aboutsummaryrefslogtreecommitdiff
path: root/drivers/spi/spi-sh-hspi.c
diff options
context:
space:
mode:
authorKuninori Morimoto <kuninori.morimoto.gx@renesas.com>2012-03-14 02:48:05 -0700
committerGrant Likely <grant.likely@secretlab.ca>2012-03-15 03:41:01 -0600
commit49e599b8595f9d33276860c6a02e05f240c4ceca (patch)
tree50259b5e076f6551a86e7b8dcfcf96aaf3f19398 /drivers/spi/spi-sh-hspi.c
parentec139b67ad00647239b804d6f15315b83dba9a58 (diff)
downloadlinux-linaro-stable-49e599b8595f9d33276860c6a02e05f240c4ceca.tar.gz
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>
Diffstat (limited to 'drivers/spi/spi-sh-hspi.c')
-rw-r--r--drivers/spi/spi-sh-hspi.c86
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);