From ecde2ad896297eed23d9c78b740ce2b0906e76b9 Mon Sep 17 00:00:00 2001
From: Wolfram Sang <wsa+renesas@sang-engineering.com>
Date: Fri, 10 Nov 2017 12:52:10 +0100
Subject: [PATCH 0425/1795] i2c: sh_mobile: send STOP according to datasheet
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

We initiate STOP (or REP_START) on the second last WAIT interrupt
currently. This works fine but is not according to the datasheet which
says to do it on the last WAIT interrupt. This also simplifies the code
quite a lot, so let's do it.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
(cherry picked from commit a4fde7e5c9d6432ba863ee53debf27f10b370678)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 drivers/i2c/busses/i2c-sh_mobile.c | 29 ++++++-----------------------
 1 file changed, 6 insertions(+), 23 deletions(-)

diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
index 40a66d466c3c..c904be631db3 100644
--- a/drivers/i2c/busses/i2c-sh_mobile.c
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -40,21 +40,21 @@
 /* BUS:     S     A8     ACK   P(*)                                         */
 /* IRQ:       DTE   WAIT                                                    */
 /* ICIC:                                                                    */
-/* ICCR: 0x94 0x90                                                          */
+/* ICCR: 0x94       0x90                                                    */
 /* ICDR:      A8                                                            */
 /*                                                                          */
 /* 1 byte transmit                                                          */
 /* BUS:     S     A8     ACK   D8(1)   ACK   P(*)                           */
 /* IRQ:       DTE   WAIT         WAIT                                       */
 /* ICIC:      -DTE                                                          */
-/* ICCR: 0x94       0x90                                                    */
+/* ICCR: 0x94                    0x90                                       */
 /* ICDR:      A8    D8(1)                                                   */
 /*                                                                          */
 /* 2 byte transmit                                                          */
 /* BUS:     S     A8     ACK   D8(1)   ACK   D8(2)   ACK   P(*)             */
 /* IRQ:       DTE   WAIT         WAIT          WAIT                         */
 /* ICIC:      -DTE                                                          */
-/* ICCR: 0x94                    0x90                                       */
+/* ICCR: 0x94                                  0x90                         */
 /* ICDR:      A8    D8(1)        D8(2)                                      */
 /*                                                                          */
 /* 3 bytes or more, +---------+ gets repeated                               */
@@ -113,7 +113,6 @@ enum sh_mobile_i2c_op {
 	OP_TX_FIRST,
 	OP_TX,
 	OP_TX_STOP,
-	OP_TX_STOP_DATA,
 	OP_TX_TO_RX,
 	OP_RX,
 	OP_RX_STOP,
@@ -319,10 +318,7 @@ static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
 	case OP_TX: /* write data */
 		iic_wr(pd, ICDR, data);
 		break;
-	case OP_TX_STOP_DATA: /* write data and issue a stop afterwards */
-		iic_wr(pd, ICDR, data);
-		/* fallthrough */
-	case OP_TX_STOP: /* issue a stop */
+	case OP_TX_STOP: /* issue a stop (or rep_start) */
 		iic_wr(pd, ICCR, pd->send_stop ? ICCR_ICE | ICCR_TRS
 					       : ICCR_ICE | ICCR_TRS | ICCR_BBSY);
 		break;
@@ -356,11 +352,6 @@ static bool sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data *pd)
 	return pd->pos == -1;
 }
 
-static bool sh_mobile_i2c_is_last_byte(struct sh_mobile_i2c_data *pd)
-{
-	return pd->pos == pd->msg->len - 1;
-}
-
 static void sh_mobile_i2c_get_data(struct sh_mobile_i2c_data *pd,
 				   unsigned char *buf)
 {
@@ -378,20 +369,12 @@ static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
 	unsigned char data;
 
 	if (pd->pos == pd->msg->len) {
-		/* Send stop if we haven't yet (DMA case) */
-		if (pd->send_stop && pd->stop_after_dma)
-			i2c_op(pd, OP_TX_STOP, 0);
+		i2c_op(pd, OP_TX_STOP, 0);
 		return 1;
 	}
 
 	sh_mobile_i2c_get_data(pd, &data);
-
-	if (sh_mobile_i2c_is_last_byte(pd))
-		i2c_op(pd, OP_TX_STOP_DATA, data);
-	else if (sh_mobile_i2c_is_first_byte(pd))
-		i2c_op(pd, OP_TX_FIRST, data);
-	else
-		i2c_op(pd, OP_TX, data);
+	i2c_op(pd, sh_mobile_i2c_is_first_byte(pd) ? OP_TX_FIRST : OP_TX, data);
 
 	pd->pos++;
 	return 0;
-- 
2.19.0