LXR linux/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
  24struct 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
  35static 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
  47static 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
  68static 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
  90static 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
 148err_out:
 149        spi_master_put(master);
 150
 151        return ret;
 152}
 153
 154static const struct of_device_id clps711x_spi_dt_ids[] = {
 155        { .compatible = "cirrus,ep7209-spi", },
 156        { }
 157};
 158MODULE_DEVICE_TABLE(of, clps711x_spi_dt_ids);
 159
 160static 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};
 167module_platform_driver(clps711x_spi_driver);
 168
 169MODULE_LICENSE("GPL");
 170MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
 171MODULE_DESCRIPTION("CLPS711X SPI bus driver");
 172MODULE_ALIAS("platform:" DRIVER_NAME);
 173