@@ -73,8 +73,9 @@ struct chip_data {
#define LPSS_CAPS_CS_EN_MASK (0xf << LPSS_CAPS_CS_EN_SHIFT)
#define LPSS_PRIV_CLOCK_GATE 0x38
-#define LPSS_PRIV_CLOCK_GATE_CLK_CTL_MASK 0x3
-#define LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_ON 0x3
+#define LPSS_PRIV_CLOCK_GATE_CLK_CTL_MASK 0x3
+#define LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_ON 0x3
+#define LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_OFF 0x0
struct lpss_config {
/* LPSS offset from drv_data->ioaddr */
@@ -321,6 +322,20 @@ static void __lpss_ssp_write_priv(struct driver_data *drv_data,
writel(value, drv_data->lpss_base + offset);
}
+static bool __lpss_ssp_update_priv(struct driver_data *drv_data, unsigned int offset,
+ u32 mask, u32 value)
+{
+ u32 new, curr;
+
+ curr = __lpss_ssp_read_priv(drv_data, offset);
+ new = (curr & ~mask) | (value & mask);
+ if (new == curr)
+ return false;
+
+ __lpss_ssp_write_priv(drv_data, offset, new);
+ return true;
+}
+
/*
* lpss_ssp_setup - perform LPSS SSP specific setup
* @drv_data: pointer to the driver private data
@@ -337,21 +352,16 @@ static void lpss_ssp_setup(struct driver_data *drv_data)
drv_data->lpss_base = drv_data->ssp->mmio_base + config->offset;
/* Enable software chip select control */
- value = __lpss_ssp_read_priv(drv_data, config->reg_cs_ctrl);
- value &= ~(LPSS_CS_CONTROL_SW_MODE | LPSS_CS_CONTROL_CS_HIGH);
- value |= LPSS_CS_CONTROL_SW_MODE | LPSS_CS_CONTROL_CS_HIGH;
- __lpss_ssp_write_priv(drv_data, config->reg_cs_ctrl, value);
+ value = LPSS_CS_CONTROL_SW_MODE | LPSS_CS_CONTROL_CS_HIGH;
+ __lpss_ssp_update_priv(drv_data, config->reg_cs_ctrl, value, value);
/* Enable multiblock DMA transfers */
if (drv_data->controller_info->enable_dma) {
- __lpss_ssp_write_priv(drv_data, config->reg_ssp, 1);
+ __lpss_ssp_update_priv(drv_data, config->reg_ssp, BIT(0), BIT(0));
if (config->reg_general >= 0) {
- value = __lpss_ssp_read_priv(drv_data,
- config->reg_general);
- value |= LPSS_GENERAL_REG_RXTO_HOLDOFF_DISABLE;
- __lpss_ssp_write_priv(drv_data,
- config->reg_general, value);
+ value = LPSS_GENERAL_REG_RXTO_HOLDOFF_DISABLE;
+ __lpss_ssp_update_priv(drv_data, config->reg_general, value, value);
}
}
}
@@ -361,30 +371,19 @@ static void lpss_ssp_select_cs(struct spi_device *spi,
{
struct driver_data *drv_data =
spi_controller_get_devdata(spi->controller);
- u32 value, cs;
+ u32 cs;
- if (!config->cs_sel_mask)
+ cs = spi_get_chipselect(spi, 0) << config->cs_sel_shift;
+ if (!__lpss_ssp_update_priv(drv_data, config->reg_cs_ctrl, config->cs_sel_mask, cs))
return;
- value = __lpss_ssp_read_priv(drv_data, config->reg_cs_ctrl);
-
- cs = spi_get_chipselect(spi, 0);
- 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->controller->max_speed_hz / 2));
- }
+ /*
+ * 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.
+ */
+ ndelay(1000000000 / (drv_data->controller->max_speed_hz / 2));
}
static void lpss_ssp_cs_control(struct spi_device *spi, bool enable)
@@ -392,34 +391,27 @@ static void lpss_ssp_cs_control(struct spi_device *spi, bool enable)
struct driver_data *drv_data =
spi_controller_get_devdata(spi->controller);
const struct lpss_config *config;
- u32 value;
+ u32 mask;
config = lpss_get_config(drv_data);
if (enable)
lpss_ssp_select_cs(spi, config);
- value = __lpss_ssp_read_priv(drv_data, config->reg_cs_ctrl);
- if (enable)
- value &= ~LPSS_CS_CONTROL_CS_HIGH;
- else
- value |= LPSS_CS_CONTROL_CS_HIGH;
- __lpss_ssp_write_priv(drv_data, config->reg_cs_ctrl, value);
+ mask = LPSS_CS_CONTROL_CS_HIGH;
+ __lpss_ssp_update_priv(drv_data, config->reg_cs_ctrl, mask, enable ? mask : 0);
if (config->cs_clk_stays_gated) {
- u32 clkgate;
-
/*
* Changing CS alone when dynamic clock gating is on won't
* actually flip CS at that time. This ruins SPI transfers
* that specify delays, or have no data. Toggle the clock mode
* to force on briefly to poke the CS pin to move.
*/
- clkgate = __lpss_ssp_read_priv(drv_data, LPSS_PRIV_CLOCK_GATE);
- value = (clkgate & ~LPSS_PRIV_CLOCK_GATE_CLK_CTL_MASK) |
- LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_ON;
-
- __lpss_ssp_write_priv(drv_data, LPSS_PRIV_CLOCK_GATE, value);
- __lpss_ssp_write_priv(drv_data, LPSS_PRIV_CLOCK_GATE, clkgate);
+ mask = LPSS_PRIV_CLOCK_GATE_CLK_CTL_MASK;
+ if (__lpss_ssp_update_priv(drv_data, LPSS_PRIV_CLOCK_GATE, mask,
+ LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_ON))
+ __lpss_ssp_update_priv(drv_data, LPSS_PRIV_CLOCK_GATE, mask,
+ LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_OFF);
}
}
In a few places we repeat RMW IO operations on LPSS private registers. Let's introduce a helper to make the code better to read and maintain. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> --- drivers/spi/spi-pxa2xx.c | 88 ++++++++++++++++++---------------------- 1 file changed, 40 insertions(+), 48 deletions(-)