1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2014-2015 Pengutronix, Markus Pargmann <mpa@pengutronix.de> 4 */ 5 6 #include <linux/clk.h> 7 #include <linux/interrupt.h> 8 #include <linux/irqchip/chained_irq.h> 9 #include <linux/irqdesc.h> 10 #include <linux/irqdomain.h> 11 #include <linux/irq.h> 12 #include <linux/mfd/imx25-tsadc.h> 13 #include <linux/module.h> 14 #include <linux/of.h> 15 #include <linux/of_platform.h> 16 #include <linux/platform_device.h> 17 #include <linux/regmap.h> 18 19 static struct regmap_config mx25_tsadc_regmap_config = { 20 .fast_io = true, 21 .max_register = 8, 22 .reg_bits = 32, 23 .val_bits = 32, 24 .reg_stride = 4, 25 }; 26 27 static void mx25_tsadc_irq_handler(struct irq_desc *desc) 28 { 29 struct mx25_tsadc *tsadc = irq_desc_get_handler_data(desc); 30 struct irq_chip *chip = irq_desc_get_chip(desc); 31 u32 status; 32 33 chained_irq_enter(chip, desc); 34 35 regmap_read(tsadc->regs, MX25_TSC_TGSR, &status); 36 37 if (status & MX25_TGSR_GCQ_INT) 38 generic_handle_domain_irq(tsadc->domain, 1); 39 40 if (status & MX25_TGSR_TCQ_INT) 41 generic_handle_domain_irq(tsadc->domain, 0); 42 43 chained_irq_exit(chip, desc); 44 } 45 46 static int mx25_tsadc_domain_map(struct irq_domain *d, unsigned int irq, 47 irq_hw_number_t hwirq) 48 { 49 struct mx25_tsadc *tsadc = d->host_data; 50 51 irq_set_chip_data(irq, tsadc); 52 irq_set_chip_and_handler(irq, &dummy_irq_chip, 53 handle_level_irq); 54 irq_modify_status(irq, IRQ_NOREQUEST, IRQ_NOPROBE); 55 56 return 0; 57 } 58 59 static const struct irq_domain_ops mx25_tsadc_domain_ops = { 60 .map = mx25_tsadc_domain_map, 61 .xlate = irq_domain_xlate_onecell, 62 }; 63 64 static int mx25_tsadc_setup_irq(struct platform_device *pdev, 65 struct mx25_tsadc *tsadc) 66 { 67 struct device *dev = &pdev->dev; 68 struct device_node *np = dev->of_node; 69 int irq; 70 71 irq = platform_get_irq(pdev, 0); 72 if (irq < 0) 73 return irq; 74 75 tsadc->domain = irq_domain_add_simple(np, 2, 0, &mx25_tsadc_domain_ops, 76 tsadc); 77 if (!tsadc->domain) { 78 dev_err(dev, "Failed to add irq domain\n"); 79 return -ENOMEM; 80 } 81 82 irq_set_chained_handler_and_data(irq, mx25_tsadc_irq_handler, tsadc); 83 84 return 0; 85 } 86 87 static int mx25_tsadc_unset_irq(struct platform_device *pdev) 88 { 89 struct mx25_tsadc *tsadc = platform_get_drvdata(pdev); 90 int irq = platform_get_irq(pdev, 0); 91 92 if (irq >= 0) { 93 irq_set_chained_handler_and_data(irq, NULL, NULL); 94 irq_domain_remove(tsadc->domain); 95 } 96 97 return 0; 98 } 99 100 static void mx25_tsadc_setup_clk(struct platform_device *pdev, 101 struct mx25_tsadc *tsadc) 102 { 103 unsigned clk_div; 104 105 /* 106 * According to the datasheet the ADC clock should never 107 * exceed 1,75 MHz. Base clock is the IPG and the ADC unit uses 108 * a funny clock divider. To keep the ADC conversion time constant 109 * adapt the ADC internal clock divider to the IPG clock rate. 110 */ 111 112 dev_dbg(&pdev->dev, "Found master clock at %lu Hz\n", 113 clk_get_rate(tsadc->clk)); 114 115 clk_div = DIV_ROUND_UP(clk_get_rate(tsadc->clk), 1750000); 116 