Patchwork [U-Boot,V2,4/6] SPI: added support for MX51 to mxc_spi

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Submitter Stefano Babic
Date April 19, 2010, 7:56 a.m.
Message ID <1271663820-7358-4-git-send-email-sbabic@denx.de>
Download mbox | patch
Permalink /patch/71766/
State Accepted
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Comments

Stefano Babic - April 19, 2010, 7:56 a.m.
This patch add SPI support for the MX51 processor.

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

This is the second version to get support for MX51 in the driver.
As reported by Tom Rix, the previous patch broke several MX31 boards
and mixed supporting the MX51 processor with fixing some issues.
This patch adds only support for the MX51 processor and postpone
(if required) supporting not-word aligned buffers to a later patch.

Other changes I can summarize:

Comments from Tom Rix:
	- do no make common definition of certain registers
	- consistency inside code

Comments from Liu Hui:
	- most comments drop out because are related to fix
	not word aligned buffers.
	- added CONFIG_MX51 to protect only MX51 related code

 drivers/spi/mxc_spi.c |  231 ++++++++++++++++++++++++++++++++++++++++++++-----
 1 files changed, 210 insertions(+), 21 deletions(-)

Patch

diff --git a/drivers/spi/mxc_spi.c b/drivers/spi/mxc_spi.c
index 3a45200..65f43ad 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;
@@ -191,7 +372,6 @@  static int decode_cs(struct mxc_spi_slave *mxcs, unsigned int cs)
 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
 			unsigned int max_hz, unsigned int mode)
 {
-	unsigned int ctrl_reg;
 	struct mxc_spi_slave *mxcs;
 	int ret;
 
@@ -210,6 +390,19 @@  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 +415,8 @@  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;
 }