diff options
| -rw-r--r-- | drivers/spi/mxc_spi.c | 231 |
1 files changed, 211 insertions, 20 deletions
diff --git a/drivers/spi/mxc_spi.c b/drivers/spi/mxc_spi.c index 3a45200..e15a63c 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 +391,20 @@ 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; } |