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spi: altera: support indirect access to the registers

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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: Xu Yilun <yilun.xu@intel.com>
Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Signed-off-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Russ Weight <russell.h.weight@intel.com>
Reviewed-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/1592531021-11412-3-git-send-email-yilun.xu@intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Xu Yilun 2020-06-19 09:43:40 +08:00 committed by Mark Brown
parent 3c6519736e
commit 3820061d38
No known key found for this signature in database
GPG key ID: 24D68B725D5487D0
1 changed files with 48 additions and 16 deletions
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64
drivers/spi/spi-altera.c
View file

@ -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;
@ -264,19 +271,38 @@ static int altera_spi_probe(struct platform_device *pdev)
hw = spi_master_get_devdata(master);
hw->dev = &pdev->dev;
/* find and map our resources */
res = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(res)) {
err = PTR_ERR(res);
goto exit;
}
if (platid)
type = platid->driver_data;
hw->regmap = devm_regmap_init_mmio(&pdev->dev, res,
&spi_altera_config);
if (IS_ERR(hw->regmap)) {
dev_err(&pdev->dev, "regmap mmio init failed\n");
err = PTR_ERR(hw->regmap);
goto exit;
/* 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);
goto exit;
}
hw->regmap = devm_regmap_init_mmio(&pdev->dev, res,
&spi_altera_config);
if (IS_ERR(hw->regmap)) {
dev_err(&pdev->dev, "regmap mmio init failed\n");
err = PTR_ERR(hw->regmap);
goto exit;
}
}
/* program defaults into the registers */
@ -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);