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...@intel.com>
Signed-off-by: Matthew Gerlach <matthew.gerl...@linux.intel.com>
Signed-off-by: Wu Hao <hao...@intel.com>
Signed-off-by: Russ Weight <russell.h.wei...@intel.com>
Reviewed-by : Tom Rix <t...@redhat.com>
---
drivers/spi/spi-altera.c | 62 ++++++++++++++++++++++++++++++++++++------------
1 file changed, 47 insertions(+), 15 deletions(-)
diff --git a/drivers/spi/spi-altera.c b/drivers/spi/spi-altera.c
index b215bdf..4f7717f 100644
--- a/drivers/spi/spi-altera.c
+++ b/drivers/spi/spi-altera.c
@@ -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;
+ if (platid)
+ type = platid->driver_data;
+
/* find and map our resources */
- res = devm_platform_ioremap_resource(pdev, 0);
- if (IS_ERR(res)) {
- err = PTR_ERR(res);
- goto exit;
- }
+ if (type == ALTERA_SPI_TYPE_SUBDEV) {
+ struct resource *regoff;
- 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;
+ 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);
--
2.7.4
