[PATCH 4/6] spi: altera: use regmap instead of direct mmio register access
From: Xu Yilun
Date: Wed Jun 10 2020 - 23:29:13 EST
This patch adds support for regmap. It allows this driver to
be compatible if low layer register access method is changed
in some cases.
Signed-off-by: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
Signed-off-by: Wu Hao <hao.wu@xxxxxxxxx>
Signed-off-by: Xu Yilun <yilun.xu@xxxxxxxxx>
Signed-off-by: Russ Weight <russell.h.weight@xxxxxxxxx>
---
drivers/spi/Kconfig | 1 +
drivers/spi/spi-altera.c | 103 ++++++++++++++++++++++++++++++++++++---------
include/linux/spi/altera.h | 6 +++
3 files changed, 90 insertions(+), 20 deletions(-)
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 8f1f8fc..6d79fc7 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -59,6 +59,7 @@ comment "SPI Master Controller Drivers"
config SPI_ALTERA
tristate "Altera SPI Controller"
+ select REGMAP_MMIO
help
This is the driver for the Altera SPI Controller.
diff --git a/drivers/spi/spi-altera.c b/drivers/spi/spi-altera.c
index aa9d1a2..8d47c57 100644
--- a/drivers/spi/spi-altera.c
+++ b/drivers/spi/spi-altera.c
@@ -44,7 +44,6 @@
#define ALTERA_SPI_MAX_CS 32
struct altera_spi {
- void __iomem *base;
int irq;
int len;
int count;
@@ -54,8 +53,45 @@ struct altera_spi {
/* data buffers */
const unsigned char *tx;
unsigned char *rx;
+
+ struct regmap *regmap;
+ u32 base;
+
+ struct device *dev;
+};
+
+static const struct regmap_config spi_altera_config = {
+ .reg_bits = 32,
+ .reg_stride = 4,
+ .val_bits = 32,
+ .fast_io = true,
};
+static int altr_spi_writel(struct altera_spi *hw, unsigned int reg,
+ unsigned int val)
+{
+ int ret;
+
+ ret = regmap_write(hw->regmap, hw->base + reg, val);
+ if (ret)
+ dev_err(hw->dev, "fail to write reg 0x%x val 0x%x: %d\n",
+ reg, val, ret);
+
+ return ret;
+}
+
+static int altr_spi_readl(struct altera_spi *hw, unsigned int reg,
+ unsigned int *val)
+{
+ int ret;
+
+ ret = regmap_read(hw->regmap, hw->base + reg, val);
+ if (ret)
+ dev_err(hw->dev, "fail to read reg 0x%x: %d\n", reg, ret);
+
+ return ret;
+}
+
static inline struct altera_spi *altera_spi_to_hw(struct spi_device *sdev)
{
return spi_master_get_devdata(sdev->master);
@@ -67,12 +103,13 @@ static void altera_spi_set_cs(struct spi_device *spi, bool is_high)
if (is_high) {
hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK;
- writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
- writel(0, hw->base + ALTERA_SPI_SLAVE_SEL);
+ altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr);
+ altr_spi_writel(hw, ALTERA_SPI_SLAVE_SEL, 0);
} else {
- writel(BIT(spi->chip_select), hw->base + ALTERA_SPI_SLAVE_SEL);
+ altr_spi_writel(hw, ALTERA_SPI_SLAVE_SEL,
+ BIT(spi->chip_select));
hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK;
- writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
+ altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr);
}
}
@@ -99,14 +136,14 @@ static void altera_spi_tx_word(struct altera_spi *hw)
}
}
- writel(txd, hw->base + ALTERA_SPI_TXDATA);
+ altr_spi_writel(hw, ALTERA_SPI_TXDATA, txd);
}
static void altera_spi_rx_word(struct altera_spi *hw)
{
unsigned int rxd;
- rxd = readl(hw->base + ALTERA_SPI_RXDATA);
+ altr_spi_readl(hw, ALTERA_SPI_RXDATA, &rxd);
if (hw->rx) {
switch (hw->bytes_per_word) {
case 1:
@@ -133,6 +170,7 @@ static int altera_spi_txrx(struct spi_master *master,
struct spi_device *spi, struct spi_transfer *t)
{
struct altera_spi *hw = spi_master_get_devdata(master);
+ u32 val;
hw->tx = t->tx_buf;
hw->rx = t->rx_buf;
@@ -143,7 +181,7 @@ static int altera_spi_txrx(struct spi_master *master,
