--- /dev/null
+/*
+ * Copyright (C) 2012 - 2014 Allwinner Tech
+ * Pan Nan <pannan@allwinnertech.com>
+ *
+ * Copyright (C) 2014 Maxime Ripard
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset.h>
+
+#include <linux/spi/spi.h>
+
+#define SUN6I_FIFO_DEPTH 128
+
+#define SUN6I_GBL_CTL_REG 0x04
+#define SUN6I_GBL_CTL_BUS_ENABLE BIT(0)
+#define SUN6I_GBL_CTL_MASTER BIT(1)
+#define SUN6I_GBL_CTL_TP BIT(7)
+#define SUN6I_GBL_CTL_RST BIT(31)
+
+#define SUN6I_TFR_CTL_REG 0x08
+#define SUN6I_TFR_CTL_CPHA BIT(0)
+#define SUN6I_TFR_CTL_CPOL BIT(1)
+#define SUN6I_TFR_CTL_SPOL BIT(2)
+#define SUN6I_TFR_CTL_CS_MASK 0x30
+#define SUN6I_TFR_CTL_CS(cs) (((cs) << 4) & SUN6I_TFR_CTL_CS_MASK)
+#define SUN6I_TFR_CTL_CS_MANUAL BIT(6)
+#define SUN6I_TFR_CTL_CS_LEVEL BIT(7)
+#define SUN6I_TFR_CTL_DHB BIT(8)
+#define SUN6I_TFR_CTL_FBS BIT(12)
+#define SUN6I_TFR_CTL_XCH BIT(31)
+
+#define SUN6I_INT_CTL_REG 0x10
+#define SUN6I_INT_CTL_RF_OVF BIT(8)
+#define SUN6I_INT_CTL_TC BIT(12)
+
+#define SUN6I_INT_STA_REG 0x14
+
+#define SUN6I_FIFO_CTL_REG 0x18
+#define SUN6I_FIFO_CTL_RF_RST BIT(15)
+#define SUN6I_FIFO_CTL_TF_RST BIT(31)
+
+#define SUN6I_FIFO_STA_REG 0x1c
+#define SUN6I_FIFO_STA_RF_CNT_MASK 0x7f
+#define SUN6I_FIFO_STA_RF_CNT_BITS 0
+#define SUN6I_FIFO_STA_TF_CNT_MASK 0x7f
+#define SUN6I_FIFO_STA_TF_CNT_BITS 16
+
+#define SUN6I_CLK_CTL_REG 0x24
+#define SUN6I_CLK_CTL_CDR2_MASK 0xff
+#define SUN6I_CLK_CTL_CDR2(div) (((div) & SUN6I_CLK_CTL_CDR2_MASK) << 0)
+#define SUN6I_CLK_CTL_CDR1_MASK 0xf
+#define SUN6I_CLK_CTL_CDR1(div) (((div) & SUN6I_CLK_CTL_CDR1_MASK) << 8)
+#define SUN6I_CLK_CTL_DRS BIT(12)
+
+#define SUN6I_BURST_CNT_REG 0x30
+#define SUN6I_BURST_CNT(cnt) ((cnt) & 0xffffff)
+
+#define SUN6I_XMIT_CNT_REG 0x34
+#define SUN6I_XMIT_CNT(cnt) ((cnt) & 0xffffff)
+
+#define SUN6I_BURST_CTL_CNT_REG 0x38
+#define SUN6I_BURST_CTL_CNT_STC(cnt) ((cnt) & 0xffffff)
+
+#define SUN6I_TXDATA_REG 0x200
+#define SUN6I_RXDATA_REG 0x300
+
+struct sun6i_spi {
+ struct spi_master *master;
+ void __iomem *base_addr;
+ struct clk *hclk;
+ struct clk *mclk;
+ struct reset_control *rstc;
+
+ struct completion done;
+
+ const u8 *tx_buf;
+ u8 *rx_buf;
+ int len;
+};
+
+static inline u32 sun6i_spi_read(struct sun6i_spi *sspi, u32 reg)
+{
+ return readl(sspi->base_addr + reg);
+}
+
+static inline void sun6i_spi_write(struct sun6i_spi *sspi, u32 reg, u32 value)
+{
+ writel(value, sspi->base_addr + reg);
+}
+
+static inline void sun6i_spi_drain_fifo(struct sun6i_spi *sspi, int len)
+{
+ u32 reg, cnt;
+ u8 byte;
+
+ /* See how much data is available */
+ reg = sun6i_spi_read(sspi, SUN6I_FIFO_STA_REG);
+ reg &= SUN6I_FIFO_STA_RF_CNT_MASK;
