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path: root/drivers/spi/spi-mpc512x-psc.c
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Diffstat (limited to 'drivers/spi/spi-mpc512x-psc.c')
-rw-r--r--drivers/spi/spi-mpc512x-psc.c610
1 files changed, 610 insertions, 0 deletions
diff --git a/drivers/spi/spi-mpc512x-psc.c b/drivers/spi/spi-mpc512x-psc.c
new file mode 100644
index 000000000..965d2bdcf
--- /dev/null
+++ b/drivers/spi/spi-mpc512x-psc.c
@@ -0,0 +1,610 @@
+/*
+ * MPC512x PSC in SPI mode driver.
+ *
+ * Copyright (C) 2007,2008 Freescale Semiconductor Inc.
+ * Original port from 52xx driver:
+ * Hongjun Chen <hong-jun.chen@freescale.com>
+ *
+ * Fork of mpc52xx_psc_spi.c:
+ * Copyright (C) 2006 TOPTICA Photonics AG., Dragos Carp
+ *
+ * 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/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/completion.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/clk.h>
+#include <linux/spi/spi.h>
+#include <linux/fsl_devices.h>
+#include <linux/gpio.h>
+#include <asm/mpc52xx_psc.h>
+
+struct mpc512x_psc_spi {
+ void (*cs_control)(struct spi_device *spi, bool on);
+
+ /* driver internal data */
+ struct mpc52xx_psc __iomem *psc;
+ struct mpc512x_psc_fifo __iomem *fifo;
+ unsigned int irq;
+ u8 bits_per_word;
+ struct clk *clk_mclk;
+ struct clk *clk_ipg;
+ u32 mclk_rate;
+
+ struct completion txisrdone;
+};
+
+/* controller state */
+struct mpc512x_psc_spi_cs {
+ int bits_per_word;
+ int speed_hz;
+};
+
+/* set clock freq, clock ramp, bits per work
+ * if t is NULL then reset the values to the default values
+ */
+static int mpc512x_psc_spi_transfer_setup(struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct mpc512x_psc_spi_cs *cs = spi->controller_state;
+
+ cs->speed_hz = (t && t->speed_hz)
+ ? t->speed_hz : spi->max_speed_hz;
+ cs->bits_per_word = (t && t->bits_per_word)
+ ? t->bits_per_word : spi->bits_per_word;
+ cs->bits_per_word = ((cs->bits_per_word + 7) / 8) * 8;
+ return 0;
+}
+
+static void mpc512x_psc_spi_activate_cs(struct spi_device *spi)
+{
+ struct mpc512x_psc_spi_cs *cs = spi->controller_state;
+ struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master);
+ struct mpc52xx_psc __iomem *psc = mps->psc;
+ u32 sicr;
+ u32 ccr;
+ int speed;
+ u16 bclkdiv;
+
+ sicr = in_be32(&psc->sicr);
+
+ /* Set clock phase and polarity */
+ if (spi->mode & SPI_CPHA)
+ sicr |= 0x00001000;
+ else
+ sicr &= ~0x00001000;
+
+ if (spi->mode & SPI_CPOL)
+ sicr |= 0x00002000;
+ else
+ sicr &= ~0x00002000;
+
+ if (spi->mode & SPI_LSB_FIRST)
+ sicr |= 0x10000000;
+ else
+ sicr &= ~0x10000000;
+ out_be32(&psc->sicr, sicr);
+
+ ccr = in_be32(&psc->ccr);
+ ccr &= 0xFF000000;
+ speed = cs->speed_hz;
+ if (!speed)
+ speed = 1000000; /* default 1MHz */
+ bclkdiv = (mps->mclk_rate / speed) - 1;
+
+ ccr |= (((bclkdiv & 0xff) << 16) | (((bclkdiv >> 8) & 0xff) << 8));
+ out_be32(&psc->ccr, ccr);
+ mps->bits_per_word = cs->bits_per_word;
+
+ if (mps->cs_control && gpio_is_valid(spi->cs_gpio))
+ mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 1 : 0);
+}
+
+static void mpc512x_psc_spi_deactivate_cs(struct spi_device *spi)
+{
+ struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master);
+
+ if (mps->cs_control && gpio_is_valid(spi->cs_gpio))
+ mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 0 : 1);
+
+}
+
+/* extract and scale size field in txsz or rxsz */
+#define MPC512x_PSC_FIFO_SZ(sz) ((sz & 0x7ff) << 2);
+
+#define EOFBYTE 1
+
