SPI: added support for MX51 to mxc_spi

This patch add SPI support for the MX51 processor.

Signed-off-by: Stefano Babic <sbabic@denx.de>

diff --git a/drivers/spi/mxc_spi.c b/drivers/spi/mxc_spi.c
index 3a45200..e15a63c 100644 (file)
--- a/drivers/spi/mxc_spi.c
+++ b/drivers/spi/mxc_spi.c
@@ -31,7 +31,7 @@
 #error "i.MX27 CSPI not supported due to drastic differences in register definisions" \
 "See linux mxc_spi driver from Freescale for details."
 
-#else
+#elif defined(CONFIG_MX31)
 
 #include <asm/arch/mx31.h>
 
@@ -56,6 +56,9 @@
 #define MXC_CSPICTRL_CHIPSELECT(x)     (((x) & 0x3) << 24)
 #define MXC_CSPICTRL_BITCOUNT(x)       (((x) & 0x1f) << 8)
 #define MXC_CSPICTRL_DATARATE(x)       (((x) & 0x7) << 16)
+#define MXC_CSPICTRL_TC                (1 << 8)
+#define MXC_CSPICTRL_RXOVF     (1 << 6)
+#define MXC_CSPICTRL_MAXBITS   0x1f
 
 #define MXC_CSPIPERIOD_32KHZ   (1 << 15)
 
@@ -65,12 +68,63 @@ static unsigned long spi_bases[] = {
        0x53f84000,
 };
 
+#define OUT    MX31_GPIO_DIRECTION_OUT
+#define mxc_gpio_direction     mx31_gpio_direction
+#define mxc_gpio_set           mx31_gpio_set
+#elif defined(CONFIG_MX51)
+#include <asm/arch/imx-regs.h>
+#include <asm/arch/clock.h>
+
+#define MXC_CSPIRXDATA         0x00
+#define MXC_CSPITXDATA         0x04
+#define MXC_CSPICTRL           0x08
+#define MXC_CSPICON            0x0C
+#define MXC_CSPIINT            0x10
+#define MXC_CSPIDMA            0x14
+#define MXC_CSPISTAT           0x18
+#define MXC_CSPIPERIOD         0x1C
+#define MXC_CSPIRESET          0x00
+#define MXC_CSPICTRL_EN                (1 << 0)
+#define MXC_CSPICTRL_MODE      (1 << 1)
+#define MXC_CSPICTRL_XCH       (1 << 2)
+#define MXC_CSPICTRL_CHIPSELECT(x)     (((x) & 0x3) << 12)
+#define MXC_CSPICTRL_BITCOUNT(x)       (((x) & 0xfff) << 20)
+#define MXC_CSPICTRL_PREDIV(x) (((x) & 0xF) << 12)
+#define MXC_CSPICTRL_POSTDIV(x)        (((x) & 0xF) << 8)
+#define MXC_CSPICTRL_SELCHAN(x)        (((x) & 0x3) << 18)
+#define MXC_CSPICTRL_MAXBITS   0xfff
+#define MXC_CSPICTRL_TC                (1 << 7)
+#define MXC_CSPICTRL_RXOVF     (1 << 6)
+
+#define MXC_CSPIPERIOD_32KHZ   (1 << 15)
+
+/* Bit position inside CTRL register to be associated with SS */
+#define MXC_CSPICTRL_CHAN      18
+
+/* Bit position inside CON register to be associated with SS */
+#define MXC_CSPICON_POL                4
+#define MXC_CSPICON_PHA                0
+#define MXC_CSPICON_SSPOL      12
+
+static unsigned long spi_bases[] = {
+       CSPI1_BASE_ADDR,
+       CSPI2_BASE_ADDR,
+       CSPI3_BASE_ADDR,
+};
+#define mxc_gpio_direction(gpio, dir)  (0)
+#define mxc_gpio_set(gpio, value)      {}
+#define OUT    1
+#else
+#error "Unsupported architecture"
 #endif
 
 struct mxc_spi_slave {
        struct spi_slave slave;
        unsigned long   base;
        u32             ctrl_reg;
+#if defined(CONFIG_MX51)
+       u32             cfg_reg;
+#endif
        int             gpio;
 };
 
@@ -89,34 +143,161 @@ static inline void reg_write(unsigned long addr, u32 val)
        *(volatile unsigned long*)addr = val;
 }
 
