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path: root/drivers/spi/spi-pxa2xx.c
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Diffstat (limited to 'drivers/spi/spi-pxa2xx.c')
-rw-r--r--drivers/spi/spi-pxa2xx.c64
1 files changed, 40 insertions, 24 deletions
diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
index 7d6d3b7..81d68e0 100644
--- a/drivers/spi/spi-pxa2xx.c
+++ b/drivers/spi/spi-pxa2xx.c
@@ -65,8 +65,6 @@ MODULE_ALIAS("platform:pxa2xx-spi");
#define LPSS_GENERAL_REG_RXTO_HOLDOFF_DISABLE BIT(24)
#define LPSS_CS_CONTROL_SW_MODE BIT(0)
#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)
@@ -82,6 +80,9 @@ struct lpss_config {
u32 rx_threshold;
u32 tx_threshold_lo;
u32 tx_threshold_hi;
+ /* Chip select control */
+ unsigned cs_sel_shift;
+ unsigned cs_sel_mask;
};
/* Keep these sorted with enum pxa_ssp_type */
@@ -125,6 +126,8 @@ static const struct lpss_config lpss_platforms[] = {
.rx_threshold = 1,
.tx_threshold_lo = 16,
.tx_threshold_hi = 48,
+ .cs_sel_shift = 8,
+ .cs_sel_mask = 3 << 8,
},
};
@@ -288,37 +291,50 @@ static void lpss_ssp_setup(struct driver_data *drv_data)
}
}
+static void lpss_ssp_select_cs(struct driver_data *drv_data,
+ const struct lpss_config *config)
+{
+ u32 value, cs;
+
+ if (!config->cs_sel_mask)
+ return;
+
+ value = __lpss_ssp_read_priv(drv_data, config->reg_cs_ctrl);
+
+ cs = drv_data->cur_msg->spi->chip_select;
+ cs <<= config->cs_sel_shift;
+ if (cs != (value & config->cs_sel_mask)) {
+ /*
+ * When switching another chip select output active the
+ * output must be selected first and wait 2 ssp_clk cycles
+ * before changing state to active. Otherwise a short
+ * glitch will occur on the previous chip select since
+ * output select is latched but state control is not.
+ */
+ value &= ~config->cs_sel_mask;
+ value |= cs;
+ __lpss_ssp_write_priv(drv_data,
+ config->reg_cs_ctrl, value);
+ ndelay(1000000000 /
+ (drv_data->master->max_speed_hz / 2));
+ }
+}
+
static void lpss_ssp_cs_control(struct driver_data *drv_data, bool enable)
{
const struct lpss_config *config;
- u32 value, cs;
+ u32 value;
config = lpss_get_config(drv_data);
+ if (enable)
+ lpss_ssp_select_cs(drv_data, config);
+
value = __lpss_ssp_read_priv(drv_data, config->reg_cs_ctrl);
- if (enable) {
- cs = drv_data->cur_msg->spi->chip_select;
- cs <<= LPSS_CS_CONTROL_CS_SEL_SHIFT;
- if (cs != (value & LPSS_CS_CONTROL_CS_SEL_MASK)) {
- /*
- * When switching another chip select output active
- * the output must be selected first and wait 2 ssp_clk
- * cycles before changing state to active. Otherwise
- * a short glitch will occur on the previous chip
- * select since output select is latched but state
- * control is not.
- */
- value &= ~LPSS_CS_CONTROL_CS_SEL_MASK;
- value |= cs;
- __lpss_ssp_write_priv(drv_data,
- config->reg_cs_ctrl, value);
- ndelay(1000000000 /
- (drv_data->master->max_speed_hz / 2));
- }
+ if (enable)
value &= ~LPSS_CS_CONTROL_CS_HIGH;
- } else {
+ else
value |= LPSS_CS_CONTROL_CS_HIGH;
- }
__lpss_ssp_write_priv(drv_data, config->reg_cs_ctrl, value);
}