Commit 37457607 authored by Leilk Liu's avatar Leilk Liu Committed by Mark Brown
Browse files

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: default avatarLeilk Liu <leilk.liu@mediatek.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 58a984c7

drivers/spi/spi-mt65xx.c

+52 −13
Original line number Diff line number Diff line
@@ -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) {
@@ -512,22 +518,35 @@ 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);

		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:

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