1 files changed, 89 insertions, 37 deletions

diff --git a/drivers/spi/spi_s3c24xx.c b/drivers/spi/spi_s3c24xx.c
index 03695b67ebd5..33d94f76b9ef 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);