diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-ep93xx.c | 57 |
1 files changed, 25 insertions, 32 deletions
diff --git a/drivers/spi/spi-ep93xx.c b/drivers/spi/spi-ep93xx.c index 6cdfc4036b75..2e64806b40af 100644 --- a/drivers/spi/spi-ep93xx.c +++ b/drivers/spi/spi-ep93xx.c @@ -136,18 +136,10 @@ struct ep93xx_spi { /** * struct ep93xx_spi_chip - SPI device hardware settings * @spi: back pointer to the SPI device - * @div_cpsr: cpsr (pre-scaler) divider - * @div_scr: scr divider * @ops: private chip operations - * - * This structure is used to store hardware register specific settings for each - * SPI device. Settings are written to hardware by function - * ep93xx_spi_chip_setup(). */ struct ep93xx_spi_chip { const struct spi_device *spi; - u8 div_cpsr; - u8 div_scr; struct ep93xx_spi_chip_ops *ops; }; @@ -224,17 +216,13 @@ static void ep93xx_spi_disable_interrupts(const struct ep93xx_spi *espi) /** * ep93xx_spi_calc_divisors() - calculates SPI clock divisors * @espi: ep93xx SPI controller struct - * @chip: divisors are calculated for this chip * @rate: desired SPI output clock rate - * - * Function calculates cpsr (clock pre-scaler) and scr divisors based on - * given @rate and places them to @chip->div_cpsr and @chip->div_scr. If, - * for some reason, divisors cannot be calculated nothing is stored and - * %-EINVAL is returned. + * @div_cpsr: pointer to return the cpsr (pre-scaler) divider + * @div_scr: pointer to return the scr divider */ static int ep93xx_spi_calc_divisors(const struct ep93xx_spi *espi, - struct ep93xx_spi_chip *chip, - unsigned long rate) + unsigned long rate, + u8 *div_cpsr, u8 *div_scr) { unsigned long spi_clk_rate = clk_get_rate(espi->clk); int cpsr, scr; @@ -257,8 +245,8 @@ static int ep93xx_spi_calc_divisors(const struct ep93xx_spi *espi, for (cpsr = 2; cpsr <= 254; cpsr += 2) { for (scr = 0; scr <= 255; scr++) { if ((spi_clk_rate / (cpsr * (scr + 1))) <= rate) { - chip->div_scr = (u8)scr; - chip->div_cpsr = (u8)cpsr; + *div_scr = (u8)scr; + *div_cpsr = (u8)cpsr; return 0; } } @@ -389,29 +377,35 @@ static void ep93xx_spi_cleanup(struct spi_device *spi) * ep93xx_spi_chip_setup() - configures hardware according to given @chip * @espi: ep93xx SPI controller struct * @chip: chip specific settings + * @speed_hz: transfer speed * @bits_per_word: transfer bits_per_word - * - * This function sets up the actual hardware registers with settings given in - * @chip. Note that no validation is done so make sure that callers validate - * settings before calling this. */ -static void ep93xx_spi_chip_setup(const struct ep93xx_spi *espi, - const struct ep93xx_spi_chip *chip, - u8 bits_per_word) +static int ep93xx_spi_chip_setup(const struct ep93xx_spi *espi, + const struct ep93xx_spi_chip *chip, + u32 speed_hz, u8 bits_per_word) { u8 dss = bits_per_word_to_dss(bits_per_word); + u8 div_cpsr = 0; + u8 div_scr = 0; u16 cr0; + int err; + + err = ep93xx_spi_calc_divisors(espi, speed_hz, &div_cpsr, &div_scr); + if (err) + return err; - cr0 = chip->div_scr << SSPCR0_SCR_SHIFT; + cr0 = div_scr << SSPCR0_SCR_SHIFT; cr0 |= (chip->spi->mode & (SPI_CPHA|SPI_CPOL)) << SSPCR0_MODE_SHIFT; cr0 |= dss; dev_dbg(&espi->pdev->dev, "setup: mode %d, cpsr %d, scr %d, dss %d\n", - chip->spi->mode, chip->div_cpsr, chip->div_scr, dss); + chip->spi->mode, div_cpsr, div_scr, dss); dev_dbg(&espi->pdev->dev, "setup: cr0 %#x", cr0); - ep93xx_spi_write_u8(espi, SSPCPSR, chip->div_cpsr); + ep93xx_spi_write_u8(espi, SSPCPSR, div_cpsr); ep93xx_spi_write_u16(espi, SSPCR0, cr0); + + return 0; } static void ep93xx_do_write(struct ep93xx_spi *espi, struct spi_transfer *t) @@ -687,15 +681,14 @@ static void ep93xx_spi_process_transfer(struct ep93xx_spi *espi, msg->state = t; - err = ep93xx_spi_calc_divisors(espi, chip, t->speed_hz); + err = ep93xx_spi_chip_setup(espi, chip, t->speed_hz, t->bits_per_word); if (err) { - dev_err(&espi->pdev->dev, "failed to adjust speed\n"); + dev_err(&espi->pdev->dev, + "failed to setup chip for transfer\n"); msg->status = err; return; } - ep93xx_spi_chip_setup(espi, chip, t->bits_per_word); - espi->rx = 0; espi->tx = 0; |