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>

1 files changed, 70 insertions, 16 deletions

diff --git a/drivers/spi/spi-sh-hspi.c b/drivers/spi/spi-sh-hspi.c
index 42906731c40d..5784734d257d 100644
--- 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);