+ cnt = reg >> SUN6I_FIFO_STA_RF_CNT_BITS;
+
+ if (len > cnt)
+ len = cnt;
+
+ while (len--) {
+ byte = readb(sspi->base_addr + SUN6I_RXDATA_REG);
+ if (sspi->rx_buf)
+ *sspi->rx_buf++ = byte;
+ }
+}
+
+static inline void sun6i_spi_fill_fifo(struct sun6i_spi *sspi, int len)
+{
+ u8 byte;
+
+ if (len > sspi->len)
+ len = sspi->len;
+
+ while (len--) {
+ byte = sspi->tx_buf ? *sspi->tx_buf++ : 0;
+ writeb(byte, sspi->base_addr + SUN6I_TXDATA_REG);
+ sspi->len--;
+ }
+}
+
+static void sun6i_spi_set_cs(struct spi_device *spi, bool enable)
+{
+ struct sun6i_spi *sspi = spi_master_get_devdata(spi->master);
+ u32 reg;
+
+ reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
+ reg &= ~SUN6I_TFR_CTL_CS_MASK;
+ reg |= SUN6I_TFR_CTL_CS(spi->chip_select);
+
+ if (enable)
+ reg |= SUN6I_TFR_CTL_CS_LEVEL;
+ else
+ reg &= ~SUN6I_TFR_CTL_CS_LEVEL;
+
+ sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg);
+}
+
+
+static int sun6i_spi_transfer_one(struct spi_master *master,
+ struct spi_device *spi,
+ struct spi_transfer *tfr)
+{
+ struct sun6i_spi *sspi = spi_master_get_devdata(master);
+ unsigned int mclk_rate, div, timeout;
+ unsigned int tx_len = 0;
+ int ret = 0;
+ u32 reg;
+
+ /* We don't support transfer larger than the FIFO */
+ if (tfr->len > SUN6I_FIFO_DEPTH)
+ return -EINVAL;
+
+ reinit_completion(&sspi->done);
+ sspi->tx_buf = tfr->tx_buf;
+ sspi->rx_buf = tfr->rx_buf;
+ sspi->len = tfr->len;
+
+ /* Clear pending interrupts */
+ sun6i_spi_write(sspi, SUN6I_INT_STA_REG, ~0);
+
+ /* Reset FIFO */
+ sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG,
+ SUN6I_FIFO_CTL_RF_RST | SUN6I_FIFO_CTL_TF_RST);
+
+ /*
+ * Setup the transfer control register: Chip Select,
+ * polarities, etc.
+ */
+ reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
+
+ if (spi->mode & SPI_CPOL)
+ reg |= SUN6I_TFR_CTL_CPOL;
+ else
+ reg &= ~SUN6I_TFR_CTL_CPOL;
+
+ if (spi->mode & SPI_CPHA)
+ reg |= SUN6I_TFR_CTL_CPHA;
+ else
+ reg &= ~SUN6I_TFR_CTL_CPHA;
+
+ if (spi->mode & SPI_LSB_FIRST)
+ reg |= SUN6I_TFR_CTL_FBS;
+ else
+ reg &= ~SUN6I_TFR_CTL_FBS;
+
+ /*
+ * If it's a TX only transfer, we don't want to fill the RX
+ * FIFO with bogus data
+ */
+ if (sspi->rx_buf)
+ reg &= ~SUN6I_TFR_CTL_DHB;
+ else
+ reg |= SUN6I_TFR_CTL_DHB;
+
+ /* We want to control the chip select manually */
+ reg |= SUN6I_TFR_CTL_CS_MANUAL;
+
+ sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg);
+
+ /* Ensure that we have a parent clock fast enough */
+ mclk_rate = clk_get_rate(sspi->mclk);
+ if (mclk_rate < (2 * spi->max_speed_hz)) {
+ clk_set_rate(sspi->mclk, 2 * spi->max_speed_hz);
+ mclk_rate = clk_get_rate(sspi->mclk);
+ }
+
+ /*
+ * Setup clock divider.
