From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1cgwMQ-0002iO-5v for barebox@lists.infradead.org; Thu, 23 Feb 2017 16:35:24 +0000 From: Bastian Stender Date: Thu, 23 Feb 2017 17:34:49 +0100 Message-Id: <20170223163450.6611-1-bst@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH 1/2] i2c: mv64xxx: add software delays To: barebox@lists.infradead.org Cc: Bastian Stender As stated in Marvell's Functional Specifications in MV-S107021-U0 Rev. A on page 420 ff. software delays are needed. "SW delay represent a delay of at least 2 internal clock cycles". These delays are hereby implemented. The original kernel driver compensates the needed software delays with the time the interrupts take. Signed-off-by: Bastian Stender --- drivers/i2c/busses/i2c-mv64xxx.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c index 9b9e6c953f..45d5a2b6dc 100644 --- a/drivers/i2c/busses/i2c-mv64xxx.c +++ b/drivers/i2c/busses/i2c-mv64xxx.c @@ -270,6 +270,7 @@ mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status) } /* FALLTHRU */ case STATUS_MAST_RD_DATA_ACK: /* 0x50 */ + udelay(2); if (status != STATUS_MAST_RD_DATA_ACK) drv_data->action = ACTION_CONTINUE; else { @@ -280,6 +281,7 @@ mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status) if (drv_data->bytes_left == 1) drv_data->cntl_bits &= ~REG_CONTROL_ACK; + udelay(2); break; case STATUS_MAST_RD_DATA_NO_ACK: /* 0x58 */ @@ -318,6 +320,8 @@ static void mv64xxx_i2c_send_start(struct mv64xxx_i2c_data *drv_data) mv64xxx_i2c_prepare_for_io(drv_data, drv_data->msgs); mv64xxx_write(drv_data, drv_data->cntl_bits | REG_CONTROL_START, drv_data->reg_offsets.control); + + udelay(2); } static void @@ -333,7 +337,7 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data) mv64xxx_i2c_send_start(drv_data); if (drv_data->errata_delay) - udelay(5); + udelay(3); /* * We're never at the start of the message here, and by this @@ -349,6 +353,7 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data) break; case ACTION_SEND_ADDR_1: + udelay(2); mv64xxx_write(drv_data, drv_data->addr1, drv_data->reg_offsets.data); mv64xxx_write(drv_data, drv_data->cntl_bits, @@ -360,9 +365,11 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data) drv_data->reg_offsets.data); mv64xxx_write(drv_data, drv_data->cntl_bits, drv_data->reg_offsets.control); + udelay(2); break; case ACTION_SEND_DATA: + udelay(2); mv64xxx_write(drv_data, drv_data->msg->buf[drv_data->byte_posn++], drv_data->reg_offsets.data); mv64xxx_write(drv_data, drv_data->cntl_bits, @@ -383,8 +390,9 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data) mv64xxx_write(drv_data, drv_data->cntl_bits | REG_CONTROL_STOP, drv_data->reg_offsets.control); drv_data->block = false; + udelay(2); if (drv_data->errata_delay) - udelay(5); + udelay(3); break; -- 2.11.0 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox