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ramips: improve rt2880 spi wait ready function

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use loops_per_jiffy, spi clock speed and write bytes to get the
spi loop count. if loop to 0 than spi operation timeout.
remove usleep. we only write 1 byte to spi device. use busy loop
would be better.

Signed-off-by: Michael Lee <igvtee@gmail.com>

SVN-Revision: 47575
This commit is contained in:
John Crispin 2015-11-22 11:48:34 +00:00
parent 702c480dfe
commit bf89d139e1
1 changed files with 15 additions and 16 deletions
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31
target/linux/ramips/patches-3.18/0050-SPI-ralink-add-Ralink-SoC-spi-driver.patch
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@ -41,7 +41,7 @@ Acked-by: John Crispin <blogic@openwrt.org>
spi-s3c24xx-hw-$(CONFIG_SPI_S3C24XX_FIQ) += spi-s3c24xx-fiq.o
--- /dev/null
+++ b/drivers/spi/spi-rt2880.c
@@ -0,0 +1,480 @@
@@ -0,0 +1,479 @@
+/*
+ * spi-rt2880.c -- Ralink RT288x/RT305x SPI controller driver
+ *
@ -70,8 +70,6 @@ Acked-by: John Crispin <blogic@openwrt.org>
+#define DRIVER_NAME "spi-rt2880"
+/* only one slave is supported*/
+#define RALINK_NUM_CHIPSELECTS 1
+/* in usec */
+#define RALINK_SPI_WAIT_MAX_LOOP 2000
+
+#define RAMIPS_SPI_STAT 0x00
+#define RAMIPS_SPI_CFG 0x10
@ -173,6 +171,7 @@ Acked-by: John Crispin <blogic@openwrt.org>
+ void __iomem *base;
+ unsigned int sys_freq;
+ unsigned int speed;
+ u16 wait_loops;
+ struct clk *clk;
+};
+
@ -238,6 +237,11 @@ Acked-by: John Crispin <blogic@openwrt.org>
+ reg = rt2880_spi_read(rs, RAMIPS_SPI_CFG);
+ reg = ((reg & ~SPICFG_SPICLK_PRESCALE_MASK) | prescale);
+ rt2880_spi_write(rs, RAMIPS_SPI_CFG, reg);
+
+ /* some tolerance. double and add 100 */
+ rs->wait_loops = (8 * HZ * loops_per_jiffy) /
+ (clk_get_rate(rs->clk) / rate);
+ rs->wait_loops = (rs->wait_loops << 1) + 100;
+ rs->speed = speed;
+ return 0;
+}
@ -273,20 +277,15 @@ Acked-by: John Crispin <blogic@openwrt.org>
+ rt2880_spi_setbits(rs, RAMIPS_SPI_CTL, SPICTL_SPIENA);
+}
+
+static inline int rt2880_spi_wait_till_ready(struct rt2880_spi *rs)
+static int rt2880_spi_wait_ready(struct rt2880_spi *rs, int len)
+{
+ int i;
+
+ for (i = 0; i < RALINK_SPI_WAIT_MAX_LOOP; i++) {
+ u32 status;
+
+ status = rt2880_spi_read(rs, RAMIPS_SPI_STAT);
+ if ((status & SPISTAT_BUSY) == 0)
+ return 0;
+ int loop = rs->wait_loops * len;
+
+ while ((rt2880_spi_read(rs, RAMIPS_SPI_STAT) & SPISTAT_BUSY) && --loop)
+ cpu_relax();
+ udelay(1);
+ }
+
+ if (loop)
+ return 0;
+
+ return -ETIMEDOUT;
+}
@ -308,7 +307,7 @@ Acked-by: John Crispin <blogic@openwrt.org>
+ for (count = 0; count < xfer->len; count++) {
+ rt2880_spi_write(rs, RAMIPS_SPI_DATA, tx[count]);
+ rt2880_spi_setbits(rs, RAMIPS_SPI_CTL, SPICTL_STARTWR);
+ err = rt2880_spi_wait_till_ready(rs);
+ err = rt2880_spi_wait_ready(rs, 1);
+ if (err) {
+ dev_err(&spi->dev, "TX failed, err=%d\n", err);
+ goto out;
@ -319,7 +318,7 @@ Acked-by: John Crispin <blogic@openwrt.org>
+ if (rx) {
+ for (count = 0; count < xfer->len; count++) {
+ rt2880_spi_setbits(rs, RAMIPS_SPI_CTL, SPICTL_STARTRD);
+ err = rt2880_spi_wait_till_ready(rs);
+ err = rt2880_spi_wait_ready(rs, 1);
+ if (err) {
+ dev_err(&spi->dev, "RX failed, err=%d\n", err);
+ goto out;