+static int mpc512x_psc_spi_transfer_rxtx(struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master);
+ struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
+ size_t tx_len = t->len;
+ size_t rx_len = t->len;
+ u8 *tx_buf = (u8 *)t->tx_buf;
+ u8 *rx_buf = (u8 *)t->rx_buf;
+
+ if (!tx_buf && !rx_buf && t->len)
+ return -EINVAL;
+
+ while (rx_len || tx_len) {
+ size_t txcount;
+ u8 data;
+ size_t fifosz;
+ size_t rxcount;
+ int rxtries;
+
+ /*
+ * send the TX bytes in as large a chunk as possible
+ * but neither exceed the TX nor the RX FIFOs
+ */
+ fifosz = MPC512x_PSC_FIFO_SZ(in_be32(&fifo->txsz));
+ txcount = min(fifosz, tx_len);
+ fifosz = MPC512x_PSC_FIFO_SZ(in_be32(&fifo->rxsz));
+ fifosz -= in_be32(&fifo->rxcnt) + 1;
+ txcount = min(fifosz, txcount);
+ if (txcount) {
+
+ /* fill the TX FIFO */
+ while (txcount-- > 0) {
+ data = tx_buf ? *tx_buf++ : 0;
+ if (tx_len == EOFBYTE && t->cs_change)
+ setbits32(&fifo->txcmd,
+ MPC512x_PSC_FIFO_EOF);
+ out_8(&fifo->txdata_8, data);
+ tx_len--;
+ }
+
+ /* have the ISR trigger when the TX FIFO is empty */
+ reinit_completion(&mps->txisrdone);
+ out_be32(&fifo->txisr, MPC512x_PSC_FIFO_EMPTY);
+ out_be32(&fifo->tximr, MPC512x_PSC_FIFO_EMPTY);
+ wait_for_completion(&mps->txisrdone);
+ }
+
+ /*
+ * consume as much RX data as the FIFO holds, while we
+ * iterate over the transfer's TX data length
+ *
+ * only insist in draining all the remaining RX bytes
+ * when the TX bytes were exhausted (that's at the very
+ * end of this transfer, not when still iterating over
+ * the transfer's chunks)
+ */
+ rxtries = 50;
+ do {
+
+ /*
+ * grab whatever was in the FIFO when we started
+ * looking, don't bother fetching what was added to
+ * the FIFO while we read from it -- we'll return
+ * here eventually and prefer sending out remaining
+ * TX data
+ */
+ fifosz = in_be32(&fifo->rxcnt);
+ rxcount = min(fifosz, rx_len);
+ while (rxcount-- > 0) {
+ data = in_8(&fifo->rxdata_8);
+ if (rx_buf)
+ *rx_buf++ = data;
+ rx_len--;
+ }
+
+ /*
+ * come back later if there still is TX data to send,
+ * bail out of the RX drain loop if all of the TX data
+ * was sent and all of the RX data was received (i.e.
+ * when the transmission has completed)
+ */
+ if (tx_len)
+ break;
+ if (!rx_len)
+ break;
+
+ /*
+ * TX data transmission has completed while RX data
+ * is still pending -- that's a transient situation
+ * which depends on wire speed and specific
+ * hardware implementation details (buffering) yet
+ * should resolve very quickly
+ *
+ * just yield for a moment to not hog the CPU for
+ * too long when running SPI at low speed
+ *
+ * the timeout range is rather arbitrary and tries
+ * to balance throughput against system load; the
+ * chosen values result in a minimal timeout of 50
+ * times 10us and thus work at speeds as low as
+ * some 20kbps, while the maximum timeout at the
+ * transfer's end could be 5ms _if_ nothing else
+ * ticks in the system _and_ RX data still wasn't
+ * received, which only occurs in situations that
+ * are exceptional; removing the unpredictability
+ * of the timeout either decreases throughput
+ * (longer timeouts), or puts more load on the
+ * system (fixed short timeouts) or requires the
+ * use of a timeout API instead of a counter and an
+ * unknown inner delay
+ */
+ usleep_range(10, 100);
+
+ } while (--rxtries > 0);
+ if (!tx_len && rx_len && !rxtries) {
+ /*
+ * not enough RX bytes even after several retries
+ * and the resulting rather long timeout?
