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author | Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> | 2012-03-14 02:48:05 -0700 |
---|---|---|
committer | Grant Likely <grant.likely@secretlab.ca> | 2012-03-15 03:41:01 -0600 |
commit | 49e599b8595f9d33276860c6a02e05f240c4ceca (patch) | |
tree | 50259b5e076f6551a86e7b8dcfcf96aaf3f19398 /drivers | |
parent | ec139b67ad00647239b804d6f15315b83dba9a58 (diff) | |
download | op-kernel-dev-49e599b8595f9d33276860c6a02e05f240c4ceca.zip op-kernel-dev-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')
-rw-r--r-- | drivers/spi/spi-sh-hspi.c | 86 |
1 files changed, 70 insertions, 16 deletions
diff --git a/drivers/spi/spi-sh-hspi.c b/drivers/spi/spi-sh-hspi.c index 4290673..5784734 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); |