1 /* 2 * Copyright (C) 2014 Linaro Ltd 3 * 4 * Author: Ulf Hansson <[email protected]> 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/kernel.h> 12 #include <linux/slab.h> 13 #include <linux/device.h> 14 #include <linux/err.h> 15 #include <linux/gpio/consumer.h> 16 17 #include <linux/mmc/host.h> 18 19 #include "pwrseq.h" 20 21 struct mmc_pwrseq_simple { 22 struct mmc_pwrseq pwrseq; 23 bool clk_enabled; 24 struct clk *ext_clk; 25 struct gpio_descs *reset_gpios; 26 }; 27 28 #define to_pwrseq_simple(p) container_of(p, struct mmc_pwrseq_simple, pwrseq) 29 30 static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq, 31 int value) 32 { 33 struct gpio_descs *reset_gpios = pwrseq->reset_gpios; 34 35 if (!IS_ERR(reset_gpios)) { 36 int i; 37 int values[reset_gpios->ndescs]; 38 39 for (i = 0; i < reset_gpios->ndescs; i++) 40 values[i] = value; 41 42 gpiod_set_array_value_cansleep( 43 reset_gpios->ndescs, reset_gpios->desc, values); 44 } 45 } 46 47 static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host) 48 { 49 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq); 50 51 if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) { 52 clk_prepare_enable(pwrseq->ext_clk); 53 pwrseq->clk_enabled = true; 54 } 55 56 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1); 57 } 58 59 static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host) 60 { 61 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq); 62 63 mmc_pwrseq_simple_set_gpios_value(pwrseq, 0); 64 } 65 66 static void mmc_pwrseq_simple_power_off(struct mmc_host *host) 67 { 68 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq); 69 70 mmc_pwrseq_simple_set_gpios_value(pwrseq, 1); 71 72 if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) { 73 clk_disable_unprepare(pwrseq->ext_clk); 74 pwrseq->clk_enabled = false; 75 } 76 } 77 78 static void mmc_pwrseq_simple_free(struct mmc_host *host) 79 { 80 struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq); 81 82 if (!IS_ERR(pwrseq->reset_gpios)) 83 gpiod_put_array(pwrseq->reset_gpios); 84 85 if (!IS_ERR(pwrseq->ext_clk)) 86 clk_put(pwrseq->ext_clk); 87 88 kfree(pwrseq); 89 } 90 91 static const struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = { 92 .pre_power_on = mmc_pwrseq_simple_pre_power_on, 93 .post_power_on = mmc_pwrseq_simple_post_power_on, 94 .power_off = mmc_pwrseq_simple_power_off, 95 .free = mmc_pwrseq_simple_free, 96 }; 97 98 struct mmc_pwrseq *mmc_pwrseq_simple_alloc(struct mmc_host *host, 99 struct device *dev) 100 { 101 struct mmc_pwrseq_simple *pwrseq; 102 int ret = 0; 103 104 pwrseq = kzalloc(sizeof(*pwrseq), GFP_KERNEL); 105 if (!pwrseq) 106 return ERR_PTR(-ENOMEM); 107 108 pwrseq->ext_clk = clk_get(dev, "ext_clock"); 109 if (IS_ERR(pwrseq->ext_clk) && 110 PTR_ERR(pwrseq->ext_clk) != -ENOENT) { 111 ret = PTR_ERR(pwrseq->ext_clk); 112 goto free; 113 } 114 115 pwrseq->reset_gpios = gpiod_get_array(dev, "reset", GPIOD_OUT_HIGH); 116 if (IS_ERR(pwrseq->reset_gpios) && 117 PTR_ERR(pwrseq->reset_gpios) != -ENOENT && 118 PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) { 119 ret = PTR_ERR(pwrseq->reset_gpios); 120 goto clk_put; 121 } 122 123 pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops; 124 125 return &pwrseq->pwrseq; 126 clk_put: 127 if (!IS_ERR(pwrseq->ext_clk)) 128 clk_put(pwrseq->ext_clk); 129 free: 130 kfree(pwrseq); 131 return ERR_PTR(ret); 132 } 133