+ *
+ * We have two choices there. Either we can use the clock
+ * divide rate 1, which is calculated thanks to this formula:
+ * SPI_CLK = MOD_CLK / (2 ^ cdr)
+ * Or we can use CDR2, which is calculated with the formula:
+ * SPI_CLK = MOD_CLK / (2 * (cdr + 1))
+ * Wether we use the former or the latter is set through the
+ * DRS bit.
+ *
+ * First try CDR2, and if we can't reach the expected
+ * frequency, fall back to CDR1.
+ */
+ div = mclk_rate / (2 * spi->max_speed_hz);
+ if (div <= (SUN6I_CLK_CTL_CDR2_MASK + 1)) {
+ if (div > 0)
+ div--;
+
+ reg = SUN6I_CLK_CTL_CDR2(div) | SUN6I_CLK_CTL_DRS;
+ } else {
+ div = ilog2(mclk_rate) - ilog2(spi->max_speed_hz);
+ reg = SUN6I_CLK_CTL_CDR1(div);
+ }
+
+ sun6i_spi_write(sspi, SUN6I_CLK_CTL_REG, reg);
+
+ /* Setup the transfer now... */
+ if (sspi->tx_buf)
+ tx_len = tfr->len;
+
+ /* Setup the counters */
+ sun6i_spi_write(sspi, SUN6I_BURST_CNT_REG, SUN6I_BURST_CNT(tfr->len));
+ sun6i_spi_write(sspi, SUN6I_XMIT_CNT_REG, SUN6I_XMIT_CNT(tx_len));
+ sun6i_spi_write(sspi, SUN6I_BURST_CTL_CNT_REG,
+ SUN6I_BURST_CTL_CNT_STC(tx_len));
+
+ /* Fill the TX FIFO */
+ sun6i_spi_fill_fifo(sspi, SUN6I_FIFO_DEPTH);
+
+ /* Enable the interrupts */
+ sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, SUN6I_INT_CTL_TC);
+
+ /* Start the transfer */
+ reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
+ sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg | SUN6I_TFR_CTL_XCH);
+
+ timeout = wait_for_completion_timeout(&sspi->done,
+ msecs_to_jiffies(1000));
+ if (!timeout) {
+ ret = -ETIMEDOUT;
+ goto out;
+ }
+
+ sun6i_spi_drain_fifo(sspi, SUN6I_FIFO_DEPTH);
+
+out:
+ sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, 0);
+
+ return ret;
+}
+
+static irqreturn_t sun6i_spi_handler(int irq, void *dev_id)
+{
+ struct sun6i_spi *sspi = dev_id;
+ u32 status = sun6i_spi_read(sspi, SUN6I_INT_STA_REG);
+
+ /* Transfer complete */
+ if (status & SUN6I_INT_CTL_TC) {
+ sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TC);
+ complete(&sspi->done);
+ return IRQ_HANDLED;
+ }
+
+ return IRQ_NONE;
+}
+
+static int sun6i_spi_runtime_resume(struct device *dev)
+{
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct sun6i_spi *sspi = spi_master_get_devdata(master);
+ int ret;
+
+ ret = clk_prepare_enable(sspi->hclk);
+ if (ret) {
+ dev_err(dev, "Couldn't enable AHB clock\n");
+ goto out;
+ }
+
+ ret = clk_prepare_enable(sspi->mclk);
+ if (ret) {
+ dev_err(dev, "Couldn't enable module clock\n");
+ goto err;
+ }
+
+ ret = reset_control_deassert(sspi->rstc);
+ if (ret) {
+ dev_err(dev, "Couldn't deassert the device from reset\n");
+ goto err2;
+ }
+
+ sun6i_spi_write(sspi, SUN6I_GBL_CTL_REG,
+ SUN6I_GBL_CTL_BUS_ENABLE | SUN6I_GBL_CTL_MASTER | SUN6I_GBL_CTL_TP);
+
+ return 0;
+
+err2:
+ clk_disable_unprepare(sspi->mclk);
+err:
+ clk_disable_unprepare(sspi->hclk);
+out:
+ return ret;
+}
+
+static int sun6i_spi_runtime_suspend(struct device *dev)
+{
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct sun6i_spi *sspi = spi_master_get_devdata(master);
+
+ reset_control_assert(sspi->rstc);
+ clk_disable_unprepare(sspi->mclk);
+ clk_disable_unprepare(sspi->hclk);
+
+ return 0;
+}
+
+static int sun6i_spi_probe(struct platform_device *pdev)
+{
+ struct spi_master *master;
+ struct sun6i_spi *sspi;
+ struct resource *res;
+ int ret = 0, irq;
