Re: [PATCH v2 2/2] spi: add SPI controller driver for UniPhier SoC
From: Masahiro Yamada
Date: Thu Jul 26 2018 - 05:13:54 EST
Hi.
2018-07-26 16:09 GMT+09:00 Keiji Hayashibara <hayashibara.keiji@xxxxxxxxxxxxx>:
> Add SPI controller driver implemented in Socionext UniPhier SoCs.
>
> UniPhier SoCs have two types SPI controllers; SCSSI supports a
> single channel, and MCSSI supports multiple channels.
> This driver supports SCSSI only.
>
> This controller has 32bit TX/RX FIFO with depth of eight entry,
> and supports the SPI master mode only.
>
> This commit is implemented in PIO transfer mode, not DMA transfer.
>
> Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx>
> Signed-off-by: Keiji Hayashibara <hayashibara.keiji@xxxxxxxxxxxxx>
> ---
> drivers/spi/Kconfig | 13 ++
> drivers/spi/Makefile | 1 +
> drivers/spi/spi-uniphier.c | 539 +++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 553 insertions(+)
> create mode 100644 drivers/spi/spi-uniphier.c
>
> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> index ad5d68e..671d078 100644
> --- a/drivers/spi/Kconfig
> +++ b/drivers/spi/Kconfig
> @@ -688,6 +688,19 @@ config SPI_TXX9
> help
> SPI driver for Toshiba TXx9 MIPS SoCs
>
> +config SPI_UNIPHIER
> + tristate "Socionext UniPhier SPI Controller"
> + depends on (ARCH_UNIPHIER || COMPILE_TEST) && OF
> + help
> + This enables a driver for the Socionext UniPhier SoC SCSSI SPI controller.
> +
> + UniPhier SoCs have SCSSI and MCSSI SPI controllers.
> + Every UniPhier SoC has SCSSI which supports single channel.
> + Older UniPhier Pro4/Pro5 also has MCSSI which support multiple channels.
> + This driver supports SCSSI only.
> +
> + If your SoC supports SCSSI, say Y here.
> +
> config SPI_XCOMM
> tristate "Analog Devices AD-FMCOMMS1-EBZ SPI-I2C-bridge driver"
> depends on I2C
> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
> index cb1f437..a90d559 100644
> --- a/drivers/spi/Makefile
> +++ b/drivers/spi/Makefile
> @@ -101,6 +101,7 @@ spi-thunderx-objs := spi-cavium.o spi-cavium-thunderx.o
> obj-$(CONFIG_SPI_THUNDERX) += spi-thunderx.o
> obj-$(CONFIG_SPI_TOPCLIFF_PCH) += spi-topcliff-pch.o
> obj-$(CONFIG_SPI_TXX9) += spi-txx9.o
> +obj-$(CONFIG_SPI_UNIPHIER) += spi-uniphier.o
> obj-$(CONFIG_SPI_XCOMM) += spi-xcomm.o
> obj-$(CONFIG_SPI_XILINX) += spi-xilinx.o
> obj-$(CONFIG_SPI_XLP) += spi-xlp.o
> diff --git a/drivers/spi/spi-uniphier.c b/drivers/spi/spi-uniphier.c
> new file mode 100644
> index 0000000..2e80bb0
> --- /dev/null
> +++ b/drivers/spi/spi-uniphier.c
> @@ -0,0 +1,539 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// spi-uniphier.c - Socionext UniPhier SPI controller driver
> +// Copyright 2012 Panasonic Corporation
> +// Copyright 2016-2018 Socionext Inc.
> +
> +#include <asm/unaligned.h>
> +#include <linux/kernel.h>
> +#include <linux/bitfield.h>
> +#include <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/spi/spi.h>
> +
> +#define SSI_TIMEOUT 2000 /* ms */
> +#define SSI_MAX_CLK_DIVIDER 254
> +#define SSI_MIN_CLK_DIVIDER 4
> +
> +struct uniphier_spi_priv {
> + void __iomem *base;
> + int irq;
irq is unnecessary because it is only used in probe().
Use a stack variable.
