diff options
| -rw-r--r-- | drivers/spi/spi-sun6i.c | 91 |
1 files changed, 61 insertions, 30 deletions
diff --git a/drivers/spi/spi-sun6i.c b/drivers/spi/spi-sun6i.c index 01a01cd86db5b..e4efab3104694 100644 --- a/drivers/spi/spi-sun6i.c +++ b/drivers/spi/spi-sun6i.c @@ -42,7 +42,9 @@ #define SUN6I_TFR_CTL_CS_MANUAL BIT(6) #define SUN6I_TFR_CTL_CS_LEVEL BIT(7) #define SUN6I_TFR_CTL_DHB BIT(8) +#define SUN6I_TFR_CTL_SDC BIT(11) #define SUN6I_TFR_CTL_FBS BIT(12) +#define SUN6I_TFR_CTL_SDM BIT(13) #define SUN6I_TFR_CTL_XCH BIT(31) #define SUN6I_INT_CTL_REG 0x10 @@ -87,6 +89,7 @@ struct sun6i_spi_cfg { unsigned long fifo_depth; + bool has_clk_ctl; }; struct sun6i_spi { @@ -260,7 +263,7 @@ static int sun6i_spi_transfer_one(struct spi_master *master, struct spi_transfer *tfr) { struct sun6i_spi *sspi = spi_master_get_devdata(master); - unsigned int mclk_rate, div, div_cdr1, div_cdr2, timeout; + unsigned int div, div_cdr1, div_cdr2, timeout; unsigned int start, end, tx_time; unsigned int trig_level; unsigned int tx_len = 0, rx_len = 0; @@ -350,39 +353,65 @@ static int sun6i_spi_transfer_one(struct spi_master *master, sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg); - /* Ensure that we have a parent clock fast enough */ - mclk_rate = clk_get_rate(sspi->mclk); - if (mclk_rate < (2 * tfr->speed_hz)) { - clk_set_rate(sspi->mclk, 2 * tfr->speed_hz); - mclk_rate = clk_get_rate(sspi->mclk); - } + if (sspi->cfg->has_clk_ctl) { + unsigned int mclk_rate = clk_get_rate(sspi->mclk); - /* - * Setup clock divider. - * - * We have two choices there. Either we can use the clock - * divide rate 1, which is calculated thanks to this formula: - * SPI_CLK = MOD_CLK / (2 ^ cdr) - * Or we can use CDR2, which is calculated with the formula: - * SPI_CLK = MOD_CLK / (2 * (cdr + 1)) - * Wether we use the former or the latter is set through the - * DRS bit. - * - * First try CDR2, and if we can't reach the expected - * frequency, fall back to CDR1. - */ - div_cdr1 = DIV_ROUND_UP(mclk_rate, tfr->speed_hz); - div_cdr2 = DIV_ROUND_UP(div_cdr1, 2); - if (div_cdr2 <= (SUN6I_CLK_CTL_CDR2_MASK + 1)) { - reg = SUN6I_CLK_CTL_CDR2(div_cdr2 - 1) | SUN6I_CLK_CTL_DRS; - tfr->effective_speed_hz = mclk_rate / (2 * div_cdr2); + /* Ensure that we have a parent clock fast enough */ + if (mclk_rate < (2 * tfr->speed_hz)) { + clk_set_rate(sspi->mclk, 2 * tfr->speed_hz); + mclk_rate = clk_get_rate(sspi->mclk); + } + + /* + * Setup clock divider. + * + * We have two choices there. Either we can use the clock + * divide rate 1, which is calculated thanks to this formula: + * SPI_CLK = MOD_CLK / (2 ^ cdr) + * Or we can use CDR2, which is calculated with the formula: + * SPI_CLK = MOD_CLK / (2 * (cdr + 1)) + * Wether we use the former or the latter is set through the + * DRS bit. + * + * First try CDR2, and if we can't reach the expected + * frequency, fall back to CDR1. + */ + div_cdr1 = DIV_ROUND_UP(mclk_rate, tfr->speed_hz); + div_cdr2 = DIV_ROUND_UP(div_cdr1, 2); + if (div_cdr2 <= (SUN6I_CLK_CTL_CDR2_MASK + 1)) { + reg = SUN6I_CLK_CTL_CDR2(div_cdr2 - 1) | SUN6I_CLK_CTL_DRS; + tfr->effective_speed_hz = mclk_rate / (2 * div_cdr2); + } else { + div = min(SUN6I_CLK_CTL_CDR1_MASK, order_base_2(div_cdr1)); + reg = SUN6I_CLK_CTL_CDR1(div); + tfr->effective_speed_hz = mclk_rate / (1 << div); + } + + sun6i_spi_write(sspi, SUN6I_CLK_CTL_REG, reg); } else { - div = min(SUN6I_CLK_CTL_CDR1_MASK, order_base_2(div_cdr1)); - reg = SUN6I_CLK_CTL_CDR1(div); - tfr->effective_speed_hz = mclk_rate / (1 << div); + clk_set_rate(sspi->mclk, tfr->speed_hz); + tfr->effective_speed_hz = clk_get_rate(sspi->mclk); + + /* + * Configure work mode. + * + * There are three work modes depending on the controller clock + * frequency: + * - normal sample mode : CLK <= 24MHz SDM=1 SDC=0 + * - delay half-cycle sample mode : CLK <= 40MHz SDM=0 SDC=0 + * - delay one-cycle sample mode : CLK >= 80MHz SDM=0 SDC=1 + */ + reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG); + reg &= ~(SUN6I_TFR_CTL_SDM | SUN6I_TFR_CTL_SDC); + + if (tfr->effective_speed_hz <= 24000000) + reg |= SUN6I_TFR_CTL_SDM; + else if (tfr->effective_speed_hz >= 80000000) + reg |= SUN6I_TFR_CTL_SDC; + + sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg); } - sun6i_spi_write(sspi, SUN6I_CLK_CTL_REG, reg); /* Finally enable the bus - doing so before might raise SCK to HIGH */ reg = sun6i_spi_read(sspi, SUN6I_GBL_CTL_REG); reg |= SUN6I_GBL_CTL_BUS_ENABLE; @@ -701,10 +730,12 @@ static void sun6i_spi_remove(struct platform_device *pdev) static const struct sun6i_spi_cfg sun6i_a31_spi_cfg = { .fifo_depth = SUN6I_FIFO_DEPTH, + .has_clk_ctl = true, }; static const struct sun6i_spi_cfg sun8i_h3_spi_cfg = { .fifo_depth = SUN8I_FIFO_DEPTH, + .has_clk_ctl = true, }; static const struct of_device_id sun6i_spi_match[] = { |