+
+ master = spi_alloc_master(&pdev->dev, sizeof(struct sun6i_spi));
+ if (!master) {
+ dev_err(&pdev->dev, "Unable to allocate SPI Master\n");
+ return -ENOMEM;
+ }
+
+ platform_set_drvdata(pdev, master);
+ sspi = spi_master_get_devdata(master);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ sspi->base_addr = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(sspi->base_addr)) {
+ ret = PTR_ERR(sspi->base_addr);
+ goto err_free_master;
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "No spi IRQ specified\n");
+ ret = -ENXIO;
+ goto err_free_master;
+ }
+
+ ret = devm_request_irq(&pdev->dev, irq, sun6i_spi_handler,
+ 0, "sun6i-spi", sspi);
+ if (ret) {
+ dev_err(&pdev->dev, "Cannot request IRQ\n");
+ goto err_free_master;
+ }
+
+ sspi->master = master;
+ master->set_cs = sun6i_spi_set_cs;
+ master->transfer_one = sun6i_spi_transfer_one;
+ master->num_chipselect = 4;
+ master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
+ master->bits_per_word_mask = SPI_BPW_MASK(8);
+ master->dev.of_node = pdev->dev.of_node;
+ master->auto_runtime_pm = true;
+
+ sspi->hclk = devm_clk_get(&pdev->dev, "ahb");
+ if (IS_ERR(sspi->hclk)) {
+ dev_err(&pdev->dev, "Unable to acquire AHB clock\n");
+ ret = PTR_ERR(sspi->hclk);
+ goto err_free_master;
+ }
+
+ sspi->mclk = devm_clk_get(&pdev->dev, "mod");
+ if (IS_ERR(sspi->mclk)) {
+ dev_err(&pdev->dev, "Unable to acquire module clock\n");
+ ret = PTR_ERR(sspi->mclk);
+ goto err_free_master;
+ }
+
+ init_completion(&sspi->done);
+
+ sspi->rstc = devm_reset_control_get(&pdev->dev, NULL);
+ if (IS_ERR(sspi->rstc)) {
+ dev_err(&pdev->dev, "Couldn't get reset controller\n");
+ ret = PTR_ERR(sspi->rstc);
+ goto err_free_master;
+ }
+
+ /*
+ * This wake-up/shutdown pattern is to be able to have the
+ * device woken up, even if runtime_pm is disabled
+ */
+ ret = sun6i_spi_runtime_resume(&pdev->dev);
+ if (ret) {
+ dev_err(&pdev->dev, "Couldn't resume the device\n");
+ goto err_free_master;
+ }
+
+ pm_runtime_set_active(&pdev->dev);
+ pm_runtime_enable(&pdev->dev);
+ pm_runtime_idle(&pdev->dev);
+
+ ret = devm_spi_register_master(&pdev->dev, master);
+ if (ret) {
+ dev_err(&pdev->dev, "cannot register SPI master\n");
+ goto err_pm_disable;
+ }
+
+ return 0;
+
+err_pm_disable:
+ pm_runtime_disable(&pdev->dev);
+ sun6i_spi_runtime_suspend(&pdev->dev);
+err_free_master:
+ spi_master_put(master);
+ return ret;
+}
+
+static int sun6i_spi_remove(struct platform_device *pdev)
+{
+ pm_runtime_disable(&pdev->dev);
+
+ return 0;
+}
+
+static const struct of_device_id sun6i_spi_match[] = {
+ { .compatible = "allwinner,sun6i-a31-spi", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, sun6i_spi_match);
+
+static const struct dev_pm_ops sun6i_spi_pm_ops = {
+ .runtime_resume = sun6i_spi_runtime_resume,
+ .runtime_suspend = sun6i_spi_runtime_suspend,
+};
+
+static struct platform_driver sun6i_spi_driver = {
+ .probe = sun6i_spi_probe,
+ .remove = sun6i_spi_remove,
+ .driver = {
+ .name = "sun6i-spi",
+ .of_match_table = sun6i_spi_match,
+ .pm = &sun6i_spi_pm_ops,
+ },
+};
+module_platform_driver(sun6i_spi_driver);
+
+MODULE_AUTHOR("Pan Nan <pannan@allwinnertech.com>");
+MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
+MODULE_DESCRIPTION("Allwinner A31 SPI controller driver");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff