From 23853973d9b76eb8b3cf46157689bc6187e141d9 Mon Sep 17 00:00:00 2001 From: Brian Niebuhr Date: Fri, 13 Aug 2010 10:57:44 +0530 Subject: [PATCH] spi: davinci: enable GPIO lines to be used as chip selects Sometimes, the chip selects provided by SPI module are muxed with other functionality and cannot be used in some designs. In such cases, it becomes convenient to use an available GPIO line as chip select. This patch enables the DaVinci SPI driver to treat specific GPIO lines as chip selects based on information provided in platform data. Signed-off-by: Brian Niebuhr Tested-By: Michael Williamson Signed-off-by: Sekhar Nori --- arch/arm/mach-davinci/include/mach/spi.h | 3 ++ drivers/spi/davinci_spi.c | 39 +++++++++++++++++++----- 2 files changed, 35 insertions(+), 7 deletions(-) diff --git a/arch/arm/mach-davinci/include/mach/spi.h b/arch/arm/mach-davinci/include/mach/spi.h index 2cb326e536bb..734d1fb99614 100644 --- a/arch/arm/mach-davinci/include/mach/spi.h +++ b/arch/arm/mach-davinci/include/mach/spi.h @@ -19,6 +19,8 @@ #ifndef __ARCH_ARM_DAVINCI_SPI_H #define __ARCH_ARM_DAVINCI_SPI_H +#define SPI_INTERN_CS 0xFF + enum { SPI_VERSION_1, /* For DM355/DM365/DM6467 */ SPI_VERSION_2, /* For DA8xx */ @@ -38,6 +40,7 @@ struct davinci_spi_platform_data { u8 use_dma; u8 c2tdelay; u8 t2cdelay; + u8 *chip_sel; }; #endif /* __ARCH_ARM_DAVINCI_SPI_H */ diff --git a/drivers/spi/davinci_spi.c b/drivers/spi/davinci_spi.c index 82dddf83daf7..d5d7014e6ae2 100644 --- a/drivers/spi/davinci_spi.c +++ b/drivers/spi/davinci_spi.c @@ -238,20 +238,32 @@ static void davinci_spi_chipselect(struct spi_device *spi, int value) struct davinci_spi_platform_data *pdata; u8 chip_sel = spi->chip_select; u16 spidat1_cfg = CS_DEFAULT; + bool gpio_chipsel = false; davinci_spi = spi_master_get_devdata(spi->master); pdata = davinci_spi->pdata; + if (pdata->chip_sel && chip_sel < pdata->num_chipselect && + pdata->chip_sel[chip_sel] != SPI_INTERN_CS) + gpio_chipsel = true; + /* * Board specific chip select logic decides the polarity and cs * line for the controller */ - if (value == BITBANG_CS_ACTIVE) { - spidat1_cfg |= SPIDAT1_CSHOLD_MASK; - spidat1_cfg &= ~(0x1 << chip_sel); - } + if (gpio_chipsel) { + if (value == BITBANG_CS_ACTIVE) + gpio_set_value(pdata->chip_sel[chip_sel], 0); + else + gpio_set_value(pdata->chip_sel[chip_sel], 1); + } else { + if (value == BITBANG_CS_ACTIVE) { + spidat1_cfg |= SPIDAT1_CSHOLD_MASK; + spidat1_cfg &= ~(0x1 << chip_sel); + } - iowrite16(spidat1_cfg, davinci_spi->base + SPIDAT1 + 2); + iowrite16(spidat1_cfg, davinci_spi->base + SPIDAT1 + 2); + } } /** @@ -546,6 +558,7 @@ static void davinci_spi_cleanup(struct spi_device *spi) static int davinci_spi_bufs_prep(struct spi_device *spi, struct davinci_spi *davinci_spi) { + struct davinci_spi_platform_data *pdata; int op_mode = 0; /* @@ -558,8 +571,12 @@ static int davinci_spi_bufs_prep(struct spi_device *spi, op_mode = SPIPC0_DIFUN_MASK | SPIPC0_DOFUN_MASK | SPIPC0_CLKFUN_MASK; - if (!(spi->mode & SPI_NO_CS)) - op_mode |= 1 << spi->chip_select; + if (!(spi->mode & SPI_NO_CS)) { + pdata = davinci_spi->pdata; + if (!pdata->chip_sel || + pdata->chip_sel[spi->chip_select] == SPI_INTERN_CS) + op_mode |= 1 << spi->chip_select; + } if (spi->mode & SPI_READY) op_mode |= SPIPC0_SPIENA_MASK; @@ -1101,6 +1118,14 @@ static int davinci_spi_probe(struct platform_device *pdev) udelay(100); iowrite32(1, davinci_spi->base + SPIGCR0); + /* initialize chip selects */ + if (pdata->chip_sel) { + for (i = 0; i < pdata->num_chipselect; i++) { + if (pdata->chip_sel[i] != SPI_INTERN_CS) + gpio_direction_output(pdata->chip_sel[i], 1); + } + } + /* Clock internal */ if (davinci_spi->pdata->clk_internal) set_io_bits(davinci_spi->base + SPIGCR1, -- 2.39.5