+ */
+ rxcount = in_be32(&fifo->rxcnt);
+ dev_warn(&spi->dev,
+ "short xfer, missing %zd RX bytes, FIFO level %zd\n",
+ rx_len, rxcount);
+ }
+
+ /*
+ * drain and drop RX data which "should not be there" in
+ * the first place, for undisturbed transmission this turns
+ * into a NOP (except for the FIFO level fetch)
+ */
+ if (!tx_len && !rx_len) {
+ while (in_be32(&fifo->rxcnt))
+ in_8(&fifo->rxdata_8);
+ }
+
+ }
+ return 0;
+}
+
+static int mpc512x_psc_spi_msg_xfer(struct spi_master *master,
+ struct spi_message *m)
+{
+ struct spi_device *spi;
+ unsigned cs_change;
+ int status;
+ struct spi_transfer *t;
+
+ spi = m->spi;
+ cs_change = 1;
+ status = 0;
+ list_for_each_entry(t, &m->transfers, transfer_list) {
+ if (t->bits_per_word || t->speed_hz) {
+ status = mpc512x_psc_spi_transfer_setup(spi, t);
+ if (status < 0)
+ break;
+ }
+
+ if (cs_change)
+ mpc512x_psc_spi_activate_cs(spi);
+ cs_change = t->cs_change;
+
+ status = mpc512x_psc_spi_transfer_rxtx(spi, t);
+ if (status)
+ break;
+ m->actual_length += t->len;
+
+ if (t->delay_usecs)
+ udelay(t->delay_usecs);
+
+ if (cs_change)
+ mpc512x_psc_spi_deactivate_cs(spi);
+ }
+
+ m->status = status;
+ if (m->complete)
+ m->complete(m->context);
+
+ if (status || !cs_change)
+ mpc512x_psc_spi_deactivate_cs(spi);
+
+ mpc512x_psc_spi_transfer_setup(spi, NULL);
+
+ spi_finalize_current_message(master);
+ return status;
+}
+
+static int mpc512x_psc_spi_prep_xfer_hw(struct spi_master *master)
+{
+ struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
+ struct mpc52xx_psc __iomem *psc = mps->psc;
+
+ dev_dbg(&master->dev, "%s()\n", __func__);
+
+ /* Zero MR2 */
+ in_8(&psc->mode);
+ out_8(&psc->mode, 0x0);
+
+ /* enable transmitter/receiver */
+ out_8(&psc->command, MPC52xx_PSC_TX_ENABLE | MPC52xx_PSC_RX_ENABLE);
+
+ return 0;
+}
+
+static int mpc512x_psc_spi_unprep_xfer_hw(struct spi_master *master)
+{
+ struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
+ struct mpc52xx_psc __iomem *psc = mps->psc;
+ struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
+
+ dev_dbg(&master->dev, "%s()\n", __func__);
+
+ /* disable transmitter/receiver and fifo interrupt */
+ out_8(&psc->command, MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
+ out_be32(&fifo->tximr, 0);
+
+ return 0;
+}
+
+static int mpc512x_psc_spi_setup(struct spi_device *spi)
+{
+ struct mpc512x_psc_spi_cs *cs = spi->controller_state;
+ int ret;
+
+ if (spi->bits_per_word % 8)
+ return -EINVAL;
+
+ if (!cs) {
+ cs = kzalloc(sizeof *cs, GFP_KERNEL);
+ if (!cs)
+ return -ENOMEM;
+
+ if (gpio_is_valid(spi->cs_gpio)) {
+ ret = gpio_request(spi->cs_gpio, dev_name(&spi->dev));
+ if (ret) {
+ dev_err(&spi->dev, "can't get CS gpio: %d\n",
+ ret);
+ kfree(cs);
+ return ret;
+ }
+ gpio_direction_output(spi->cs_gpio,
+ spi->mode & SPI_CS_HIGH ? 0 : 1);
+ }
+
+ spi->controller_state = cs;
+ }
+
+ cs->bits_per_word = spi->bits_per_word;
+ cs->speed_hz = spi->max_speed_hz;
+
+ return 0;
+}
+
+static void mpc512x_psc_spi_cleanup(struct spi_device *spi)
+{
+ if (gpio_is_valid(spi->cs_gpio))
