diff options
author | Leilk Liu <leilk.liu@mediatek.com> | 2015-10-26 16:09:44 +0800 |
---|---|---|
committer | Mark Brown <broonie@kernel.org> | 2015-10-27 13:33:42 +0900 |
commit | 37457607ecaffe56718a0e423548edeb3d4a11b7 (patch) | |
tree | e37b60c5ff7f4e83cd76eaaf05640c146088669f /drivers/spi/spi-mt65xx.c | |
parent | 58a984c79a68d508ccfccf4b82c0eaf7f487c399 (diff) | |
download | linux-37457607ecaffe56718a0e423548edeb3d4a11b7.tar.gz |
spi: mediatek: mt8173 spi multiple devices support
mt8173 IC spi HW has 4 gpio group, it's possible to support
max <= 4 slave devices, even mtk spi HW is not congruent to spi core.
1. When a device do a spi_message transfer, spi HW should know
which pad-group this device is on, and then writes pad-select
register.
2. Mtk pad-select register just selects which MISO pin HW will
receive data. For example, pad-select=1(select spi1 pins), HW just
receives data from spi1 MISO, but it still send waveform to all 4
group cs/clk/mosi. If cs pin in other groups is still spi mode,
after spi1 is selected(by active cs pin), devices on other group
will also be selected.
Signed-off-by: Leilk Liu <leilk.liu@mediatek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi-mt65xx.c')
-rw-r--r-- | drivers/spi/spi-mt65xx.c | 65 |
1 files changed, 52 insertions, 13 deletions
diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c index 406695a42e19..563954a61424 100644 --- a/drivers/spi/spi-mt65xx.c +++ b/drivers/spi/spi-mt65xx.c @@ -20,6 +20,7 @@ #include <linux/ioport.h> #include <linux/module.h> #include <linux/of.h> +#include <linux/of_gpio.h> #include <linux/platform_device.h> #include <linux/platform_data/spi-mt65xx.h> #include <linux/pm_runtime.h> @@ -84,7 +85,8 @@ struct mtk_spi_compatible { struct mtk_spi { void __iomem *base; u32 state; - u32 pad_sel; + int pad_num; + u32 *pad_sel; struct clk *parent_clk, *sel_clk, *spi_clk; struct spi_transfer *cur_transfer; u32 xfer_len; @@ -188,7 +190,8 @@ static int mtk_spi_prepare_message(struct spi_master *master, /* pad select */ if (mdata->dev_comp->need_pad_sel) - writel(mdata->pad_sel, mdata->base + SPI_PAD_SEL_REG); + writel(mdata->pad_sel[spi->chip_select], + mdata->base + SPI_PAD_SEL_REG); return 0; } @@ -407,6 +410,9 @@ static int mtk_spi_setup(struct spi_device *spi) if (!spi->controller_data) spi->controller_data = (void *)&mtk_default_chip_info; + if (mdata->dev_comp->need_pad_sel) + gpio_direction_output(spi->cs_gpio, !(spi->mode & SPI_CS_HIGH)); + return 0; } @@ -481,7 +487,7 @@ static int mtk_spi_probe(struct platform_device *pdev) struct mtk_spi *mdata; const struct of_device_id *of_id; struct resource *res; - int irq, ret; + int i, irq, ret; master = spi_alloc_master(&pdev->dev, sizeof(*mdata)); if (!master) { @@ -512,21 +518,34 @@ static int mtk_spi_probe(struct platform_device *pdev) master->flags = SPI_MASTER_MUST_TX; if (mdata->dev_comp->need_pad_sel) { - ret = of_property_read_u32(pdev->dev.of_node, - "mediatek,pad-select", - &mdata->pad_sel); - if (ret) { - dev_err(&pdev->dev, "failed to read pad select: %d\n", - ret); + mdata->pad_num = of_property_count_u32_elems( + pdev->dev.of_node, + "mediatek,pad-select"); + if (mdata->pad_num < 0) { + dev_err(&pdev->dev, + "No 'mediatek,pad-select' property\n"); + ret = -EINVAL; goto err_put_master; } - if (mdata->pad_sel > MT8173_SPI_MAX_PAD_SEL) { - dev_err(&pdev->dev, "wrong pad-select: %u\n", - mdata->pad_sel); - ret = -EINVAL; + mdata->pad_sel = devm_kmalloc_array(&pdev->dev, mdata->pad_num, + sizeof(u32), GFP_KERNEL); + if (!mdata->pad_sel) { + ret = -ENOMEM; goto err_put_master; } + + for (i = 0; i < mdata->pad_num; i++) { + of_property_read_u32_index(pdev->dev.of_node, + "mediatek,pad-select", + i, &mdata->pad_sel[i]); + if (mdata->pad_sel[i] > MT8173_SPI_MAX_PAD_SEL) { + dev_err(&pdev->dev, "wrong pad-sel[%d]: %u\n", + i, mdata->pad_sel[i]); + ret = -EINVAL; + goto err_put_master; + } + } } platform_set_drvdata(pdev, master); @@ -604,6 +623,26 @@ static int mtk_spi_probe(struct platform_device *pdev) goto err_put_master; } + if (mdata->dev_comp->need_pad_sel) { + if (mdata->pad_num != master->num_chipselect) { + dev_err(&pdev->dev, + "pad_num does not match num_chipselect(%d != %d)\n", + mdata->pad_num, master->num_chipselect); + ret = -EINVAL; + goto err_put_master; + } + + for (i = 0; i < master->num_chipselect; i++) { + ret = devm_gpio_request(&pdev->dev, master->cs_gpios[i], + dev_name(&pdev->dev)); + if (ret) { + dev_err(&pdev->dev, + "can't get CS GPIO %i\n", i); + goto err_put_master; + } + } + } + return 0; err_disable_clk: |