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Message-Id: <1591845911-10197-5-git-send-email-yilun.xu@intel.com>
Date: Thu, 11 Jun 2020 11:25:09 +0800
From: Xu Yilun <yilun.xu@...el.com>
To: broonie@...nel.org, linux-spi@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: trix@...hat.com, yilun.xu@...el.com, hao.wu@...el.com,
matthew.gerlach@...ux.intel.com, russell.h.weight@...el.com
Subject: [PATCH 4/6] spi: altera: use regmap instead of direct mmio register access
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@...ux.intel.com>
Signed-off-by: Wu Hao <hao.wu@...el.com>
Signed-off-by: Xu Yilun <yilun.xu@...el.com>
Signed-off-by: Russ Weight <russell.h.weight@...el.com>
---
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
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