spi/imx: add support for imx51's eCSPI and CSPI

i.MX51 comes with two eCSPI interfaces (that are quite different from
what was known before---the tried and tested Freescale way) and a CSPI
interface that is identical to the devices found on i.MX25 and i.MX35.

This patch is a merge of two very similar patches (by Jason Wang and Sascha
Hauer resp.) plus a (now hopefully correct) reimplementation of the
clock calculation.

Acked-by: Jason Wang <jason77.wang@gmail.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 139 insertions, 1 deletions

diff --git a/drivers/spi/spi_imx.c b/drivers/spi/spi_imx.c
index 23db9840b9ae..6bab2cfd93c1 100644
--- a/drivers/spi/spi_imx.c
+++ b/drivers/spi/spi_imx.c
@@ -65,6 +65,7 @@ enum spi_imx_devtype {
         SPI_IMX_VER_0_4,
         SPI_IMX_VER_0_5,
         SPI_IMX_VER_0_7,
+        SPI_IMX_VER_2_3,
         SPI_IMX_VER_AUTODETECT,
 };
 
@@ -155,7 +156,7 @@ static unsigned int spi_imx_clkdiv_1(unsigned int fin,
         return max;
 }
 
-/* MX1, MX31, MX35 */
+/* MX1, MX31, MX35, MX51 CSPI */
 static unsigned int spi_imx_clkdiv_2(unsigned int fin,
                 unsigned int fspi)
 {
@@ -170,6 +171,128 @@ static unsigned int spi_imx_clkdiv_2(unsigned int fin,
         return 7;
 }
 