+void spi_cs_activate(struct spi_slave *slave)
+{
+       struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave);
+       if (mxcs->gpio > 0)
+               mxc_gpio_set(mxcs->gpio, mxcs->ctrl_reg & MXC_CSPICTRL_SSPOL);
+}
+
+void spi_cs_deactivate(struct spi_slave *slave)
+{
+       struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave);
+       if (mxcs->gpio > 0)
+               mxc_gpio_set(mxcs->gpio,
+                             !(mxcs->ctrl_reg & MXC_CSPICTRL_SSPOL));
+}
+
+#ifdef CONFIG_MX51
+static s32 spi_cfg(struct mxc_spi_slave *mxcs, unsigned int cs,
+               unsigned int max_hz, unsigned int mode)
+{
+       u32 clk_src = mxc_get_clock(MXC_CSPI_CLK);
+       s32 pre_div = 0, post_div = 0, i, reg_ctrl, reg_config;
+       u32 ss_pol = 0, sclkpol = 0, sclkpha = 0;
+
+       if (max_hz == 0) {
+               printf("Error: desired clock is 0\n");
+               return -1;
+       }
+
+       reg_ctrl = reg_read(mxcs->base + MXC_CSPICTRL);
+
+       /* Reset spi */
+       reg_write(mxcs->base + MXC_CSPICTRL, 0);
+       reg_write(mxcs->base + MXC_CSPICTRL, (reg_ctrl | 0x1));
+
+       /*
+        * The following computation is taken directly from Freescale's code.
+        */
+       if (clk_src > max_hz) {
+               pre_div = clk_src / max_hz;
+               if (pre_div > 16) {
+                       post_div = pre_div / 16;
+                       pre_div = 15;
+               }
+               if (post_div != 0) {
+                       for (i = 0; i < 16; i++) {
+                               if ((1 << i) >= post_div)
+                                       break;
+                       }
+                       if (i == 16) {
+                               printf("Error: no divider for the freq: %d\n",
+                                       max_hz);
+                               return -1;
+                       }
+                       post_div = i;
+               }
+       }
+
+       debug("pre_div = %d, post_div=%d\n", pre_div, post_div);
+       reg_ctrl = (reg_ctrl & ~MXC_CSPICTRL_SELCHAN(3)) |
+               MXC_CSPICTRL_SELCHAN(cs);
+       reg_ctrl = (reg_ctrl & ~MXC_CSPICTRL_PREDIV(0x0F)) |
+               MXC_CSPICTRL_PREDIV(pre_div);
+       reg_ctrl = (reg_ctrl & ~MXC_CSPICTRL_POSTDIV(0x0F)) |
+               MXC_CSPICTRL_POSTDIV(post_div);
+
+       /* always set to master mode */
+       reg_ctrl |= 1 << (cs + 4);
+
+       /* We need to disable SPI before changing registers */
+       reg_ctrl &= ~MXC_CSPICTRL_EN;
+
+       if (mode & SPI_CS_HIGH)
+               ss_pol = 1;
+
+       if (!(mode & SPI_CPOL))
+               sclkpol = 1;
+
+       if (mode & SPI_CPHA)
+               sclkpha = 1;
+
+       reg_config = reg_read(mxcs->base + MXC_CSPICON);
+
+       /*
+        * Configuration register setup
+        * The MX51 has support different setup for each SS
+        */
+       reg_config = (reg_config & ~(1 << (cs + MXC_CSPICON_SSPOL))) |
+               (ss_pol << (cs + MXC_CSPICON_SSPOL));
+       reg_config = (reg_config & ~(1 << (cs + MXC_CSPICON_POL))) |
+               (sclkpol << (cs + MXC_CSPICON_POL));
+       reg_config = (reg_config & ~(1 << (cs + MXC_CSPICON_PHA))) |
+               (sclkpha << (cs + MXC_CSPICON_PHA));
+
+       debug("reg_ctrl = 0x%x\n", reg_ctrl);
+       reg_write(mxcs->base + MXC_CSPICTRL, reg_ctrl);
+       debug("reg_config = 0x%x\n", reg_config);
+       reg_write(mxcs->base + MXC_CSPICON, reg_config);
+
+       /* save config register and control register */
+       mxcs->ctrl_reg = reg_ctrl;
+       mxcs->cfg_reg = reg_config;
+
+       /* clear interrupt reg */
+       reg_write(mxcs->base + MXC_CSPIINT, 0);
+       reg_write(mxcs->base + MXC_CSPISTAT,
+               MXC_CSPICTRL_TC | MXC_CSPICTRL_RXOVF);
+
+       return 0;
+}
+#endif
+
 static u32 spi_xchg_single(struct spi_slave *slave, u32 data, int bitlen,
                           unsigned long flags)
 {
        struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave);
-       unsigned int cfg_reg = reg_read(mxcs->base + MXC_CSPICTRL);
 