> + struct clk *clk;
> + struct spi_master *master;
> + struct completion xfer_done;
> +
> + int error;
> + unsigned int tx_bytes;
> + unsigned int rx_bytes;
> + const u8 *tx_buf;
> + u8 *rx_buf;
> +
> + bool is_save_param;
> + u8 bits_per_word;
> + u16 mode;
> + u32 speed_hz;
> +};
> +
> +#define SSI_CTL 0x0
> +#define SSI_CTL_EN BIT(0)
> +
> +#define SSI_CKS 0x4
> +#define SSI_CKS_CKRAT_MASK GENMASK(7, 0)
> +#define SSI_CKS_CKPHS BIT(14)
> +#define SSI_CKS_CKINIT BIT(13)
> +#define SSI_CKS_CKDLY BIT(12)
> +
> +#define SSI_TXWDS 0x8
> +#define SSI_TXWDS_WDLEN_MASK GENMASK(13, 8)
> +#define SSI_TXWDS_TDTF_MASK GENMASK(7, 6)
> +#define SSI_TXWDS_DTLEN_MASK GENMASK(5, 0)
> +
> +#define SSI_RXWDS 0xc
> +#define SSI_RXWDS_DTLEN_MASK GENMASK(5, 0)
> +
> +#define SSI_FPS 0x10
> +#define SSI_FPS_FSPOL BIT(15)
> +#define SSI_FPS_FSTRT BIT(14)
> +
> +#define SSI_SR 0x14
> +#define SSI_SR_RNE BIT(0)
> +
> +#define SSI_IE 0x18
> +#define SSI_IE_RCIE BIT(3)
> +#define SSI_IE_RORIE BIT(0)
> +
> +#define SSI_IS 0x1c
> +#define SSI_IS_RXRS BIT(9)
> +#define SSI_IS_RCID BIT(3)
> +#define SSI_IS_RORID BIT(0)
> +
> +#define SSI_IC 0x1c
> +#define SSI_IC_TCIC BIT(4)
> +#define SSI_IC_RCIC BIT(3)
> +#define SSI_IC_RORIC BIT(0)
> +
> +#define SSI_FC 0x20
> +#define SSI_FC_TXFFL BIT(12)
> +#define SSI_FC_TXFTH_MASK GENMASK(11, 8)
> +#define SSI_FC_RXFFL BIT(4)
> +#define SSI_FC_RXFTH_MASK GENMASK(3, 0)
> +
> +#define SSI_TXDR 0x24
> +#define SSI_RXDR 0x24
> +
> +#define SSI_FIFO_DEPTH 8U
> +
> +static inline unsigned int bytes_per_word(unsigned int bits)
> +{
> + return bits <= 8 ? 1 : (bits <= 16 ? 2 : 4);
> +}
> +
> +static inline void uniphier_spi_irq_enable(struct spi_device *spi, u32 mask)
> +{
> + struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
> + u32 val;
> +
> + val = readl(priv->base + SSI_IE);
> + val |= mask;
> + writel(val, priv->base + SSI_IE);
> +}
> +
> +static inline void uniphier_spi_irq_disable(struct spi_device *spi, u32 mask)
> +{
> + struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
> + u32 val;
> +
> + val = readl(priv->base + SSI_IE);
> + val &= ~mask;
> + writel(val, priv->base + SSI_IE);
> +}
> +
> +static void uniphier_spi_set_mode(struct spi_device *spi)
> +{
> + struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
> + u32 val1, val2;
> +
> + /*
> + * clock setting
> + * CKPHS capture timing. 0:rising edge, 1:falling edge
> + * CKINIT clock initial level. 0:low, 1:high
> + * CKDLY clock delay. 0:no delay, 1:delay depending on FSTRT
> + * (FSTRT=0: 1 clock, FSTRT=1: 0.5 clock)
> + *
> + * frame setting
> + * FSPOL frame signal porarity. 0: low, 1: high
> + * FSTRT start frame timing
> + * 0: rising edge of clock, 1: falling edge of clock
> + */
> + switch (spi->mode & (SPI_CPOL | SPI_CPHA)) {
> + case SPI_MODE_0:
> + /* CKPHS=1, CKINIT=0, CKDLY=1, FSTRT=0 */
> + val1 = SSI_CKS_CKPHS | SSI_CKS_CKDLY;
> + val2 = 0;
> + break;
> + case SPI_MODE_1:
> + /* CKPHS=0, CKINIT=0, CKDLY=0, FSTRT=1 */
> + val1 = 0;
> + val2 = SSI_FPS_FSTRT;
> + break;
> + case SPI_MODE_2:
> + /* CKPHS=0, CKINIT=1, CKDLY=1, FSTRT=1 */
> + val1 = SSI_CKS_CKINIT | SSI_CKS_CKDLY;
> + val2 = SSI_FPS_FSTRT;
> + break;
> + case SPI_MODE_3:
> + /* CKPHS=1, CKINIT=1, CKDLY=0, FSTRT=0 */
> + val1 = SSI_CKS_CKPHS | SSI_CKS_CKINIT;
> + val2 = 0;
> + break;
> + }
> +
> + if (!(spi->mode & SPI_CS_HIGH))
> + val2 |= SSI_FPS_FSPOL;
> +
> + writel(val1, priv->base + SSI_CKS);
> + writel(val2, priv->base + SSI_FPS);