dev_dbg(&pdev->dev, "Setting up ADC clock divider to %u\n", clk_div); 117 118 /* adc clock = IPG clock / (2 * div + 2) */ 119 clk_div -= 2; 120 clk_div /= 2; 121 122 /* 123 * the ADC clock divider changes its behaviour when values below 4 124 * are used: it is fixed to "/ 10" in this case 125 */ 126 clk_div = max_t(unsigned, 4, clk_div); 127 128 dev_dbg(&pdev->dev, "Resulting ADC conversion clock at %lu Hz\n", 129 clk_get_rate(tsadc->clk) / (2 * clk_div + 2)); 130 131 regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, 132 MX25_TGCR_ADCCLKCFG(0x1f), 133 MX25_TGCR_ADCCLKCFG(clk_div)); 134 } 135 136 static int mx25_tsadc_probe(struct platform_device *pdev) 137 { 138 struct device *dev = &pdev->dev; 139 struct mx25_tsadc *tsadc; 140 struct resource *res; 141 int ret; 142 void __iomem *iomem; 143 144 tsadc = devm_kzalloc(dev, sizeof(*tsadc), GFP_KERNEL); 145 if (!tsadc) 146 return -ENOMEM; 147 148 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 149 iomem = devm_ioremap_resource(dev, res); 150 if (IS_ERR(iomem)) 151 return PTR_ERR(iomem); 152 153 tsadc->regs = devm_regmap_init_mmio(dev, iomem, 154 &mx25_tsadc_regmap_config); 155 if (IS_ERR(tsadc->regs)) { 156 dev_err(dev, "Failed to initialize regmap\n"); 157 return PTR_ERR(tsadc->regs); 158 } 159 160 tsadc->clk = devm_clk_get(dev, "ipg"); 161 if (IS_ERR(tsadc->clk)) { 162 dev_err(dev, "Failed to get ipg clock\n"); 163 return PTR_ERR(tsadc->clk); 164 } 165 166 /* setup clock according to the datasheet */ 167 mx25_tsadc_setup_clk(pdev, tsadc); 168 169 /* Enable clock and reset the component */ 170 regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_CLK_EN, 171 MX25_TGCR_CLK_EN); 172 regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_TSC_RST, 173 MX25_TGCR_TSC_RST); 174 175 /* Setup powersaving mode, but enable internal reference voltage */ 176 regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_POWERMODE_MASK, 177 MX25_TGCR_POWERMODE_SAVE); 178 regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_INTREFEN, 179 MX25_TGCR_INTREFEN); 180 181 ret = mx25_tsadc_setup_irq(pdev, tsadc); 182 if (ret) 183 return ret; 184 185 platform_set_drvdata(pdev, tsadc); 186 187 ret = devm_of_platform_populate(dev); 188 if (ret) 189 goto err_irq; 190 191 return 0; 192 193 err_irq: 194 mx25_tsadc_unset_irq(pdev); 195 196 return ret; 197 } 198 199 static int mx25_tsadc_remove(struct platform_device *pdev) 200 { 201 mx25_tsadc_unset_irq(pdev); 202 203 return 0; 204 } 205 206 static const struct of_device_id mx25_tsadc_ids[] = { 207 { .compatible = "fsl,imx25-tsadc" }, 208 { /* Sentinel */ } 209 }; 210 MODULE_DEVICE_TABLE(of, mx25_tsadc_ids); 211 212 static struct platform_driver mx25_tsadc_driver = { 213 .driver = { 214 .name = "mx25-tsadc", 215 .of_match_table = mx25_tsadc_ids, 216 }, 217 .probe = mx25_tsadc_probe, 218 .remove = mx25_tsadc_remove, 219 }; 220 module_platform_driver(mx25_tsadc_driver); 221 222 MODULE_DESCRIPTION("MFD for ADC/TSC for Freescale mx25"); 223 MODULE_AUTHOR("Markus Pargmann <mpa@pengutronix.de>"); 224 MODULE_LICENSE("GPL v2"); 225 MODULE_ALIAS("platform:mx25-tsadc"); 226