1 /* 2 * TWL6040 clock module driver for OMAP4 McPDM functional clock 3 * 4 * Copyright (C) 2012 Texas Instruments Inc. 5 * Peter Ujfalusi <peter.ujfalusi@ti.com> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * version 2 as published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, but 12 * WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 19 * 02110-1301 USA 20 * 21 */ 22 23 #include <linux/module.h> 24 #include <linux/slab.h> 25 #include <linux/platform_device.h> 26 #include <linux/mfd/twl6040.h> 27 #include <linux/clk-provider.h> 28 29 struct twl6040_pdmclk { 30 struct twl6040 *twl6040; 31 struct device *dev; 32 struct clk_hw pdmclk_hw; 33 int enabled; 34 }; 35 36 static int twl6040_pdmclk_is_prepared(struct clk_hw *hw) 37 { 38 struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk, 39 pdmclk_hw); 40 41 return pdmclk->enabled; 42 } 43 44 static int twl6040_pdmclk_reset_one_clock(struct twl6040_pdmclk *pdmclk, 45 unsigned int reg) 46 { 47 const u8 reset_mask = TWL6040_HPLLRST; /* Same for HPPLL and LPPLL */ 48 int ret; 49 50 ret = twl6040_set_bits(pdmclk->twl6040, reg, reset_mask); 51 if (ret < 0) 52 return ret; 53 54 ret = twl6040_clear_bits(pdmclk->twl6040, reg, reset_mask); 55 if (ret < 0) 56 return ret; 57 58 return 0; 59 } 60 61 /* 62 * TWL6040A2 Phoenix Audio IC erratum #6: "PDM Clock Generation Issue At 63 * Cold Temperature". This affects cold boot and deeper idle states it 64 * seems. The workaround consists of resetting HPPLL and LPPLL. 65 */ 66 static int twl6040_pdmclk_quirk_reset_clocks(struct twl6040_pdmclk *pdmclk) 67 { 68 int ret; 69 70 ret = twl6040_pdmclk_reset_one_clock(pdmclk, TWL6040_REG_HPPLLCTL); 71 if (ret) 72 return ret; 73 74 ret = twl6040_pdmclk_reset_one_clock(pdmclk, TWL6040_REG_LPPLLCTL); 75 if (ret) 76 return ret; 77 78 return 0; 79 } 80 81 static int twl6040_pdmclk_prepare(struct clk_hw *hw) 82 { 83 struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk, 84 pdmclk_hw); 85 int ret; 86 87 ret = twl6040_power(pdmclk->twl6040, 1); 88 if (ret) 89 return ret; 90 91 ret = twl6040_pdmclk_quirk_reset_clocks(pdmclk); 92 if (ret) 93 goto out_err; 94 95 pdmclk->enabled = 1; 96 97 return 0; 98 99 out_err: 100 dev_err(pdmclk->dev, "%s: error %i\n", __func__, ret); 101 twl6040_power(pdmclk->twl6040, 0); 102 103 return ret; 104 } 105 106 static void twl6040_pdmclk_unprepare(struct clk_hw *hw) 107 { 108 struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk, 109 pdmclk_hw); 110 int ret; 111 112 ret = twl6040_power(pdmclk->twl6040, 0); 113 if (!ret) 114 pdmclk->enabled = 0; 115 116 } 117 118 static unsigned long twl6040_pdmclk_recalc_rate(struct clk_hw *hw, 119 unsigned long parent_rate) 120 { 121 struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk, 122 pdmclk_hw); 123 124 return twl6040_get_sysclk(pdmclk->twl6040); 125 } 126 127 static const struct clk_ops twl6040_pdmclk_ops = { 128 .is_prepared = twl6040_pdmclk_is_prepared, 129 .prepare = twl6040_pdmclk_prepare, 130 .unprepare = twl6040_pdmclk_unprepare, 131 .recalc_rate = twl6040_pdmclk_recalc_rate, 132 }; 133 134 static const struct clk_init_data twl6040_pdmclk_init = { 135 .name = "pdmclk", 136 .ops = &twl6040_pdmclk_ops, 137 .flags = CLK_GET_RATE_NOCACHE, 138 }; 139 140 static int twl6040_pdmclk_probe(struct platform_device *pdev) 141 { 142 struct twl6040 *twl6040 = dev_get_drvdata(pdev->dev.parent); 143 struct twl6040_pdmclk *clkdata; 144 int ret; 145 146 clkdata = devm_kzalloc(&pdev->dev, sizeof(*clkdata), GFP_KERNEL); 147 if (!clkdata) 148 return -ENOMEM; 149 150 clkdata->dev = &pdev->dev; 151 clkdata->twl6040 = twl6040; 152 153 clkdata->pdmclk_hw.init = &twl6040_pdmclk_init; 154 ret = devm_clk_hw_register(&pdev->dev, &clkdata->pdmclk_hw); 155 if (ret) 156 return ret; 157 158 platform_set_drvdata(pdev, clkdata); 159 160 return devm_of_clk_add_hw_provider(&pdev->dev, of_clk_hw_simple_get, 161 &clkdata->pdmclk_hw); 162 } 163 164 static struct platform_driver twl6040_pdmclk_driver = { 165 .driver = { 166 .name = "twl6040-pdmclk", 167 }, 168 .probe = twl6040_pdmclk_probe, 169 }; 170 171 module_platform_driver(twl6040_pdmclk_driver); 172 173 MODULE_DESCRIPTION("TWL6040 clock driver for McPDM functional clock"); 174 MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>"); 175 MODULE_ALIAS("platform:twl6040-pdmclk"); 176 MODULE_LICENSE("GPL"); 177