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 struct clk *ext_clk; 31 struct gpio_descs *reset_gpios; 32 }; 33 34 #define to_pwrseq_simple(p) container_of(p, struct mmc_pwrseq_simple, pwrseq) 35 36 static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq, 37 int value) 38 { 39 struct gpio_descs *reset_gpios = pwrseq->reset_gpios; 40 41 if (!IS_ERR(reset_gpios)) { 42 int i; 43 int values[reset_gpios->ndescs]; 44 45 for (i = 0; i < reset_gpios->ndescs; i++) 46 values[i] = value; 47 48 gpiod_set_array_value_cansleep( 49 reset_gpios->ndescs, reset_gpios->desc, values); 50 } 51 } 52 53 static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host) 54 { 55 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq); 56 57 if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) { 58 clk_prepare_enable(pwrseq->ext_clk); 59 pwrseq->clk_enabled = true; 60 } 61 62 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1); 63 } 64 65 static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host) 66 { 67 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq); 68 69 mmc_pwrseq_simple_set_gpios_value(pwrseq, 0); 70 71 if (pwrseq->post_power_on_delay_ms) 72 msleep(pwrseq->post_power_on_delay_ms); 73 } 74 75 static void mmc_pwrseq_simple_power_off(struct mmc_host *host) 76 { 77 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq); 78 79 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1); 80 81 if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) { 82 clk_disable_unprepare(pwrseq->ext_clk); 83 pwrseq->clk_enabled = false; 84 } 85 } 86 87 static const struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = { 88 .pre_power_on = mmc_pwrseq_simple_pre_power_on, 89 .post_power_on = mmc_pwrseq_simple_post_power_on, 90 .power_off = mmc_pwrseq_simple_power_off, 91 }; 92 93 static const struct of_device_id mmc_pwrseq_simple_of_match[] = { 94 { .compatible = "mmc-pwrseq-simple",}, 95 {/* sentinel */}, 96 }; 97 MODULE_DEVICE_TABLE(of, mmc_pwrseq_simple_of_match); 98 99 static int mmc_pwrseq_simple_probe(struct platform_device *pdev) 100 { 101 struct mmc_pwrseq_simple *pwrseq; 102 struct device *dev = &pdev->dev; 103 104 pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL); 105 if (!pwrseq) 106 return -ENOMEM; 107 108 pwrseq->ext_clk = devm_clk_get(dev, "ext_clock"); 109 if (IS_ERR(pwrseq->ext_clk) && PTR_ERR(pwrseq->ext_clk) != -ENOENT) 110 return PTR_ERR(pwrseq->ext_clk); 111 112 pwrseq->reset_gpios = devm_gpiod_get_array(dev, "reset", 113 GPIOD_OUT_HIGH); 114 if (IS_ERR(pwrseq->reset_gpios) && 115 PTR_ERR(pwrseq->reset_gpios) != -ENOENT && 116 PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) { 117 return PTR_ERR(pwrseq->reset_gpios); 118 } 119 120 device_property_read_u32(dev, "post-power-on-delay-ms", 121 &pwrseq->post_power_on_delay_ms); 122 123 pwrseq->pwrseq.dev = dev; 124 pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops; 125 pwrseq->pwrseq.owner = THIS_MODULE; 126 platform_set_drvdata(pdev, pwrseq); 127 128 return mmc_pwrseq_register(&pwrseq->pwrseq); 129 } 130 131 static int mmc_pwrseq_simple_remove(struct platform_device *pdev) 132 { 133 struct mmc_pwrseq_simple *pwrseq = platform_get_drvdata(pdev); 134 135 mmc_pwrseq_unregister(&pwrseq->pwrseq); 136 137 return 0; 138 } 139 140 static struct platform_driver mmc_pwrseq_simple_driver = { 141 .probe = mmc_pwrseq_simple_probe, 142 .remove = mmc_pwrseq_simple_remove, 143 .driver = { 144 .name = "pwrseq_simple", 145 .of_match_table = mmc_pwrseq_simple_of_match, 146 }, 147 }; 148 149 module_platform_driver(mmc_pwrseq_simple_driver); 150 MODULE_LICENSE("GPL v2"); 151