--- /dev/null
+/*
+ * CLPS711X SPI bus driver
+ *
+ * Copyright (C) 2012-2014 Alexander Shiyan <shc_work@mail.ru>
+ *
+ * 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/io.h>
+#include <linux/clk.h>
+#include <linux/gpio.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mfd/syscon/clps711x.h>
+#include <linux/spi/spi.h>
+#include <linux/platform_data/spi-clps711x.h>
+
+#define DRIVER_NAME "spi-clps711x"
+
+#define SYNCIO_FRMLEN(x) ((x) << 8)
+#define SYNCIO_TXFRMEN (1 << 14)
+
+struct spi_clps711x_data {
+ void __iomem *syncio;
+ struct regmap *syscon;
+ struct clk *spi_clk;
+
+ u8 *tx_buf;
+ u8 *rx_buf;
+ unsigned int bpw;
+ int len;
+};
+
+static int spi_clps711x_setup(struct spi_device *spi)
+{
+ /* We are expect that SPI-device is not selected */
+ gpio_direction_output(spi->cs_gpio, !(spi->mode & SPI_CS_HIGH));
+
+ return 0;
+}
+
+static int spi_clps711x_prepare_message(struct spi_master *master,
+ struct spi_message *msg)
+{
+ struct spi_clps711x_data *hw = spi_master_get_devdata(master);
+ struct spi_device *spi = msg->spi;
+
+ /* Setup mode for transfer */
+ return regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCKNSEN,
+ (spi->mode & SPI_CPHA) ?
+ SYSCON3_ADCCKNSEN : 0);
+}
+
+static int spi_clps711x_transfer_one(struct spi_master *master,
+ struct spi_device *spi,
+ struct spi_transfer *xfer)
+{
+ struct spi_clps711x_data *hw = spi_master_get_devdata(master);
+ u8 data;
+
+ clk_set_rate(hw->spi_clk, xfer->speed_hz ? : spi->max_speed_hz);
+
+ hw->len = xfer->len;
+ hw->bpw = xfer->bits_per_word;
+ hw->tx_buf = (u8 *)xfer->tx_buf;
+ hw->rx_buf = (u8 *)xfer->rx_buf;
+
+ /* Initiate transfer */
+ data = hw->tx_buf ? *hw->tx_buf++ : 0;
+ writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN, hw->syncio);
+
+ return 1;
+}
+
+static irqreturn_t spi_clps711x_isr(int irq, void *dev_id)
+{
+ struct spi_master *master = dev_id;
+ struct spi_clps711x_data *hw = spi_master_get_devdata(master);
+ u8 data;
+
+ /* Handle RX */
+ data = readb(hw->syncio);
+ if (hw->rx_buf)
+ *hw->rx_buf++ = data;
+
+ /* Handle TX */
+ if (--hw->len > 0) {
+ data = hw->tx_buf ? *hw->tx_buf++ : 0;
+ writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN,
+ hw->syncio);
+ } else
+ spi_finalize_current_transfer(master);
+
+ return IRQ_HANDLED;
+}
+
+static int spi_clps711x_probe(struct platform_device *pdev)
+{
+ struct spi_clps711x_data *hw;
+ struct spi_clps711x_pdata *pdata = dev_get_platdata(&pdev->dev);
+ struct spi_master *master;
+ struct resource *res;
+ int i, irq, ret;
+
+ if (!pdata) {
+ dev_err(&pdev->dev, "No platform data supplied\n");
+ return -EINVAL;
+ }
+
+ if (pdata->num_chipselect < 1) {
+ dev_err(&pdev->dev, "At least one CS must be defined\n");
+ return -EINVAL;
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+
+ master = spi_alloc_master(&pdev->dev, sizeof(*hw));
+ if (!master)
+ return -ENOMEM;
+
+ master->cs_gpios = devm_kzalloc(&pdev->dev, sizeof(int) *
+ pdata->num_chipselect, GFP_KERNEL);
+ if (!master->cs_gpios) {
+ ret = -ENOMEM;
+ goto err_out;
+ }
+
+ master->bus_num = pdev->id;
+ master->mode_bits = SPI_CPHA | SPI_CS_HIGH;
+ master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 8);
+ master->num_chipselect = pdata->num_chipselect;
+ master->setup = spi_clps711x_setup;
+ master->prepare_message = spi_clps711x_prepare_message;
+ master->transfer_one = spi_clps711x_transfer_one;
+
+ hw = spi_master_get_devdata(master);
+
+ for (i = 0; i < master->num_chipselect; i++) {
+ master->cs_gpios[i] = pdata->chipselect[i];
+ ret = devm_gpio_request(&pdev->dev, master->cs_gpios[i],
+ DRIVER_NAME);
+ if (ret) {
+ dev_err(&pdev->dev, "Can't get CS GPIO %i\n", i);
+ goto err_out;
+ }
+ }
+
+ hw->spi_clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(hw->spi_clk)) {
+ ret = PTR_ERR(hw->spi_clk);
+ goto err_out;
+ }
+
+ hw->syscon = syscon_regmap_lookup_by_pdevname("syscon.3");
+ if (IS_ERR(hw->syscon)) {
+ ret = PTR_ERR(hw->syscon);
+ goto err_out;
+ }
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ hw->syncio = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(hw->syncio)) {
+ ret = PTR_ERR(hw->syncio);
+ goto err_out;
+ }
+
+ /* Disable extended mode due hardware problems */
+ regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCON, 0);
+
+ /* Clear possible pending interrupt */
+ readl(hw->syncio);
+
+ ret = devm_request_irq(&pdev->dev, irq, spi_clps711x_isr, 0,
+ dev_name(&pdev->dev), master);
+ if (ret)
+ goto err_out;
+
+ ret = devm_spi_register_master(&pdev->dev, master);
+ if (!ret) {
+ dev_info(&pdev->dev,
+ "SPI bus driver initialized. Master clock %u Hz\n",
+ master->max_speed_hz);
+ return 0;
+ }
+
+ dev_err(&pdev->dev, "Failed to register master\n");
+
+err_out:
+ spi_master_put(master);
+
+ return ret;
+}
+
+static struct platform_driver clps711x_spi_driver = {
+ .driver = {
+ .name = DRIVER_NAME,
+ },
+ .probe = spi_clps711x_probe,
+};
+module_platform_driver(clps711x_spi_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
+MODULE_DESCRIPTION("CLPS711X SPI bus driver");
+MODULE_ALIAS("platform:" DRIVER_NAME);
Code Review / kvmfornfv.git / blobdiff