> +
> + val1 = 0;
> + if (spi->mode & SPI_LSB_FIRST)
> + val1 |= FIELD_PREP(SSI_TXWDS_TDTF_MASK, 1);
> + writel(val1, priv->base + SSI_TXWDS);
> + writel(val1, priv->base + SSI_RXWDS);
> +}
> +
> +static void uniphier_spi_set_transfer_size(struct spi_device *spi, int size)
> +{
> + struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
> + u32 val;
> +
> + val = readl(priv->base + SSI_TXWDS);
> + val &= ~(SSI_TXWDS_WDLEN_MASK | SSI_TXWDS_DTLEN_MASK);
> + val |= FIELD_PREP(SSI_TXWDS_WDLEN_MASK, size);
> + val |= FIELD_PREP(SSI_TXWDS_DTLEN_MASK, size);
> + writel(val, priv->base + SSI_TXWDS);
> +
> + val = readl(priv->base + SSI_RXWDS);
> + val &= ~SSI_RXWDS_DTLEN_MASK;
> + val |= FIELD_PREP(SSI_RXWDS_DTLEN_MASK, size);
> + writel(val, priv->base + SSI_RXWDS);
> +}
> +
> +static int uniphier_spi_set_baudrate(struct spi_device *spi, unsigned int speed)
> +{
> + struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
> + u32 val, ckrat;
> +
> + /*
> + * the supported rates are even numbers from 4 to 254. (4,6,8...254)
> + * round up as we look for equal or less speed
> + */
> + ckrat = DIV_ROUND_UP(clk_get_rate(priv->clk), speed);
> + ckrat = roundup(ckrat, 2);
> +
> + /* check if requested speed is too small */
> + if (ckrat > SSI_MAX_CLK_DIVIDER)
> + return -EINVAL;
> +
> + if (ckrat < SSI_MIN_CLK_DIVIDER)
> + ckrat = SSI_MIN_CLK_DIVIDER;
> +
> + val = readl(priv->base + SSI_CKS);
> + val &= ~SSI_CKS_CKRAT_MASK;
> + val |= ckrat & SSI_CKS_CKRAT_MASK;
> + writel(val, priv->base + SSI_CKS);
> +
> + return 0;
> +}
> +
> +static int uniphier_spi_setup_transfer(struct spi_device *spi,
> + struct spi_transfer *t)
> +{
> + struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
> + u32 val;
> + int ret;
> +
> + priv->error = 0;
> + priv->tx_buf = t->tx_buf;
> + priv->rx_buf = t->rx_buf;
> + priv->tx_bytes = priv->rx_bytes = t->len;
> +
> + if (!priv->is_save_param || priv->mode != spi->mode) {
> + uniphier_spi_set_mode(spi);
> + priv->mode = spi->mode;
> + }
> +
> + if (!priv->is_save_param || priv->bits_per_word != t->bits_per_word) {
> + uniphier_spi_set_transfer_size(spi, t->bits_per_word);
> + priv->bits_per_word = t->bits_per_word;
> + }
> +
> + if (!priv->is_save_param || priv->speed_hz != t->speed_hz) {
> + ret = uniphier_spi_set_baudrate(spi, t->speed_hz);
> + if (ret)
> + return ret;
> + priv->speed_hz = t->speed_hz;
> + }
> +
> + if (!priv->is_save_param)
> + priv->is_save_param = true;
> +
> + /* reset FIFOs */
> + val = SSI_FC_TXFFL | SSI_FC_RXFFL;
> + writel(val, priv->base + SSI_FC);
> +
> + return 0;
> +}
> +
> +static void uniphier_spi_send(struct uniphier_spi_priv *priv)
> +{
> + int wsize;
> + u32 val = 0;
> +
> + wsize = min(bytes_per_word(priv->bits_per_word), priv->tx_bytes);
> + priv->tx_bytes -= wsize;
> +
> + if (priv->tx_buf) {
> + switch (wsize) {
> + case 1:
> + val = *priv->tx_buf;
> + break;
> + case 2:
> + val = get_unaligned_le16(priv->tx_buf);
> + break;
> + case 4:
> + val = get_unaligned_le32(priv->tx_buf);
> + break;
> + }
> +
> + priv->tx_buf += wsize;
> + }
> +
> + writel(val, priv->base + SSI_TXDR);
> +}
> +
> +static void uniphier_spi_recv(struct uniphier_spi_priv *priv)
> +{
> + int rsize;
> + u32 val;
> +
> + rsize = min(bytes_per_word(priv->bits_per_word), priv->rx_bytes);
> + priv->rx_bytes -= rsize;
> +
> + val = readl(priv->base + SSI_RXDR);
> +
> + if (priv->rx_buf) {
> + switch (rsize) {
> + case 1:
> + *priv->rx_buf = (u8)val;
Is this cast necessary?
