[PATCH] omap_uwire: use the per transfer wordsize and speed overrides

Each transfer in an SPI message can have its wordsize and speed override.
Add a uwire_setup_transfer to handle this.

Allocate a per SPI device controller state struct, where we cache the
current bits_per_word and the functional clock divider. The latter cannot
be set for each CS in HW, so we have to reset it whenever a new device is
selected.

Signed-off-by: Imre Deak <imre.deak@nokia.com>

diff --git a/drivers/spi/omap_uwire.c b/drivers/spi/omap_uwire.c
index 39e822704b880b4dca7678214aab8f1abb8e49ce..6851eecd407886aed1b9907a8148fc884ba7a196 100644 (file)
--- a/drivers/spi/omap_uwire.c
+++ b/drivers/spi/omap_uwire.c
@@ -94,6 +94,11 @@ struct uwire_spi {
        struct clk              *ck;
 };
 
+struct uwire_state {
+       unsigned        bits_per_word;
+       unsigned        div1_idx;
+};
+
 /* REVISIT compile time constant for idx_shift? */
 static unsigned int uwire_idx_shift;
 
@@ -153,11 +158,23 @@ static int wait_uwire_csr_flag(u16 mask, u16 val, int might_not_catch)
        return 0;
 }
 
+static void uwire_set_clk1_div(int div1_idx)
+{
+       u16 w;
+
+       w = uwire_read_reg(UWIRE_SR3);
+       w &= ~(0x03 << 1);
+       w |= div1_idx << 1;
+       uwire_write_reg(UWIRE_SR3, w);
+}
+
 static void uwire_chipselect(struct spi_device *spi, int value)
 {
+       struct  uwire_state *ust = spi->controller_state;
        u16     w;
        int     old_cs;
 
+
        BUG_ON(wait_uwire_csr_flag(CSRB, 0, 0));
 
        w = uwire_read_reg(UWIRE_CSR);
@@ -169,6 +186,7 @@ static void uwire_chipselect(struct spi_device *spi, int value)
        }
        /* activate specfied chipselect */
        if (value == BITBANG_CS_ACTIVE) {
+               uwire_set_clk1_div(ust->div1_idx);
                /* invert clock? */
                if (spi->mode & SPI_CPOL)
                        uwire_write_reg(UWIRE_SR4, 1);
@@ -183,8 +201,9 @@ static void uwire_chipselect(struct spi_device *spi, int value)
 
 static int uwire_txrx(struct spi_device *spi, struct spi_transfer *t)
 {
+       struct uwire_state *ust = spi->controller_state;
        unsigned        len = t->len;
-       unsigned        bits = spi->bits_per_word;
+       unsigned        bits = ust->bits_per_word;
        unsigned        bytes;
        u16             val, w;
        int             status = 0;;
@@ -196,9 +215,6 @@ static int uwire_txrx(struct spi_device *spi, struct spi_transfer *t)
        if (t->tx_buf && t->rx_buf)
                return -EPERM;
 
-       if (!bits)
-               bits = 8;
-
        w = spi->chip_select << 10;
        w |= CS_CMD;
 
@@ -291,15 +307,17 @@ eio:
        return -EIO;
 }
 
-static int uwire_setup(struct spi_device *spi)
+static int uwire_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
 {
+       struct uwire_state      *ust = spi->controller_state;
        struct uwire_spi        *uwire;
        unsigned                flags = 0;
+       unsigned                bits;
+       unsigned                hz;
        unsigned long           rate;
        int                     div1_idx;
        int                     div1;
        int                     div2;
-       u16                     w;
        int                     status;
 
        uwire = spi_master_get_devdata(spi->master);
@@ -310,12 +328,19 @@ static int uwire_setup(struct spi_device *spi)
                goto done;
        }
 
+       bits = spi->bits_per_word;
+       if (t != NULL && t->bits_per_word)
+               bits = t->bits_per_word;
+       if (!bits)
+               bits = 8;
+
        if (spi->bits_per_word > 16) {
                pr_debug("%s: wordsize %d?\n", spi->dev.bus_id,
                                spi->bits_per_word);
                status = -ENODEV;
                goto done;
        }
+       ust->bits_per_word = bits;
 
        /* mode 0..3, clock inverted separately;
         * standard nCS signaling;
@@ -341,6 +366,16 @@ static int uwire_setup(struct spi_device *spi)
        /* assume it's already enabled */
        rate = clk_get_rate(uwire->ck);
 
+       hz = spi->max_speed_hz;
+       if (t != NULL && t->speed_hz)
+               hz = t->speed_hz;
+
+       if (!hz) {
+               pr_debug("%s: zero speed?\n", spi->dev.bus_id, hz);
+               status = -EINVAL;
+               goto done;
+       }
+
        /* F_INT = mpu_per_clk / DIV1 */
        for (div1_idx = 0; div1_idx < 4; div1_idx++) {
                switch (div1_idx) {
@@ -358,22 +393,22 @@ static int uwire_setup(struct spi_device *spi)
                        div1 = 10;
                        break;
                }
-               div2 = (rate / div1 + spi->max_speed_hz - 1) /
-                       spi->max_speed_hz;
+               div2 = (rate / div1 + hz - 1) / hz;
                if (div2 <= 8)
                        break;
        }
        if (div1_idx == 4) {
                pr_debug("%s: lowest clock %ld, need %d\n",
-                       spi->dev.bus_id, rate / 10 / 8, spi->max_speed_hz);
+                       spi->dev.bus_id, rate / 10 / 8, hz);
                        status = -EDOM;
                        goto done;
        }
 
-       w = uwire_read_reg(UWIRE_SR3);
-       w &= ~(0x03 << 1);
-       w |= div1_idx << 1;
-       uwire_write_reg(UWIRE_SR3, w);
+       /* we have to cache this and reset in uwire_chipselect as this is a
+        * global parameter and another uwire device can change it under
+        * us */
+       ust->div1_idx = div1_idx;
+       uwire_set_clk1_div(div1_idx);
 
        rate /= div1;
 
@@ -407,6 +442,25 @@ done:
        return status;
 }
 
+static int uwire_setup(struct spi_device *spi)
+{
+       struct uwire_state *ust = spi->controller_state;
+
+       if (ust == NULL) {
+               ust = kzalloc(sizeof(*ust), SLAB_KERNEL);
+               if (ust == NULL)
+                       return -ENOMEM;
+               spi->controller_state = ust;
+       }
+
+       return uwire_setup_transfer(spi, NULL);
+}
+
+static void uwire_cleanup(const struct spi_device *spi)
+{
+       kfree(spi->controller_state);
+}
+
 static void uwire_off(struct uwire_spi *uwire)
 {
        uwire_write_reg(UWIRE_SR3, 0);
@@ -446,9 +500,11 @@ static int uwire_probe(struct platform_device *pdev)
        master->bus_num = 2;    /* "official" */
        master->num_chipselect = 4;
        master->setup = uwire_setup;
+       master->cleanup = uwire_cleanup;
 
        uwire->bitbang.master = master;
        uwire->bitbang.chipselect = uwire_chipselect;
+       uwire->bitbang.setup_transfer = uwire_setup_transfer;
        uwire->bitbang.txrx_bufs = uwire_txrx;
 
        status = spi_bitbang_start(&uwire->bitbang);