1 /* 2 * CLPS711X SPI bus driver 3 * 4 * Copyright (C) 2012-2014 Alexander Shiyan <shc_work@mail.ru> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 */ 11 12 #include <linux/io.h> 13 #include <linux/clk.h> 14 #include <linux/gpio.h> 15 #include <linux/delay.h> 16 #include <linux/module.h> 17 #include <linux/interrupt.h> 18 #include <linux/platform_device.h> 19 #include <linux/regmap.h> 20 #include <linux/mfd/syscon.h> 21 #include <linux/mfd/syscon/clps711x.h> 22 #include <linux/spi/spi.h> 23 #include <linux/platform_data/spi-clps711x.h> 24 25 #define DRIVER_NAME "spi-clps711x" 26 27 #define SYNCIO_FRMLEN(x) ((x) << 8) 28 #define SYNCIO_TXFRMEN (1 << 14) 29 30 struct spi_clps711x_data { 31 void __iomem *syncio; 32 struct regmap *syscon; 33 struct regmap *syscon1; 34 struct clk *spi_clk; 35 36 u8 *tx_buf; 37 u8 *rx_buf; 38 unsigned int bpw; 39 int len; 40 }; 41 42 static int spi_clps711x_setup(struct spi_device *spi) 43 { 44 /* We are expect that SPI-device is not selected */ 45 gpio_direction_output(spi->cs_gpio, !(spi->mode & SPI_CS_HIGH)); 46 47 return 0; 48 } 49 50 static void spi_clps711x_setup_xfer(struct spi_device *spi, 51 struct spi_transfer *xfer) 52 { 53 struct spi_master *master = spi->master; 54 struct spi_clps711x_data *hw = spi_master_get_devdata(master); 55 56 /* Setup SPI frequency divider */ 57 if (xfer->speed_hz >= master->max_speed_hz) 58 regmap_update_bits(hw->syscon1, SYSCON_OFFSET, 59 SYSCON1_ADCKSEL_MASK, SYSCON1_ADCKSEL(3)); 60 else if (xfer->speed_hz >= (master->max_speed_hz / 2)) 61 regmap_update_bits(hw->syscon1, SYSCON_OFFSET, 62 SYSCON1_ADCKSEL_MASK, SYSCON1_ADCKSEL(2)); 63 else if (xfer->speed_hz >= (master->max_speed_hz / 8)) 64 regmap_update_bits(hw->syscon1, SYSCON_OFFSET, 65 SYSCON1_ADCKSEL_MASK, SYSCON1_ADCKSEL(1)); 66 else 67 regmap_update_bits(hw->syscon1, SYSCON_OFFSET, 68 SYSCON1_ADCKSEL_MASK, SYSCON1_ADCKSEL(0)); 69 } 70 71 static int spi_clps711x_prepare_message(struct spi_master *master, 72 struct spi_message *msg) 73 { 74 struct spi_clps711x_data *hw = spi_master_get_devdata(master); 75 struct spi_device *spi = msg->spi; 76 77 /* Setup mode for transfer */ 78 return regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCKNSEN, 79 (spi->mode & SPI_CPHA) ? 80 SYSCON3_ADCCKNSEN : 0); 81 } 82 83 static int spi_clps711x_transfer_one(struct spi_master *master, 84 struct spi_device *spi, 85 struct spi_transfer *xfer) 86 { 87 struct spi_clps711x_data *hw = spi_master_get_devdata(master); 88 u8 data; 89 90 spi_clps711x_setup_xfer(spi, xfer); 91 92 hw->len = xfer->len; 93 hw->bpw = xfer->bits_per_word; 94 hw->tx_buf = (u8 *)xfer->tx_buf; 95 hw->rx_buf = (u8 *)xfer->rx_buf; 96 97 /* Initiate transfer */ 98 data = hw->tx_buf ? *hw->tx_buf++ : 0; 99 writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN, hw->syncio); 100 101 return 1; 102 } 103 104 static irqreturn_t spi_clps711x_isr(int irq, void *dev_id) 105 { 106 struct spi_master *master = dev_id; 107 struct spi_clps711x_data *hw = spi_master_get_devdata(master); 108 u8 data; 109 110 /* Handle RX */ 111 data = readb(hw->syncio); 112 if (hw->rx_buf) 113 *hw->rx_buf++ = data; 114 115 /* Handle TX */ 116 if (--hw->len > 0) { 117 data = hw->tx_buf ? *hw->tx_buf++ : 0; 118 writel(data | SYNCIO_FRMLEN(hw->bpw) | SYNCIO_TXFRMEN, 119 hw->syncio); 120 } else 121 spi_finalize_current_transfer(master); 122 123 return