> + break;
> + case 2:
> + put_unaligned_le16(val, priv->rx_buf);
> + break;
> + case 4:
> + put_unaligned_le32(val, priv->rx_buf);
> + break;
> + }
> +
> + priv->rx_buf += rsize;
> + }
> +}
> +
> +static void uniphier_spi_fill_tx_fifo(struct uniphier_spi_priv *priv)
> +{
> + unsigned int tx_count;
> + u32 val;
> +
> + tx_count = DIV_ROUND_UP(priv->tx_bytes,
> + bytes_per_word(priv->bits_per_word));
> + tx_count = min(tx_count, SSI_FIFO_DEPTH);
> +
> + /* set fifo threthold */
Typo. threshold
> + val = readl(priv->base + SSI_FC);
> + val &= ~(SSI_FC_TXFTH_MASK | SSI_FC_RXFTH_MASK);
> + val |= FIELD_PREP(SSI_FC_TXFTH_MASK, tx_count);
> + val |= FIELD_PREP(SSI_FC_RXFTH_MASK, tx_count);
> + writel(val, priv->base + SSI_FC);
> +
> + while (tx_count--)
> + uniphier_spi_send(priv);
> +}
> +
> +static void uniphier_spi_set_cs(struct spi_device *spi, bool enable)
> +{
> + struct uniphier_spi_priv *priv = spi_master_get_devdata(spi->master);
> + u32 val;
> +
> + val = readl(priv->base + SSI_FPS);
> +
> + if (enable)
> + val |= SSI_FPS_FSPOL;
> + else
> + val &= ~SSI_FPS_FSPOL;
> +
> + writel(val, priv->base + SSI_FPS);
> +}
> +
> +static int uniphier_spi_transfer_one(struct spi_master *master,
> + struct spi_device *spi,
> + struct spi_transfer *t)
> +{
> + struct uniphier_spi_priv *priv = spi_master_get_devdata(master);
> + int status;
> +
> + status = uniphier_spi_setup_transfer(spi, t);
> + if (status < 0)
> + return status;
> +
> + reinit_completion(&priv->xfer_done);
> +
> + uniphier_spi_fill_tx_fifo(priv);
> +
> + uniphier_spi_irq_enable(spi, SSI_IE_RCIE | SSI_IE_RORIE);
> +
> + status = wait_for_completion_timeout(&priv->xfer_done,
> + msecs_to_jiffies(SSI_TIMEOUT));
> +
> + uniphier_spi_irq_disable(spi, SSI_IE_RCIE | SSI_IE_RORIE);
> +
> + if (status < 0)
> + return status;
> +
> + return priv->error;
> +}
> +
> +static int uniphier_spi_prepare_transfer_hardware(struct spi_master *master)
> +{
> + struct uniphier_spi_priv *priv = spi_master_get_devdata(master);
> +
> + writel(SSI_CTL_EN, priv->base + SSI_CTL);
> +
> + return 0;
> +}
> +
> +static int uniphier_spi_unprepare_transfer_hardware(struct spi_master *master)
> +{
> + struct uniphier_spi_priv *priv = spi_master_get_devdata(master);
> +
> + writel(0, priv->base + SSI_CTL);
> +
> + return 0;
> +}
> +
> +static irqreturn_t uniphier_spi_handler(int irq, void *dev_id)
> +{
> + struct uniphier_spi_priv *priv = dev_id;
> + u32 val, stat;
> +
> + stat = readl(priv->base + SSI_IS);
> + val = SSI_IC_TCIC | SSI_IC_RCIC | SSI_IC_RORIC;
> + writel(val, priv->base + SSI_IC);
> +
> + /* rx fifo overrun */
> + if (stat & SSI_IS_RORID) {
> + priv->error = -EIO;
> + goto done;
> + }
> +
> + /* rx complete */
> + if ((stat & SSI_IS_RCID) && (stat & SSI_IS_RXRS)) {
> + while ((readl(priv->base + SSI_SR) & SSI_SR_RNE) &&
> + (priv->rx_bytes - priv->tx_bytes) > 0)
> + uniphier_spi_recv(priv);
> +
> + if ((readl(priv->base + SSI_SR) & SSI_SR_RNE) ||
> + (priv->rx_bytes != priv->tx_bytes)) {
> + priv->error = -EIO;
> + goto done;
> + } else if (priv->rx_bytes == 0)
> + goto done;
> +
> + /* next tx transfer */
> + uniphier_spi_fill_tx_fifo(priv);
> +
> + return IRQ_HANDLED;
> + }
> +
> + return IRQ_NONE;
> +
> +done:
> + complete(&priv->xfer_done);
> + return IRQ_HANDLED;
> +}
> +
> +static int uniphier_spi_probe(struct platform_device *pdev)