if (hw->irq >= 0) {
/* enable receive interrupt */
hw->imr |= ALTERA_SPI_CONTROL_IRRDY_MSK;
- writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
+ altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr);
/* send the first byte */
altera_spi_tx_word(hw);
@@ -151,9 +189,13 @@ static int altera_spi_txrx(struct spi_master *master,
while (hw->count < hw->len) {
altera_spi_tx_word(hw);
- while (!(readl(hw->base + ALTERA_SPI_STATUS) &
- ALTERA_SPI_STATUS_RRDY_MSK))
+ for (;;) {
+ altr_spi_readl(hw, ALTERA_SPI_STATUS, &val);
+ if (val & ALTERA_SPI_STATUS_RRDY_MSK)
+ break;
+
cpu_relax();
+ }
altera_spi_rx_word(hw);
}
@@ -175,7 +217,7 @@ static irqreturn_t altera_spi_irq(int irq, void *dev)
} else {
/* disable receive interrupt */
hw->imr &= ~ALTERA_SPI_CONTROL_IRRDY_MSK;
- writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
+ altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr);
spi_finalize_current_transfer(master);
}
@@ -188,7 +230,9 @@ static int altera_spi_probe(struct platform_device *pdev)
struct altera_spi_platform_data *pdata = dev_get_platdata(&pdev->dev);
struct altera_spi *hw;
struct spi_master *master;
+ void __iomem *res;
int err = -ENODEV;
+ u32 val;
u16 i;
master = spi_alloc_master(&pdev->dev, sizeof(struct altera_spi));
@@ -220,19 +264,38 @@ static int altera_spi_probe(struct platform_device *pdev)
master->set_cs = altera_spi_set_cs;
hw = spi_master_get_devdata(master);
+ hw->dev = &pdev->dev;
/* find and map our resources */
- hw->base = devm_platform_ioremap_resource(pdev, 0);
- if (IS_ERR(hw->base)) {
- err = PTR_ERR(hw->base);
- goto exit;
+ if (pdata && pdata->use_parent_regmap) {
+ hw->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+ if (!hw->regmap) {
+ dev_err(&pdev->dev, "get regmap failed\n");
+ goto exit;
+ }
+ hw->base = pdata->regoff;
+ } else {
+ 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 */
hw->imr = 0; /* disable spi interrupts */
- writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
- writel(0, hw->base + ALTERA_SPI_STATUS); /* clear status reg */
- if (readl(hw->base + ALTERA_SPI_STATUS) & ALTERA_SPI_STATUS_RRDY_MSK)
- readl(hw->base + ALTERA_SPI_RXDATA); /* flush rxdata */
+ altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr);
+ altr_spi_writel(hw, ALTERA_SPI_STATUS, 0); /* clear status reg */
+ altr_spi_readl(hw, ALTERA_SPI_STATUS, &val);
+ if (val & ALTERA_SPI_STATUS_RRDY_MSK)
+ altr_spi_readl(hw, ALTERA_SPI_RXDATA, &val); /* flush rxdata */
/* irq is optional */
hw->irq = platform_get_irq(pdev, 0);
if (hw->irq >= 0) {
@@ -255,7 +318,7 @@ static int altera_spi_probe(struct platform_device *pdev)
}
}
- dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
+ dev_info(&pdev->dev, "base %u, irq %d\n", hw->base, hw->irq);
return 0;
exit:
diff --git a/include/linux/spi/altera.h b/include/linux/spi/altera.h
index 2d42641..164ab7b 100644
--- a/include/linux/spi/altera.h
+++ b/include/linux/spi/altera.h
@@ -17,6 +17,10 @@
* @num_devices: Number of devices that shall be added when the driver
* is probed.
* @devices: The devices to add.
+ * @use_parent_regmap: If true, device uses parent regmap to access its
+ * registers. Otherwise try map platform mmio resources.
+ * @regoff: Offset of the device register base in parent regmap.
+ * This field is ignored when use_parent_regmap == false.
*/
struct altera_spi_platform_data {
u16 mode_bits;
@@ -24,6 +28,8 @@ struct altera_spi_platform_data {
u32 bits_per_word_mask;
u16 num_devices;
struct spi_board_info *devices;
+ bool use_parent_regmap;
+ u32 regoff;
};
#endif /* __LINUX_SPI_ALTERA_H */
--
2.7.4