diff options
Diffstat (limited to 'drivers/spi/spi-pxa2xx.c')
-rw-r--r-- | drivers/spi/spi-pxa2xx.c | 92 |
1 files changed, 42 insertions, 50 deletions
diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c index bf1f34b0ffc8..5f9cac41baff 100644 --- a/drivers/spi/spi-pxa2xx.c +++ b/drivers/spi/spi-pxa2xx.c @@ -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); } } @@ -1468,7 +1460,7 @@ out_error_dma_irq_alloc: return status; } -EXPORT_SYMBOL_NS_GPL(pxa2xx_spi_probe, SPI_PXA2xx); +EXPORT_SYMBOL_NS_GPL(pxa2xx_spi_probe, "SPI_PXA2xx"); void pxa2xx_spi_remove(struct device *dev) { @@ -1488,7 +1480,7 @@ void pxa2xx_spi_remove(struct device *dev) /* Release IRQ */ free_irq(ssp->irq, drv_data); } -EXPORT_SYMBOL_NS_GPL(pxa2xx_spi_remove, SPI_PXA2xx); +EXPORT_SYMBOL_NS_GPL(pxa2xx_spi_remove, "SPI_PXA2xx"); static int pxa2xx_spi_suspend(struct device *dev) { |