spi: sh-hspi: control spi clock more correctly

Current sh-hspi had used platform-specific speed.
This patch remove it, and use spi_transfer specific speed.
It removes unnecessary flags from struct sh_hspi_info,
but struct sh_hspi_info is still exist, since sh-hspi needs
platform info in the future.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

diff --git a/drivers/spi/spi-sh-hspi.c b/drivers/spi/spi-sh-hspi.c
index 4290673..5784734 100644 (file)
--- a/drivers/spi/spi-sh-hspi.c
+++ b/drivers/spi/spi-sh-hspi.c
@@ -22,6 +22,8 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  *
  */
+
+#include <linux/clk.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/timer.h>
@@ -50,6 +52,7 @@ struct hspi_priv {
        void __iomem *addr;
        struct spi_master *master;
        struct device *dev;
+       struct clk *clk;
 };
 
 /*
@@ -162,6 +165,59 @@ static int hspi_unprepare_transfer(struct spi_master *master)
        return 0;
 }
 
+static void hspi_hw_setup(struct hspi_priv *hspi,
+                         struct spi_message *msg,
+                         struct spi_transfer *t)
+{
+       struct spi_device *spi = msg->spi;
+       struct device *dev = hspi->dev;
+       u32 target_rate;
+       u32 spcr, idiv_clk;
+       u32 rate, best_rate, min, tmp;
+
+       target_rate = t ? t->speed_hz : 0;
+       if (!target_rate)
+               target_rate = spi->max_speed_hz;
+
+       /*
+        * find best IDIV/CLKCx settings
+        */
+       min = ~0;
+       best_rate = 0;
+       spcr = 0;
+       for (idiv_clk = 0x00; idiv_clk <= 0x3F; idiv_clk++) {
+               rate = clk_get_rate(hspi->clk);
+
+               /* IDIV calculation */
+               if (idiv_clk & (1 << 5))
+                       rate /= 128;
+               else
+                       rate /= 16;
+
+               /* CLKCx calculation */
+               rate /= (((idiv_clk & 0x1F) + 1) * 2) ;
+
+               /* save best settings */
+               tmp = abs(target_rate - rate);
+               if (tmp < min) {
+                       min = tmp;
+                       spcr = idiv_clk;
+                       best_rate = rate;
+               }
+       }
+
+       if (spi->mode & SPI_CPHA)
+               spcr |= 1 << 7;
+       if (spi->mode & SPI_CPOL)
+               spcr |= 1 << 6;
+
+       dev_dbg(dev, "speed %d/%d\n", target_rate, best_rate);
+
+       hspi_write(hspi, SPCR, spcr);
+       hspi_write(hspi, SPSR, 0x0);
+       hspi_write(hspi, SPSCR, 0x1);   /* master mode */
+}
+
 static int hspi_transfer_one_message(struct spi_master *master,
                                     struct spi_message *msg)
 {
@@ -173,6 +229,8 @@ static int hspi_transfer_one_message(struct spi_master *master,
 
        ret = 0;
        list_for_each_entry(t, &msg->transfers, transfer_list) {
+               hspi_hw_setup(hspi, msg, t);
+
                if (t->tx_buf) {
                        ret = hspi_push(hspi, msg, t);
                        if (ret < 0)
@@ -197,28 +255,12 @@ static int hspi_setup(struct spi_device *spi)
 {
        struct hspi_priv *hspi = spi_master_get_devdata(spi->master);
        struct device *dev = hspi->dev;
-       struct sh_hspi_info *info = hspi2info(hspi);
-       u32 data;
 
        if (8 != spi->bits_per_word) {
                dev_err(dev, "bits_per_word should be 8\n");
                return -EIO;
        }
 
-       /* setup first of all in under pm_runtime */
-       data = SH_HSPI_CLK_DIVC(info->flags);
-
-       if (info->flags & SH_HSPI_FBS)
-               data |= 1 << 7;
-       if (info->flags & SH_HSPI_CLKP_HIGH)
-               data |= 1 << 6;
-       if (info->flags & SH_HSPI_IDIV_DIV128)
-               data |= 1 << 5;
-
-       hspi_write(hspi, SPCR, data);
-       hspi_write(hspi, SPSR, 0x0);
-       hspi_write(hspi, SPSCR, 0x1);   /* master mode */
-
        dev_dbg(dev, "%s setup\n", spi->modalias);
 
        return 0;
@@ -237,6 +279,7 @@ static int __devinit hspi_probe(struct platform_device *pdev)
        struct resource *res;
        struct spi_master *master;
        struct hspi_priv *hspi;
+       struct clk *clk;
        int ret;
 
        /* get base addr */
@@ -252,12 +295,20 @@ static int __devinit hspi_probe(struct platform_device *pdev)
                return -ENOMEM;
        }
 
+       clk = clk_get(NULL, "shyway_clk");
+       if (!clk) {
+               dev_err(&pdev->dev, "shyway_clk is required\n");
+               ret = -EINVAL;
+               goto error0;
+       }
+
        hspi = spi_master_get_devdata(master);
        dev_set_drvdata(&pdev->dev, hspi);
 
        /* init hspi */
        hspi->master    = master;
        hspi->dev       = &pdev->dev;
+       hspi->clk       = clk;
        hspi->addr      = devm_ioremap(hspi->dev,
                                       res->start, resource_size(res));
        if (!hspi->addr) {
@@ -289,6 +340,8 @@ static int __devinit hspi_probe(struct platform_device *pdev)
  error2:
        devm_iounmap(hspi->dev, hspi->addr);
  error1:
+       clk_put(clk);
+ error0:
        spi_master_put(master);
 
        return ret;
@@ -300,6 +353,7 @@ static int __devexit hspi_remove(struct platform_device *pdev)
 
        pm_runtime_disable(&pdev->dev);
 
+       clk_put(hspi->clk);
        spi_unregister_master(hspi->master);
        devm_iounmap(hspi->dev, hspi->addr);
 

diff --git a/include/linux/spi/sh_hspi.h b/include/linux/spi/sh_hspi.h
index 956d112..a1121f8 100644 (file)
--- a/include/linux/spi/sh_hspi.h
+++ b/include/linux/spi/sh_hspi.h
@@ -17,18 +17,7 @@
 #ifndef SH_HSPI_H
 #define SH_HSPI_H
 
-/*
- * flags
- *
- *
- */
-#define SH_HSPI_CLK_DIVC(d)            (d & 0xFF)
-
-#define SH_HSPI_FBS            (1 << 8)
-#define SH_HSPI_CLKP_HIGH      (1 << 9)        /* default LOW */
-#define SH_HSPI_IDIV_DIV128    (1 << 10)       /* default div16 */
 struct sh_hspi_info {
-       u32     flags;
 };
 
 #endif