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); 173