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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>
This commit is contained in:
Leilk Liu 2015-10-26 16:09:44 +08:00 committed by Mark Brown
parent 58a984c79a
commit 37457607ec
1 changed files with 52 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

65
drivers/spi/spi-mt65xx.c
View File

@ -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: