drivers/power/power_spi.c

   1 /*
   2  * Copyright (C) 2011 Samsung Electronics
   3  * Lukasz Majewski <l.majewski@samsung.com>
   4  *
   5  * (C) Copyright 2010
   6  * Stefano Babic, DENX Software Engineering, sbabic@denx.de
   7  *
   8  * (C) Copyright 2008-2009 Freescale Semiconductor, Inc.
   9  *
  10  * SPDX-License-Identifier:     GPL-2.0+
  11  */
  12
  13 #include <common.h>
  14 #include <linux/types.h>
  15 #include <power/pmic.h>
  16 #include <spi.h>
  17
  18 static struct spi_slave *slave;
  19
  20 static u32 pmic_reg(struct pmic *p, u32 reg, u32 *val, u32 write)
  21 {
  22         u32 pmic_tx, pmic_rx;
  23         u32 tmp;
  24
  25         if (!slave) {
  26                 slave = spi_setup_slave(p->bus, p->hw.spi.cs, p->hw.spi.clk,
  27                                         p->hw.spi.mode);
  28
  29                 if (!slave)
  30                         return -ENODEV;
  31         }
  32
  33         if (check_reg(p, reg))
  34                 return -EINVAL;
  35
  36         if (spi_claim_bus(slave))
  37                 return -EBUSY;
  38
  39         pmic_tx = p->hw.spi.prepare_tx(reg, val, write);
  40
  41         tmp = cpu_to_be32(pmic_tx);
  42
  43         if (spi_xfer(slave, pmic_spi_bitlen, &tmp, &pmic_rx,
  44                         pmic_spi_flags))
  45                 goto err;
  46
  47         if (write) {
  48                 pmic_tx = p->hw.spi.prepare_tx(reg, val, 0);
  49                 tmp = cpu_to_be32(pmic_tx);
  50                 if (spi_xfer(slave, pmic_spi_bitlen, &tmp, &pmic_rx,
  51                         pmic_spi_flags))
  52                         goto err;
  53         }
  54
  55         spi_release_bus(slave);
  56         *val = cpu_to_be32(pmic_rx);
  57
  58         return 0;
  59
  60 err:
  61         spi_release_bus(slave);
  62         return -ENOTSUPP;
  63 }
  64
  65 int pmic_reg_write(struct pmic *p, u32 reg, u32 val)
  66 {
  67         return pmic_reg(p, reg, &val, 1);
  68 }
  69
  70 int pmic_reg_read(struct pmic *p, u32 reg, u32 *val)
  71 {
  72         return pmic_reg(p, reg, val, 0);
  73 }