Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753209Ab3IRSQv (ORCPT ); Wed, 18 Sep 2013 14:16:51 -0400 Received: from hqemgate14.nvidia.com ([216.228.121.143]:9511 "EHLO hqemgate14.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751606Ab3IRSQt (ORCPT ); Wed, 18 Sep 2013 14:16:49 -0400 X-PGP-Universal: processed; by hqnvupgp07.nvidia.com on Wed, 18 Sep 2013 11:16:48 -0700 From: Rhyland Klein To: Grant Likely , Laxman Dewangan CC: , , , Simon Glass , Olof Johansson , Rhyland Klein Subject: [IP REVIEW] spi/tegra114: Correct support for cs_change Date: Wed, 18 Sep 2013 14:13:39 -0400 Message-ID: <1379528019-6042-1-git-send-email-rklein@nvidia.com> X-Mailer: git-send-email 1.7.9.5 X-NVConfidentiality: public MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4739 Lines: 158 The tegra114 driver wasn't currently handling the cs_change functionality. It is meant to invert normal behavior, and we were only using it to possibly delay at the end of a transfer. This patch modifies the logic so that the cs state will be toggled after every individual transfer or NOT toggled at the end of the last transfer if cs_change is set in that transfer struct. Also, this builds in logic so that if a different device tries to start a transfer while CS is active from a different device, it will abort the previous transfer and start a new one for the new device. This work was based on the spi-atmel driver. Signed-off-by: Rhyland Klein --- drivers/spi/spi-tegra114.c | 59 ++++++++++++++++++++++++++++++++++++++------ 1 file changed, 52 insertions(+), 7 deletions(-) diff --git a/drivers/spi/spi-tegra114.c b/drivers/spi/spi-tegra114.c index 145dd43..a9973de 100644 --- a/drivers/spi/spi-tegra114.c +++ b/drivers/spi/spi-tegra114.c @@ -182,6 +182,7 @@ struct tegra_spi_data { u32 cur_speed; struct spi_device *cur_spi; + struct spi_device *cs_control; unsigned cur_pos; unsigned cur_len; unsigned words_per_32bit; @@ -717,7 +718,12 @@ static int tegra_spi_start_transfer_one(struct spi_device *spi, else if (req_mode == SPI_MODE_3) command1 |= SPI_CONTROL_MODE_3; - tegra_spi_writel(tspi, command1, SPI_COMMAND1); + if (tspi->cs_control) { + if (tspi->cs_control != spi) + tegra_spi_writel(tspi, command1, SPI_COMMAND1); + tspi->cs_control = NULL; + } else + tegra_spi_writel(tspi, command1, SPI_COMMAND1); command1 |= SPI_CS_SW_HW; if (spi->mode & SPI_CS_HIGH) @@ -732,6 +738,9 @@ static int tegra_spi_start_transfer_one(struct spi_device *spi, command1 |= SPI_BIT_LENGTH(bits_per_word - 1); } + if (t->len == 0 && !t->tx_buf && !t->rx_buf) + return 0; + if (tspi->is_packed) command1 |= SPI_PACKED; @@ -803,6 +812,17 @@ static int tegra_spi_setup(struct spi_device *spi) return 0; } +static void tegra_spi_transfer_delay(int delay) +{ + if (!delay) + return; + + if (delay >= 1000) + mdelay(delay / 1000); + + udelay(delay % 1000); +} + static int tegra_spi_transfer_one_message(struct spi_master *master, struct spi_message *msg) { @@ -812,6 +832,7 @@ static int tegra_spi_transfer_one_message(struct spi_master *master, struct spi_transfer *xfer; struct spi_device *spi = msg->spi; int ret; + bool skip = false; msg->status = 0; msg->actual_length = 0; @@ -819,13 +840,20 @@ static int tegra_spi_transfer_one_message(struct spi_master *master, single_xfer = list_is_singular(&msg->transfers); list_for_each_entry(xfer, &msg->transfers, transfer_list) { INIT_COMPLETION(tspi->xfer_completion); + ret = tegra_spi_start_transfer_one(spi, xfer, is_first_msg, single_xfer); if (ret < 0) { dev_err(tspi->dev, "spi can not start transfer, err %d\n", ret); - goto exit; + goto complete_xfer; + } + + if (xfer->len == 0 && !xfer->tx_buf && !xfer->rx_buf) { + skip = true; + goto complete_xfer; } + is_first_msg = false; ret = wait_for_completion_timeout(&tspi->xfer_completion, SPI_DMA_TIMEOUT); @@ -833,24 +861,41 @@ static int tegra_spi_transfer_one_message(struct spi_master *master, dev_err(tspi->dev, "spi trasfer timeout, err %d\n", ret); ret = -EIO; - goto exit; + goto complete_xfer; } if (tspi->tx_status || tspi->rx_status) { dev_err(tspi->dev, "Error in Transfer\n"); ret = -EIO; - goto exit; + goto complete_xfer; } msg->actual_length += xfer->len; - if (xfer->cs_change && xfer->delay_usecs) { + +complete_xfer: + if (ret < 0 || skip) { tegra_spi_writel(tspi, tspi->def_command1_reg, SPI_COMMAND1); - udelay(xfer->delay_usecs); + tegra_spi_transfer_delay(xfer->delay_usecs); + goto exit; + } else if (msg->transfers.prev == &xfer->transfer_list) { + /* This is the last transfer in message */ + if (xfer->cs_change) + tspi->cs_control = spi; + else { + tegra_spi_writel(tspi, tspi->def_command1_reg, + SPI_COMMAND1); + tegra_spi_transfer_delay(xfer->delay_usecs); + } + } else if (xfer->cs_change) { + tegra_spi_writel(tspi, tspi->def_command1_reg, + SPI_COMMAND1); + tegra_spi_transfer_delay(xfer->delay_usecs); } + } ret = 0; exit: - tegra_spi_writel(tspi, tspi->def_command1_reg, SPI_COMMAND1); + msg->status = ret; spi_finalize_current_message(master); return ret; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/