drivers/spi/spi-clps711x.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  CLPS711X SPI bus driver
   4  *
   5  *  Copyright (C) 2012-2016 Alexander Shiyan <shc_work@mail.ru>
   6  */
   7
   8 #include <linux/io.h>
   9 #include <linux/clk.h>
  10 #include <linux/gpio/consumer.h>
  11 #include <linux/module.h>
  12 #include <linux/of.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/regmap.h>
  16 #include <linux/mfd/syscon.h>
  17 #include <linux/mfd/syscon/clps711x.h>
  18 #include <linux/spi/spi.h>
  19
  20 #define DRIVER_NAME             "clps711x-spi"
  21
  22 #define SYNCIO_FRMLEN(x)        ((x) << 8)
  23 #define SYNCIO_TXFRMEN          (1 << 14)
  24
  25 struct spi_clps711x_data {
  26         void __iomem            *syncio;
  27         struct regmap           *syscon;
  28         struct clk              *spi_clk;
  29
  30         u8                      *tx_buf;
  31         u8                      *rx_buf;
  32         unsigned int            bpw;
  33         int                     len;
  34 };
  35
  36 static int spi_clps711x_prepare_message(struct spi_controller *host,
  37                                         struct spi_message *msg)
  38 {
  39         struct spi_clps711x_data *hw = spi_controller_get_devdata(host);
  40         struct spi_device *spi = msg->spi;
  41
  42         /* Setup mode for transfer */
  43         return regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCKNSEN,
  44                                   (spi->mode & SPI_CPHA) ?
  45                                   SYSCON3_ADCCKNSEN : 0);
  46 }
  47
  48 static int spi_clps711x_transfer_one(struct spi_controller *host,
  49                                      struct spi_device *spi,
  50                                      struct spi_transfer *xfer)
  51 {
  52         struct spi_clps711x_data *hw = spi_controller_get_devdata(host);
  53         u8 data;
  54
  55         clk_set_rate(hw->spi_clk, xfer->speed_hz ? : spi->max_speed_hz);
  56
  57         hw->len = xfer->len;
  58         hw->bpw = xfer->bits_per_word;
  59         hw->tx_buf = (u8 *)xfer->tx_buf;
  60         hw->rx_buf = (u8 *)xfer->rx_buf;
  61
  62         /* Initiate transfer */
  63         data = hw->tx_buf ? *hw->tx_buf++ : 0;
  64         writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN, hw->syncio);
  65
  66         return 1;
  67 }
  68
  69 static irqreturn_t spi_clps711x_isr(int irq, void *dev_id)
  70 {
  71         struct spi_controller *host = dev_id;
  72         struct spi_clps711x_data *hw = spi_controller_get_devdata(host);
  73         u8 data;
  74
  75         /* Handle RX */
  76         data = readb(hw->syncio);
  77         if (hw->rx_buf)
  78                 *hw->rx_buf++ = data;
  79
  80         /* Handle TX */
  81         if (--hw->len > 0) {
  82                 data = hw->tx_buf ? *hw->tx_buf++ : 0;
  83                 writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN,
  84                        hw->syncio);
  85         } else
  86                 spi_finalize_current_transfer(host);
  87
  88         return IRQ_HANDLED;
  89 }
  90
  91 static int spi_clps711x_probe(struct platform_device *pdev)
  92 {
  93         struct device_node *np = pdev->dev.of_node;
  94         struct spi_clps711x_data *hw;
  95         struct spi_controller *host;
  96         int irq, ret;
  97
  98         irq = platform_get_irq(pdev, 0);
  99         if (irq < 0)
 100                 return irq;
 101
 102         host = spi_alloc_host(&pdev->dev, sizeof(*hw));
 103         if (!host)
 104                 return -ENOMEM;
 105
 106         host->use_gpio_descriptors = true;
 107         host->bus_num = -1;
 108         host->mode_bits = SPI_CPHA | SPI_CS_HIGH;
 109         host->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 8);
 110         host->dev.of_node = pdev->dev.of_node;
 111         host->prepare_message = spi_clps711x_prepare_message;
 112         host->transfer_one = spi_clps711x_transfer_one;
 113
 114         hw = spi_controller_get_devdata(host);
 115
 116         hw->spi_clk = devm_clk_get(&pdev->dev, NULL);
 117         if (IS_ERR(hw->spi_clk)) {
 118                 ret = PTR_ERR(hw->spi_clk);
 119                 goto err_out;
 120         }
 121
 122         hw->syscon = syscon_regmap_lookup_by_phandle(np, "syscon");
 123         if (IS_ERR(hw->syscon)) {
 124                 ret = PTR_ERR(hw->syscon);
 125                 goto err_out;
 126         }
 127
 128         hw->syncio = devm_platform_ioremap_resource(pdev, 0);
 129         if (IS_ERR(hw->syncio)) {
 130                 ret = PTR_ERR(hw->syncio);
 131                 goto err_out;
 132         }
 133
 134         /* Disable extended mode due hardware problems */
 135         regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCON, 0);
 136
 137         /* Clear possible pending interrupt */
 138         readl(hw->syncio);
 139
 140         ret = devm_request_irq(&pdev->dev, irq, spi_clps711x_isr, 0,
 141                                dev_name(&pdev->dev), host);
 142         if (ret)
 143                 goto err_out;
 144
 145         ret = devm_spi_register_controller(&pdev->dev, host);
 146         if (!ret)
 147                 return 0;
 148
 149 err_out:
 150         spi_controller_put(host);
 151
 152         return ret;
 153 }
 154
 155 static const struct of_device_id clps711x_spi_dt_ids[] = {
 156         { .compatible = "cirrus,ep7209-spi", },
 157         { }
 158 };
 159 MODULE_DEVICE_TABLE(of, clps711x_spi_dt_ids);
 160
 161 static struct platform_driver clps711x_spi_driver = {
 162         .driver = {
 163                 .name   = DRIVER_NAME,
 164                 .of_match_table = clps711x_spi_dt_ids,
 165         },
 166         .probe  = spi_clps711x_probe,
 167 };
 168 module_platform_driver(clps711x_spi_driver);
 169
 170 MODULE_LICENSE("GPL");
 171 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
 172 MODULE_DESCRIPTION("CLPS711X SPI bus driver");
 173 MODULE_ALIAS("platform:" DRIVER_NAME);