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/interrupt.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/regmap.h>
  15 #include <linux/mfd/syscon.h>
  16 #include <linux/mfd/syscon/clps711x.h>
  17 #include <linux/spi/spi.h>
  18
  19 #define DRIVER_NAME             "clps711x-spi"
  20
  21 #define SYNCIO_FRMLEN(x)        ((x) << 8)
  22 #define SYNCIO_TXFRMEN          (1 << 14)
  23
  24 struct spi_clps711x_data {
  25         void __iomem            *syncio;
  26         struct regmap           *syscon;
  27         struct clk              *spi_clk;
  28
  29         u8                      *tx_buf;
  30         u8                      *rx_buf;
  31         unsigned int            bpw;
  32         int                     len;
  33 };
  34
  35 static int spi_clps711x_prepare_message(struct spi_master *master,
  36                                         struct spi_message *msg)
  37 {
  38         struct spi_clps711x_data *hw = spi_master_get_devdata(master);
  39         struct spi_device *spi = msg->spi;
  40
  41         /* Setup mode for transfer */
  42         return regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCKNSEN,
  43                                   (spi->mode & SPI_CPHA) ?
  44                                   SYSCON3_ADCCKNSEN : 0);
  45 }
  46
  47 static int spi_clps711x_transfer_one(struct spi_master *master,
  48                                      struct spi_device *spi,
  49                                      struct spi_transfer *xfer)
  50 {
  51         struct spi_clps711x_data *hw = spi_master_get_devdata(master);
  52         u8 data;
  53
  54         clk_set_rate(hw->spi_clk, xfer->speed_hz ? : spi->max_speed_hz);
  55
  56         hw->len = xfer->len;
  57         hw->bpw = xfer->bits_per_word;
  58         hw->tx_buf = (u8 *)xfer->tx_buf;
  59         hw->rx_buf = (u8 *)xfer->rx_buf;
  60
  61         /* Initiate transfer */
  62         data = hw->tx_buf ? *hw->tx_buf++ : 0;
  63         writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN, hw->syncio);
  64
  65         return 1;
  66 }
  67
  68 static irqreturn_t spi_clps711x_isr(int irq, void *dev_id)
  69 {
  70         struct spi_master *master = dev_id;
  71         struct spi_clps711x_data *hw = spi_master_get_devdata(master);
  72         u8 data;
  73
  74         /* Handle RX */
  75         data = readb(hw->syncio);
  76         if (hw->rx_buf)
  77                 *hw->rx_buf++ = data;
  78
  79         /* Handle TX */
  80         if (--hw->len > 0) {
  81                 data = hw->tx_buf ? *hw->tx_buf++ : 0;
  82                 writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN,
  83                        hw->syncio);
  84         } else
  85                 spi_finalize_current_transfer(master);
  86
  87         return IRQ_HANDLED;
  88 }
  89
  90 static int spi_clps711x_probe(struct platform_device *pdev)
  91 {
  92         struct spi_clps711x_data *hw;
  93         struct spi_master *master;
  94         int irq, ret;
  95
  96         irq = platform_get_irq(pdev, 0);
  97         if (irq < 0)
  98                 return irq;
  99
 100         master = spi_alloc_master(&pdev->dev, sizeof(*hw));
 101         if (!master)
 102                 return -ENOMEM;
 103
 104         master->use_gpio_descriptors = true;
 105         master->bus_num = -1;
 106         master->mode_bits = SPI_CPHA | SPI_CS_HIGH;
 107         master->bits_per_word_mask =  SPI_BPW_RANGE_MASK(1, 8);
 108         master->dev.of_node = pdev->dev.of_node;
 109         master->prepare_message = spi_clps711x_prepare_message;
 110         master->transfer_one = spi_clps711x_transfer_one;
 111
 112         hw = spi_master_get_devdata(master);
 113
 114         hw->spi_clk = devm_clk_get(&pdev->dev, NULL);
 115         if (IS_ERR(hw->spi_clk)) {
 116                 ret = PTR_ERR(hw->spi_clk);
 117                 goto err_out;
 118         }
 119
 120         hw->syscon =
 121                 syscon_regmap_lookup_by_compatible("cirrus,ep7209-syscon3");
 122         if (IS_ERR(hw->syscon)) {
 123                 ret = PTR_ERR(hw->syscon);
 124                 goto err_out;
 125         }
 126
 127         hw->syncio = devm_platform_ioremap_resource(pdev, 0);
 128         if (IS_ERR(hw->syncio)) {
 129                 ret = PTR_ERR(hw->syncio);
 130                 goto err_out;
 131         }
 132
 133         /* Disable extended mode due hardware problems */
 134         regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCON, 0);
 135
 136         /* Clear possible pending interrupt */
 137         readl(hw->syncio);
 138
 139         ret = devm_request_irq(&pdev->dev, irq, spi_clps711x_isr, 0,
 140                                dev_name(&pdev->dev), master);
 141         if (ret)
 142                 goto err_out;
 143
 144         ret = devm_spi_register_master(&pdev->dev, master);
 145         if (!ret)
 146                 return 0;
 147
 148 err_out:
 149         spi_master_put(master);
 150
 151         return ret;
 152 }
 153
 154 static const struct of_device_id clps711x_spi_dt_ids[] = {
 155         { .compatible = "cirrus,ep7209-spi", },
 156         { }
 157 };
 158 MODULE_DEVICE_TABLE(of, clps711x_spi_dt_ids);
 159
 160 static struct platform_driver clps711x_spi_driver = {
 161         .driver = {
 162                 .name   = DRIVER_NAME,
 163                 .of_match_table = clps711x_spi_dt_ids,
 164         },
 165         .probe  = spi_clps711x_probe,
 166 };
 167 module_platform_driver(clps711x_spi_driver);
 168
 169 MODULE_LICENSE("GPL");
 170 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
 171 MODULE_DESCRIPTION("CLPS711X SPI bus driver");
 172 MODULE_ALIAS("platform:" DRIVER_NAME);