1 /* 2 * Copyright (C) 2014 Linaro Ltd 3 * 4 * Author: Ulf Hansson <ulf.hansson@linaro.org> 5 * 6 * License terms: GNU General Public License (GPL) version 2 7 * 8 * Simple MMC power sequence management 9 */ 10 #include <linux/clk.h> 11 #include <linux/init.h> 12 #include <linux/kernel.h> 13 #include <linux/platform_device.h> 14 #include <linux/module.h> 15 #include <linux/slab.h> 16 #include <linux/device.h> 17 #include <linux/err.h> 18 #include <linux/gpio/consumer.h> 19 #include <linux/delay.h> 20 #include <linux/property.h> 21 22 #include <linux/mmc/host.h> 23 24 #include "pwrseq.h" 25 26 struct mmc_pwrseq_simple { 27 struct mmc_pwrseq pwrseq; 28 bool clk_enabled; 29 u32 post_power_on_delay_ms; 30 u32 power_off_delay_us; 31 struct clk *ext_clk; 32 struct gpio_descs *reset_gpios; 33 }; 34 35 #define to_pwrseq_simple(p) container_of(p, struct mmc_pwrseq_simple, pwrseq) 36 37 static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq, 38 int value) 39 { 40 struct gpio_descs *reset_gpios = pwrseq->reset_gpios; 41 42 if (!IS_ERR(reset_gpios)) { 43 unsigned long *values; 44 int nvalues = reset_gpios->ndescs; 45 46 values = bitmap_alloc(nvalues, GFP_KERNEL); 47 if (!values) 48 return; 49 50 if (value) 51 bitmap_fill(values, nvalues); 52 else 53 bitmap_zero(values, nvalues); 54 55 gpiod_set_array_value_cansleep(nvalues, reset_gpios->desc, 56 reset_gpios->info, values); 57 58 kfree(values); 59 } 60 } 61 62 static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host) 63 { 64 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq); 65 66 if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) { 67 clk_prepare_enable(pwrseq->ext_clk); 68 pwrseq->clk_enabled = true; 69 } 70 71 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1); 72 } 73 74 static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host) 75 { 76 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq); 77 78 mmc_pwrseq_simple_set_gpios_value(pwrseq, 0); 79 80 if (pwrseq->post_power_on_delay_ms) 81 msleep(pwrseq->post_power_on_delay_ms); 82 } 83 84 static void mmc_pwrseq_simple_power_off(struct mmc_host *host) 85 { 86 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq); 87 88 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1); 89 90 if (pwrseq->power_off_delay_us) 91 usleep_range(pwrseq->power_off_delay_us, 92 2 * pwrseq->power_off_delay_us); 93 94 if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) { 95 clk_disable_unprepare(pwrseq->ext_clk); 96 pwrseq->clk_enabled = false; 97 } 98 } 99 100 static const struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = { 101 .pre_power_on = mmc_pwrseq_simple_pre_power_on, 102 .post_power_on = mmc_pwrseq_simple_post_power_on, 103 .power_off = mmc_pwrseq_simple_power_off, 104 }; 105 106 static const struct of_device_id mmc_pwrseq_simple_of_match[] = { 107 { .compatible = "mmc-pwrseq-simple",}, 108 {/* sentinel */}, 109 }; 110 MODULE_DEVICE_TABLE(of, mmc_pwrseq_simple_of_match); 111 112 static int mmc_pwrseq_simple_probe(struct platform_device *pdev) 113 { 114 struct mmc_pwrseq_simple *pwrseq; 115 struct device *dev = &pdev->dev; 116 117 pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL); 118 if (!pwrseq) 119 return -ENOMEM; 120 121 pwrseq->ext_clk = devm_clk_get(dev, "ext_clock"); 122 if (IS_ERR(pwrseq->ext_clk) && PTR_ERR(pwrseq->ext_clk) != -ENOENT) 123 return PTR_ERR(pwrseq->ext_clk); 124 125 pwrseq->reset_gpios = devm_gpiod_get_array(dev, "reset", 126 GPIOD_OUT_HIGH); 127 if (IS_ERR(pwrseq->reset_gpios) && 128 PTR_ERR(pwrseq->reset_gpios) != -ENOENT && 129 PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) { 130 return PTR_ERR(pwrseq->reset_gpios); 131 } 132 133 device_property_read_u32(dev, "post-power-on-delay-ms", 134 &pwrseq->post_power_on_delay_ms); 135 device_property_read_u32(dev, "power-off-delay-us", 136 &pwrseq->power_off_delay_us); 137 138 pwrseq->pwrseq.dev = dev; 139 pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops; 140 pwrseq->pwrseq.owner = THIS_MODULE; 141 platform_set_drvdata(pdev, pwrseq); 142 143 return mmc_pwrseq_register(&pwrseq->pwrseq); 144 } 145 146 static int mmc_pwrseq_simple_remove(struct platform_device *pdev) 147 { 148 struct mmc_pwrseq_simple *pwrseq = platform_get_drvdata(pdev); 149 150 mmc_pwrseq_unregister(&pwrseq->pwrseq); 151 152 return 0; 153 } 154 155 static struct platform_driver mmc_pwrseq_simple_driver = { 156 .probe = mmc_pwrseq_simple_probe, 157 .remove = mmc_pwrseq_simple_remove, 158 .driver = { 159 .name = "pwrseq_simple", 160 .of_match_table = mmc_pwrseq_simple_of_match, 161 }, 162 }; 163 164 module_platform_driver(mmc_pwrseq_simple_driver); 165 MODULE_LICENSE("GPL v2"); 166