> +{
> + struct uniphier_spi_priv *priv;
> + struct spi_master *master;
> + struct resource *res;
> + unsigned long clksrc;
> + int ret;
> +
> + master = spi_alloc_master(&pdev->dev, sizeof(*priv));
> + if (!master)
> + return -ENOMEM;
> +
> + platform_set_drvdata(pdev, master);
> +
> + priv = spi_master_get_devdata(master);
> + priv->master = master;
> + priv->is_save_param = false;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + priv->base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(priv->base)) {
> + ret = PTR_ERR(priv->base);
> + goto out_master_put;
> + }
> +
> + priv->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(priv->clk)) {
> + dev_err(&pdev->dev, "failed to get clock\n");
> + ret = PTR_ERR(priv->clk);
> + goto out_master_put;
> + }
> +
> + ret = clk_prepare_enable(priv->clk);
> + if (ret)
> + goto out_master_put;
> +
> + priv->irq = platform_get_irq(pdev, 0);
> + if (priv->irq < 0) {
> + dev_err(&pdev->dev, "failed to get IRQ\n");
> + ret = -ENXIO;
> + goto out_disable_clk;
> + }
> +
> + ret = devm_request_irq(&pdev->dev, priv->irq, uniphier_spi_handler,
> + 0, "uniphier-spi", priv);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to request IRQ\n");
> + goto out_disable_clk;
> + }
> +
> + init_completion(&priv->xfer_done);
> +
> + clksrc = clk_get_rate(priv->clk);
How about 'clk_rate' ?
> + master->max_speed_hz = DIV_ROUND_UP(clksrc, SSI_MIN_CLK_DIVIDER);
> + master->min_speed_hz = DIV_ROUND_UP(clksrc, SSI_MAX_CLK_DIVIDER);
> + master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
> + master->dev.of_node = pdev->dev.of_node;
> + master->bus_num = pdev->id;
> + master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
> +
> + master->set_cs = uniphier_spi_set_cs;
> + master->transfer_one = uniphier_spi_transfer_one;
> + master->prepare_transfer_hardware
> + = uniphier_spi_prepare_transfer_hardware;
> + master->unprepare_transfer_hardware
> + = uniphier_spi_unprepare_transfer_hardware;
> + master->num_chipselect = 1;
> +
> + ret = devm_spi_register_master(&pdev->dev, master);
> + if (ret)
> + goto out_disable_clk;
> +
> + return ret;
I think
return 0;
will be clearer.
> +
> +out_disable_clk:
> + clk_disable_unprepare(priv->clk);
> +
> +out_master_put:
> + spi_master_put(master);
> + return ret;
> +}
> +
> +static int uniphier_spi_remove(struct platform_device *pdev)
> +{
> + struct uniphier_spi_priv *priv = platform_get_drvdata(pdev);
> +
> + clk_disable_unprepare(priv->clk);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id uniphier_spi_match[] = {
> + { .compatible = "socionext,uniphier-scssi", },
> + { /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, uniphier_spi_match);
> +
> +static struct platform_driver uniphier_spi_driver = {
> + .probe = uniphier_spi_probe,
> + .remove = uniphier_spi_remove,
> + .driver = {
> + .name = "uniphier-spi",
> + .of_match_table = uniphier_spi_match,
> + },
> +};
> +module_platform_driver(uniphier_spi_driver);
> +
> +MODULE_AUTHOR("Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx>");
> +MODULE_AUTHOR("Keiji Hayashibara <hayashibara.keiji@xxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Socionext UniPhier SPI controller driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.7.4
>
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--
Best Regards
Masahiro Yamada