+ gpio_free(spi->cs_gpio);
+ kfree(spi->controller_state);
+}
+
+static int mpc512x_psc_spi_port_config(struct spi_master *master,
+ struct mpc512x_psc_spi *mps)
+{
+ struct mpc52xx_psc __iomem *psc = mps->psc;
+ struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
+ u32 sicr;
+ u32 ccr;
+ int speed;
+ u16 bclkdiv;
+
+ /* Reset the PSC into a known state */
+ out_8(&psc->command, MPC52xx_PSC_RST_RX);
+ out_8(&psc->command, MPC52xx_PSC_RST_TX);
+ out_8(&psc->command, MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
+
+ /* Disable psc interrupts all useful interrupts are in fifo */
+ out_be16(&psc->isr_imr.imr, 0);
+
+ /* Disable fifo interrupts, will be enabled later */
+ out_be32(&fifo->tximr, 0);
+ out_be32(&fifo->rximr, 0);
+
+ /* Setup fifo slice address and size */
+ /*out_be32(&fifo->txsz, 0x0fe00004);*/
+ /*out_be32(&fifo->rxsz, 0x0ff00004);*/
+
+ sicr = 0x01000000 | /* SIM = 0001 -- 8 bit */
+ 0x00800000 | /* GenClk = 1 -- internal clk */
+ 0x00008000 | /* SPI = 1 */
+ 0x00004000 | /* MSTR = 1 -- SPI master */
+ 0x00000800; /* UseEOF = 1 -- SS low until EOF */
+
+ out_be32(&psc->sicr, sicr);
+
+ ccr = in_be32(&psc->ccr);
+ ccr &= 0xFF000000;
+ speed = 1000000; /* default 1MHz */
+ bclkdiv = (mps->mclk_rate / speed) - 1;
+ ccr |= (((bclkdiv & 0xff) << 16) | (((bclkdiv >> 8) & 0xff) << 8));
+ out_be32(&psc->ccr, ccr);
+
+ /* Set 2ms DTL delay */
+ out_8(&psc->ctur, 0x00);
+ out_8(&psc->ctlr, 0x82);
+
+ /* we don't use the alarms */
+ out_be32(&fifo->rxalarm, 0xfff);
+ out_be32(&fifo->txalarm, 0);
+
+ /* Enable FIFO slices for Rx/Tx */
+ out_be32(&fifo->rxcmd,
+ MPC512x_PSC_FIFO_ENABLE_SLICE | MPC512x_PSC_FIFO_ENABLE_DMA);
+ out_be32(&fifo->txcmd,
+ MPC512x_PSC_FIFO_ENABLE_SLICE | MPC512x_PSC_FIFO_ENABLE_DMA);
+
+ mps->bits_per_word = 8;
+
+ return 0;
+}
+
+static irqreturn_t mpc512x_psc_spi_isr(int irq, void *dev_id)
+{
+ struct mpc512x_psc_spi *mps = (struct mpc512x_psc_spi *)dev_id;
+ struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
+
+ /* clear interrupt and wake up the rx/tx routine */
+ if (in_be32(&fifo->txisr) &
+ in_be32(&fifo->tximr) & MPC512x_PSC_FIFO_EMPTY) {
+ out_be32(&fifo->txisr, MPC512x_PSC_FIFO_EMPTY);
+ out_be32(&fifo->tximr, 0);
+ complete(&mps->txisrdone);
+ return IRQ_HANDLED;
+ }
+ return IRQ_NONE;
+}
+
+static void mpc512x_spi_cs_control(struct spi_device *spi, bool onoff)
+{
+ gpio_set_value(spi->cs_gpio, onoff);
+}
+
+static int mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr,
+ u32 size, unsigned int irq)
+{
+ struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
+ struct mpc512x_psc_spi *mps;
+ struct spi_master *master;
+ int ret;
+ void *tempp;
+ struct clk *clk;
+
+ master = spi_alloc_master(dev, sizeof *mps);
+ if (master == NULL)
+ return -ENOMEM;
+
+ dev_set_drvdata(dev, master);
+ mps = spi_master_get_devdata(master);
+ mps->irq = irq;
+
+ if (pdata == NULL) {
+ mps->cs_control = mpc512x_spi_cs_control;
+ } else {
+ mps->cs_control = pdata->cs_control;
+ master->bus_num = pdata->bus_num;
+ master->num_chipselect = pdata->max_chipselect;
