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authorNikita Kiryanov <nikita@compulab.co.il>2014-08-20 15:08:50 +0300
committerJagannadha Sutradharudu Teki <jaganna@xilinx.com>2014-09-24 17:25:39 +0530
commit155fa9af95ac5be857a7327e7a968a296e60d4c8 (patch)
treea35b45e4eee9707e0661e0da7f86b28b6ab393b6 /drivers/spi
parent01d2aaf61ba7d532dee7002a2049d2b972992122 (diff)
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spi: mxc: fix sf probe when using mxc_spi
MXC SPI driver has a feature whereas a GPIO line can be used to force CS high across multiple transactions. This is set up by embedding the GPIO information in the CS value: cs = (cs | gpio << 8) This merge of cs and gpio data into one value breaks the sf probe command: if the use of gpio is required, invoking "sf probe <cs>" will not work, because the CS argument doesn't have the GPIO information in it. Instead, the user must use "sf probe <cs | gpio << 8>". For example, if bank 2 gpio 30 is used to force cs high on cs 0, bus 0, then instead of typing "sf probe 0" the user now must type "sf probe 15872". This is inconsistent with the description of the sf probe command, and forces the user to be aware of implementaiton details. Fix this by introducing a new board function: board_spi_cs_gpio(), which will accept a naked CS value, and provide the driver with the relevant GPIO, if one is necessary. Cc: Eric Nelson <eric.nelson@boundarydevices.com> Cc: Eric Benard <eric@eukrea.com> Cc: Fabio Estevam <fabio.estevam@freescale.com> Cc: Tim Harvey <tharvey@gateworks.com> Cc: Stefano Babic <sbabic@denx.de> Cc: Tom Rini <trini@ti.com> Cc: Marek Vasut <marex@denx.de> Reviewed-by: Marek Vasut <marex@denx.de> Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il> Reviewed-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/mxc_spi.c48
1 files changed, 25 insertions, 23 deletions
diff --git a/drivers/spi/mxc_spi.c b/drivers/spi/mxc_spi.c
index 2d5f385..026f680 100644
--- a/drivers/spi/mxc_spi.c
+++ b/drivers/spi/mxc_spi.c
@@ -25,6 +25,11 @@ static unsigned long spi_bases[] = {
MXC_SPI_BASE_ADDRESSES
};
+__weak int board_spi_cs_gpio(unsigned bus, unsigned cs)
+{
+ return -1;
+}
+
#define OUT MXC_GPIO_DIRECTION_OUT
#define reg_read readl
@@ -371,31 +376,30 @@ void spi_init(void)
{
}
-static int decode_cs(struct mxc_spi_slave *mxcs, unsigned int cs)
+/*
+ * Some SPI devices require active chip-select over multiple
+ * transactions, we achieve this using a GPIO. Still, the SPI
+ * controller has to be configured to use one of its own chipselects.
+ * To use this feature you have to implement board_spi_cs_gpio() to assign
+ * a gpio value for each cs (-1 if cs doesn't need to use gpio).
+ * You must use some unused on this SPI controller cs between 0 and 3.
+ */
+static int setup_cs_gpio(struct mxc_spi_slave *mxcs,
+ unsigned int bus, unsigned int cs)
{
int ret;
- /*
- * Some SPI devices require active chip-select over multiple
- * transactions, we achieve this using a GPIO. Still, the SPI
- * controller has to be configured to use one of its own chipselects.
- * To use this feature you have to call spi_setup_slave() with
- * cs = internal_cs | (gpio << 8), and you have to use some unused
- * on this SPI controller cs between 0 and 3.
- */
- if (cs > 3) {
- mxcs->gpio = cs >> 8;
- cs &= 3;
- ret = gpio_direction_output(mxcs->gpio, !(mxcs->ss_pol));
- if (ret) {
- printf("mxc_spi: cannot setup gpio %d\n", mxcs->gpio);
- return -EINVAL;
- }
- } else {
- mxcs->gpio = -1;
+ mxcs->gpio = board_spi_cs_gpio(bus, cs);
+ if (mxcs->gpio == -1)
+ return 0;
+
+ ret = gpio_direction_output(mxcs->gpio, !(mxcs->ss_pol));
+ if (ret) {
+ printf("mxc_spi: cannot setup gpio %d\n", mxcs->gpio);
+ return -EINVAL;
}
- return cs;
+ return 0;
}
struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
@@ -415,14 +419,12 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
mxcs->ss_pol = (mode & SPI_CS_HIGH) ? 1 : 0;
- ret = decode_cs(mxcs, cs);
+ ret = setup_cs_gpio(mxcs, bus, cs);
if (ret < 0) {
free(mxcs);
return NULL;
}
- cs = ret;
-
mxcs->base = spi_bases[bus];
ret = spi_cfg_mxc(mxcs, cs, max_hz, mode);