diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi_s3c24xx.c | 126 |
1 files changed, 89 insertions, 37 deletions
diff --git a/drivers/spi/spi_s3c24xx.c b/drivers/spi/spi_s3c24xx.c index 03695b67ebd..33d94f76b9e 100644 --- a/drivers/spi/spi_s3c24xx.c +++ b/drivers/spi/spi_s3c24xx.c @@ -28,6 +28,20 @@ #include <plat/regs-spi.h> #include <mach/spi.h> +/** + * s3c24xx_spi_devstate - per device data + * @hz: Last frequency calculated for @sppre field. + * @mode: Last mode setting for the @spcon field. + * @spcon: Value to write to the SPCON register. + * @sppre: Value to write to the SPPRE register. + */ +struct s3c24xx_spi_devstate { + unsigned int hz; + unsigned int mode; + u8 spcon; + u8 sppre; +}; + struct s3c24xx_spi { /* bitbang has to be first */ struct spi_bitbang bitbang; @@ -68,43 +82,31 @@ static void s3c24xx_spi_gpiocs(struct s3c2410_spi_info *spi, int cs, int pol) static void s3c24xx_spi_chipsel(struct spi_device *spi, int value) { + struct s3c24xx_spi_devstate *cs = spi->controller_state; struct s3c24xx_spi *hw = to_hw(spi); unsigned int cspol = spi->mode & SPI_CS_HIGH ? 1 : 0; - unsigned int spcon; + + /* change the chipselect state and the state of the spi engine clock */ switch (value) { case BITBANG_CS_INACTIVE: hw->set_cs(hw->pdata, spi->chip_select, cspol^1); + writeb(cs->spcon, hw->regs + S3C2410_SPCON); break; case BITBANG_CS_ACTIVE: - spcon = readb(hw->regs + S3C2410_SPCON); - - if (spi->mode & SPI_CPHA) - spcon |= S3C2410_SPCON_CPHA_FMTB; - else - spcon &= ~S3C2410_SPCON_CPHA_FMTB; - - if (spi->mode & SPI_CPOL) - spcon |= S3C2410_SPCON_CPOL_HIGH; - else - spcon &= ~S3C2410_SPCON_CPOL_HIGH; - - spcon |= S3C2410_SPCON_ENSCK; - - /* write new configration */ - - writeb(spcon, hw->regs + S3C2410_SPCON); + writeb(cs->spcon | S3C2410_SPCON_ENSCK, + hw->regs + S3C2410_SPCON); hw->set_cs(hw->pdata, spi->chip_select, cspol); - break; } } -static int s3c24xx_spi_setupxfer(struct spi_device *spi, - struct spi_transfer *t) +static int s3c24xx_spi_update_state(struct spi_device *spi, + struct spi_transfer *t) { struct s3c24xx_spi *hw = to_hw(spi); + struct s3c24xx_spi_devstate *cs = spi->controller_state; unsigned int bpw; unsigned int hz; unsigned int div; @@ -124,41 +126,89 @@ static int s3c24xx_spi_setupxfer(struct spi_device *spi, return -EINVAL; } - clk = clk_get_rate(hw->clk); - div = DIV_ROUND_UP(clk, hz * 2) - 1; + if (spi->mode != cs->mode) { + u8 spcon = SPCON_DEFAULT; - if (div > 255) - div = 255; + if (spi->mode & SPI_CPHA) + spcon |= S3C2410_SPCON_CPHA_FMTB; - dev_dbg(&spi->dev, "setting pre-scaler to %d (wanted %d, got %ld)\n", - div, hz, clk / (2 * (div + 1))); + if (spi->mode & SPI_CPOL) + spcon |= S3C2410_SPCON_CPOL_HIGH; + cs->mode = spi->mode; + cs->spcon = spcon; + } - writeb(div, hw->regs + S3C2410_SPPRE); + if (cs->hz != hz) { + clk = clk_get_rate(hw->clk); + div = DIV_ROUND_UP(clk, hz * 2) - 1; - spin_lock(&hw->bitbang.lock); - if (!hw->bitbang.busy) { - hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE); - /* need to ndelay for 0.5 clocktick ? */ + if (div > 255) + div = 255; + + dev_dbg(&spi->dev, "pre-scaler=%d (wanted %d, got %ld)\n", + div, hz, clk / (2 * (div + 1))); + + cs->hz = hz; + cs->sppre = div; } - spin_unlock(&hw->bitbang.lock); return 0; } +static int s3c24xx_spi_setupxfer(struct spi_device *spi, + struct spi_transfer *t) +{ + struct s3c24xx_spi_devstate *cs = spi->controller_state; + struct s3c24xx_spi *hw = to_hw(spi); + int ret; + + ret = s3c24xx_spi_update_state(spi, t); + if (!ret) + writeb(cs->sppre, hw->regs + S3C2410_SPPRE); + + return ret; +} + static int s3c24xx_spi_setup(struct spi_device *spi) { + struct s3c24xx_spi_devstate *cs = spi->controller_state; + struct s3c24xx_spi *hw = to_hw(spi); int ret; - ret = s3c24xx_spi_setupxfer(spi, NULL); - if (ret < 0) { - dev_err(&spi->dev, "setupxfer returned %d\n", ret); + /* allocate settings on the first call */ + if (!cs) { + cs = kzalloc(sizeof(struct s3c24xx_spi_devstate), GFP_KERNEL); + if (!cs) { + dev_err(&spi->dev, "no memory for controller state\n"); + return -ENOMEM; + } + + cs->spcon = SPCON_DEFAULT; + cs->hz = -1; + spi->controller_state = cs; + } + + /* initialise the state from the device */ + ret = s3c24xx_spi_update_state(spi, NULL); + if (ret) return ret; + + spin_lock(&hw->bitbang.lock); + if (!hw->bitbang.busy) { + hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE); + /* need to ndelay for 0.5 clocktick ? */ } + spin_unlock(&hw->bitbang.lock); return 0; } +static void s3c24xx_spi_cleanup(struct spi_device *spi) +{ + kfree(spi->controller_state); +} + static inline unsigned int hw_txbyte(struct s3c24xx_spi *hw, int count) { return hw->tx ? hw->tx[count] : 0; @@ -286,7 +336,9 @@ static int __init s3c24xx_spi_probe(struct platform_device *pdev) hw->bitbang.setup_transfer = s3c24xx_spi_setupxfer; hw->bitbang.chipselect = s3c24xx_spi_chipsel; hw->bitbang.txrx_bufs = s3c24xx_spi_txrx; - hw->bitbang.master->setup = s3c24xx_spi_setup; + + hw->master->setup = s3c24xx_spi_setup; + hw->master->cleanup = s3c24xx_spi_cleanup; dev_dbg(hw->dev, "bitbang at %p\n", &hw->bitbang); |