diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-atmel.c | 56 | ||||
| -rw-r--r-- | drivers/spi/spi-orion.c | 83 |
2 files changed, 98 insertions, 41 deletions
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c index 8feac599e9ab..9fb00ac3ac2e 100644 --- a/drivers/spi/spi-atmel.c +++ b/drivers/spi/spi-atmel.c @@ -24,6 +24,7 @@ #include <linux/io.h> #include <linux/gpio.h> +#include <linux/of_gpio.h> #include <linux/pinctrl/consumer.h> #include <linux/pm_runtime.h> @@ -295,6 +296,7 @@ struct atmel_spi { int irq; struct clk *clk; struct platform_device *pdev; + unsigned long spi_clk; struct spi_transfer *current_transfer; int current_remaining_bytes; @@ -864,7 +866,7 @@ static int atmel_spi_set_xfer_speed(struct atmel_spi *as, unsigned long bus_hz; /* v1 chips start out at half the peripheral bus speed. */ - bus_hz = clk_get_rate(as->clk); + bus_hz = as->spi_clk; if (!atmel_spi_is_v2(as)) bus_hz /= 2; @@ -1204,7 +1206,6 @@ static int atmel_spi_setup(struct spi_device *spi) u32 csr; unsigned int bits = spi->bits_per_word; unsigned int npcs_pin; - int ret; as = spi_master_get_devdata(spi->master); @@ -1247,16 +1248,9 @@ static int atmel_spi_setup(struct spi_device *spi) if (!asd) return -ENOMEM; - if (as->use_cs_gpios) { - ret = gpio_request(npcs_pin, dev_name(&spi->dev)); - if (ret) { - kfree(asd); - return ret; - } - + if (as->use_cs_gpios) gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH)); - } asd->npcs_pin = npcs_pin; spi->controller_state = asd; @@ -1471,13 +1465,11 @@ msg_done: static void atmel_spi_cleanup(struct spi_device *spi) { struct atmel_spi_device *asd = spi->controller_state; - unsigned gpio = (unsigned long) spi->controller_data; if (!asd) return; spi->controller_state = NULL; - gpio_free(gpio); kfree(asd); } @@ -1499,6 +1491,39 @@ static void atmel_get_caps(struct atmel_spi *as) } /*-------------------------------------------------------------------------*/ +static int atmel_spi_gpio_cs(struct platform_device *pdev) +{ + struct spi_master *master = platform_get_drvdata(pdev); + struct atmel_spi *as = spi_master_get_devdata(master); + struct device_node *np = master->dev.of_node; + int i; + int ret = 0; + int nb = 0; + + if (!as->use_cs_gpios) + return 0; + + if (!np) + return 0; + + nb = of_gpio_named_count(np, "cs-gpios"); + for (i = 0; i < nb; i++) { + int cs_gpio = of_get_named_gpio(pdev->dev.of_node, + "cs-gpios", i); + + if (cs_gpio == -EPROBE_DEFER) + return cs_gpio; + + if (gpio_is_valid(cs_gpio)) { + ret = devm_gpio_request(&pdev->dev, cs_gpio, + dev_name(&pdev->dev)); + if (ret) + return ret; + } + } + + return 0; +} static int atmel_spi_probe(struct platform_device *pdev) { @@ -1577,6 +1602,10 @@ static int atmel_spi_probe(struct platform_device *pdev) master->num_chipselect = 4; } + ret = atmel_spi_gpio_cs(pdev); + if (ret) + goto out_unmap_regs; + as->use_dma = false; as->use_pdc = false; if (as->caps.has_dma_support) { @@ -1606,6 +1635,9 @@ static int atmel_spi_probe(struct platform_device *pdev) ret = clk_prepare_enable(clk); if (ret) goto out_free_irq; + + as->spi_clk = clk_get_rate(clk); + spi_writel(as, CR, SPI_BIT(SWRST)); spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */ if (as->caps.has_wdrbt) { diff --git a/drivers/spi/spi-orion.c b/drivers/spi/spi-orion.c index ded37025b445..6b001c4a5640 100644 --- a/drivers/spi/spi-orion.c +++ b/drivers/spi/spi-orion.c @@ -138,37 +138,62 @@ static int orion_spi_baudrate_set(struct spi_device *spi, unsigned int speed) tclk_hz = clk_get_rate(orion_spi->clk); if (devdata->typ == ARMADA_SPI) { - unsigned int clk, spr, sppr, sppr2, err; - unsigned int best_spr, best_sppr, best_err; - - best_err = speed; - best_spr = 0; - best_sppr = 0; - - /* Iterate over the valid range looking for best fit */ - for (sppr = 0; sppr < 8; sppr++) { - sppr2 = 0x1 << sppr; - - spr = tclk_hz / sppr2; - spr = DIV_ROUND_UP(spr, speed); - if ((spr == 0) || (spr > 15)) - continue; - - clk = tclk_hz / (spr * sppr2); - err = speed - clk; - - if (err < best_err) { - best_spr = spr; - best_sppr = sppr; - best_err = err; - } - } + /* + * Given the core_clk (tclk_hz) and the target rate (speed) we + * determine the best values for SPR (in [0 .. 15]) and SPPR (in + * [0..7]) such that + * + * core_clk / (SPR * 2 ** SPPR) + * + * is as big as possible but not bigger than speed. + */ - if ((best_sppr == 0) && (best_spr == 0)) - return -EINVAL; + /* best integer divider: */ + unsigned divider = DIV_ROUND_UP(tclk_hz, speed); + unsigned spr, sppr; + + if (divider < 16) { + /* This is the easy case, divider is less than 16 */ + spr = divider; + sppr = 0; + + } else { + unsigned two_pow_sppr; + /* + * Find the highest bit set in divider. This and the + * three next bits define SPR (apart from rounding). + * SPPR is then the number of zero bits that must be + * appended: + */ + sppr = fls(divider) - 4; + + /* + * As SPR only has 4 bits, we have to round divider up + * to the next multiple of 2 ** sppr. + */ + two_pow_sppr = 1 << sppr; + divider = (divider + two_pow_sppr - 1) & -two_pow_sppr; + + /* + * recalculate sppr as rounding up divider might have + * increased it enough to change the position of the + * highest set bit. In this case the bit that now + * doesn't make it into SPR is 0, so there is no need to + * round again. + */ + sppr = fls(divider) - 4; + spr = divider >> sppr; + + /* + * Now do range checking. SPR is constructed to have a + * width of 4 bits, so this is fine for sure. So we + * still need to check for sppr to fit into 3 bits: + */ + if (sppr > 7) + return -EINVAL; + } - prescale = ((best_sppr & 0x6) << 5) | - ((best_sppr & 0x1) << 4) | best_spr; + prescale = ((sppr & 0x6) << 5) | ((sppr & 0x1) << 4) | spr; } else { /* * the supported rates are: 4,6,8...30 |