+ }
+
+ master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
+ master->setup = mpc512x_psc_spi_setup;
+ master->prepare_transfer_hardware = mpc512x_psc_spi_prep_xfer_hw;
+ master->transfer_one_message = mpc512x_psc_spi_msg_xfer;
+ master->unprepare_transfer_hardware = mpc512x_psc_spi_unprep_xfer_hw;
+ master->cleanup = mpc512x_psc_spi_cleanup;
+ master->dev.of_node = dev->of_node;
+
+ tempp = devm_ioremap(dev, regaddr, size);
+ if (!tempp) {
+ dev_err(dev, "could not ioremap I/O port range\n");
+ ret = -EFAULT;
+ goto free_master;
+ }
+ mps->psc = tempp;
+ mps->fifo =
+ (struct mpc512x_psc_fifo *)(tempp + sizeof(struct mpc52xx_psc));
+ ret = devm_request_irq(dev, mps->irq, mpc512x_psc_spi_isr, IRQF_SHARED,
+ "mpc512x-psc-spi", mps);
+ if (ret)
+ goto free_master;
+ init_completion(&mps->txisrdone);
+
+ clk = devm_clk_get(dev, "mclk");
+ if (IS_ERR(clk)) {
+ ret = PTR_ERR(clk);
+ goto free_master;
+ }
+ ret = clk_prepare_enable(clk);
+ if (ret)
+ goto free_master;
+ mps->clk_mclk = clk;
+ mps->mclk_rate = clk_get_rate(clk);
+
+ clk = devm_clk_get(dev, "ipg");
+ if (IS_ERR(clk)) {
+ ret = PTR_ERR(clk);
+ goto free_mclk_clock;
+ }
+ ret = clk_prepare_enable(clk);
+ if (ret)
+ goto free_mclk_clock;
+ mps->clk_ipg = clk;
+
+ ret = mpc512x_psc_spi_port_config(master, mps);
+ if (ret < 0)
+ goto free_ipg_clock;
+
+ ret = devm_spi_register_master(dev, master);
+ if (ret < 0)
+ goto free_ipg_clock;
+
+ return ret;
+
+free_ipg_clock:
+ clk_disable_unprepare(mps->clk_ipg);
+free_mclk_clock:
+ clk_disable_unprepare(mps->clk_mclk);
+free_master:
+ spi_master_put(master);
+
+ return ret;
+}
+
+static int mpc512x_psc_spi_do_remove(struct device *dev)
+{
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
+
+ clk_disable_unprepare(mps->clk_mclk);
+ clk_disable_unprepare(mps->clk_ipg);
+
+ return 0;
+}
+
+static int mpc512x_psc_spi_of_probe(struct platform_device *op)
+{
+ const u32 *regaddr_p;
+ u64 regaddr64, size64;
+
+ regaddr_p = of_get_address(op->dev.of_node, 0, &size64, NULL);
+ if (!regaddr_p) {
+ dev_err(&op->dev, "Invalid PSC address\n");
+ return -EINVAL;
+ }
+ regaddr64 = of_translate_address(op->dev.of_node, regaddr_p);
+
+ return mpc512x_psc_spi_do_probe(&op->dev, (u32) regaddr64, (u32) size64,
+ irq_of_parse_and_map(op->dev.of_node, 0));
+}
+
+static int mpc512x_psc_spi_of_remove(struct platform_device *op)
+{
+ return mpc512x_psc_spi_do_remove(&op->dev);
+}
+
+static const struct of_device_id mpc512x_psc_spi_of_match[] = {
+ { .compatible = "fsl,mpc5121-psc-spi", },
+ {},
+};
+
+MODULE_DEVICE_TABLE(of, mpc512x_psc_spi_of_match);
+
+static struct platform_driver mpc512x_psc_spi_of_driver = {
+ .probe = mpc512x_psc_spi_of_probe,
+ .remove = mpc512x_psc_spi_of_remove,
+ .driver = {
+ .name = "mpc512x-psc-spi",
+ .of_match_table = mpc512x_psc_spi_of_match,
+ },
+};
+module_platform_driver(mpc512x_psc_spi_of_driver);
+
+MODULE_AUTHOR("John Rigby");
+MODULE_DESCRIPTION("MPC512x PSC SPI Driver");
+MODULE_LICENSE("GPL");
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-01 01:00:28 +0000