7 @@
		/* SDA ___\___XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXAAAAAAAAA___/ */
		/* SCL \_/1\_/2\_/3\_/4\_/5\_/6\_/7\_/8\___/9\_____/ */
		/* */
		/* S D7 D6 D5 D4 D3 D2 D1 D0 P */
		/* S D7 D6 D5 D4 D3 D2 D1 D0 P() /
		/* ___ */
		/* WAIT IRQ ________________________________/ \___________ */
		/* TACK IRQ ____________________________________/ \_______ */
		@@ -103,6 +103,11 @@
		/* _______________________________________________ */
		/* BUSY __/ \_ */
		/* */
		/* () The STOP condition is only sent by the master at the end of the last /
		/* I2C message or if the I2C_M_STOP flag is set. Similarly, the BUSY bit is */
		/* only cleared after the STOP condition, so, between messages we have to */
		/* poll for the DTE bit. */
		/* */

		enum sh_mobile_i2c_op {
		OP_START = 0,
		@@ -132,6 +137,7 @@ struct sh_mobile_i2c_data {
		struct i2c_msg *msg;
		int pos;
		int sr;
		bool send_stop;
		};

		#define IIC_FLAG_HAS_ICIC67 (1 << 0)
		@@ -322,7 +328,7 @@ static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
		break;
		case OP_TX_STOP: /* write data and issue a stop afterwards */
		iic_wr(pd, ICDR, data);
		iic_wr(pd, ICCR, 0x90);
		iic_wr(pd, ICCR, pd->send_stop ? 0x90 : 0x94);
		break;
		case OP_TX_TO_RX: /* select read mode */
		iic_wr(pd, ICCR, 0x81);
		@@ -469,13 +475,15 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
		return IRQ_HANDLED;
		}

		static int start_ch(struct sh_mobile_i2c_data pd, struct i2c_msg usr_msg)
		static int start_ch(struct sh_mobile_i2c_data pd, struct i2c_msg usr_msg,
		bool do_init)
		{
		if (usr_msg->len == 0 && (usr_msg->flags & I2C_M_RD)) {
		dev_err(pd->dev, "Unsupported zero length i2c read\n");
		return -EIO;
		}

		if (do_init) {
		/* Initialize channel registers */
		iic_set_clr(pd, ICCR, 0, ICCR_ICE);

		@@ -485,6 +493,7 @@ static int start_ch(struct sh_mobile_i2c_data pd, struct i2c_msg usr_msg)
		/* Set the clock */
		iic_wr(pd, ICCL, pd->iccl & 0xff);
		iic_wr(pd, ICCH, pd->icch & 0xff);
		}

		pd->msg = usr_msg;
		pd->pos = -1;
		@@ -495,6 +504,30 @@ static int start_ch(struct sh_mobile_i2c_data pd, struct i2c_msg usr_msg)
		return 0;
		}

		static int poll_dte(struct sh_mobile_i2c_data *pd)
		{
		int i;

		for (i = 1000; i; i--) {
		u_int8_t val = iic_rd(pd, ICSR);

		if (val & ICSR_DTE)
		break;

		if (val & ICSR_TACK)
		return -EIO;

		udelay(10);
		}

		if (!i) {
		dev_warn(pd->dev, "Timeout polling for DTE!\n");
		return -ETIMEDOUT;
		}

		return 0;
		}

		static int poll_busy(struct sh_mobile_i2c_data *pd)
		{
		int i;
		@@ -539,12 +572,15 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,

		/* Process all messages */
		for (i = 0; i < num; i++) {
		bool do_start = pd->send_stop \|\| !i;
		msg = &msgs[i];
		pd->send_stop = i == num - 1 \|\| msg->flags & I2C_M_STOP;

		err = start_ch(pd, msg);
		err = start_ch(pd, msg, do_start);
		if (err)
		break;

		if (do_start)
		i2c_op(pd, OP_START, 0);

		/* The interrupt handler takes care of the rest... */
		@@ -557,7 +593,10 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
		break;
		}

		if (pd->send_stop)
		err = poll_busy(pd);
		else
		err = poll_dte(pd);
		if (err < 0)
		break;
		}
		@@ -571,7 +610,7 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,

		static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
		{
		return I2C_FUNC_I2C \| I2C_FUNC_SMBUS_EMUL;
		return I2C_FUNC_I2C \| I2C_FUNC_SMBUS_EMUL \| I2C_FUNC_PROTOCOL_MANGLING;
		}

		static struct i2c_algorithm sh_mobile_i2c_algorithm = {