-       mxcs->ctrl_reg = (mxcs->ctrl_reg & ~MXC_CSPICTRL_BITCOUNT(31)) |
+       if (flags & SPI_XFER_BEGIN)
+               spi_cs_activate(slave);
+
+       mxcs->ctrl_reg = (mxcs->ctrl_reg &
+               ~MXC_CSPICTRL_BITCOUNT(MXC_CSPICTRL_MAXBITS)) |
                MXC_CSPICTRL_BITCOUNT(bitlen - 1);
 
-       if (cfg_reg != mxcs->ctrl_reg)
-               reg_write(mxcs->base + MXC_CSPICTRL, mxcs->ctrl_reg);
+       reg_write(mxcs->base + MXC_CSPICTRL, mxcs->ctrl_reg | MXC_CSPICTRL_EN);
+#ifdef CONFIG_MX51
+       reg_write(mxcs->base + MXC_CSPICON, mxcs->cfg_reg);
+#endif
 
-       if (mxcs->gpio > 0 && (flags & SPI_XFER_BEGIN))
-               mx31_gpio_set(mxcs->gpio, mxcs->ctrl_reg & MXC_CSPICTRL_SSPOL);
+       /* Clear interrupt register */
+       reg_write(mxcs->base + MXC_CSPISTAT,
+               MXC_CSPICTRL_TC | MXC_CSPICTRL_RXOVF);
 
+       debug("Sending SPI 0x%x\n", data);
        reg_write(mxcs->base + MXC_CSPITXDATA, data);
 
-       reg_write(mxcs->base + MXC_CSPICTRL, mxcs->ctrl_reg | MXC_CSPICTRL_XCH);
+       /* FIFO is written, now starts the transfer setting the XCH bit */
+       reg_write(mxcs->base + MXC_CSPICTRL, mxcs->ctrl_reg |
+               MXC_CSPICTRL_EN | MXC_CSPICTRL_XCH);
 
-       while (reg_read(mxcs->base + MXC_CSPICTRL) & MXC_CSPICTRL_XCH)
+       /* Wait until the TC (Transfer completed) bit is set */
+       while ((reg_read(mxcs->base + MXC_CSPISTAT) & MXC_CSPICTRL_TC) == 0)
                ;
 
-       if (mxcs->gpio > 0 && (flags & SPI_XFER_END)) {
-               mx31_gpio_set(mxcs->gpio,
-                             !(mxcs->ctrl_reg & MXC_CSPICTRL_SSPOL));
-       }
+       /* Transfer completed, clear any pending request */
+       reg_write(mxcs->base + MXC_CSPISTAT,
+               MXC_CSPICTRL_TC | MXC_CSPICTRL_RXOVF);
+
+       data = reg_read(mxcs->base + MXC_CSPIRXDATA);
+       debug("SPI Rx: 0x%x\n", data);
+
+       if (flags & SPI_XFER_END)
+               spi_cs_deactivate(slave);
+
+       return data;
 
-       return reg_read(mxcs->base + MXC_CSPIRXDATA);
 }
 
 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
@@ -176,7 +357,7 @@ static int decode_cs(struct mxc_spi_slave *mxcs, unsigned int cs)
        if (cs > 3) {
                mxcs->gpio = cs >> 8;
                cs &= 3;
-               ret = mx31_gpio_direction(mxcs->gpio, MX31_GPIO_DIRECTION_OUT);
+               ret = mxc_gpio_direction(mxcs->gpio, OUT);
                if (ret) {
                        printf("mxc_spi: cannot setup gpio %d\n", mxcs->gpio);
                        return -EINVAL;
@@ -210,6 +391,20 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
 
        cs = ret;
 
+       mxcs->slave.bus = bus;
+       mxcs->slave.cs = cs;
+       mxcs->base = spi_bases[bus];
+
+#ifdef CONFIG_MX51
+       /* Can be used for i.MX31 too ? */
+       ctrl_reg = 0;
+       ret = spi_cfg(mxcs, cs, max_hz, mode);
+       if (ret) {
+               printf("mxc_spi: cannot setup SPI controller\n");
+               free(mxcs);
+               return NULL;
+       }
+#else
        ctrl_reg = MXC_CSPICTRL_CHIPSELECT(cs) |
                MXC_CSPICTRL_BITCOUNT(31) |
                MXC_CSPICTRL_DATARATE(7) | /* FIXME: calculate data rate */
@@ -222,12 +417,8 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
                ctrl_reg |= MXC_CSPICTRL_POL;
        if (mode & SPI_CS_HIGH)
                ctrl_reg |= MXC_CSPICTRL_SSPOL;
-
-       mxcs->slave.bus = bus;
-       mxcs->slave.cs = cs;
-       mxcs->base = spi_bases[bus];
        mxcs->ctrl_reg = ctrl_reg;
-
+#endif
        return &mxcs->slave;
 }