spi: pxa2xx: Detect number of enabled Intel LPSS SPI chip select signals

[cascardo/linux.git] / drivers / spi / spi-pxa2xx.c

diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
index 040f6bb..a5c2dce 100644 (file)
--- a/drivers/spi/spi-pxa2xx.c
+++ b/drivers/spi/spi-pxa2xx.c
@@ -13,6 +13,7 @@
  * GNU General Public License for more details.
  */
 
+#include <linux/bitops.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/device.h>
@@ -66,6 +67,8 @@ MODULE_ALIAS("platform:pxa2xx-spi");
 #define LPSS_CS_CONTROL_CS_HIGH                        BIT(1)
 #define LPSS_CS_CONTROL_CS_SEL_SHIFT           8
 #define LPSS_CS_CONTROL_CS_SEL_MASK            (3 << LPSS_CS_CONTROL_CS_SEL_SHIFT)
+#define LPSS_CAPS_CS_EN_SHIFT                  9
+#define LPSS_CAPS_CS_EN_MASK                   (0xf << LPSS_CAPS_CS_EN_SHIFT)
 
 struct lpss_config {
        /* LPSS offset from drv_data->ioaddr */
@@ -74,6 +77,7 @@ struct lpss_config {
        int reg_general;
        int reg_ssp;
        int reg_cs_ctrl;
+       int reg_capabilities;
        /* FIFO thresholds */
        u32 rx_threshold;
        u32 tx_threshold_lo;
@@ -87,6 +91,7 @@ static const struct lpss_config lpss_platforms[] = {
                .reg_general = 0x08,
                .reg_ssp = 0x0c,
                .reg_cs_ctrl = 0x18,
+               .reg_capabilities = -1,
                .rx_threshold = 64,
                .tx_threshold_lo = 160,
                .tx_threshold_hi = 224,
@@ -96,6 +101,7 @@ static const struct lpss_config lpss_platforms[] = {
                .reg_general = 0x08,
                .reg_ssp = 0x0c,
                .reg_cs_ctrl = 0x18,
+               .reg_capabilities = -1,
                .rx_threshold = 64,
                .tx_threshold_lo = 160,
                .tx_threshold_hi = 224,
@@ -105,6 +111,7 @@ static const struct lpss_config lpss_platforms[] = {
                .reg_general = -1,
                .reg_ssp = 0x20,
                .reg_cs_ctrl = 0x24,
+               .reg_capabilities = 0xfc,
                .rx_threshold = 1,
                .tx_threshold_lo = 32,
                .tx_threshold_hi = 56,
@@ -1400,6 +1407,7 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
        struct spi_master *master;
        struct driver_data *drv_data;
        struct ssp_device *ssp;
+       const struct lpss_config *config;
        int status;
        u32 tmp;
 
@@ -1439,7 +1447,6 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
        master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LOOP;
 
        master->bus_num = ssp->port_id;
-       master->num_chipselect = platform_info->num_chipselect;
        master->dma_alignment = DMA_ALIGNMENT;
        master->cleanup = cleanup;
        master->setup = setup;
@@ -1525,6 +1532,19 @@ static int pxa2xx_spi_probe(struct platform_device *pdev)
        if (is_lpss_ssp(drv_data))
                lpss_ssp_setup(drv_data);
 
+       if (is_lpss_ssp(drv_data)) {
+               lpss_ssp_setup(drv_data);
+               config = lpss_get_config(drv_data);
+               if (config->reg_capabilities >= 0) {
+                       tmp = __lpss_ssp_read_priv(drv_data,
+                                                  config->reg_capabilities);
+                       tmp &= LPSS_CAPS_CS_EN_MASK;
+                       tmp >>= LPSS_CAPS_CS_EN_SHIFT;
+                       platform_info->num_chipselect = ffz(tmp);
+               }
+       }
+       master->num_chipselect = platform_info->num_chipselect;
+
        tasklet_init(&drv_data->pump_transfers, pump_transfers,
                     (unsigned long)drv_data);