[U-Boot] [PATCH V3 4/6] SPI: added support for MX51 to mxc_spi
Stefano Babic
sbabic at denx.de
Mon Apr 19 23:06:05 CEST 2010
This patch add SPI support for the MX51 processor.
Signed-off-by: Stefano Babic <sbabic at denx.de>
---
Changes: line errouneously removed before submitting the patch
(Thanks Magnus Lilja to point out the mistake).
drivers/spi/mxc_spi.c | 230 ++++++++++++++++++++++++++++++++++++++++++++----
1 files changed, 210 insertions(+), 20 deletions(-)
diff --git a/drivers/spi/mxc_spi.c b/drivers/spi/mxc_spi.c
index 3a45200..dd465f9 100644
--- 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 +391,19 @@ 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 ? */
+ 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 +416,8 @@ 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;
}
--
1.6.3.3
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