Unverified Commit 3820061d authored by Xu Yilun's avatar Xu Yilun Committed by Mark Brown
Browse files

spi: altera: support indirect access to the registers 



This patch adds support for indirect access to the registers via parent
regmap.

The use case is, the spi master is a sub device of a Multifunction
device, which is connected to host by some indirect bus. To support this
device type, a new platform_device_id is introduced, and the driver tries
to get parent regmap for register accessing like many MFD sub device
drivers do.

Signed-off-by: default avatarXu Yilun <yilun.xu@intel.com>
Signed-off-by: default avatarMatthew Gerlach <matthew.gerlach@linux.intel.com>
Signed-off-by: default avatarWu Hao <hao.wu@intel.com>
Signed-off-by: default avatarRuss Weight <russell.h.weight@intel.com>
Reviewed-by: default avatarTom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/1592531021-11412-3-git-send-email-yilun.xu@intel.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 3c651973

drivers/spi/spi-altera.c

+47 −15
Original line number Diff line number Diff line
@@ -43,6 +43,11 @@ 


#define ALTERA_SPI_MAX_CS		32



enum altera_spi_type {

	ALTERA_SPI_TYPE_UNKNOWN,

	ALTERA_SPI_TYPE_SUBDEV,

};



struct altera_spi {

	int irq;

	int len;
@@ -55,6 +60,7 @@ struct altera_spi { 
	unsigned char *rx;



	struct regmap *regmap;

	u32 regoff;

	struct device *dev;

};
@@ -70,7 +76,7 @@ static int altr_spi_writel(struct altera_spi *hw, unsigned int reg, 
{

	int ret;



	ret = regmap_write(hw->regmap, reg, val);

	ret = regmap_write(hw->regmap, hw->regoff + reg, val);

	if (ret)

		dev_err(hw->dev, "fail to write reg 0x%x val 0x%x: %d\n",

			reg, val, ret);
@@ -83,7 +89,7 @@ static int altr_spi_readl(struct altera_spi *hw, unsigned int reg, 
{

	int ret;



	ret = regmap_read(hw->regmap, reg, val);

	ret = regmap_read(hw->regmap, hw->regoff + reg, val);

	if (ret)

		dev_err(hw->dev, "fail to read reg 0x%x: %d\n", reg, ret);
@@ -225,10 +231,11 @@ static irqreturn_t altera_spi_irq(int irq, void *dev) 


static int altera_spi_probe(struct platform_device *pdev)

{

	const struct platform_device_id *platid = platform_get_device_id(pdev);

	struct altera_spi_platform_data *pdata = dev_get_platdata(&pdev->dev);

	enum altera_spi_type type = ALTERA_SPI_TYPE_UNKNOWN;

	struct altera_spi *hw;

	struct spi_master *master;

	void __iomem *res;

	int err = -ENODEV;

	u32 val;

	u16 i;
@@ -264,7 +271,25 @@ static int altera_spi_probe(struct platform_device *pdev) 
	hw = spi_master_get_devdata(master);

	hw->dev = &pdev->dev;



	if (platid)

		type = platid->driver_data;



	/* find and map our resources */

	if (type == ALTERA_SPI_TYPE_SUBDEV) {

		struct resource *regoff;



		hw->regmap = dev_get_regmap(pdev->dev.parent, NULL);

		if (!hw->regmap) {

			dev_err(&pdev->dev, "get regmap failed\n");

			goto exit;

		}



		regoff = platform_get_resource(pdev, IORESOURCE_REG, 0);

		if (regoff)

			hw->regoff = regoff->start;

	} else {

		void __iomem *res;



		res = devm_platform_ioremap_resource(pdev, 0);

		if (IS_ERR(res)) {

			err = PTR_ERR(res);
@@ -278,6 +303,7 @@ static int altera_spi_probe(struct platform_device *pdev) 
			err = PTR_ERR(hw->regmap);

			goto exit;

		}

	}



	/* program defaults into the registers */

	hw->imr = 0;		/* disable spi interrupts */
@@ -308,7 +334,7 @@ static int altera_spi_probe(struct platform_device *pdev) 
		}

	}



	dev_info(&pdev->dev, "base %p, irq %d\n", res, hw->irq);

	dev_info(&pdev->dev, "regoff %u, irq %d\n", hw->regoff, hw->irq);



	return 0;

exit:
@@ -325,6 +351,11 @@ static const struct of_device_id altera_spi_match[] = { 
MODULE_DEVICE_TABLE(of, altera_spi_match);

#endif /* CONFIG_OF */



static const struct platform_device_id altera_spi_ids[] = {

	{ "subdev_spi_altera", ALTERA_SPI_TYPE_SUBDEV },

	{ }

};



static struct platform_driver altera_spi_driver = {

	.probe = altera_spi_probe,

	.driver = {
@@ -332,6 +363,7 @@ static struct platform_driver altera_spi_driver = { 
		.pm = NULL,

		.of_match_table = of_match_ptr(altera_spi_match),

	},

	.id_table	= altera_spi_ids,

};

module_platform_driver(altera_spi_driver);

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