From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760072AbZBFHRg (ORCPT ); Fri, 6 Feb 2009 02:17:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757001AbZBFHLc (ORCPT ); Fri, 6 Feb 2009 02:11:32 -0500 Received: from nwd2mail10.analog.com ([137.71.25.55]:13578 "EHLO nwd2mail10.analog.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752796AbZBFHLW (ORCPT ); Fri, 6 Feb 2009 02:11:22 -0500 X-IronPort-AV: E=Sophos;i="4.37,390,1231131600"; d="scan'208";a="82422025" From: Bryan Wu To: dbrownell@users.sourceforge.net, akpm@linux-foundation.org Cc: spi-devel-general@lists.sourceforge.net, linux-kernel@vger.kernel.org, Michael Hennerich , Bryan Wu Subject: [PATCH 19/20] Blackfin SPI Driver: Add GPIO controlled SPI Slave Select support Date: Fri, 6 Feb 2009 15:13:07 +0800 Message-Id: <1233904388-5765-20-git-send-email-cooloney@kernel.org> X-Mailer: git-send-email 1.5.6.3 In-Reply-To: <1233904388-5765-1-git-send-email-cooloney@kernel.org> References: <1233904388-5765-1-git-send-email-cooloney@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Michael Hennerich This patch adds support for GPIO controlled SPI Chip Selects. To make use of this feature, set chip_select = 0 and add a proper cs_gpio to your controller_data. struct spi_board_info .chip_select = 0 struct bfin5xx_spi_chip .cs_gpio = GPIO_P### There are various SPI devices that require SPI MODE_0, and need to have the Chip Selects asserted during the entire transfer. Consider using SPI_MODE_3 (SPI_CPHA | SPI_CPOL) if your device allows it. Signed-off-by: Michael Hennerich Signed-off-by: Bryan Wu --- arch/blackfin/include/asm/bfin5xx_spi.h | 1 + drivers/spi/spi_bfin5xx.c | 40 ++++++++++++++++++++++++------ 2 files changed, 33 insertions(+), 8 deletions(-) diff --git a/arch/blackfin/include/asm/bfin5xx_spi.h b/arch/blackfin/include/asm/bfin5xx_spi.h index e1bb164..da8b9ca 100644 --- a/arch/blackfin/include/asm/bfin5xx_spi.h +++ b/arch/blackfin/include/asm/bfin5xx_spi.h @@ -124,6 +124,7 @@ struct bfin5xx_spi_chip { u8 bits_per_word; u8 cs_change_per_word; u16 cs_chg_udelay; /* Some devices require 16-bit delays */ + u32 cs_gpio; }; #endif /* _SPI_CHANNEL_H_ */ diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c index 9459c42..3e63a5d 100644 --- a/drivers/spi/spi_bfin5xx.c +++ b/drivers/spi/spi_bfin5xx.c @@ -111,6 +111,7 @@ struct chip_data { u8 bits_per_word; /* 8 or 16 */ u8 cs_change_per_word; u16 cs_chg_udelay; /* Some devices require > 255usec delay */ + u32 cs_gpio; void (*write) (struct driver_data *); void (*read) (struct driver_data *); void (*duplex) (struct driver_data *); @@ -177,22 +178,30 @@ static int bfin_spi_flush(struct driver_data *drv_data) /* Chip select operation functions for cs_change flag */ static void bfin_spi_cs_active(struct driver_data *drv_data, struct chip_data *chip) { - u16 flag = read_FLAG(drv_data); + if (likely(chip->chip_select_num)) { + u16 flag = read_FLAG(drv_data); - flag |= chip->flag; - flag &= ~(chip->flag << 8); + flag |= chip->flag; + flag &= ~(chip->flag << 8); - write_FLAG(drv_data, flag); + write_FLAG(drv_data, flag); + } else { + gpio_set_value(chip->cs_gpio, 0); + } } static void bfin_spi_cs_deactive(struct driver_data *drv_data, struct chip_data *chip) { - u16 flag = read_FLAG(drv_data); + if (likely(chip->chip_select_num)) { + u16 flag = read_FLAG(drv_data); - flag &= ~chip->flag; - flag |= (chip->flag << 8); + flag &= ~chip->flag; + flag |= (chip->flag << 8); - write_FLAG(drv_data, flag); + write_FLAG(drv_data, flag); + } else { + gpio_set_value(chip->cs_gpio, 1); + } /* Move delay here for consistency */ if (chip->cs_chg_udelay) @@ -1036,6 +1045,7 @@ static int bfin_spi_setup(struct spi_device *spi) struct bfin5xx_spi_chip *chip_info = NULL; struct chip_data *chip; struct driver_data *drv_data = spi_master_get_devdata(spi->master); + int ret; /* Abort device setup if requested features are not supported */ if (spi->mode & ~(SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST)) { @@ -1081,6 +1091,7 @@ static int bfin_spi_setup(struct spi_device *spi) chip->bits_per_word = chip_info->bits_per_word; chip->cs_change_per_word = chip_info->cs_change_per_word; chip->cs_chg_udelay = chip_info->cs_chg_udelay; + chip->cs_gpio = chip_info->cs_gpio; } /* translate common spi framework into our register */ @@ -1121,6 +1132,16 @@ static int bfin_spi_setup(struct spi_device *spi) chip->flag = 1 << (spi->chip_select); chip->chip_select_num = spi->chip_select; + if (chip->chip_select_num == 0) { + ret = gpio_request(chip->cs_gpio, spi->modalias); + if (ret) { + if (drv_data->dma_requested) + free_dma(drv_data->dma_channel); + return ret; + } + gpio_direction_output(chip->cs_gpio, 1); + } + switch (chip->bits_per_word) { case 8: chip->n_bytes = 1; @@ -1186,6 +1207,9 @@ static void bfin_spi_cleanup(struct spi_device *spi) peripheral_free(ssel[spi->master->bus_num] [chip->chip_select_num-1]); + if (chip->chip_select_num == 0) + gpio_free(chip->cs_gpio); + kfree(chip); } -- 1.5.6.3