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path: root/drivers/spi/spi-ep93xx.c
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Diffstat (limited to 'drivers/spi/spi-ep93xx.c')
-rw-r--r--drivers/spi/spi-ep93xx.c57
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;