drivers/spi/spi-clps711x.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  *  CLPS711X SPI bus driver
0004  *
0005  *  Copyright (C) 2012-2016 Alexander Shiyan <shc_work@mail.ru>
0006  */
0007
0008 #include <linux/io.h>
0009 #include <linux/clk.h>
0010 #include <linux/gpio/consumer.h>
0011 #include <linux/module.h>
0012 #include <linux/of.h>
0013 #include <linux/interrupt.h>
0014 #include <linux/platform_device.h>
0015 #include <linux/regmap.h>
0016 #include <linux/mfd/syscon.h>
0017 #include <linux/mfd/syscon/clps711x.h>
0018 #include <linux/spi/spi.h>
0019
0020 #define DRIVER_NAME     "clps711x-spi"
0021
0022 #define SYNCIO_FRMLEN(x)    ((x) << 8)
0023 #define SYNCIO_TXFRMEN      (1 << 14)
0024
0025 struct spi_clps711x_data {
0026     void __iomem        *syncio;
0027     struct regmap       *syscon;
0028     struct clk      *spi_clk;
0029
0030     u8          *tx_buf;
0031     u8          *rx_buf;
0032     unsigned int        bpw;
0033     int         len;
0034 };
0035
0036 static int spi_clps711x_prepare_message(struct spi_master *master,
0037                     struct spi_message *msg)
0038 {
0039     struct spi_clps711x_data *hw = spi_master_get_devdata(master);
0040     struct spi_device *spi = msg->spi;
0041
0042     /* Setup mode for transfer */
0043     return regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCKNSEN,
0044                   (spi->mode & SPI_CPHA) ?
0045                   SYSCON3_ADCCKNSEN : 0);
0046 }
0047
0048 static int spi_clps711x_transfer_one(struct spi_master *master,
0049                      struct spi_device *spi,
0050                      struct spi_transfer *xfer)
0051 {
0052     struct spi_clps711x_data *hw = spi_master_get_devdata(master);
0053     u8 data;
0054
0055     clk_set_rate(hw->spi_clk, xfer->speed_hz ? : spi->max_speed_hz);
0056
0057     hw->len = xfer->len;
0058     hw->bpw = xfer->bits_per_word;
0059     hw->tx_buf = (u8 *)xfer->tx_buf;
0060     hw->rx_buf = (u8 *)xfer->rx_buf;
0061
0062     /* Initiate transfer */
0063     data = hw->tx_buf ? *hw->tx_buf++ : 0;
0064     writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN, hw->syncio);
0065
0066     return 1;
0067 }
0068
0069 static irqreturn_t spi_clps711x_isr(int irq, void *dev_id)
0070 {
0071     struct spi_master *master = dev_id;
0072     struct spi_clps711x_data *hw = spi_master_get_devdata(master);
0073     u8 data;
0074
0075     /* Handle RX */
0076     data = readb(hw->syncio);
0077     if (hw->rx_buf)
0078         *hw->rx_buf++ = data;
0079
0080     /* Handle TX */
0081     if (--hw->len > 0) {
0082         data = hw->tx_buf ? *hw->tx_buf++ : 0;
0083         writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN,
0084                hw->syncio);
0085     } else
0086         spi_finalize_current_transfer(master);
0087
0088     return IRQ_HANDLED;
0089 }
0090
0091 static int spi_clps711x_probe(struct platform_device *pdev)
0092 {
0093     struct device_node *np = pdev->dev.of_node;
0094     struct spi_clps711x_data *hw;
0095     struct spi_master *master;
0096     int irq, ret;
0097
0098     irq = platform_get_irq(pdev, 0);
0099     if (irq < 0)
0100         return irq;
0101
0102     master = spi_alloc_master(&pdev->dev, sizeof(*hw));
0103     if (!master)
0104         return -ENOMEM;
0105
0106     master->use_gpio_descriptors = true;
0107     master->bus_num = -1;
0108     master->mode_bits = SPI_CPHA | SPI_CS_HIGH;
0109     master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 8);
0110     master->dev.of_node = pdev->dev.of_node;
0111     master->prepare_message = spi_clps711x_prepare_message;
0112     master->transfer_one = spi_clps711x_transfer_one;
0113
0114     hw = spi_master_get_devdata(master);
0115
0116     hw->spi_clk = devm_clk_get(&pdev->dev, NULL);
0117     if (IS_ERR(hw->spi_clk)) {
0118         ret = PTR_ERR(hw->spi_clk);
0119         goto err_out;
0120     }
0121
0122     hw->syscon = syscon_regmap_lookup_by_phandle(np, "syscon");
0123     if (IS_ERR(hw->syscon)) {
0124         ret = PTR_ERR(hw->syscon);
0125         goto err_out;
0126     }
0127
0128     hw->syncio = devm_platform_ioremap_resource(pdev, 0);
0129     if (IS_ERR(hw->syncio)) {
0130         ret = PTR_ERR(hw->syncio);
0131         goto err_out;
0132     }
0133
0134     /* Disable extended mode due hardware problems */
0135     regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCON, 0);
0136
0137     /* Clear possible pending interrupt */
0138     readl(hw->syncio);
0139
0140     ret = devm_request_irq(&pdev->dev, irq, spi_clps711x_isr, 0,
0141                    dev_name(&pdev->dev), master);
0142     if (ret)
0143         goto err_out;
0144
0145     ret = devm_spi_register_master(&pdev->dev, master);
0146     if (!ret)
0147         return 0;
0148
0149 err_out:
0150     spi_master_put(master);
0151
0152     return ret;
0153 }
0154
0155 static const struct of_device_id clps711x_spi_dt_ids[] = {
0156     { .compatible = "cirrus,ep7209-spi", },
0157     { }
0158 };
0159 MODULE_DEVICE_TABLE(of, clps711x_spi_dt_ids);
0160
0161 static struct platform_driver clps711x_spi_driver = {
0162     .driver = {
0163         .name   = DRIVER_NAME,
0164         .of_match_table = clps711x_spi_dt_ids,
0165     },
0166     .probe  = spi_clps711x_probe,
0167 };
0168 module_platform_driver(clps711x_spi_driver);
0169
0170 MODULE_LICENSE("GPL");
0171 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
0172 MODULE_DESCRIPTION("CLPS711X SPI bus driver");
0173 MODULE_ALIAS("platform:" DRIVER_NAME);