+#define SPI_IMX2_3_CTRL         0x08
+#define SPI_IMX2_3_CTRL_ENABLE          (1 <<  0)
+#define SPI_IMX2_3_CTRL_XCH             (1 <<  2)
+#define SPI_IMX2_3_CTRL_MODE(cs)        (1 << ((cs) +  4))
+#define SPI_IMX2_3_CTRL_POSTDIV_OFFSET  8
+#define SPI_IMX2_3_CTRL_PREDIV_OFFSET   12
+#define SPI_IMX2_3_CTRL_CS(cs)          ((cs) << 18)
+#define SPI_IMX2_3_CTRL_BL_OFFSET       20
+
+#define SPI_IMX2_3_CONFIG       0x0c
+#define SPI_IMX2_3_CONFIG_SCLKPHA(cs)   (1 << ((cs) +  0))
+#define SPI_IMX2_3_CONFIG_SCLKPOL(cs)   (1 << ((cs) +  4))
+#define SPI_IMX2_3_CONFIG_SBBCTRL(cs)   (1 << ((cs) +  8))
+#define SPI_IMX2_3_CONFIG_SSBPOL(cs)    (1 << ((cs) + 12))
+
+#define SPI_IMX2_3_INT          0x10
+#define SPI_IMX2_3_INT_TEEN             (1 <<  0)
+#define SPI_IMX2_3_INT_RREN             (1 <<  3)
+
+#define SPI_IMX2_3_STAT         0x18
+#define SPI_IMX2_3_STAT_RR              (1 <<  3)
+
+/* MX51 eCSPI */
+static unsigned int spi_imx2_3_clkdiv(unsigned int fin, unsigned int fspi)
+{
+        /*
+         * there are two 4-bit dividers, the pre-divider divides by
+         * $pre, the post-divider by 2^$post
+         */
+        unsigned int pre, post;
+
+        if (unlikely(fspi > fin))
+                return 0;
+
+        post = fls(fin) - fls(fspi);
+        if (fin > fspi << post)
+                post++;
+
+        /* now we have: (fin <= fspi << post) with post being minimal */
+
+        post = max(4U, post) - 4;
+        if (unlikely(post > 0xf)) {
+                pr_err("%s: cannot set clock freq: %u (base freq: %u)\n",
+                                __func__, fspi, fin);
+                return 0xff;
+        }
+
+        pre = DIV_ROUND_UP(fin, fspi << post) - 1;
+
+        pr_debug("%s: fin: %u, fspi: %u, post: %u, pre: %u\n",
+                        __func__, fin, fspi, post, pre);
+        return (pre << SPI_IMX2_3_CTRL_PREDIV_OFFSET) |
+                (post << SPI_IMX2_3_CTRL_POSTDIV_OFFSET);
+}
+
+static void __maybe_unused spi_imx2_3_intctrl(struct spi_imx_data *spi_imx, int enable)
+{
+        unsigned val = 0;
+
+        if (enable & MXC_INT_TE)
+                val |= SPI_IMX2_3_INT_TEEN;
+
+        if (enable & MXC_INT_RR)
+                val |= SPI_IMX2_3_INT_RREN;
+
+        writel(val, spi_imx->base + SPI_IMX2_3_INT);
+}
+
+static void __maybe_unused spi_imx2_3_trigger(struct spi_imx_data *spi_imx)
+{
+        u32 reg;
+
+        reg = readl(spi_imx->base + SPI_IMX2_3_CTRL);
+        reg |= SPI_IMX2_3_CTRL_XCH;
+        writel(reg, spi_imx->base + SPI_IMX2_3_CTRL);
+}
+
+static int __maybe_unused spi_imx2_3_config(struct spi_imx_data *spi_imx,
+                struct spi_imx_config *config)
+{
+        u32 ctrl = SPI_IMX2_3_CTRL_ENABLE, cfg = 0;
+
+        /* set master mode */
+        ctrl |= SPI_IMX2_3_CTRL_MODE(config->cs);
+
+        /* set clock speed */
+        ctrl |= spi_imx2_3_clkdiv(spi_imx->spi_clk, config->speed_hz);
+
+        /* set chip select to use */
+        ctrl |= SPI_IMX2_3_CTRL_CS(config->cs);
+
+        ctrl |= (config->bpw - 1) << SPI_IMX2_3_CTRL_BL_OFFSET;
+
+        cfg |= SPI_IMX2_3_CONFIG_SBBCTRL(config->cs);
+
+        if (config->mode & SPI_CPHA)
+                cfg |= SPI_IMX2_3_CONFIG_SCLKPHA(config->cs);
+
+        if (config->mode & SPI_CPOL)
+                cfg |= SPI_IMX2_3_CONFIG_SCLKPOL(config->cs);
+
+        if (config->mode & SPI_CS_HIGH)
+                cfg |= SPI_IMX2_3_CONFIG_SSBPOL(config->cs);
+
+        writel(ctrl, spi_imx->base + SPI_IMX2_3_CTRL);
+        writel(cfg, spi_imx->base + SPI_IMX2_3_CONFIG);
+
+        return 0;
+}
+
+static int __maybe_unused spi_imx2_3_rx_available(struct spi_imx_data *spi_imx)
+{
+        return readl(spi_imx->base + SPI_IMX2_3_STAT) & SPI_IMX2_3_STAT_RR;
+}
+
+static void __maybe_unused spi_imx2_3_reset(struct spi_imx_data *spi_imx)
+{
+        /* drain receive buffer */
+        while (spi_imx2_3_rx_available(spi_imx))
+                readl(spi_imx->base + MXC_CSPIRXDATA);
+}
+
 #define MX31_INTREG_TEEN        (1 << 0)
 #define MX31_INTREG_RREN        (1 << 3)
 
@@ -447,6 +570,15 @@ static struct spi_imx_devtype_data spi_imx_devtype_data[] __devinitdata = {
                 .reset = spi_imx0_4_reset,
         },
 #endif
+#ifdef CONFIG_SPI_IMX_VER_2_3
+        [SPI_IMX_VER_2_3] = {
+                .intctrl = spi_imx2_3_intctrl,
+                .config = spi_imx2_3_config,
+                .trigger = spi_imx2_3_trigger,
+                .rx_available = spi_imx2_3_rx_available,
+                .reset = spi_imx2_3_reset,
+        },
+#endif
 };
 
 static void spi_imx_chipselect(struct spi_device *spi, int is_active)
@@ -603,6 +735,12 @@ static struct platform_device_id spi_imx_devtype[] = {
                 .name = "imx35-cspi",
                 .driver_data = SPI_IMX_VER_0_7,
         }, {
+                .name = "imx51-cspi",
+                .driver_data = SPI_IMX_VER_0_7,
+        }, {
+                .name = "imx51-ecspi",
+                .driver_data = SPI_IMX_VER_2_3,
+        }, {
                 /* sentinel */
         }
 };