IRQ_HANDLED; 124 } 125 126 static int spi_clps711x_probe(struct platform_device *pdev) 127 { 128 struct spi_clps711x_data *hw; 129 struct spi_clps711x_pdata *pdata = dev_get_platdata(&pdev->dev); 130 struct spi_master *master; 131 struct resource *res; 132 int i, irq, ret; 133 134 if (!pdata) { 135 dev_err(&pdev->dev, "No platform data supplied\n"); 136 return -EINVAL; 137 } 138 139 if (pdata->num_chipselect < 1) { 140 dev_err(&pdev->dev, "At least one CS must be defined\n"); 141 return -EINVAL; 142 } 143 144 irq = platform_get_irq(pdev, 0); 145 if (irq < 0) 146 return irq; 147 148 master = spi_alloc_master(&pdev->dev, sizeof(*hw)); 149 if (!master) 150 return -ENOMEM; 151 152 master->cs_gpios = devm_kzalloc(&pdev->dev, sizeof(int) * 153 pdata->num_chipselect, GFP_KERNEL); 154 if (!master->cs_gpios) { 155 ret = -ENOMEM; 156 goto err_out; 157 } 158 159 master->bus_num = pdev->id; 160 master->mode_bits = SPI_CPHA | SPI_CS_HIGH; 161 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 8); 162 master->num_chipselect = pdata->num_chipselect; 163 master->setup = spi_clps711x_setup; 164 master->prepare_message = spi_clps711x_prepare_message; 165 master->transfer_one = spi_clps711x_transfer_one; 166 167 hw = spi_master_get_devdata(master); 168 169 for (i = 0; i < master->num_chipselect; i++) { 170 master->cs_gpios[i] = pdata->chipselect[i]; 171 ret = devm_gpio_request(&pdev->dev, master->cs_gpios[i], 172 DRIVER_NAME); 173 if (ret) { 174 dev_err(&pdev->dev, "Can't get CS GPIO %i\n", i); 175 goto err_out; 176 } 177 } 178 179 hw->spi_clk = devm_clk_get(&pdev->dev, "spi"); 180 if (IS_ERR(hw->spi_clk)) { 181 dev_err(&pdev->dev, "Can't get clocks\n"); 182 ret = PTR_ERR(hw->spi_clk); 183 goto err_out; 184 } 185 master->max_speed_hz = clk_get_rate(hw->spi_clk); 186 187 hw->syscon = syscon_regmap_lookup_by_pdevname("syscon.3"); 188 if (IS_ERR(hw->syscon)) { 189 ret = PTR_ERR(hw->syscon); 190 goto err_out; 191 } 192 193 hw->syscon1 = syscon_regmap_lookup_by_pdevname("syscon.1"); 194 if (IS_ERR(hw->syscon1)) { 195 ret = PTR_ERR(hw->syscon1); 196 goto err_out; 197 } 198 199 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 200 hw->syncio = devm_ioremap_resource(&pdev->dev, res); 201 if (IS_ERR(hw->syncio)) { 202 ret = PTR_ERR(hw->syncio); 203 goto err_out; 204 } 205 206 /* Disable extended mode due hardware problems */ 207 regmap_update_bits(hw->syscon, SYSCON_OFFSET, SYSCON3_ADCCON, 0); 208 209 /* Clear possible pending interrupt */ 210 readl(hw->syncio); 211 212 ret = devm_request_irq(&pdev->dev, irq, spi_clps711x_isr, 0, 213 dev_name(&pdev->dev), master); 214 if (ret) 215 goto err_out; 216 217 ret = devm_spi_register_master(&pdev->dev, master); 218 if (!ret) { 219 dev_info(&pdev->dev, 220 "SPI bus driver initialized. Master clock %u Hz\n", 221 master->max_speed_hz); 222 return 0; 223 } 224 225 dev_err(&pdev->dev, "Failed to register master\n"); 226 227 err_out: 228 spi_master_put(master); 229 230 return ret; 231 } 232 233 static struct platform_driver clps711x_spi_driver = { 234 .driver = { 235 .name = DRIVER_NAME, 236 .owner = THIS_MODULE, 237 }, 238 .probe = spi_clps711x_probe, 239 }; 240 module_platform_driver(clps711x_spi_driver); 241 242 MODULE_LICENSE("GPL"); 243 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>"); 244 MODULE_DESCRIPTION("CLPS711X SPI bus driver"); 245 MODULE_ALIAS("platform:" DRIVER_NAME); 246