spi: dw: fix multiple slaves with different baudrates

Add current master clock to dws struct and compare it against the
requestedtransfer speed. Update clock divider only if necessary.

Signed-off-by: Matthias Seidel <kernel@mseidel.net>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c
index c09bb745693a0ffdd3be164c05f0f33b0c461d8a..c85e4b327a4a7d762cc7eb7af2299dba2f521f0e 100644 (file)
--- a/drivers/spi/spi-dw.c
+++ b/drivers/spi/spi-dw.c
@@ -283,7 +283,6 @@ static int dw_spi_transfer_one(struct spi_master *master,
        struct chip_data *chip = spi_get_ctldata(spi);
        u8 imask = 0;
        u16 txlevel = 0;
-       u16 clk_div;
        u32 cr0;
        int ret;
 
@@ -298,13 +297,13 @@ static int dw_spi_transfer_one(struct spi_master *master,
        spi_enable_chip(dws, 0);
 
        /* Handle per transfer options for bpw and speed */
-       if (transfer->speed_hz != chip->speed_hz) {
-               /* clk_div doesn't support odd number */
-               clk_div = (dws->max_freq / transfer->speed_hz + 1) & 0xfffe;
-
-               chip->speed_hz = transfer->speed_hz;
-               chip->clk_div = clk_div;
-
+       if (transfer->speed_hz != dws->current_freq) {
+               if (transfer->speed_hz != chip->speed_hz) {
+                       /* clk_div doesn't support odd number */
+                       chip->clk_div = (dws->max_freq / transfer->speed_hz + 1) & 0xfffe;
+                       chip->speed_hz = transfer->speed_hz;
+               }
+               dws->current_freq = transfer->speed_hz;
                spi_set_clk(dws, chip->clk_div);
        }
        if (transfer->bits_per_word == 8) {

diff --git a/drivers/spi/spi-dw.h b/drivers/spi/spi-dw.h
index 61bc3cbab38d5b766554e559c011cbf3aa98fb05..c21ca02f8ec5fcb1d6ca74ee15f43028d03044c7 100644 (file)
--- a/drivers/spi/spi-dw.h
+++ b/drivers/spi/spi-dw.h
@@ -123,6 +123,7 @@ struct dw_spi {
        u8                      n_bytes;        /* current is a 1/2 bytes op */
        u32                     dma_width;
        irqreturn_t             (*transfer_handler)(struct dw_spi *dws);
+       u32                     current_freq;   /* frequency in hz */
 
        /* DMA info */
        int                     dma_inited;