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_master *master, 37 struct spi_message *msg) 38 { 39 struct spi_clps711x_data *hw = spi_master_get_devdata(master); 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_master *master, 49 struct spi_device *spi, 50 struct spi_transfer *xfer) 51 { 52 struct spi_clps711x_data *hw = spi_master_get_devdata(master); 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_master *master = dev_id; 72 struct spi_clps711x_data *hw = spi_master_get_devdata(master); 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(master); 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_master *master; 96 int irq, ret; 97 98 irq = platform_get_irq(pdev, 0); 99 if (irq < 0) 100 return irq; 101 102 master = spi_alloc_master(&pdev->dev, sizeof(*hw)); 103 if (!master) 104 return -ENOMEM; 105 106 master->use_gpio_descriptors = true; 107 master->bus_num = -1; 108 master->mode_bits = SPI_CPHA | SPI_CS_HIGH; 109 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 8); 110 master->dev.of_node = pdev->dev.of_node; 111 master->prepare_message = spi_clps711x_prepare_message; 112 master->transfer_one = spi_clps711x_transfer_one; 113 114 hw = spi_master_get_devdata(master); 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), master); 142 if (ret) 143 goto err_out; 144 145 ret = devm_spi_register_master(&pdev->dev, master); 146 if (!ret) 147 return 0; 148 149 err_out: 150 spi_master_put(master); 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); 174